bank.rs

//! The `bank` module tracks client accounts and the progress of on-chain
//! programs.
//!
//! A single bank relates to a block produced by a single leader and each bank
//! except for the genesis bank points back to a parent bank.
//!
//! The bank is the main entrypoint for processing verified transactions with the function
//! `Bank::process_transactions`
//!
//! It does this by loading the accounts using the reference it holds on the account store,
//! and then passing those to the message_processor which handles loading the programs specified
//! by the Transaction and executing it.
//!
//! The bank then stores the results to the accounts store.
//!
//! It then has apis for retrieving if a transaction has been processed and it's status.
//! See `get_signature_status` et al.
//!
//! Bank lifecycle:
//!
//! A bank is newly created and open to transactions. Transactions are applied
//! until either the bank reached the tick count when the node is the leader for that slot, or the
//! node has applied all transactions present in all `Entry`s in the slot.
//!
//! Once it is complete, the bank can then be frozen. After frozen, no more transactions can
//! be applied or state changes made. At the frozen step, rent will be applied and various
//! sysvar special accounts update to the new state of the system.
//!
//! After frozen, and the bank has had the appropriate number of votes on it, then it can become
//! rooted. At this point, it will not be able to be removed from the chain and the
//! state is finalized.
//!
//! It offers a high-level API that signs transactions
//! on behalf of the caller, and a low-level API for when they have
//! already been signed and verified.
use crate::{
    accounts::{
        AccountAddressFilter, Accounts, TransactionAccounts, TransactionLoadResult,
        TransactionLoaders,
    },
    accounts_db::{AccountShrinkThreshold, ErrorCounters, SnapshotStorage, SnapshotStorages},
    accounts_index::{AccountSecondaryIndexes, IndexKey, ScanResult},
    ancestors::{Ancestors, AncestorsForSerialization},
    blockhash_queue::BlockhashQueue,
    builtins::{self, ActivationType},
    epoch_stakes::{EpochStakes, NodeVoteAccounts},
    inline_spl_token_v2_0,
    instruction_recorder::InstructionRecorder,
    log_collector::LogCollector,
    message_processor::{ExecuteDetailsTimings, Executors, MessageProcessor},
    rent_collector::RentCollector,
    stake_weighted_timestamp::{
        calculate_stake_weighted_timestamp, MaxAllowableDrift, MAX_ALLOWABLE_DRIFT_PERCENTAGE,
        MAX_ALLOWABLE_DRIFT_PERCENTAGE_FAST, MAX_ALLOWABLE_DRIFT_PERCENTAGE_SLOW,
    },
    stakes::Stakes,
    status_cache::{SlotDelta, StatusCache},
    system_instruction_processor::{get_system_account_kind, SystemAccountKind},
    transaction_batch::TransactionBatch,
    vote_account::ArcVoteAccount,
};
use byteorder::{ByteOrder, LittleEndian};
use itertools::Itertools;
use log::*;
use rayon::ThreadPool;
use solana_measure::measure::Measure;
use solana_metrics::{datapoint_debug, inc_new_counter_debug, inc_new_counter_info};
use solana_sdk::{
    account::{
        create_account_shared_data_with_fields as create_account, from_account, Account,
        AccountSharedData, InheritableAccountFields, ReadableAccount, WritableAccount,
    },
    account_utils::StateMut,
    clock::{
        BankId, Epoch, Slot, SlotCount, SlotIndex, UnixTimestamp, DEFAULT_TICKS_PER_SECOND,
        INITIAL_RENT_EPOCH, MAX_PROCESSING_AGE, MAX_RECENT_BLOCKHASHES,
        MAX_TRANSACTION_FORWARDING_DELAY, SECONDS_PER_DAY,
    },
    compute_budget,
    epoch_info::EpochInfo,
    epoch_schedule::EpochSchedule,
    feature,
    feature_set::{self, tx_wide_compute_cap, FeatureSet},
    fee_calculator::{FeeCalculator, FeeRateGovernor},
    genesis_config::{ClusterType, GenesisConfig},
    hard_forks::HardForks,
    hash::{extend_and_hash, hashv, Hash},
    incinerator,
    inflation::Inflation,
    instruction::{CompiledInstruction, InstructionError},
    lamports::LamportsError,
    message::Message,
    native_loader,
    native_token::sol_to_lamports,
    nonce, nonce_account,
    process_instruction::{
        BpfComputeBudget, ComputeMeter, Executor, ProcessInstructionWithContext,
    },
    program_utils::limited_deserialize,
    pubkey::Pubkey,
    recent_blockhashes_account,
    sanitized_transaction::{SanitizedTransaction, SanitizedTransactionSlice},
    signature::{Keypair, Signature},
    slot_hashes::SlotHashes,
    slot_history::SlotHistory,
    stake::{self, state::Delegation},
    system_transaction,
    sysvar::{self},
    timing::years_as_slots,
    transaction::{self, Result, Transaction, TransactionError},
};
use solana_stake_program::stake_state::{self, InflationPointCalculationEvent, PointValue};
use solana_vote_program::{
    vote_instruction::VoteInstruction,
    vote_state::{VoteState, VoteStateVersions},
};
use std::{
    borrow::Cow,
    cell::RefCell,
    collections::{HashMap, HashSet},
    convert::{TryFrom, TryInto},
    fmt, mem,
    ops::RangeInclusive,
    path::PathBuf,
    ptr,
    rc::Rc,
    sync::{
        atomic::{AtomicBool, AtomicU64, Ordering::Relaxed},
        LockResult, RwLockWriteGuard, {Arc, RwLock, RwLockReadGuard},
    },
    time::Duration,
    time::Instant,
};

pub const SECONDS_PER_YEAR: f64 = 365.25 * 24.0 * 60.0 * 60.0;

pub const MAX_LEADER_SCHEDULE_STAKES: Epoch = 5;

#[derive(Clone, Debug, Default, PartialEq)]
pub struct RentDebits(pub Vec<(Pubkey, RewardInfo)>);
impl RentDebits {
    pub fn push(&mut self, account: &Pubkey, rent: u64, post_balance: u64) {
        if rent != 0 {
            let rent_debit = i64::try_from(rent).ok().and_then(|r| r.checked_neg());
            if let Some(rent_debit) = rent_debit {
                let reward_info = RewardInfo {
                    reward_type: RewardType::Rent,
                    lamports: rent_debit,
                    post_balance,
                    commission: None, // Not applicable
                };
                self.0.push((*account, reward_info));
            } else {
                warn!("out of range rent debit from {}: {}", account, rent);
            }
        }
    }
}

#[derive(Default, Debug)]
pub struct ExecuteTimings {
    pub check_us: u64,
    pub load_us: u64,
    pub execute_us: u64,
    pub store_us: u64,
    pub total_batches_len: usize,
    pub num_execute_batches: u64,
    pub details: ExecuteDetailsTimings,
}
impl ExecuteTimings {
    pub fn accumulate(&mut self, other: &ExecuteTimings) {
        self.check_us += other.check_us;
        self.load_us += other.load_us;
        self.execute_us += other.execute_us;
        self.store_us += other.store_us;
        self.total_batches_len += other.total_batches_len;
        self.num_execute_batches += other.num_execute_batches;
        self.details.accumulate(&other.details);
    }
}

type BankStatusCache = StatusCache<Result<()>>;
#[frozen_abi(digest = "HhY4tMP5KZU9fw9VLpMMUikfvNVCLksocZBUKjt8ZjYH")]
pub type BankSlotDelta = SlotDelta<Result<()>>;
type TransactionAccountRefCells = Vec<(Pubkey, Rc<RefCell<AccountSharedData>>)>;
type TransactionLoaderRefCells = Vec<Vec<(Pubkey, Rc<RefCell<AccountSharedData>>)>>;

// Eager rent collection repeats in cyclic manner.
// Each cycle is composed of <partition_count> number of tiny pubkey subranges
// to scan, which is always multiple of the number of slots in epoch.
type PartitionIndex = u64;
type PartitionsPerCycle = u64;
type Partition = (PartitionIndex, PartitionIndex, PartitionsPerCycle);
type RentCollectionCycleParams = (
    Epoch,
    SlotCount,
    bool,
    Epoch,
    EpochCount,
    PartitionsPerCycle,
);

type EpochCount = u64;

#[derive(Clone)]
pub struct Builtin {
    pub name: String,
    pub id: Pubkey,
    pub process_instruction_with_context: ProcessInstructionWithContext,
}

impl Builtin {
    pub fn new(
        name: &str,
        id: Pubkey,
        process_instruction_with_context: ProcessInstructionWithContext,
    ) -> Self {
        Self {
            name: name.to_string(),
            id,
            process_instruction_with_context,
        }
    }
}

impl fmt::Debug for Builtin {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, "Builtin [name={}, id={}]", self.name, self.id)
    }
}

/// Copy-on-write holder of CachedExecutors
#[derive(AbiExample, Debug, Default)]
struct CowCachedExecutors {
    shared: bool,
    executors: Arc<RwLock<CachedExecutors>>,
}
impl Clone for CowCachedExecutors {
    fn clone(&self) -> Self {
        Self {
            shared: true,
            executors: self.executors.clone(),
        }
    }
}
impl CowCachedExecutors {
    fn clone_with_epoch(&self, epoch: u64) -> Self {
        let executors_raw = self.read().unwrap();
        if executors_raw.current_epoch() == epoch {
            self.clone()
        } else {
            Self {
                shared: false,
                executors: Arc::new(RwLock::new(executors_raw.clone_with_epoch(epoch))),
            }
        }
    }
    fn new(executors: Arc<RwLock<CachedExecutors>>) -> Self {
        Self {
            shared: true,
            executors,
        }
    }
    fn read(&self) -> LockResult<RwLockReadGuard<CachedExecutors>> {
        self.executors.read()
    }
    fn write(&mut self) -> LockResult<RwLockWriteGuard<CachedExecutors>> {
        if self.shared {
            self.shared = false;
            let local_cache = (*self.executors.read().unwrap()).clone();
            self.executors = Arc::new(RwLock::new(local_cache));
        }
        self.executors.write()
    }
}

#[cfg(RUSTC_WITH_SPECIALIZATION)]
impl AbiExample for Builtin {
    fn example() -> Self {
        Self {
            name: String::default(),
            id: Pubkey::default(),
            process_instruction_with_context: |_, _, _| Ok(()),
        }
    }
}

#[derive(Clone, Debug)]
pub struct Builtins {
    /// Builtin programs that are always available
    pub genesis_builtins: Vec<Builtin>,

    /// Builtin programs activated dynamically by feature
    pub feature_builtins: Vec<(Builtin, Pubkey, ActivationType)>,
}

const MAX_CACHED_EXECUTORS: usize = 100; // 10 MB assuming programs are around 100k
#[derive(Debug)]
struct CachedExecutorsEntry {
    prev_epoch_count: u64,
    epoch_count: AtomicU64,
    executor: Arc<dyn Executor>,
}
/// LFU Cache of executors with single-epoch memory of usage counts
#[derive(Debug)]
struct CachedExecutors {
    max: usize,
    current_epoch: Epoch,
    executors: HashMap<Pubkey, CachedExecutorsEntry>,
}
impl Default for CachedExecutors {
    fn default() -> Self {
        Self {
            max: MAX_CACHED_EXECUTORS,
            current_epoch: 0,
            executors: HashMap::new(),
        }
    }
}

#[cfg(RUSTC_WITH_SPECIALIZATION)]
impl AbiExample for CachedExecutors {
    fn example() -> Self {
        // Delegate AbiExample impl to Default before going deep and stuck with
        // not easily impl-able Arc<dyn Executor> due to rust's coherence issue
        // This is safe because CachedExecutors isn't serializable by definition.
        Self::default()
    }
}

impl Clone for CachedExecutors {
    fn clone(&self) -> Self {
        self.clone_with_epoch(self.current_epoch)
    }
}
impl CachedExecutors {
    fn current_epoch(&self) -> Epoch {
        self.current_epoch
    }

    fn clone_with_epoch(&self, epoch: Epoch) -> Self {
        let mut executors = HashMap::new();
        for (key, entry) in self.executors.iter() {
            // The total_count = prev_epoch_count + epoch_count will be used for LFU eviction.
            // If the epoch has changed, we store the prev_epoch_count and reset the epoch_count to 0.
            if epoch > self.current_epoch {
                executors.insert(
                    *key,
                    CachedExecutorsEntry {
                        prev_epoch_count: entry.epoch_count.load(Relaxed),
                        epoch_count: AtomicU64::new(0),
                        executor: entry.executor.clone(),
                    },
                );
            } else {
                executors.insert(
                    *key,
                    CachedExecutorsEntry {
                        prev_epoch_count: entry.prev_epoch_count,
                        epoch_count: AtomicU64::new(entry.epoch_count.load(Relaxed)),
                        executor: entry.executor.clone(),
                    },
                );
            }
        }
        Self {
            max: self.max,
            current_epoch: epoch,
            executors,
        }
    }

    fn new(max: usize, current_epoch: Epoch) -> Self {
        Self {
            max,
            current_epoch,
            executors: HashMap::new(),
        }
    }
    fn get(&self, pubkey: &Pubkey) -> Option<Arc<dyn Executor>> {
        self.executors.get(pubkey).map(|entry| {
            entry.epoch_count.fetch_add(1, Relaxed);
            entry.executor.clone()
        })
    }
    fn put(&mut self, pubkey: &Pubkey, executor: Arc<dyn Executor>) {
        if !self.executors.contains_key(pubkey) && self.executors.len() >= self.max {
            let mut least = u64::MAX;
            let default_key = Pubkey::default();
            let mut least_key = &default_key;

            for (key, entry) in self.executors.iter() {
                let count = entry.prev_epoch_count + entry.epoch_count.load(Relaxed);
                if count < least {
                    least = count;
                    least_key = key;
                }
            }
            let least_key = *least_key;
            let _ = self.executors.remove(&least_key);
        }
        let _ = self.executors.insert(
            *pubkey,
            CachedExecutorsEntry {
                prev_epoch_count: 0,
                epoch_count: AtomicU64::new(0),
                executor,
            },
        );
    }
    fn remove(&mut self, pubkey: &Pubkey) {
        let _ = self.executors.remove(pubkey);
    }
}

pub struct TransactionComputeMeter {
    remaining: u64,
}
impl TransactionComputeMeter {
    pub fn new(cap: u64) -> Self {
        Self { remaining: cap }
    }
}
impl ComputeMeter for TransactionComputeMeter {
    fn consume(&mut self, amount: u64) -> std::result::Result<(), InstructionError> {
        let exceeded = self.remaining < amount;
        self.remaining = self.remaining.saturating_sub(amount);
        if exceeded {
            return Err(InstructionError::ComputationalBudgetExceeded);
        }
        Ok(())
    }
    fn get_remaining(&self) -> u64 {
        self.remaining
    }
}

#[derive(Default, Debug)]
pub struct BankRc {
    /// where all the Accounts are stored
    pub accounts: Arc<Accounts>,

    /// Previous checkpoint of this bank
    pub(crate) parent: RwLock<Option<Arc<Bank>>>,

    /// Current slot
    pub(crate) slot: Slot,

    pub(crate) bank_id_generator: Arc<AtomicU64>,
}

#[cfg(RUSTC_WITH_SPECIALIZATION)]
use solana_frozen_abi::abi_example::AbiExample;

#[cfg(RUSTC_WITH_SPECIALIZATION)]
impl AbiExample for BankRc {
    fn example() -> Self {
        BankRc {
            // Set parent to None to cut the recursion into another Bank
            parent: RwLock::new(None),
            // AbiExample for Accounts is specially implemented to contain a storage example
            accounts: AbiExample::example(),
            slot: AbiExample::example(),
            bank_id_generator: Arc::new(AtomicU64::new(0)),
        }
    }
}

impl BankRc {
    pub(crate) fn new(accounts: Accounts, slot: Slot) -> Self {
        Self {
            accounts: Arc::new(accounts),
            parent: RwLock::new(None),
            slot,
            bank_id_generator: Arc::new(AtomicU64::new(0)),
        }
    }

    pub fn get_snapshot_storages(&self, slot: Slot) -> SnapshotStorages {
        self.accounts
            .accounts_db
            .get_snapshot_storages(slot, None)
            .0
    }
}

#[derive(Default, Debug, AbiExample)]
pub struct StatusCacheRc {
    /// where all the Accounts are stored
    /// A cache of signature statuses
    pub status_cache: Arc<RwLock<BankStatusCache>>,
}

impl StatusCacheRc {
    pub fn slot_deltas(&self, slots: &[Slot]) -> Vec<BankSlotDelta> {
        let sc = self.status_cache.read().unwrap();
        sc.slot_deltas(slots)
    }

    pub fn roots(&self) -> Vec<Slot> {
        self.status_cache
            .read()
            .unwrap()
            .roots()
            .iter()
            .cloned()
            .sorted()
            .collect()
    }

    pub fn append(&self, slot_deltas: &[BankSlotDelta]) {
        let mut sc = self.status_cache.write().unwrap();
        sc.append(slot_deltas);
    }
}

pub type TransactionCheckResult = (Result<()>, Option<NonceRollbackPartial>);
pub type TransactionExecutionResult = (Result<()>, Option<NonceRollbackFull>);
pub struct TransactionResults {
    pub fee_collection_results: Vec<Result<()>>,
    pub execution_results: Vec<TransactionExecutionResult>,
    pub overwritten_vote_accounts: Vec<OverwrittenVoteAccount>,
    pub rent_debits: Vec<RentDebits>,
}
pub struct TransactionSimulationResult {
    pub result: Result<()>,
    pub logs: TransactionLogMessages,
    pub post_simulation_accounts: Vec<(Pubkey, AccountSharedData)>,
    pub units_consumed: u64,
}
pub struct TransactionBalancesSet {
    pub pre_balances: TransactionBalances,
    pub post_balances: TransactionBalances,
}
pub struct OverwrittenVoteAccount {
    pub account: ArcVoteAccount,
    pub transaction_index: usize,
    pub transaction_result_index: usize,
}

impl TransactionBalancesSet {
    pub fn new(pre_balances: TransactionBalances, post_balances: TransactionBalances) -> Self {
        assert_eq!(pre_balances.len(), post_balances.len());
        Self {
            pre_balances,
            post_balances,
        }
    }
}
pub type TransactionBalances = Vec<Vec<u64>>;

/// An ordered list of instructions that were invoked during a transaction instruction
pub type InnerInstructions = Vec<CompiledInstruction>;

/// A list of instructions that were invoked during each instruction of a transaction
pub type InnerInstructionsList = Vec<InnerInstructions>;

/// A list of log messages emitted during a transaction
pub type TransactionLogMessages = Vec<String>;

#[derive(Serialize, Deserialize, AbiExample, AbiEnumVisitor, Debug, PartialEq)]
pub enum TransactionLogCollectorFilter {
    All,
    AllWithVotes,
    None,
    OnlyMentionedAddresses,
}

impl Default for TransactionLogCollectorFilter {
    fn default() -> Self {
        Self::None
    }
}

#[derive(AbiExample, Debug, Default)]
pub struct TransactionLogCollectorConfig {
    pub mentioned_addresses: HashSet<Pubkey>,
    pub filter: TransactionLogCollectorFilter,
}

#[derive(AbiExample, Clone, Debug)]
pub struct TransactionLogInfo {
    pub signature: Signature,
    pub result: Result<()>,
    pub is_vote: bool,
    pub log_messages: TransactionLogMessages,
}

#[derive(AbiExample, Default, Debug)]
pub struct TransactionLogCollector {
    // All the logs collected for from this Bank.  Exact contents depend on the
    // active `TransactionLogCollectorFilter`
    pub logs: Vec<TransactionLogInfo>,

    // For each `mentioned_addresses`, maintain a list of indices into `logs` to easily
    // locate the logs from transactions that included the mentioned addresses.
    pub mentioned_address_map: HashMap<Pubkey, Vec<usize>>,
}

pub trait NonceRollbackInfo {
    fn nonce_address(&self) -> &Pubkey;
    fn nonce_account(&self) -> &AccountSharedData;
    fn fee_calculator(&self) -> Option<FeeCalculator>;
    fn fee_account(&self) -> Option<&AccountSharedData>;
}

#[derive(Clone, Debug, Default, PartialEq)]
pub struct NonceRollbackPartial {
    nonce_address: Pubkey,
    nonce_account: AccountSharedData,
}

impl NonceRollbackPartial {
    pub fn new(nonce_address: Pubkey, nonce_account: AccountSharedData) -> Self {
        Self {
            nonce_address,
            nonce_account,
        }
    }
}

impl NonceRollbackInfo for NonceRollbackPartial {
    fn nonce_address(&self) -> &Pubkey {
        &self.nonce_address
    }
    fn nonce_account(&self) -> &AccountSharedData {
        &self.nonce_account
    }
    fn fee_calculator(&self) -> Option<FeeCalculator> {
        nonce_account::fee_calculator_of(&self.nonce_account)
    }
    fn fee_account(&self) -> Option<&AccountSharedData> {
        None
    }
}

#[derive(Clone, Debug, Default, PartialEq)]
pub struct NonceRollbackFull {
    nonce_address: Pubkey,
    nonce_account: AccountSharedData,
    fee_account: Option<AccountSharedData>,
}

impl NonceRollbackFull {
    #[cfg(test)]
    pub fn new(
        nonce_address: Pubkey,
        nonce_account: AccountSharedData,
        fee_account: Option<AccountSharedData>,
    ) -> Self {
        Self {
            nonce_address,
            nonce_account,
            fee_account,
        }
    }
    pub fn from_partial(
        partial: NonceRollbackPartial,
        message: &Message,
        accounts: &[(Pubkey, AccountSharedData)],
    ) -> Result<Self> {
        let NonceRollbackPartial {
            nonce_address,
            nonce_account,
        } = partial;
        let fee_payer = (0..message.account_keys.len()).find_map(|i| {
            if let Some((k, a)) = &accounts.get(i) {
                if message.is_non_loader_key(i) {
                    return Some((k, a));
                }
            }
            None
        });
        if let Some((fee_pubkey, fee_account)) = fee_payer {
            if *fee_pubkey == nonce_address {
                Ok(Self {
                    nonce_address,
                    nonce_account: fee_account.clone(),
                    fee_account: None,
                })
            } else {
                Ok(Self {
                    nonce_address,
                    nonce_account,
                    fee_account: Some(fee_account.clone()),
                })
            }
        } else {
            Err(TransactionError::AccountNotFound)
        }
    }
}

impl NonceRollbackInfo for NonceRollbackFull {
    fn nonce_address(&self) -> &Pubkey {
        &self.nonce_address
    }
    fn nonce_account(&self) -> &AccountSharedData {
        &self.nonce_account
    }
    fn fee_calculator(&self) -> Option<FeeCalculator> {
        nonce_account::fee_calculator_of(&self.nonce_account)
    }
    fn fee_account(&self) -> Option<&AccountSharedData> {
        self.fee_account.as_ref()
    }
}

// Bank's common fields shared by all supported snapshot versions for deserialization.
// Sync fields with BankFieldsToSerialize! This is paired with it.
// All members are made public to remain Bank's members private and to make versioned deserializer workable on this
#[derive(Clone, Debug, Default)]
pub(crate) struct BankFieldsToDeserialize {
    pub(crate) blockhash_queue: BlockhashQueue,
    pub(crate) ancestors: AncestorsForSerialization,
    pub(crate) hash: Hash,
    pub(crate) parent_hash: Hash,
    pub(crate) parent_slot: Slot,
    pub(crate) hard_forks: HardForks,
    pub(crate) transaction_count: u64,
    pub(crate) tick_height: u64,
    pub(crate) signature_count: u64,
    pub(crate) capitalization: u64,
    pub(crate) max_tick_height: u64,
    pub(crate) hashes_per_tick: Option<u64>,
    pub(crate) ticks_per_slot: u64,
    pub(crate) ns_per_slot: u128,
    pub(crate) genesis_creation_time: UnixTimestamp,
    pub(crate) slots_per_year: f64,
    pub(crate) unused: u64,
    pub(crate) slot: Slot,
    pub(crate) epoch: Epoch,
    pub(crate) block_height: u64,
    pub(crate) collector_id: Pubkey,
    pub(crate) collector_fees: u64,
    pub(crate) fee_calculator: FeeCalculator,
    pub(crate) fee_rate_governor: FeeRateGovernor,
    pub(crate) collected_rent: u64,
    pub(crate) rent_collector: RentCollector,
    pub(crate) epoch_schedule: EpochSchedule,
    pub(crate) inflation: Inflation,
    pub(crate) stakes: Stakes,
    pub(crate) epoch_stakes: HashMap<Epoch, EpochStakes>,
    pub(crate) is_delta: bool,
}

// Bank's common fields shared by all supported snapshot versions for serialization.
// This is separated from BankFieldsToDeserialize to avoid cloning by using refs.
// So, sync fields with BankFieldsToDeserialize!
// all members are made public to keep Bank private and to make versioned serializer workable on this
#[derive(Debug)]
pub(crate) struct BankFieldsToSerialize<'a> {
    pub(crate) blockhash_queue: &'a RwLock<BlockhashQueue>,
    pub(crate) ancestors: &'a AncestorsForSerialization,
    pub(crate) hash: Hash,
    pub(crate) parent_hash: Hash,
    pub(crate) parent_slot: Slot,
    pub(crate) hard_forks: &'a RwLock<HardForks>,
    pub(crate) transaction_count: u64,
    pub(crate) tick_height: u64,
    pub(crate) signature_count: u64,
    pub(crate) capitalization: u64,
    pub(crate) max_tick_height: u64,
    pub(crate) hashes_per_tick: Option<u64>,
    pub(crate) ticks_per_slot: u64,
    pub(crate) ns_per_slot: u128,
    pub(crate) genesis_creation_time: UnixTimestamp,
    pub(crate) slots_per_year: f64,
    pub(crate) unused: u64,
    pub(crate) slot: Slot,
    pub(crate) epoch: Epoch,
    pub(crate) block_height: u64,
    pub(crate) collector_id: Pubkey,
    pub(crate) collector_fees: u64,
    pub(crate) fee_calculator: FeeCalculator,
    pub(crate) fee_rate_governor: FeeRateGovernor,
    pub(crate) collected_rent: u64,
    pub(crate) rent_collector: RentCollector,
    pub(crate) epoch_schedule: EpochSchedule,
    pub(crate) inflation: Inflation,
    pub(crate) stakes: &'a RwLock<Stakes>,
    pub(crate) epoch_stakes: &'a HashMap<Epoch, EpochStakes>,
    pub(crate) is_delta: bool,
}

// Can't derive PartialEq because RwLock doesn't implement PartialEq
impl PartialEq for Bank {
    fn eq(&self, other: &Self) -> bool {
        if ptr::eq(self, other) {
            return true;
        }
        *self.blockhash_queue.read().unwrap() == *other.blockhash_queue.read().unwrap()
            && self.ancestors == other.ancestors
            && *self.hash.read().unwrap() == *other.hash.read().unwrap()
            && self.parent_hash == other.parent_hash
            && self.parent_slot == other.parent_slot
            && *self.hard_forks.read().unwrap() == *other.hard_forks.read().unwrap()
            && self.transaction_count.load(Relaxed) == other.transaction_count.load(Relaxed)
            && self.tick_height.load(Relaxed) == other.tick_height.load(Relaxed)
            && self.signature_count.load(Relaxed) == other.signature_count.load(Relaxed)
            && self.capitalization.load(Relaxed) == other.capitalization.load(Relaxed)
            && self.max_tick_height == other.max_tick_height
            && self.hashes_per_tick == other.hashes_per_tick
            && self.ticks_per_slot == other.ticks_per_slot
            && self.ns_per_slot == other.ns_per_slot
            && self.genesis_creation_time == other.genesis_creation_time
            && self.slots_per_year == other.slots_per_year
            && self.unused == other.unused
            && self.slot == other.slot
            && self.epoch == other.epoch
            && self.block_height == other.block_height
            && self.collector_id == other.collector_id
            && self.collector_fees.load(Relaxed) == other.collector_fees.load(Relaxed)
            && self.fee_calculator == other.fee_calculator
            && self.fee_rate_governor == other.fee_rate_governor
            && self.collected_rent.load(Relaxed) == other.collected_rent.load(Relaxed)
            && self.rent_collector == other.rent_collector
            && self.epoch_schedule == other.epoch_schedule
            && *self.inflation.read().unwrap() == *other.inflation.read().unwrap()
            && *self.stakes.read().unwrap() == *other.stakes.read().unwrap()
            && self.epoch_stakes == other.epoch_stakes
            && self.is_delta.load(Relaxed) == other.is_delta.load(Relaxed)
    }
}

#[derive(Debug, PartialEq, Serialize, Deserialize, AbiExample, AbiEnumVisitor, Clone, Copy)]
pub enum RewardType {
    Fee,
    Rent,
    Staking,
    Voting,
}

#[derive(Debug)]
pub enum RewardCalculationEvent<'a, 'b> {
    Staking(&'a Pubkey, &'b InflationPointCalculationEvent),
}

fn null_tracer() -> Option<impl FnMut(&RewardCalculationEvent)> {
    None::<fn(&RewardCalculationEvent)>
}

impl fmt::Display for RewardType {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(
            f,
            "{}",
            match self {
                RewardType::Fee => "fee",
                RewardType::Rent => "rent",
                RewardType::Staking => "staking",
                RewardType::Voting => "voting",
            }
        )
    }
}

pub trait DropCallback: fmt::Debug {
    fn callback(&self, b: &Bank);
    fn clone_box(&self) -> Box<dyn DropCallback + Send + Sync>;
}

#[derive(Debug, PartialEq, Serialize, Deserialize, AbiExample, Clone, Copy)]
pub struct RewardInfo {
    pub reward_type: RewardType,
    pub lamports: i64,          // Reward amount
    pub post_balance: u64,      // Account balance in lamports after `lamports` was applied
    pub commission: Option<u8>, // Vote account commission when the reward was credited, only present for voting and staking rewards
}

#[derive(Debug, Default)]
pub struct OptionalDropCallback(Option<Box<dyn DropCallback + Send + Sync>>);

#[cfg(RUSTC_WITH_SPECIALIZATION)]
impl AbiExample for OptionalDropCallback {
    fn example() -> Self {
        Self(None)
    }
}

/// Manager for the state of all accounts and programs after processing its entries.
/// AbiExample is needed even without Serialize/Deserialize; actual (de-)serialization
/// are implemented elsewhere for versioning
#[derive(AbiExample, Debug, Default)]
pub struct Bank {
    /// References to accounts, parent and signature status
    pub rc: BankRc,

    pub src: StatusCacheRc,

    /// FIFO queue of `recent_blockhash` items
    blockhash_queue: RwLock<BlockhashQueue>,

    /// The set of parents including this bank
    pub ancestors: Ancestors,

    /// Hash of this Bank's state. Only meaningful after freezing.
    hash: RwLock<Hash>,

    /// Hash of this Bank's parent's state
    parent_hash: Hash,

    /// parent's slot
    parent_slot: Slot,

    /// slots to hard fork at
    hard_forks: Arc<RwLock<HardForks>>,

    /// The number of transactions processed without error
    transaction_count: AtomicU64,

    /// The number of transaction errors in this slot
    transaction_error_count: AtomicU64,

    /// The number of transaction entries in this slot
    transaction_entries_count: AtomicU64,

    /// The max number of transaction in an entry in this slot
    transactions_per_entry_max: AtomicU64,

    /// Bank tick height
    tick_height: AtomicU64,

    /// The number of signatures from valid transactions in this slot
    signature_count: AtomicU64,

    /// Total capitalization, used to calculate inflation
    capitalization: AtomicU64,

    // Bank max_tick_height
    max_tick_height: u64,

    /// The number of hashes in each tick. None value means hashing is disabled.
    hashes_per_tick: Option<u64>,

    /// The number of ticks in each slot.
    ticks_per_slot: u64,

    /// length of a slot in ns
    pub ns_per_slot: u128,

    /// genesis time, used for computed clock
    genesis_creation_time: UnixTimestamp,

    /// The number of slots per year, used for inflation
    slots_per_year: f64,

    /// Unused
    unused: u64,

    /// Bank slot (i.e. block)
    slot: Slot,

    bank_id: BankId,

    /// Bank epoch
    epoch: Epoch,

    /// Bank block_height
    block_height: u64,

    /// The pubkey to send transactions fees to.
    collector_id: Pubkey,

    /// Fees that have been collected
    collector_fees: AtomicU64,

    /// Latest transaction fees for transactions processed by this bank
    fee_calculator: FeeCalculator,

    /// Track cluster signature throughput and adjust fee rate
    fee_rate_governor: FeeRateGovernor,

    /// Rent that has been collected
    collected_rent: AtomicU64,

    /// latest rent collector, knows the epoch
    rent_collector: RentCollector,

    /// initialized from genesis
    epoch_schedule: EpochSchedule,

    /// inflation specs
    inflation: Arc<RwLock<Inflation>>,

    /// cache of vote_account and stake_account state for this fork
    stakes: RwLock<Stakes>,

    /// staked nodes on epoch boundaries, saved off when a bank.slot() is at
    ///   a leader schedule calculation boundary
    epoch_stakes: HashMap<Epoch, EpochStakes>,

    /// A boolean reflecting whether any entries were recorded into the PoH
    /// stream for the slot == self.slot
    is_delta: AtomicBool,

    /// The Message processor
    message_processor: MessageProcessor,

    bpf_compute_budget: Option<BpfComputeBudget>,

    /// Builtin programs activated dynamically by feature
    #[allow(clippy::rc_buffer)]
    feature_builtins: Arc<Vec<(Builtin, Pubkey, ActivationType)>>,

    /// Last time when the cluster info vote listener has synced with this bank
    pub last_vote_sync: AtomicU64,

    /// Protocol-level rewards that were distributed by this bank
    pub rewards: RwLock<Vec<(Pubkey, RewardInfo)>>,

    pub cluster_type: Option<ClusterType>,

    pub lazy_rent_collection: AtomicBool,

    pub no_stake_rewrite: AtomicBool,

    // this is temporary field only to remove rewards_pool entirely
    pub rewards_pool_pubkeys: Arc<HashSet<Pubkey>>,

    /// Cached executors
    cached_executors: RwLock<CowCachedExecutors>,

    transaction_debug_keys: Option<Arc<HashSet<Pubkey>>>,

    // Global configuration for how transaction logs should be collected across all banks
    pub transaction_log_collector_config: Arc<RwLock<TransactionLogCollectorConfig>>,

    // Logs from transactions that this Bank executed collected according to the criteria in
    // `transaction_log_collector_config`
    pub transaction_log_collector: Arc<RwLock<TransactionLogCollector>>,

    pub feature_set: Arc<FeatureSet>,

    pub drop_callback: RwLock<OptionalDropCallback>,

    pub freeze_started: AtomicBool,
}

impl Default for BlockhashQueue {
    fn default() -> Self {
        Self::new(MAX_RECENT_BLOCKHASHES)
    }
}

impl Bank {
    pub fn new(genesis_config: &GenesisConfig) -> Self {
        Self::new_with_paths(
            genesis_config,
            Vec::new(),
            &[],
            None,
            None,
            AccountSecondaryIndexes::default(),
            false,
            AccountShrinkThreshold::default(),
            false,
        )
    }

    pub fn new_no_wallclock_throttle(genesis_config: &GenesisConfig) -> Self {
        let mut bank = Self::new_with_paths(
            genesis_config,
            Vec::new(),
            &[],
            None,
            None,
            AccountSecondaryIndexes::default(),
            false,
            AccountShrinkThreshold::default(),
            false,
        );

        bank.ns_per_slot = std::u128::MAX;
        bank
    }

    #[cfg(test)]
    pub(crate) fn new_with_config(
        genesis_config: &GenesisConfig,
        account_indexes: AccountSecondaryIndexes,
        accounts_db_caching_enabled: bool,
        shrink_ratio: AccountShrinkThreshold,
    ) -> Self {
        Self::new_with_paths(
            genesis_config,
            Vec::new(),
            &[],
            None,
            None,
            account_indexes,
            accounts_db_caching_enabled,
            shrink_ratio,
            false,
        )
    }

    pub fn new_with_paths(
        genesis_config: &GenesisConfig,
        paths: Vec<PathBuf>,
        frozen_account_pubkeys: &[Pubkey],
        debug_keys: Option<Arc<HashSet<Pubkey>>>,
        additional_builtins: Option<&Builtins>,
        account_indexes: AccountSecondaryIndexes,
        accounts_db_caching_enabled: bool,
        shrink_ratio: AccountShrinkThreshold,
        debug_do_not_add_builtins: bool,
    ) -> Self {
        let mut bank = Self::default();
        bank.ancestors = Ancestors::from(vec![bank.slot()]);
        bank.transaction_debug_keys = debug_keys;
        bank.cluster_type = Some(genesis_config.cluster_type);

        bank.rc.accounts = Arc::new(Accounts::new_with_config(
            paths,
            &genesis_config.cluster_type,
            account_indexes,
            accounts_db_caching_enabled,
            shrink_ratio,
        ));
        bank.process_genesis_config(genesis_config);
        bank.finish_init(
            genesis_config,
            additional_builtins,
            debug_do_not_add_builtins,
        );

        // Freeze accounts after process_genesis_config creates the initial append vecs
        Arc::get_mut(&mut Arc::get_mut(&mut bank.rc.accounts).unwrap().accounts_db)
            .unwrap()
            .freeze_accounts(&bank.ancestors, frozen_account_pubkeys);

        // genesis needs stakes for all epochs up to the epoch implied by
        //  slot = 0 and genesis configuration
        {
            let stakes = bank.stakes.read().unwrap();
            for epoch in 0..=bank.get_leader_schedule_epoch(bank.slot) {
                bank.epoch_stakes
                    .insert(epoch, EpochStakes::new(&stakes, epoch));
            }
            bank.update_stake_history(None);
        }
        bank.update_clock(None);
        bank.update_rent();
        bank.update_epoch_schedule();
        bank.update_recent_blockhashes();
        bank
    }

    /// Create a new bank that points to an immutable checkpoint of another bank.
    pub fn new_from_parent(parent: &Arc<Bank>, collector_id: &Pubkey, slot: Slot) -> Self {
        Self::_new_from_parent(parent, collector_id, slot, &mut null_tracer())
    }

    pub fn new_from_parent_with_tracer(
        parent: &Arc<Bank>,
        collector_id: &Pubkey,
        slot: Slot,
        reward_calc_tracer: impl FnMut(&RewardCalculationEvent),
    ) -> Self {
        Self::_new_from_parent(parent, collector_id, slot, &mut Some(reward_calc_tracer))
    }

    fn _new_from_parent(
        parent: &Arc<Bank>,
        collector_id: &Pubkey,
        slot: Slot,
        reward_calc_tracer: &mut Option<impl FnMut(&RewardCalculationEvent)>,
    ) -> Self {
        parent.freeze();
        assert_ne!(slot, parent.slot());

        let epoch_schedule = parent.epoch_schedule;
        let epoch = epoch_schedule.get_epoch(slot);

        let rc = BankRc {
            accounts: Arc::new(Accounts::new_from_parent(
                &parent.rc.accounts,
                slot,
                parent.slot(),
            )),
            parent: RwLock::new(Some(parent.clone())),
            slot,
            bank_id_generator: parent.rc.bank_id_generator.clone(),
        };
        let src = StatusCacheRc {
            status_cache: parent.src.status_cache.clone(),
        };

        let fee_rate_governor =
            FeeRateGovernor::new_derived(&parent.fee_rate_governor, parent.signature_count());

        let bank_id = rc.bank_id_generator.fetch_add(1, Relaxed) + 1;
        let mut new = Bank {
            rc,
            src,
            slot,
            bank_id,
            epoch,
            blockhash_queue: RwLock::new(parent.blockhash_queue.read().unwrap().clone()),

            // TODO: clean this up, so much special-case copying...
            hashes_per_tick: parent.hashes_per_tick,
            ticks_per_slot: parent.ticks_per_slot,
            ns_per_slot: parent.ns_per_slot,
            genesis_creation_time: parent.genesis_creation_time,
            unused: parent.unused,
            slots_per_year: parent.slots_per_year,
            epoch_schedule,
            collected_rent: AtomicU64::new(0),
            rent_collector: parent.rent_collector.clone_with_epoch(epoch),
            max_tick_height: (slot + 1) * parent.ticks_per_slot,
            block_height: parent.block_height + 1,
            fee_calculator: fee_rate_governor.create_fee_calculator(),
            fee_rate_governor,
            capitalization: AtomicU64::new(parent.capitalization()),
            inflation: parent.inflation.clone(),
            transaction_count: AtomicU64::new(parent.transaction_count()),
            transaction_error_count: AtomicU64::new(0),
            transaction_entries_count: AtomicU64::new(0),
            transactions_per_entry_max: AtomicU64::new(0),
            // we will .clone_with_epoch() this soon after stake data update; so just .clone() for now
            stakes: RwLock::new(parent.stakes.read().unwrap().clone()),
            epoch_stakes: parent.epoch_stakes.clone(),
            parent_hash: parent.hash(),
            parent_slot: parent.slot(),
            collector_id: *collector_id,
            collector_fees: AtomicU64::new(0),
            ancestors: Ancestors::default(),
            hash: RwLock::new(Hash::default()),
            is_delta: AtomicBool::new(false),
            tick_height: AtomicU64::new(parent.tick_height.load(Relaxed)),
            signature_count: AtomicU64::new(0),
            message_processor: parent.message_processor.clone(),
            bpf_compute_budget: parent.bpf_compute_budget,
            feature_builtins: parent.feature_builtins.clone(),
            hard_forks: parent.hard_forks.clone(),
            last_vote_sync: AtomicU64::new(parent.last_vote_sync.load(Relaxed)),
            rewards: RwLock::new(vec![]),
            cluster_type: parent.cluster_type,
            lazy_rent_collection: AtomicBool::new(parent.lazy_rent_collection.load(Relaxed)),
            no_stake_rewrite: AtomicBool::new(parent.no_stake_rewrite.load(Relaxed)),
            rewards_pool_pubkeys: parent.rewards_pool_pubkeys.clone(),
            cached_executors: RwLock::new(
                (*parent.cached_executors.read().unwrap()).clone_with_epoch(epoch),
            ),
            transaction_debug_keys: parent.transaction_debug_keys.clone(),
            transaction_log_collector_config: parent.transaction_log_collector_config.clone(),
            transaction_log_collector: Arc::new(RwLock::new(TransactionLogCollector::default())),
            feature_set: parent.feature_set.clone(),
            drop_callback: RwLock::new(OptionalDropCallback(
                parent
                    .drop_callback
                    .read()
                    .unwrap()
                    .0
                    .as_ref()
                    .map(|drop_callback| drop_callback.clone_box()),
            )),
            freeze_started: AtomicBool::new(false),
        };

        datapoint_info!(
            "bank-new_from_parent-heights",
            ("slot_height", slot, i64),
            ("block_height", new.block_height, i64),
            ("parent_slot_height", parent.slot(), i64),
        );

        let mut ancestors = Vec::with_capacity(1 + new.parents().len());
        ancestors.push(new.slot());
        new.parents().iter().for_each(|p| {
            ancestors.push(p.slot());
        });
        new.ancestors = Ancestors::from(ancestors);

        // Following code may touch AccountsDb, requiring proper ancestors
        let parent_epoch = parent.epoch();
        if parent_epoch < new.epoch() {
            new.apply_feature_activations(false, false);
        }

        let cloned = new
            .stakes
            .read()
            .unwrap()
            .clone_with_epoch(epoch, new.stake_program_v2_enabled());
        *new.stakes.write().unwrap() = cloned;

        let leader_schedule_epoch = epoch_schedule.get_leader_schedule_epoch(slot);
        new.update_epoch_stakes(leader_schedule_epoch);
        new.update_slot_hashes();
        new.update_rewards(parent_epoch, reward_calc_tracer);
        new.update_stake_history(Some(parent_epoch));
        new.update_clock(Some(parent_epoch));
        new.update_fees();
        if !new.fix_recent_blockhashes_sysvar_delay() {
            new.update_recent_blockhashes();
        }

        new
    }

    /// Returns all ancestors excluding self.slot.
    pub(crate) fn proper_ancestors(&self) -> impl Iterator<Item = Slot> + '_ {
        self.ancestors
            .keys()
            .into_iter()
            .filter(move |slot| *slot != self.slot)
    }

    pub fn set_callback(&self, callback: Option<Box<dyn DropCallback + Send + Sync>>) {
        *self.drop_callback.write().unwrap() = OptionalDropCallback(callback);
    }

    /// Like `new_from_parent` but additionally:
    /// * Doesn't assume that the parent is anywhere near `slot`, parent could be millions of slots
    /// in the past
    /// * Adjusts the new bank's tick height to avoid having to run PoH for millions of slots
    /// * Freezes the new bank, assuming that the user will `Bank::new_from_parent` from this bank
    pub fn warp_from_parent(parent: &Arc<Bank>, collector_id: &Pubkey, slot: Slot) -> Self {
        let parent_timestamp = parent.clock().unix_timestamp;
        let mut new = Bank::new_from_parent(parent, collector_id, slot);
        new.apply_feature_activations(true, false);
        new.update_epoch_stakes(new.epoch_schedule().get_epoch(slot));
        new.tick_height.store(new.max_tick_height(), Relaxed);

        let mut clock = new.clock();
        clock.epoch_start_timestamp = parent_timestamp;
        clock.unix_timestamp = parent_timestamp;
        new.update_sysvar_account(&sysvar::clock::id(), |account| {
            create_account(
                &clock,
                new.inherit_specially_retained_account_fields(account),
            )
        });

        new.freeze();
        new
    }

    /// Create a bank from explicit arguments and deserialized fields from snapshot
    #[allow(clippy::float_cmp)]
    pub(crate) fn new_from_fields(
        bank_rc: BankRc,
        genesis_config: &GenesisConfig,
        fields: BankFieldsToDeserialize,
        debug_keys: Option<Arc<HashSet<Pubkey>>>,
        additional_builtins: Option<&Builtins>,
        debug_do_not_add_builtins: bool,
    ) -> Self {
        fn new<T: Default>() -> T {
            T::default()
        }
        let mut bank = Self {
            rc: bank_rc,
            src: new(),
            blockhash_queue: RwLock::new(fields.blockhash_queue),
            ancestors: Ancestors::from(&fields.ancestors),
            hash: RwLock::new(fields.hash),
            parent_hash: fields.parent_hash,
            parent_slot: fields.parent_slot,
            hard_forks: Arc::new(RwLock::new(fields.hard_forks)),
            transaction_count: AtomicU64::new(fields.transaction_count),
            transaction_error_count: new(),
            transaction_entries_count: new(),
            transactions_per_entry_max: new(),
            tick_height: AtomicU64::new(fields.tick_height),
            signature_count: AtomicU64::new(fields.signature_count),
            capitalization: AtomicU64::new(fields.capitalization),
            max_tick_height: fields.max_tick_height,
            hashes_per_tick: fields.hashes_per_tick,
            ticks_per_slot: fields.ticks_per_slot,
            ns_per_slot: fields.ns_per_slot,
            genesis_creation_time: fields.genesis_creation_time,
            slots_per_year: fields.slots_per_year,
            unused: genesis_config.unused,
            slot: fields.slot,
            bank_id: 0,
            epoch: fields.epoch,
            block_height: fields.block_height,
            collector_id: fields.collector_id,
            collector_fees: AtomicU64::new(fields.collector_fees),
            fee_calculator: fields.fee_calculator,
            fee_rate_governor: fields.fee_rate_governor,
            collected_rent: AtomicU64::new(fields.collected_rent),
            // clone()-ing is needed to consider a gated behavior in rent_collector
            rent_collector: fields.rent_collector.clone_with_epoch(fields.epoch),
            epoch_schedule: fields.epoch_schedule,
            inflation: Arc::new(RwLock::new(fields.inflation)),
            stakes: RwLock::new(fields.stakes),
            epoch_stakes: fields.epoch_stakes,
            is_delta: AtomicBool::new(fields.is_delta),
            message_processor: new(),
            bpf_compute_budget: None,
            feature_builtins: new(),
            last_vote_sync: new(),
            rewards: new(),
            cluster_type: Some(genesis_config.cluster_type),
            lazy_rent_collection: new(),
            no_stake_rewrite: new(),
            rewards_pool_pubkeys: new(),
            cached_executors: RwLock::new(CowCachedExecutors::new(Arc::new(RwLock::new(
                CachedExecutors::new(MAX_CACHED_EXECUTORS, fields.epoch),
            )))),
            transaction_debug_keys: debug_keys,
            transaction_log_collector_config: new(),
            transaction_log_collector: new(),
            feature_set: new(),
            drop_callback: RwLock::new(OptionalDropCallback(None)),
            freeze_started: AtomicBool::new(fields.hash != Hash::default()),
        };
        bank.finish_init(
            genesis_config,
            additional_builtins,
            debug_do_not_add_builtins,
        );

        // Sanity assertions between bank snapshot and genesis config
        // Consider removing from serializable bank state
        // (BankFieldsToSerialize/BankFieldsToDeserialize) and initializing
        // from the passed in genesis_config instead (as new()/new_with_paths() already do)
        assert_eq!(
            bank.hashes_per_tick,
            genesis_config.poh_config.hashes_per_tick
        );
        assert_eq!(bank.ticks_per_slot, genesis_config.ticks_per_slot);
        assert_eq!(
            bank.ns_per_slot,
            genesis_config.poh_config.target_tick_duration.as_nanos()
                * genesis_config.ticks_per_slot as u128
        );
        assert_eq!(bank.genesis_creation_time, genesis_config.creation_time);
        assert_eq!(bank.unused, genesis_config.unused);
        assert_eq!(bank.max_tick_height, (bank.slot + 1) * bank.ticks_per_slot);
        assert_eq!(
            bank.slots_per_year,
            years_as_slots(
                1.0,
                &genesis_config.poh_config.target_tick_duration,
                bank.ticks_per_slot,
            )
        );
        assert_eq!(bank.epoch_schedule, genesis_config.epoch_schedule);
        assert_eq!(bank.epoch, bank.epoch_schedule.get_epoch(bank.slot));
        bank.fee_rate_governor.lamports_per_signature = bank.fee_calculator.lamports_per_signature;
        assert_eq!(
            bank.fee_rate_governor.create_fee_calculator(),
            bank.fee_calculator
        );
        bank
    }

    /// Return subset of bank fields representing serializable state
    pub(crate) fn get_fields_to_serialize<'a>(
        &'a self,
        ancestors: &'a HashMap<Slot, usize>,
    ) -> BankFieldsToSerialize<'a> {
        BankFieldsToSerialize {
            blockhash_queue: &self.blockhash_queue,
            ancestors,
            hash: *self.hash.read().unwrap(),
            parent_hash: self.parent_hash,
            parent_slot: self.parent_slot,
            hard_forks: &*self.hard_forks,
            transaction_count: self.transaction_count.load(Relaxed),
            tick_height: self.tick_height.load(Relaxed),
            signature_count: self.signature_count.load(Relaxed),
            capitalization: self.capitalization.load(Relaxed),
            max_tick_height: self.max_tick_height,
            hashes_per_tick: self.hashes_per_tick,
            ticks_per_slot: self.ticks_per_slot,
            ns_per_slot: self.ns_per_slot,
            genesis_creation_time: self.genesis_creation_time,
            slots_per_year: self.slots_per_year,
            unused: self.unused,
            slot: self.slot,
            epoch: self.epoch,
            block_height: self.block_height,
            collector_id: self.collector_id,
            collector_fees: self.collector_fees.load(Relaxed),
            fee_calculator: self.fee_calculator.clone(),
            fee_rate_governor: self.fee_rate_governor.clone(),
            collected_rent: self.collected_rent.load(Relaxed),
            rent_collector: self.rent_collector.clone(),
            epoch_schedule: self.epoch_schedule,
            inflation: *self.inflation.read().unwrap(),
            stakes: &self.stakes,
            epoch_stakes: &self.epoch_stakes,
            is_delta: self.is_delta.load(Relaxed),
        }
    }

    pub fn collector_id(&self) -> &Pubkey {
        &self.collector_id
    }

    pub fn slot(&self) -> Slot {
        self.slot
    }

    pub fn bank_id(&self) -> BankId {
        self.bank_id
    }

    pub fn epoch(&self) -> Epoch {
        self.epoch
    }

    pub fn first_normal_epoch(&self) -> Epoch {
        self.epoch_schedule.first_normal_epoch
    }

    pub fn freeze_lock(&self) -> RwLockReadGuard<Hash> {
        self.hash.read().unwrap()
    }

    pub fn hash(&self) -> Hash {
        *self.hash.read().unwrap()
    }

    pub fn is_frozen(&self) -> bool {
        *self.hash.read().unwrap() != Hash::default()
    }

    pub fn freeze_started(&self) -> bool {
        self.freeze_started.load(Relaxed)
    }

    pub fn status_cache_ancestors(&self) -> Vec<u64> {
        let mut roots = self.src.status_cache.read().unwrap().roots().clone();
        let min = roots.iter().min().cloned().unwrap_or(0);
        for ancestor in self.ancestors.keys() {
            if ancestor >= min {
                roots.insert(ancestor);
            }
        }

        let mut ancestors: Vec<_> = roots.into_iter().collect();
        #[allow(clippy::stable_sort_primitive)]
        ancestors.sort();
        ancestors
    }

    /// computed unix_timestamp at this slot height
    pub fn unix_timestamp_from_genesis(&self) -> i64 {
        self.genesis_creation_time + ((self.slot as u128 * self.ns_per_slot) / 1_000_000_000) as i64
    }

    fn update_sysvar_account<F>(&self, pubkey: &Pubkey, updater: F)
    where
        F: Fn(&Option<AccountSharedData>) -> AccountSharedData,
    {
        let old_account = if !self.rent_for_sysvars() {
            // This old behavior is being retired for simpler reasoning for the benefits of all.
            // Specifically, get_sysvar_account_with_fixed_root() doesn't work nicely with eager
            // rent collection, which becomes significant for sysvars after rent_for_sysvars
            // activation. That's because get_sysvar_account_with_fixed_root() invocations by both
            // update_slot_history() and update_recent_blockhashes() ignores any updates
            // by eager rent collection in this slot.
            // Also, it turned out that get_sysvar_account_with_fixed_root()'s special
            // behavior (idempotent) isn't needed to begin with, because we're fairly certain that
            // we don't call new_from_parent() with same child slot multiple times in the
            // production code (except after proper handling of duplicate slot dumping)...
            self.get_sysvar_account_with_fixed_root(pubkey)
        } else {
            self.get_account_with_fixed_root(pubkey)
        };
        let mut new_account = updater(&old_account);

        if self.rent_for_sysvars() {
            // When new sysvar comes into existence (with RENT_UNADJUSTED_INITIAL_BALANCE lamports),
            // this code ensures that the sysvar's balance is adjusted to be rent-exempt.
            // Note that all of existing sysvar balances must be adjusted immediately (i.e. reset) upon
            // the `rent_for_sysvars` feature activation (ref: reset_all_sysvar_balances).
            //
            // More generally, this code always re-calculates for possible sysvar data size change,
            // although there is no such sysvars currently.
            self.adjust_sysvar_balance_for_rent(&mut new_account);
        }

        self.store_account_and_update_capitalization(pubkey, &new_account);
    }

    fn inherit_specially_retained_account_fields(
        &self,
        old_account: &Option<AccountSharedData>,
    ) -> InheritableAccountFields {
        const RENT_UNADJUSTED_INITIAL_BALANCE: u64 = 1;

        (
            old_account
                .as_ref()
                .map(|a| a.lamports())
                .unwrap_or(RENT_UNADJUSTED_INITIAL_BALANCE),
            if !self.rent_for_sysvars() {
                INITIAL_RENT_EPOCH
            } else {
                // start to inherit rent_epoch updated by rent collection to be consistent with
                // other normal accounts
                old_account
                    .as_ref()
                    .map(|a| a.rent_epoch())
                    .unwrap_or(INITIAL_RENT_EPOCH)
            },
        )
    }

    /// Unused conversion
    pub fn get_unused_from_slot(rooted_slot: Slot, unused: u64) -> u64 {
        (rooted_slot + (unused - 1)) / unused
    }

    pub fn clock(&self) -> sysvar::clock::Clock {
        from_account(&self.get_account(&sysvar::clock::id()).unwrap_or_default())
            .unwrap_or_default()
    }

    fn update_clock(&self, parent_epoch: Option<Epoch>) {
        let mut unix_timestamp = self.clock().unix_timestamp;
        let warp_timestamp_again = self
            .feature_set
            .activated_slot(&feature_set::warp_timestamp_again::id());
        let epoch_start_timestamp = if warp_timestamp_again == Some(self.slot()) {
            None
        } else {
            let epoch = if let Some(epoch) = parent_epoch {
                epoch
            } else {
                self.epoch()
            };
            let first_slot_in_epoch = self.epoch_schedule.get_first_slot_in_epoch(epoch);
            Some((first_slot_in_epoch, self.clock().epoch_start_timestamp))
        };
        let max_allowable_drift = if self
            .feature_set
            .is_active(&feature_set::warp_timestamp_again::id())
        {
            MaxAllowableDrift {
                fast: MAX_ALLOWABLE_DRIFT_PERCENTAGE_FAST,
                slow: MAX_ALLOWABLE_DRIFT_PERCENTAGE_SLOW,
            }
        } else {
            MaxAllowableDrift {
                fast: MAX_ALLOWABLE_DRIFT_PERCENTAGE,
                slow: MAX_ALLOWABLE_DRIFT_PERCENTAGE,
            }
        };

        let ancestor_timestamp = self.clock().unix_timestamp;
        if let Some(timestamp_estimate) =
            self.get_timestamp_estimate(max_allowable_drift, epoch_start_timestamp)
        {
            unix_timestamp = timestamp_estimate;
            if timestamp_estimate < ancestor_timestamp {
                unix_timestamp = ancestor_timestamp;
            }
        }
        datapoint_info!(
            "bank-timestamp-correction",
            ("slot", self.slot(), i64),
            ("from_genesis", self.unix_timestamp_from_genesis(), i64),
            ("corrected", unix_timestamp, i64),
            ("ancestor_timestamp", ancestor_timestamp, i64),
        );
        let mut epoch_start_timestamp =
            // On epoch boundaries, update epoch_start_timestamp
            if parent_epoch.is_some() && parent_epoch.unwrap() != self.epoch() {
                unix_timestamp
            } else {
                self.clock().epoch_start_timestamp
            };
        if self.slot == 0 {
            unix_timestamp = self.unix_timestamp_from_genesis();
            epoch_start_timestamp = self.unix_timestamp_from_genesis();
        }
        let clock = sysvar::clock::Clock {
            slot: self.slot,
            epoch_start_timestamp,
            epoch: self.epoch_schedule.get_epoch(self.slot),
            leader_schedule_epoch: self.epoch_schedule.get_leader_schedule_epoch(self.slot),
            unix_timestamp,
        };
        self.update_sysvar_account(&sysvar::clock::id(), |account| {
            create_account(
                &clock,
                self.inherit_specially_retained_account_fields(account),
            )
        });
    }

    fn update_slot_history(&self) {
        self.update_sysvar_account(&sysvar::slot_history::id(), |account| {
            let mut slot_history = account
                .as_ref()
                .map(|account| from_account::<SlotHistory, _>(account).unwrap())
                .unwrap_or_default();
            slot_history.add(self.slot());
            create_account(
                &slot_history,
                self.inherit_specially_retained_account_fields(account),
            )
        });
    }

    fn update_slot_hashes(&self) {
        self.update_sysvar_account(&sysvar::slot_hashes::id(), |account| {
            let mut slot_hashes = account
                .as_ref()
                .map(|account| from_account::<SlotHashes, _>(account).unwrap())
                .unwrap_or_default();
            slot_hashes.add(self.parent_slot, self.parent_hash);
            create_account(
                &slot_hashes,
                self.inherit_specially_retained_account_fields(account),
            )
        });
    }

    pub fn get_slot_history(&self) -> SlotHistory {
        from_account(&self.get_account(&sysvar::slot_history::id()).unwrap()).unwrap()
    }

    fn update_epoch_stakes(&mut self, leader_schedule_epoch: Epoch) {
        // update epoch_stakes cache
        //  if my parent didn't populate for this staker's epoch, we've
        //  crossed a boundary
        if self.epoch_stakes.get(&leader_schedule_epoch).is_none() {
            self.epoch_stakes.retain(|&epoch, _| {
                epoch >= leader_schedule_epoch.saturating_sub(MAX_LEADER_SCHEDULE_STAKES)
            });

            let new_epoch_stakes =
                EpochStakes::new(&self.stakes.read().unwrap(), leader_schedule_epoch);
            {
                let vote_stakes: HashMap<_, _> = self
                    .stakes
                    .read()
                    .unwrap()
                    .vote_accounts()
                    .iter()
                    .map(|(pubkey, (stake, _))| (*pubkey, *stake))
                    .collect();
                info!(
                    "new epoch stakes, epoch: {}, stakes: {:#?}, total_stake: {}",
                    leader_schedule_epoch,
                    vote_stakes,
                    new_epoch_stakes.total_stake(),
                );
            }
            self.epoch_stakes
                .insert(leader_schedule_epoch, new_epoch_stakes);
        }
    }

    fn update_fees(&self) {
        self.update_sysvar_account(&sysvar::fees::id(), |account| {
            create_account(
                &sysvar::fees::Fees::new(&self.fee_calculator),
                self.inherit_specially_retained_account_fields(account),
            )
        });
    }

    fn update_rent(&self) {
        self.update_sysvar_account(&sysvar::rent::id(), |account| {
            create_account(
                &self.rent_collector.rent,
                self.inherit_specially_retained_account_fields(account),
            )
        });
    }

    fn update_epoch_schedule(&self) {
        self.update_sysvar_account(&sysvar::epoch_schedule::id(), |account| {
            create_account(
                &self.epoch_schedule,
                self.inherit_specially_retained_account_fields(account),
            )
        });
    }

    fn update_stake_history(&self, epoch: Option<Epoch>) {
        if epoch == Some(self.epoch()) {
            return;
        }
        // if I'm the first Bank in an epoch, ensure stake_history is updated
        self.update_sysvar_account(&sysvar::stake_history::id(), |account| {
            create_account::<sysvar::stake_history::StakeHistory>(
                self.stakes.read().unwrap().history(),
                self.inherit_specially_retained_account_fields(account),
            )
        });
    }

    pub fn epoch_duration_in_years(&self, prev_epoch: Epoch) -> f64 {
        // period: time that has passed as a fraction of a year, basically the length of
        //  an epoch as a fraction of a year
        //  calculated as: slots_elapsed / (slots / year)
        self.epoch_schedule.get_slots_in_epoch(prev_epoch) as f64 / self.slots_per_year
    }

    fn rewrite_stakes(&self) -> (usize, usize) {
        let mut examined_count = 0;
        let mut rewritten_count = 0;
        self.cloned_stake_delegations()
            .into_iter()
            .for_each(|(stake_pubkey, _delegation)| {
                examined_count += 1;
                if let Some(mut stake_account) = self.get_account_with_fixed_root(&stake_pubkey) {
                    if let Ok(result) =
                        stake_state::rewrite_stakes(&mut stake_account, &self.rent_collector.rent)
                    {
                        self.store_account(&stake_pubkey, &stake_account);
                        let message = format!("rewrote stake: {}, {:?}", stake_pubkey, result);
                        info!("{}", message);
                        datapoint_info!("stake_info", ("info", message, String));
                        rewritten_count += 1;
                    }
                }
            });

        info!(
            "bank (slot: {}): rewrite_stakes: {} accounts rewritten / {} accounts examined",
            self.slot(),
            rewritten_count,
            examined_count,
        );
        datapoint_info!(
            "rewrite-stakes",
            ("examined_count", examined_count, i64),
            ("rewritten_count", rewritten_count, i64)
        );

        (examined_count, rewritten_count)
    }

    // Calculates the starting-slot for inflation from the activation slot.
    // This method assumes that `pico_inflation` will be enabled before `full_inflation`, giving
    // precedence to the latter. However, since `pico_inflation` is fixed-rate Inflation, should
    // `pico_inflation` be enabled 2nd, the incorrect start slot provided here should have no
    // effect on the inflation calculation.
    fn get_inflation_start_slot(&self) -> Slot {
        let mut slots = self
            .feature_set
            .full_inflation_features_enabled()
            .iter()
            .filter_map(|id| self.feature_set.activated_slot(id))
            .collect::<Vec<_>>();
        slots.sort_unstable();
        slots.get(0).cloned().unwrap_or_else(|| {
            self.feature_set
                .activated_slot(&feature_set::pico_inflation::id())
                .unwrap_or(0)
        })
    }

    fn get_inflation_num_slots(&self) -> u64 {
        let inflation_activation_slot = self.get_inflation_start_slot();
        // Normalize inflation_start to align with the start of rewards accrual.
        let inflation_start_slot = self.epoch_schedule.get_first_slot_in_epoch(
            self.epoch_schedule
                .get_epoch(inflation_activation_slot)
                .saturating_sub(1),
        );
        self.epoch_schedule.get_first_slot_in_epoch(self.epoch()) - inflation_start_slot
    }

    pub fn slot_in_year_for_inflation(&self) -> f64 {
        let num_slots = self.get_inflation_num_slots();

        // calculated as: num_slots / (slots / year)
        num_slots as f64 / self.slots_per_year
    }

    // update rewards based on the previous epoch
    fn update_rewards(
        &mut self,
        prev_epoch: Epoch,
        reward_calc_tracer: &mut Option<impl FnMut(&RewardCalculationEvent)>,
    ) {
        if prev_epoch == self.epoch() {
            return;
        }
        // if I'm the first Bank in an epoch, count, claim, disburse rewards from Inflation

        let slot_in_year = self.slot_in_year_for_inflation();
        let epoch_duration_in_years = self.epoch_duration_in_years(prev_epoch);

        let (validator_rate, foundation_rate) = {
            let inflation = self.inflation.read().unwrap();
            (
                (*inflation).validator(slot_in_year),
                (*inflation).foundation(slot_in_year),
            )
        };

        let capitalization = self.capitalization();
        let validator_rewards =
            (validator_rate * capitalization as f64 * epoch_duration_in_years) as u64;

        let old_vote_balance_and_staked = self.stakes.read().unwrap().vote_balance_and_staked();

        let validator_point_value = self.pay_validator_rewards(
            prev_epoch,
            validator_rewards,
            reward_calc_tracer,
            self.stake_program_v2_enabled(),
        );

        if !self
            .feature_set
            .is_active(&feature_set::deprecate_rewards_sysvar::id())
        {
            // this sysvar can be retired once `pico_inflation` is enabled on all clusters
            self.update_sysvar_account(&sysvar::rewards::id(), |account| {
                create_account(
                    &sysvar::rewards::Rewards::new(validator_point_value),
                    self.inherit_specially_retained_account_fields(account),
                )
            });
        }

        let new_vote_balance_and_staked = self.stakes.read().unwrap().vote_balance_and_staked();
        let validator_rewards_paid = new_vote_balance_and_staked - old_vote_balance_and_staked;
        assert_eq!(
            validator_rewards_paid,
            u64::try_from(
                self.rewards
                    .read()
                    .unwrap()
                    .iter()
                    .map(|(_address, reward_info)| {
                        match reward_info.reward_type {
                            RewardType::Voting | RewardType::Staking => reward_info.lamports,
                            _ => 0,
                        }
                    })
                    .sum::<i64>()
            )
            .unwrap()
        );

        // verify that we didn't pay any more than we expected to
        assert!(validator_rewards >= validator_rewards_paid);

        info!(
            "distributed inflation: {} (rounded from: {})",
            validator_rewards_paid, validator_rewards
        );

        self.capitalization
            .fetch_add(validator_rewards_paid, Relaxed);

        let active_stake = if let Some(stake_history_entry) =
            self.stakes.read().unwrap().history().get(&prev_epoch)
        {
            stake_history_entry.effective
        } else {
            0
        };

        datapoint_warn!(
            "epoch_rewards",
            ("slot", self.slot, i64),
            ("epoch", prev_epoch, i64),
            ("validator_rate", validator_rate, f64),
            ("foundation_rate", foundation_rate, f64),
            ("epoch_duration_in_years", epoch_duration_in_years, f64),
            ("validator_rewards", validator_rewards_paid, i64),
            ("active_stake", active_stake, i64),
            ("pre_capitalization", capitalization, i64),
            ("post_capitalization", self.capitalization(), i64)
        );
    }

    /// map stake delegations into resolved (pubkey, account) pairs
    ///  returns a map (has to be copied) of loaded
    ///   ( Vec<(staker info)> (voter account) ) keyed by voter pubkey
    ///
    /// Filters out invalid pairs
    fn stake_delegation_accounts(
        &self,
        reward_calc_tracer: &mut Option<impl FnMut(&RewardCalculationEvent)>,
    ) -> HashMap<Pubkey, (Vec<(Pubkey, AccountSharedData)>, AccountSharedData)> {
        let mut accounts = HashMap::new();

        self.stakes
            .read()
            .unwrap()
            .stake_delegations()
            .iter()
            .for_each(|(stake_pubkey, delegation)| {
                match (
                    self.get_account_with_fixed_root(stake_pubkey),
                    self.get_account_with_fixed_root(&delegation.voter_pubkey),
                ) {
                    (Some(stake_account), Some(vote_account)) => {
                        // call tracer to catch any illegal data if any
                        if let Some(reward_calc_tracer) = reward_calc_tracer {
                            reward_calc_tracer(&RewardCalculationEvent::Staking(
                                stake_pubkey,
                                &InflationPointCalculationEvent::Delegation(
                                    *delegation,
                                    *vote_account.owner(),
                                ),
                            ));
                        }
                        if self
                            .feature_set
                            .is_active(&feature_set::filter_stake_delegation_accounts::id())
                            && (stake_account.owner() != &stake::program::id()
                                || vote_account.owner() != &solana_vote_program::id())
                        {
                            datapoint_warn!(
                                "bank-stake_delegation_accounts-invalid-account",
                                ("slot", self.slot() as i64, i64),
                                ("stake-address", format!("{:?}", stake_pubkey), String),
                                (
                                    "vote-address",
                                    format!("{:?}", delegation.voter_pubkey),
                                    String
                                ),
                            );
                            return;
                        }
                        let entry = accounts
                            .entry(delegation.voter_pubkey)
                            .or_insert((Vec::new(), vote_account));
                        entry.0.push((*stake_pubkey, stake_account));
                    }
                    (_, _) => {}
                }
            });

        accounts
    }

    /// iterate over all stakes, redeem vote credits for each stake we can
    ///   successfully load and parse, return the lamport value of one point
    fn pay_validator_rewards(
        &mut self,
        rewarded_epoch: Epoch,
        rewards: u64,
        reward_calc_tracer: &mut Option<impl FnMut(&RewardCalculationEvent)>,
        fix_stake_deactivate: bool,
    ) -> f64 {
        let stake_history = self.stakes.read().unwrap().history().clone();

        let mut stake_delegation_accounts = self.stake_delegation_accounts(reward_calc_tracer);

        let points: u128 = stake_delegation_accounts
            .iter()
            .flat_map(|(_vote_pubkey, (stake_group, vote_account))| {
                stake_group
                    .iter()
                    .map(move |(_stake_pubkey, stake_account)| (stake_account, vote_account))
            })
            .map(|(stake_account, vote_account)| {
                stake_state::calculate_points(
                    stake_account,
                    vote_account,
                    Some(&stake_history),
                    fix_stake_deactivate,
                )
                .unwrap_or(0)
            })
            .sum();

        if points == 0 {
            return 0.0;
        }

        let point_value = PointValue { rewards, points };

        let mut rewards = vec![];
        // pay according to point value
        for (vote_pubkey, (stake_group, vote_account)) in stake_delegation_accounts.iter_mut() {
            let mut vote_account_changed = false;
            let voters_account_pre_balance = vote_account.lamports();
            let vote_state: VoteState = match StateMut::<VoteStateVersions>::state(vote_account) {
                Ok(vote_state) => vote_state.convert_to_current(),
                Err(err) => {
                    debug!(
                        "failed to deserialize vote account {}: {}",
                        vote_pubkey, err
                    );
                    continue;
                }
            };
            let commission = Some(vote_state.commission);

            for (stake_pubkey, stake_account) in stake_group.iter_mut() {
                // curry closure to add the contextual stake_pubkey
                let mut reward_calc_tracer = reward_calc_tracer.as_mut().map(|outer| {
                    let stake_pubkey = *stake_pubkey;
                    // inner
                    move |inner_event: &_| {
                        outer(&RewardCalculationEvent::Staking(&stake_pubkey, inner_event))
                    }
                });
                let redeemed = stake_state::redeem_rewards(
                    rewarded_epoch,
                    stake_account,
                    vote_account,
                    &vote_state,
                    &point_value,
                    Some(&stake_history),
                    &mut reward_calc_tracer.as_mut(),
                    fix_stake_deactivate,
                );
                if let Ok((stakers_reward, _voters_reward)) = redeemed {
                    self.store_account(stake_pubkey, stake_account);
                    vote_account_changed = true;

                    if stakers_reward > 0 {
                        rewards.push((
                            *stake_pubkey,
                            RewardInfo {
                                reward_type: RewardType::Staking,
                                lamports: stakers_reward as i64,
                                post_balance: stake_account.lamports(),
                                commission,
                            },
                        ));
                    }
                } else {
                    debug!(
                        "stake_state::redeem_rewards() failed for {}: {:?}",
                        stake_pubkey, redeemed
                    );
                }
            }

            if vote_account_changed {
                let post_balance = vote_account.lamports();
                let lamports = (post_balance - voters_account_pre_balance) as i64;
                if lamports != 0 {
                    rewards.push((
                        *vote_pubkey,
                        RewardInfo {
                            reward_type: RewardType::Voting,
                            lamports,
                            post_balance,
                            commission,
                        },
                    ));
                }
                self.store_account(vote_pubkey, vote_account);
            }
        }
        self.rewards.write().unwrap().append(&mut rewards);

        point_value.rewards as f64 / point_value.points as f64
    }

    fn update_recent_blockhashes_locked(&self, locked_blockhash_queue: &BlockhashQueue) {
        self.update_sysvar_account(&sysvar::recent_blockhashes::id(), |account| {
            let recent_blockhash_iter = locked_blockhash_queue.get_recent_blockhashes();
            recent_blockhashes_account::create_account_with_data_and_fields(
                recent_blockhash_iter,
                self.inherit_specially_retained_account_fields(account),
            )
        });
    }

    pub fn update_recent_blockhashes(&self) {
        let blockhash_queue = self.blockhash_queue.read().unwrap();
        self.update_recent_blockhashes_locked(&blockhash_queue);
    }

    fn get_timestamp_estimate(
        &self,
        max_allowable_drift: MaxAllowableDrift,
        epoch_start_timestamp: Option<(Slot, UnixTimestamp)>,
    ) -> Option<UnixTimestamp> {
        let mut get_timestamp_estimate_time = Measure::start("get_timestamp_estimate");
        let slots_per_epoch = self.epoch_schedule().slots_per_epoch;
        let recent_timestamps =
            self.vote_accounts()
                .into_iter()
                .filter_map(|(pubkey, (_, account))| {
                    let vote_state = account.vote_state();
                    let vote_state = vote_state.as_ref().ok()?;
                    let slot_delta = self.slot().checked_sub(vote_state.last_timestamp.slot)?;
                    if slot_delta <= slots_per_epoch {
                        Some((
                            pubkey,
                            (
                                vote_state.last_timestamp.slot,
                                vote_state.last_timestamp.timestamp,
                            ),
                        ))
                    } else {
                        None
                    }
                });
        let slot_duration = Duration::from_nanos(self.ns_per_slot as u64);
        let epoch = self.epoch_schedule().get_epoch(self.slot());
        let stakes = self.epoch_vote_accounts(epoch)?;
        let stake_weighted_timestamp = calculate_stake_weighted_timestamp(
            recent_timestamps,
            stakes,
            self.slot(),
            slot_duration,
            epoch_start_timestamp,
            max_allowable_drift,
            self.feature_set
                .is_active(&feature_set::warp_timestamp_again::id()),
        );
        get_timestamp_estimate_time.stop();
        datapoint_info!(
            "bank-timestamp",
            (
                "get_timestamp_estimate_us",
                get_timestamp_estimate_time.as_us(),
                i64
            ),
        );
        stake_weighted_timestamp
    }

    // Distribute collected transaction fees for this slot to collector_id (= current leader).
    //
    // Each validator is incentivized to process more transactions to earn more transaction fees.
    // Transaction fees are rewarded for the computing resource utilization cost, directly
    // proportional to their actual processing power.
    //
    // collector_id is rotated according to stake-weighted leader schedule. So the opportunity of
    // earning transaction fees are fairly distributed by stake. And missing the opportunity
    // (not producing a block as a leader) earns nothing. So, being online is incentivized as a
    // form of transaction fees as well.
    //
    // On the other hand, rent fees are distributed under slightly different philosophy, while
    // still being stake-weighted.
    // Ref: distribute_rent_to_validators
    fn collect_fees(&self) {
        let collector_fees = self.collector_fees.load(Relaxed) as u64;

        if collector_fees != 0 {
            let (deposit, mut burn) = self.fee_rate_governor.burn(collector_fees);
            // burn a portion of fees
            debug!(
                "distributed fee: {} (rounded from: {}, burned: {})",
                deposit, collector_fees, burn
            );

            match self.deposit(&self.collector_id, deposit) {
                Ok(post_balance) => {
                    if deposit != 0 {
                        self.rewards.write().unwrap().push((
                            self.collector_id,
                            RewardInfo {
                                reward_type: RewardType::Fee,
                                lamports: deposit as i64,
                                post_balance,
                                commission: None,
                            },
                        ));
                    }
                }
                Err(_) => {
                    error!(
                        "Burning {} fee instead of crediting {}",
                        deposit, self.collector_id
                    );
                    inc_new_counter_error!("bank-burned_fee_lamports", deposit as usize);
                    burn += deposit;
                }
            }
            self.capitalization.fetch_sub(burn, Relaxed);
        }
    }

    pub fn rehash(&self) {
        let mut hash = self.hash.write().unwrap();
        let new = self.hash_internal_state();
        if new != *hash {
            warn!("Updating bank hash to {}", new);
            *hash = new;
        }
    }

    pub fn freeze(&self) {
        // This lock prevents any new commits from BankingStage
        // `process_and_record_transactions_locked()` from coming
        // in after the last tick is observed. This is because in
        // BankingStage, any transaction successfully recorded in
        // `record_transactions()` is recorded after this `hash` lock
        // is grabbed. At the time of the successful record,
        // this means the PoH has not yet reached the last tick,
        // so this means freeze() hasn't been called yet. And because
        // BankingStage doesn't release this hash lock until both
        // record and commit are finished, those transactions will be
        // committed before this write lock can be obtained here.
        let mut hash = self.hash.write().unwrap();
        if *hash == Hash::default() {
            // finish up any deferred changes to account state
            self.collect_rent_eagerly();
            self.collect_fees();
            self.distribute_rent();
            self.update_slot_history();
            self.run_incinerator();

            // freeze is a one-way trip, idempotent
            self.freeze_started.store(true, Relaxed);
            *hash = self.hash_internal_state();
            self.rc.accounts.accounts_db.mark_slot_frozen(self.slot());
        }
    }

    // Should not be called outside of startup, will race with
    // concurrent cleaning logic in AccountsBackgroundService
    pub fn exhaustively_free_unused_resource(&self) {
        let mut flush = Measure::start("flush");
        // Flush all the rooted accounts. Must be called after `squash()`,
        // so that AccountsDb knows what the roots are.
        self.force_flush_accounts_cache();
        flush.stop();

        let mut clean = Measure::start("clean");
        // Don't clean the slot we're snapshotting because it may have zero-lamport
        // accounts that were included in the bank delta hash when the bank was frozen,
        // and if we clean them here, any newly created snapshot's hash for this bank
        // may not match the frozen hash.
        self.clean_accounts(true, false);
        clean.stop();

        let mut shrink = Measure::start("shrink");
        self.shrink_all_slots(false);
        shrink.stop();

        info!(
            "exhaustively_free_unused_resource() {} {} {}",
            flush, clean, shrink,
        );
    }

    pub fn epoch_schedule(&self) -> &EpochSchedule {
        &self.epoch_schedule
    }

    /// squash the parent's state up into this Bank,
    ///   this Bank becomes a root
    pub fn squash(&self) {
        self.freeze();

        //this bank and all its parents are now on the rooted path
        let mut roots = vec![self.slot()];
        roots.append(&mut self.parents().iter().map(|p| p.slot()).collect());

        let mut squash_accounts_time = Measure::start("squash_accounts_time");
        for slot in roots.iter().rev() {
            // root forks cannot be purged
            self.rc.accounts.add_root(*slot);
        }
        squash_accounts_time.stop();

        *self.rc.parent.write().unwrap() = None;

        let mut squash_cache_time = Measure::start("squash_cache_time");
        roots
            .iter()
            .for_each(|slot| self.src.status_cache.write().unwrap().add_root(*slot));
        squash_cache_time.stop();

        datapoint_debug!(
            "tower-observed",
            ("squash_accounts_ms", squash_accounts_time.as_ms(), i64),
            ("squash_cache_ms", squash_cache_time.as_ms(), i64)
        );
    }

    /// Return the more recent checkpoint of this bank instance.
    pub fn parent(&self) -> Option<Arc<Bank>> {
        self.rc.parent.read().unwrap().clone()
    }

    pub fn parent_slot(&self) -> Slot {
        self.parent_slot
    }

    pub fn parent_hash(&self) -> Hash {
        self.parent_hash
    }

    fn process_genesis_config(&mut self, genesis_config: &GenesisConfig) {
        // Bootstrap validator collects fees until `new_from_parent` is called.
        self.fee_rate_governor = genesis_config.fee_rate_governor.clone();
        self.fee_calculator = self.fee_rate_governor.create_fee_calculator();

        for (pubkey, account) in genesis_config.accounts.iter() {
            if self.get_account(pubkey).is_some() {
                panic!("{} repeated in genesis config", pubkey);
            }
            self.store_account(pubkey, &AccountSharedData::from(account.clone()));
            self.capitalization.fetch_add(account.lamports(), Relaxed);
        }
        // updating sysvars (the fees sysvar in this case) now depends on feature activations in
        // genesis_config.accounts above
        self.update_fees();

        for (pubkey, account) in genesis_config.rewards_pools.iter() {
            if self.get_account(pubkey).is_some() {
                panic!("{} repeated in genesis config", pubkey);
            }
            self.store_account(pubkey, &AccountSharedData::from(account.clone()));
        }

        // highest staked node is the first collector
        self.collector_id = self
            .stakes
            .read()
            .unwrap()
            .highest_staked_node()
            .unwrap_or_default();

        self.blockhash_queue
            .write()
            .unwrap()
            .genesis_hash(&genesis_config.hash(), &self.fee_calculator);

        self.hashes_per_tick = genesis_config.hashes_per_tick();
        self.ticks_per_slot = genesis_config.ticks_per_slot();
        self.ns_per_slot = genesis_config.ns_per_slot();
        self.genesis_creation_time = genesis_config.creation_time;
        self.unused = genesis_config.unused;
        self.max_tick_height = (self.slot + 1) * self.ticks_per_slot;
        self.slots_per_year = genesis_config.slots_per_year();

        self.epoch_schedule = genesis_config.epoch_schedule;

        self.inflation = Arc::new(RwLock::new(genesis_config.inflation));

        self.rent_collector = RentCollector::new(
            self.epoch,
            &self.epoch_schedule,
            self.slots_per_year,
            &genesis_config.rent,
        );

        // Add additional native programs specified in the genesis config
        for (name, program_id) in &genesis_config.native_instruction_processors {
            self.add_native_program(name, program_id, false);
        }
    }

    // NOTE: must hold idempotent for the same set of arguments
    pub fn add_native_program(&self, name: &str, program_id: &Pubkey, must_replace: bool) {
        let existing_genuine_program =
            if let Some(mut account) = self.get_account_with_fixed_root(program_id) {
                // it's very unlikely to be squatted at program_id as non-system account because of burden to
                // find victim's pubkey/hash. So, when account.owner is indeed native_loader's, it's
                // safe to assume it's a genuine program.
                if native_loader::check_id(account.owner()) {
                    Some(account)
                } else {
                    // malicious account is pre-occupying at program_id
                    // forcibly burn and purge it

                    self.capitalization.fetch_sub(account.lamports(), Relaxed);

                    // Resetting account balance to 0 is needed to really purge from AccountsDb and
                    // flush the Stakes cache
                    account.set_lamports(0);
                    self.store_account(program_id, &account);
                    None
                }
            } else {
                None
            };

        if must_replace {
            // updating native program

            match &existing_genuine_program {
                None => panic!(
                    "There is no account to replace with native program ({}, {}).",
                    name, program_id
                ),
                Some(account) => {
                    if *name == String::from_utf8_lossy(account.data()) {
                        // nop; it seems that already AccountsDb is updated.
                        return;
                    }
                    // continue to replace account
                }
            }
        } else {
            // introducing native program

            match &existing_genuine_program {
                None => (), // continue to add account
                Some(_account) => {
                    // nop; it seems that we already have account

                    // before returning here to retain idempotent just make sure
                    // the existing native program name is same with what we're
                    // supposed to add here (but skipping) But I can't:
                    // following assertion already catches several different names for same
                    // program_id
                    // depending on clusters...
                    // assert_eq!(name.to_owned(), String::from_utf8_lossy(&account.data));
                    return;
                }
            }
        }

        assert!(
            !self.freeze_started(),
            "Can't change frozen bank by adding not-existing new native program ({}, {}). \
            Maybe, inconsistent program activation is detected on snapshot restore?",
            name,
            program_id
        );

        // Add a bogus executable native account, which will be loaded and ignored.
        let account = native_loader::create_loadable_account_with_fields(
            name,
            self.inherit_specially_retained_account_fields(&existing_genuine_program),
        );
        self.store_account_and_update_capitalization(program_id, &account);

        debug!("Added native program {} under {:?}", name, program_id);
    }

    pub fn set_rent_burn_percentage(&mut self, burn_percent: u8) {
        self.rent_collector.rent.burn_percent = burn_percent;
    }

    pub fn set_hashes_per_tick(&mut self, hashes_per_tick: Option<u64>) {
        self.hashes_per_tick = hashes_per_tick;
    }

    /// Return the last block hash registered.
    pub fn last_blockhash(&self) -> Hash {
        self.blockhash_queue.read().unwrap().last_hash()
    }

    pub fn get_minimum_balance_for_rent_exemption(&self, data_len: usize) -> u64 {
        self.rent_collector.rent.minimum_balance(data_len)
    }

    pub fn last_blockhash_with_fee_calculator(&self) -> (Hash, FeeCalculator) {
        let blockhash_queue = self.blockhash_queue.read().unwrap();
        let last_hash = blockhash_queue.last_hash();
        (
            last_hash,
            blockhash_queue
                .get_fee_calculator(&last_hash)
                .unwrap()
                .clone(),
        )
    }

    pub fn get_fee_calculator(&self, hash: &Hash) -> Option<FeeCalculator> {
        let blockhash_queue = self.blockhash_queue.read().unwrap();
        blockhash_queue.get_fee_calculator(hash).cloned()
    }

    pub fn get_fee_rate_governor(&self) -> &FeeRateGovernor {
        &self.fee_rate_governor
    }

    // DEPRECATED
    pub fn get_blockhash_last_valid_slot(&self, blockhash: &Hash) -> Option<Slot> {
        let blockhash_queue = self.blockhash_queue.read().unwrap();
        // This calculation will need to be updated to consider epoch boundaries if BlockhashQueue
        // length is made variable by epoch
        blockhash_queue
            .get_hash_age(blockhash)
            .map(|age| self.slot + blockhash_queue.len() as u64 - age)
    }

    pub fn get_blockhash_last_valid_block_height(&self, blockhash: &Hash) -> Option<Slot> {
        let blockhash_queue = self.blockhash_queue.read().unwrap();
        // This calculation will need to be updated to consider epoch boundaries if BlockhashQueue
        // length is made variable by epoch
        blockhash_queue
            .get_hash_age(blockhash)
            .map(|age| self.block_height + blockhash_queue.len() as u64 - age)
    }

    pub fn confirmed_last_blockhash(&self) -> (Hash, FeeCalculator) {
        const NUM_BLOCKHASH_CONFIRMATIONS: usize = 3;

        let parents = self.parents();
        if parents.is_empty() {
            self.last_blockhash_with_fee_calculator()
        } else {
            let index = NUM_BLOCKHASH_CONFIRMATIONS.min(parents.len() - 1);
            parents[index].last_blockhash_with_fee_calculator()
        }
    }

    /// Forget all signatures. Useful for benchmarking.
    pub fn clear_signatures(&self) {
        self.src.status_cache.write().unwrap().clear();
    }

    pub fn clear_slot_signatures(&self, slot: Slot) {
        self.src
            .status_cache
            .write()
            .unwrap()
            .clear_slot_entries(slot);
    }

    pub fn can_commit(result: &Result<()>) -> bool {
        match result {
            Ok(_) => true,
            Err(TransactionError::InstructionError(_, _)) => true,
            Err(_) => false,
        }
    }

    fn update_transaction_statuses(
        &self,
        sanitized_txs: &[SanitizedTransaction],
        res: &[TransactionExecutionResult],
    ) {
        let mut status_cache = self.src.status_cache.write().unwrap();
        assert_eq!(sanitized_txs.len(), res.len());
        for (tx, (res, _nonce_rollback)) in sanitized_txs.iter().zip(res) {
            if Self::can_commit(res) && !tx.signatures.is_empty() {
                // Add the message hash to the status cache to ensure that this message
                // won't be processed again with a different signature.
                status_cache.insert(
                    &tx.message().recent_blockhash,
                    &tx.message_hash,
                    self.slot(),
                    res.clone(),
                );
                // Add the transaction signature to the status cache so that transaction status
                // can be queried by transaction signature over RPC. In the future, this should
                // only be added for API nodes because voting validators don't need to do this.
                status_cache.insert(
                    &tx.message().recent_blockhash,
                    &tx.signatures[0],
                    self.slot(),
                    res.clone(),
                );
            }
        }
    }

    /// Tell the bank which Entry IDs exist on the ledger. This function
    /// assumes subsequent calls correspond to later entries, and will boot
    /// the oldest ones once its internal cache is full. Once boot, the
    /// bank will reject transactions using that `hash`.
    pub fn register_tick(&self, hash: &Hash) {
        assert!(
            !self.freeze_started(),
            "register_tick() working on a bank that is already frozen or is undergoing freezing!"
        );

        inc_new_counter_debug!("bank-register_tick-registered", 1);
        let mut w_blockhash_queue = self.blockhash_queue.write().unwrap();
        if self.is_block_boundary(self.tick_height.load(Relaxed) + 1) {
            w_blockhash_queue.register_hash(hash, &self.fee_calculator);
            if self.fix_recent_blockhashes_sysvar_delay() {
                self.update_recent_blockhashes_locked(&w_blockhash_queue);
            }
        }
        // ReplayStage will start computing the accounts delta hash when it
        // detects the tick height has reached the boundary, so the system
        // needs to guarantee all account updates for the slot have been
        // committed before this tick height is incremented (like the blockhash
        // sysvar above)
        self.tick_height.fetch_add(1, Relaxed);
    }

    pub fn is_complete(&self) -> bool {
        self.tick_height() == self.max_tick_height()
    }

    pub fn is_block_boundary(&self, tick_height: u64) -> bool {
        tick_height % self.ticks_per_slot == 0
    }

    pub fn prepare_batch<'a, 'b>(
        &'a self,
        txs: impl Iterator<Item = &'b Transaction>,
    ) -> Result<TransactionBatch<'a, 'b>> {
        let sanitized_txs: Vec<SanitizedTransaction> = txs
            .map(SanitizedTransaction::try_from)
            .collect::<Result<_>>()?;
        let lock_results = self
            .rc
            .accounts
            .lock_accounts(sanitized_txs.as_transactions_iter());
        Ok(TransactionBatch::new(
            lock_results,
            self,
            Cow::Owned(sanitized_txs),
        ))
    }

    pub fn prepare_sanitized_batch<'a, 'b>(
        &'a self,
        sanitized_txs: &'b [SanitizedTransaction],
    ) -> TransactionBatch<'a, 'b> {
        let lock_results = self
            .rc
            .accounts
            .lock_accounts(sanitized_txs.as_transactions_iter());
        TransactionBatch::new(lock_results, self, Cow::Borrowed(sanitized_txs))
    }

    pub(crate) fn prepare_simulation_batch<'a, 'b>(
        &'a self,
        transaction: SanitizedTransaction<'b>,
    ) -> TransactionBatch<'a, 'b> {
        let mut batch = TransactionBatch::new(vec![Ok(())], self, Cow::Owned(vec![transaction]));
        batch.needs_unlock = false;
        batch
    }

    /// Run transactions against a frozen bank without committing the results
    pub fn simulate_transaction(&self, transaction: &Transaction) -> TransactionSimulationResult {
        assert!(self.is_frozen(), "simulation bank must be frozen");

        let batch = match SanitizedTransaction::try_from(transaction) {
            Ok(sanitized_tx) => self.prepare_simulation_batch(sanitized_tx),
            Err(err) => {
                return TransactionSimulationResult {
                    result: Err(err),
                    logs: vec![],
                    post_simulation_accounts: vec![],
                    units_consumed: 0,
                }
            }
        };

        let mut timings = ExecuteTimings::default();

        let (
            loaded_transactions,
            executed,
            _inner_instructions,
            logs,
            _retryable_transactions,
            _transaction_count,
            _signature_count,
        ) = self.load_and_execute_transactions(
            &batch,
            // After simulation, transactions will need to be forwarded to the leader
            // for processing. During forwarding, the transaction could expire if the
            // delay is not accounted for.
            MAX_PROCESSING_AGE - MAX_TRANSACTION_FORWARDING_DELAY,
            false,
            true,
            &mut timings,
        );

        let result = executed[0].0.clone().map(|_| ());
        let logs = logs.get(0).cloned().flatten().unwrap_or_default();
        let post_simulation_accounts = loaded_transactions
            .into_iter()
            .next()
            .unwrap()
            .0
            .ok()
            .map(|loaded_transaction| loaded_transaction.accounts.into_iter().collect::<Vec<_>>())
            .unwrap_or_default();

        let units_consumed = timings
            .details
            .per_program_timings
            .iter()
            .fold(0, |acc, (_, program_timing)| {
                acc + program_timing.accumulated_units
            });

        debug!("simulate_transaction: {:?}", timings);

        TransactionSimulationResult {
            result,
            logs,
            post_simulation_accounts,
            units_consumed,
        }
    }

    pub fn unlock_accounts(&self, batch: &mut TransactionBatch) {
        if batch.needs_unlock {
            batch.needs_unlock = false;
            self.rc
                .accounts
                .unlock_accounts(batch.transactions_iter(), batch.lock_results())
        }
    }

    pub fn remove_unrooted_slots(&self, slots: &[(Slot, BankId)]) {
        self.rc.accounts.accounts_db.remove_unrooted_slots(slots)
    }

    pub fn set_shrink_paths(&self, paths: Vec<PathBuf>) {
        self.rc.accounts.accounts_db.set_shrink_paths(paths);
    }

    fn check_age<'a>(
        &self,
        txs: impl Iterator<Item = &'a Transaction>,
        lock_results: Vec<Result<()>>,
        max_age: usize,
        error_counters: &mut ErrorCounters,
    ) -> Vec<TransactionCheckResult> {
        let hash_queue = self.blockhash_queue.read().unwrap();
        txs.zip(lock_results)
            .map(|(tx, lock_res)| match lock_res {
                Ok(()) => {
                    let message = tx.message();
                    let hash_age = hash_queue.check_hash_age(&message.recent_blockhash, max_age);
                    if hash_age == Some(true) {
                        (Ok(()), None)
                    } else if let Some((pubkey, acc)) = self.check_tx_durable_nonce(tx) {
                        (Ok(()), Some(NonceRollbackPartial::new(pubkey, acc)))
                    } else if hash_age == Some(false) {
                        error_counters.blockhash_too_old += 1;
                        (Err(TransactionError::BlockhashNotFound), None)
                    } else {
                        error_counters.blockhash_not_found += 1;
                        (Err(TransactionError::BlockhashNotFound), None)
                    }
                }
                Err(e) => (Err(e), None),
            })
            .collect()
    }

    fn is_tx_already_processed(
        &self,
        sanitized_tx: &SanitizedTransaction,
        status_cache: &StatusCache<Result<()>>,
    ) -> bool {
        let key = &sanitized_tx.message_hash;
        let transaction_blockhash = &sanitized_tx.message().recent_blockhash;
        status_cache
            .get_status(key, transaction_blockhash, &self.ancestors)
            .is_some()
    }

    fn check_status_cache(
        &self,
        sanitized_txs: &[SanitizedTransaction],
        lock_results: Vec<TransactionCheckResult>,
        error_counters: &mut ErrorCounters,
    ) -> Vec<TransactionCheckResult> {
        let rcache = self.src.status_cache.read().unwrap();
        sanitized_txs
            .iter()
            .zip(lock_results)
            .map(|(sanitized_tx, (lock_res, nonce_rollback))| {
                if lock_res.is_ok() && self.is_tx_already_processed(sanitized_tx, &rcache) {
                    error_counters.already_processed += 1;
                    return (Err(TransactionError::AlreadyProcessed), None);
                }

                (lock_res, nonce_rollback)
            })
            .collect()
    }

    fn filter_by_vote_transactions<'a>(
        &self,
        txs: impl Iterator<Item = &'a Transaction>,
        lock_results: Vec<TransactionCheckResult>,
        error_counters: &mut ErrorCounters,
    ) -> Vec<TransactionCheckResult> {
        txs.zip(lock_results)
            .map(|(tx, lock_res)| {
                if lock_res.0.is_ok() {
                    if is_simple_vote_transaction(tx) {
                        return lock_res;
                    }

                    error_counters.not_allowed_during_cluster_maintenance += 1;
                    return (Err(TransactionError::ClusterMaintenance), lock_res.1);
                }
                lock_res
            })
            .collect()
    }

    pub fn check_hash_age(&self, hash: &Hash, max_age: usize) -> Option<bool> {
        self.blockhash_queue
            .read()
            .unwrap()
            .check_hash_age(hash, max_age)
    }

    pub fn check_tx_durable_nonce(&self, tx: &Transaction) -> Option<(Pubkey, AccountSharedData)> {
        transaction::uses_durable_nonce(tx)
            .and_then(|nonce_ix| transaction::get_nonce_pubkey_from_instruction(nonce_ix, tx))
            .and_then(|nonce_pubkey| {
                self.get_account(nonce_pubkey)
                    .map(|acc| (*nonce_pubkey, acc))
            })
            .filter(|(_pubkey, nonce_account)| {
                nonce_account::verify_nonce_account(nonce_account, &tx.message().recent_blockhash)
            })
    }

    // Determine if the bank is currently in an upgrade epoch, where only votes are permitted
    fn upgrade_epoch(&self) -> bool {
        match self.cluster_type() {
            #[cfg(test)]
            ClusterType::Development => self.epoch == 0xdead, // Value assumed by `test_upgrade_epoch()`
            #[cfg(not(test))]
            ClusterType::Development => false,
            ClusterType::Devnet => false,
            ClusterType::Testnet => false,
            ClusterType::MainnetBeta => self.epoch == 61,
        }
    }

    pub fn check_transactions(
        &self,
        sanitized_txs: &[SanitizedTransaction],
        lock_results: &[Result<()>],
        max_age: usize,
        mut error_counters: &mut ErrorCounters,
    ) -> Vec<TransactionCheckResult> {
        let age_results = self.check_age(
            sanitized_txs.as_transactions_iter(),
            lock_results.to_vec(),
            max_age,
            &mut error_counters,
        );
        let cache_results =
            self.check_status_cache(sanitized_txs, age_results, &mut error_counters);
        if self.upgrade_epoch() {
            // Reject all non-vote transactions
            self.filter_by_vote_transactions(
                sanitized_txs.as_transactions_iter(),
                cache_results,
                &mut error_counters,
            )
        } else {
            cache_results
        }
    }

    pub fn collect_balances(&self, batch: &TransactionBatch) -> TransactionBalances {
        let mut balances: TransactionBalances = vec![];
        for transaction in batch.transactions_iter() {
            let mut transaction_balances: Vec<u64> = vec![];
            for account_key in transaction.message.account_keys.iter() {
                transaction_balances.push(self.get_balance(account_key));
            }
            balances.push(transaction_balances);
        }
        balances
    }

    #[allow(clippy::cognitive_complexity)]
    fn update_error_counters(error_counters: &ErrorCounters) {
        if 0 != error_counters.total {
            inc_new_counter_info!(
                "bank-process_transactions-error_count",
                error_counters.total
            );
        }
        if 0 != error_counters.account_not_found {
            inc_new_counter_info!(
                "bank-process_transactions-account_not_found",
                error_counters.account_not_found
            );
        }
        if 0 != error_counters.account_in_use {
            inc_new_counter_info!(
                "bank-process_transactions-account_in_use",
                error_counters.account_in_use
            );
        }
        if 0 != error_counters.account_loaded_twice {
            inc_new_counter_info!(
                "bank-process_transactions-account_loaded_twice",
                error_counters.account_loaded_twice
            );
        }
        if 0 != error_counters.blockhash_not_found {
            inc_new_counter_info!(
                "bank-process_transactions-error-blockhash_not_found",
                error_counters.blockhash_not_found
            );
        }
        if 0 != error_counters.blockhash_too_old {
            inc_new_counter_info!(
                "bank-process_transactions-error-blockhash_too_old",
                error_counters.blockhash_too_old
            );
        }
        if 0 != error_counters.invalid_account_index {
            inc_new_counter_info!(
                "bank-process_transactions-error-invalid_account_index",
                error_counters.invalid_account_index
            );
        }
        if 0 != error_counters.invalid_account_for_fee {
            inc_new_counter_info!(
                "bank-process_transactions-error-invalid_account_for_fee",
                error_counters.invalid_account_for_fee
            );
        }
        if 0 != error_counters.insufficient_funds {
            inc_new_counter_info!(
                "bank-process_transactions-error-insufficient_funds",
                error_counters.insufficient_funds
            );
        }
        if 0 != error_counters.instruction_error {
            inc_new_counter_info!(
                "bank-process_transactions-error-instruction_error",
                error_counters.instruction_error
            );
        }
        if 0 != error_counters.already_processed {
            inc_new_counter_info!(
                "bank-process_transactions-error-already_processed",
                error_counters.already_processed
            );
        }
        if 0 != error_counters.not_allowed_during_cluster_maintenance {
            inc_new_counter_info!(
                "bank-process_transactions-error-cluster-maintenance",
                error_counters.not_allowed_during_cluster_maintenance
            );
        }
    }

    /// Converts Accounts into RefCell<AccountSharedData>, this involves moving
    /// ownership by draining the source
    fn accounts_to_refcells(
        accounts: &mut TransactionAccounts,
        loaders: &mut TransactionLoaders,
    ) -> (TransactionAccountRefCells, TransactionLoaderRefCells) {
        let account_refcells: Vec<_> = accounts
            .drain(..)
            .map(|(pubkey, account)| (pubkey, Rc::new(RefCell::new(account))))
            .collect();
        let loader_refcells: Vec<Vec<_>> = loaders
            .iter_mut()
            .map(|v| {
                v.drain(..)
                    .map(|(pubkey, account)| (pubkey, Rc::new(RefCell::new(account))))
                    .collect()
            })
            .collect();
        (account_refcells, loader_refcells)
    }

    /// Converts back from RefCell<AccountSharedData> to AccountSharedData, this involves moving
    /// ownership by draining the sources
    fn refcells_to_accounts(
        accounts: &mut TransactionAccounts,
        loaders: &mut TransactionLoaders,
        mut account_refcells: TransactionAccountRefCells,
        loader_refcells: TransactionLoaderRefCells,
    ) -> std::result::Result<(), TransactionError> {
        for (pubkey, account_refcell) in account_refcells.drain(..) {
            accounts.push((
                pubkey,
                Rc::try_unwrap(account_refcell)
                    .map_err(|_| TransactionError::AccountBorrowOutstanding)?
                    .into_inner(),
            ))
        }
        for (ls, mut lrcs) in loaders.iter_mut().zip(loader_refcells) {
            for (pubkey, lrc) in lrcs.drain(..) {
                ls.push((
                    pubkey,
                    Rc::try_unwrap(lrc)
                        .map_err(|_| TransactionError::AccountBorrowOutstanding)?
                        .into_inner(),
                ))
            }
        }

        Ok(())
    }

    fn collect_log_messages(
        log_collector: Option<Rc<LogCollector>>,
    ) -> Option<TransactionLogMessages> {
        log_collector.and_then(|log_collector| Rc::try_unwrap(log_collector).map(Into::into).ok())
    }

    fn compile_recorded_instructions(
        instruction_recorders: Option<Vec<InstructionRecorder>>,
        message: &Message,
    ) -> Option<InnerInstructionsList> {
        instruction_recorders.map(|instruction_recorders| {
            instruction_recorders
                .into_iter()
                .map(|r| r.compile_instructions(message))
                .collect()
        })
    }

    /// Get any cached executors needed by the transaction
    fn get_executors(
        &self,
        message: &Message,
        loaders: &[Vec<(Pubkey, AccountSharedData)>],
    ) -> Rc<RefCell<Executors>> {
        let mut num_executors = message.account_keys.len();
        for instruction_loaders in loaders.iter() {
            num_executors += instruction_loaders.len();
        }
        let mut executors = HashMap::with_capacity(num_executors);
        let cow_cache = self.cached_executors.read().unwrap();
        let cache = cow_cache.read().unwrap();

        for key in message.account_keys.iter() {
            if let Some(executor) = cache.get(key) {
                executors.insert(*key, executor);
            }
        }
        for instruction_loaders in loaders.iter() {
            for (key, _) in instruction_loaders.iter() {
                if let Some(executor) = cache.get(key) {
                    executors.insert(*key, executor);
                }
            }
        }

        Rc::new(RefCell::new(Executors {
            executors,
            is_dirty: false,
        }))
    }

    /// Add executors back to the bank's cache if modified
    fn update_executors(&self, executors: Rc<RefCell<Executors>>) {
        let executors = executors.borrow();
        if executors.is_dirty {
            let mut cow_cache = self.cached_executors.write().unwrap();
            let mut cache = cow_cache.write().unwrap();
            for (key, executor) in executors.executors.iter() {
                cache.put(key, (*executor).clone());
            }
        }
    }

    /// Remove an executor from the bank's cache
    pub fn remove_executor(&self, pubkey: &Pubkey) {
        let mut cow_cache = self.cached_executors.write().unwrap();
        let mut cache = cow_cache.write().unwrap();
        cache.remove(pubkey);
    }

    #[allow(clippy::type_complexity)]
    pub fn load_and_execute_transactions(
        &self,
        batch: &TransactionBatch,
        max_age: usize,
        enable_cpi_recording: bool,
        enable_log_recording: bool,
        timings: &mut ExecuteTimings,
    ) -> (
        Vec<TransactionLoadResult>,
        Vec<TransactionExecutionResult>,
        Vec<Option<InnerInstructionsList>>,
        Vec<Option<TransactionLogMessages>>,
        Vec<usize>,
        u64,
        u64,
    ) {
        let sanitized_txs = batch.sanitized_transactions();
        debug!("processing transactions: {}", sanitized_txs.len());
        inc_new_counter_info!("bank-process_transactions", sanitized_txs.len());
        let mut error_counters = ErrorCounters::default();

        let retryable_txs: Vec<_> = batch
            .lock_results()
            .iter()
            .enumerate()
            .filter_map(|(index, res)| match res {
                Err(TransactionError::AccountInUse) => {
                    error_counters.account_in_use += 1;
                    Some(index)
                }
                Err(_) => None,
                Ok(_) => None,
            })
            .collect();

        let mut check_time = Measure::start("check_transactions");
        let check_results = self.check_transactions(
            sanitized_txs,
            batch.lock_results(),
            max_age,
            &mut error_counters,
        );
        check_time.stop();

        let mut load_time = Measure::start("accounts_load");
        let mut loaded_txs = self.rc.accounts.load_accounts(
            &self.ancestors,
            sanitized_txs.as_transactions_iter(),
            check_results,
            &self.blockhash_queue.read().unwrap(),
            &mut error_counters,
            &self.rent_collector,
            &self.feature_set,
        );
        load_time.stop();

        let mut execution_time = Measure::start("execution_time");
        let mut signature_count: u64 = 0;
        let mut inner_instructions: Vec<Option<InnerInstructionsList>> =
            Vec::with_capacity(sanitized_txs.len());
        let mut transaction_log_messages: Vec<Option<Vec<String>>> =
            Vec::with_capacity(sanitized_txs.len());

        let executed: Vec<TransactionExecutionResult> = loaded_txs
            .iter_mut()
            .zip(sanitized_txs.as_transactions_iter())
            .map(|(accs, tx)| match accs {
                (Err(e), _nonce_rollback) => {
                    transaction_log_messages.push(None);
                    inner_instructions.push(None);
                    (Err(e.clone()), None)
                }
                (Ok(loaded_transaction), nonce_rollback) => {
                    let feature_set = self.feature_set.clone();
                    signature_count += u64::from(tx.message().header.num_required_signatures);

                    let mut bpf_compute_budget = self
                        .bpf_compute_budget
                        .unwrap_or_else(BpfComputeBudget::new);

                    let mut process_result = if feature_set.is_active(&tx_wide_compute_cap::id()) {
                        compute_budget::process_request(&mut bpf_compute_budget, tx)
                    } else {
                        Ok(())
                    };

                    if process_result.is_ok() {
                        let executors =
                            self.get_executors(&tx.message, &loaded_transaction.loaders);

                        let (account_refcells, loader_refcells) = Self::accounts_to_refcells(
                            &mut loaded_transaction.accounts,
                            &mut loaded_transaction.loaders,
                        );

                        let instruction_recorders = if enable_cpi_recording {
                            let ix_count = tx.message.instructions.len();
                            let mut recorders = Vec::with_capacity(ix_count);
                            recorders.resize_with(ix_count, InstructionRecorder::default);
                            Some(recorders)
                        } else {
                            None
                        };

                        let log_collector = if enable_log_recording {
                            Some(Rc::new(LogCollector::default()))
                        } else {
                            None
                        };

                        let compute_meter = Rc::new(RefCell::new(TransactionComputeMeter::new(
                            bpf_compute_budget.max_units,
                        )));

                        process_result = self.message_processor.process_message(
                            tx.message(),
                            &loader_refcells,
                            &account_refcells,
                            &self.rent_collector,
                            log_collector.clone(),
                            executors.clone(),
                            instruction_recorders.as_deref(),
                            feature_set,
                            bpf_compute_budget,
                            compute_meter,
                            &mut timings.details,
                            self.rc.accounts.clone(),
                            &self.ancestors,
                        );

                        transaction_log_messages.push(Self::collect_log_messages(log_collector));
                        inner_instructions.push(Self::compile_recorded_instructions(
                            instruction_recorders,
                            &tx.message,
                        ));

                        if let Err(e) = Self::refcells_to_accounts(
                            &mut loaded_transaction.accounts,
                            &mut loaded_transaction.loaders,
                            account_refcells,
                            loader_refcells,
                        ) {
                            warn!("Account lifetime mismanagement");
                            process_result = Err(e);
                        }

                        if process_result.is_ok() {
                            self.update_executors(executors);
                        }
                    } else {
                        transaction_log_messages.push(None);
                        inner_instructions.push(None);
                    }

                    let nonce_rollback =
                        if let Err(TransactionError::InstructionError(_, _)) = &process_result {
                            error_counters.instruction_error += 1;
                            nonce_rollback.clone()
                        } else if process_result.is_err() {
                            None
                        } else {
                            nonce_rollback.clone()
                        };
                    (process_result, nonce_rollback)
                }
            })
            .collect();

        execution_time.stop();

        debug!(
            "check: {}us load: {}us execute: {}us txs_len={}",
            check_time.as_us(),
            load_time.as_us(),
            execution_time.as_us(),
            sanitized_txs.len(),
        );
        timings.check_us += check_time.as_us();
        timings.load_us += load_time.as_us();
        timings.execute_us += execution_time.as_us();

        let mut tx_count: u64 = 0;
        let err_count = &mut error_counters.total;
        let transaction_log_collector_config =
            self.transaction_log_collector_config.read().unwrap();

        for (i, ((r, _nonce_rollback), tx)) in executed.iter().zip(sanitized_txs).enumerate() {
            if let Some(debug_keys) = &self.transaction_debug_keys {
                for key in &tx.message.account_keys {
                    if debug_keys.contains(key) {
                        info!("slot: {} result: {:?} tx: {:?}", self.slot, r, tx);
                        break;
                    }
                }
            }

            if Self::can_commit(r) // Skip log collection for unprocessed transactions
                && transaction_log_collector_config.filter != TransactionLogCollectorFilter::None
            {
                let mut transaction_log_collector = self.transaction_log_collector.write().unwrap();
                let transaction_log_index = transaction_log_collector.logs.len();

                let mut mentioned_address = false;
                if !transaction_log_collector_config
                    .mentioned_addresses
                    .is_empty()
                {
                    for key in &tx.message.account_keys {
                        if transaction_log_collector_config
                            .mentioned_addresses
                            .contains(key)
                        {
                            transaction_log_collector
                                .mentioned_address_map
                                .entry(*key)
                                .or_default()
                                .push(transaction_log_index);
                            mentioned_address = true;
                        }
                    }
                }

                let is_vote = is_simple_vote_transaction(tx);
                let store = match transaction_log_collector_config.filter {
                    TransactionLogCollectorFilter::All => !is_vote || mentioned_address,
                    TransactionLogCollectorFilter::AllWithVotes => true,
                    TransactionLogCollectorFilter::None => false,
                    TransactionLogCollectorFilter::OnlyMentionedAddresses => mentioned_address,
                };

                if store {
                    if let Some(log_messages) = transaction_log_messages.get(i).cloned().flatten() {
                        transaction_log_collector.logs.push(TransactionLogInfo {
                            signature: tx.signatures[0],
                            result: r.clone(),
                            is_vote,
                            log_messages,
                        });
                    }
                }
            }

            if r.is_ok() {
                tx_count += 1;
            } else {
                if *err_count == 0 {
                    debug!("tx error: {:?} {:?}", r, tx);
                }
                *err_count += 1;
            }
        }
        if *err_count > 0 {
            debug!(
                "{} errors of {} txs",
                *err_count,
                *err_count as u64 + tx_count
            );
        }
        Self::update_error_counters(&error_counters);
        (
            loaded_txs,
            executed,
            inner_instructions,
            transaction_log_messages,
            retryable_txs,
            tx_count,
            signature_count,
        )
    }

    fn filter_program_errors_and_collect_fee<'a>(
        &self,
        txs: impl Iterator<Item = &'a Transaction>,
        executed: &[TransactionExecutionResult],
    ) -> Vec<Result<()>> {
        let hash_queue = self.blockhash_queue.read().unwrap();
        let mut fees = 0;

        let results = txs
            .zip(executed)
            .map(|(tx, (res, nonce_rollback))| {
                let (fee_calculator, is_durable_nonce) = nonce_rollback
                    .as_ref()
                    .map(|nonce_rollback| nonce_rollback.fee_calculator())
                    .map(|maybe_fee_calculator| (maybe_fee_calculator, true))
                    .unwrap_or_else(|| {
                        (
                            hash_queue
                                .get_fee_calculator(&tx.message().recent_blockhash)
                                .cloned(),
                            false,
                        )
                    });
                let fee_calculator = fee_calculator.ok_or(TransactionError::BlockhashNotFound)?;

                let fee = fee_calculator.calculate_fee(tx.message());

                let message = tx.message();
                match *res {
                    Err(TransactionError::InstructionError(_, _)) => {
                        // credit the transaction fee even in case of InstructionError
                        // necessary to withdraw from account[0] here because previous
                        // work of doing so (in accounts.load()) is ignored by store_account()
                        //
                        // ...except nonce accounts, which will have their post-load,
                        // pre-execute account state stored
                        if !is_durable_nonce {
                            self.withdraw(&message.account_keys[0], fee)?;
                        }
                        fees += fee;
                        Ok(())
                    }
                    Ok(()) => {
                        fees += fee;
                        Ok(())
                    }
                    _ => res.clone(),
                }
            })
            .collect();

        self.collector_fees.fetch_add(fees, Relaxed);
        results
    }

    pub fn commit_transactions(
        &self,
        sanitized_txs: &[SanitizedTransaction],
        loaded_txs: &mut [TransactionLoadResult],
        executed: &[TransactionExecutionResult],
        tx_count: u64,
        signature_count: u64,
        timings: &mut ExecuteTimings,
    ) -> TransactionResults {
        assert!(
            !self.freeze_started(),
            "commit_transactions() working on a bank that is already frozen or is undergoing freezing!"
        );

        self.increment_transaction_count(tx_count);
        self.increment_signature_count(signature_count);

        inc_new_counter_info!("bank-process_transactions-txs", tx_count as usize);
        inc_new_counter_info!("bank-process_transactions-sigs", signature_count as usize);

        if !sanitized_txs.is_empty() {
            let processed_tx_count = sanitized_txs.len() as u64;
            let failed_tx_count = processed_tx_count.saturating_sub(tx_count);
            self.transaction_error_count
                .fetch_add(failed_tx_count, Relaxed);
            self.transaction_entries_count.fetch_add(1, Relaxed);
            self.transactions_per_entry_max
                .fetch_max(processed_tx_count, Relaxed);
        }

        if executed
            .iter()
            .any(|(res, _nonce_rollback)| Self::can_commit(res))
        {
            self.is_delta.store(true, Relaxed);
        }

        let mut write_time = Measure::start("write_time");
        self.rc.accounts.store_cached(
            self.slot(),
            sanitized_txs.as_transactions_iter(),
            executed,
            loaded_txs,
            &self.rent_collector,
            &self.last_blockhash_with_fee_calculator(),
            self.fix_recent_blockhashes_sysvar_delay(),
            self.rent_for_sysvars(),
        );
        let rent_debits = self.collect_rent(executed, loaded_txs);

        let overwritten_vote_accounts =
            self.update_cached_accounts(sanitized_txs.as_transactions_iter(), executed, loaded_txs);

        // once committed there is no way to unroll
        write_time.stop();
        debug!(
            "store: {}us txs_len={}",
            write_time.as_us(),
            sanitized_txs.len()
        );
        timings.store_us += write_time.as_us();
        self.update_transaction_statuses(sanitized_txs, executed);
        let fee_collection_results = self
            .filter_program_errors_and_collect_fee(sanitized_txs.as_transactions_iter(), executed);

        TransactionResults {
            fee_collection_results,
            execution_results: executed.to_vec(),
            overwritten_vote_accounts,
            rent_debits,
        }
    }

    // Distribute collected rent fees for this slot to staked validators (excluding stakers)
    // according to stake.
    //
    // The nature of rent fee is the cost of doing business, every validator has to hold (or have
    // access to) the same list of accounts, so we pay according to stake, which is a rough proxy for
    // value to the network.
    //
    // Currently, rent distribution doesn't consider given validator's uptime at all (this might
    // change). That's because rent should be rewarded for the storage resource utilization cost.
    // It's treated differently from transaction fees, which is for the computing resource
    // utilization cost.
    //
    // We can't use collector_id (which is rotated according to stake-weighted leader schedule)
    // as an approximation to the ideal rent distribution to simplify and avoid this per-slot
    // computation for the distribution (time: N log N, space: N acct. stores; N = # of
    // validators).
    // The reason is that rent fee doesn't need to be incentivized for throughput unlike transaction
    // fees
    //
    // Ref: collect_fees
    #[allow(clippy::needless_collect)]
    fn distribute_rent_to_validators<I>(&self, vote_accounts: I, rent_to_be_distributed: u64)
    where
        I: IntoIterator<Item = (Pubkey, (u64, ArcVoteAccount))>,
    {
        let mut total_staked = 0;

        // Collect the stake associated with each validator.
        // Note that a validator may be present in this vector multiple times if it happens to have
        // more than one staked vote account somehow
        let mut validator_stakes = vote_accounts
            .into_iter()
            .filter_map(|(_vote_pubkey, (staked, account))| {
                if staked == 0 {
                    None
                } else {
                    total_staked += staked;
                    let node_pubkey = account.vote_state().as_ref().ok()?.node_pubkey;
                    Some((node_pubkey, staked))
                }
            })
            .collect::<Vec<(Pubkey, u64)>>();

        #[cfg(test)]
        if validator_stakes.is_empty() {
            // some tests bank.freezes() with bad staking state
            self.capitalization
                .fetch_sub(rent_to_be_distributed, Relaxed);
            return;
        }
        #[cfg(not(test))]
        assert!(!validator_stakes.is_empty());

        // Sort first by stake and then by validator identity pubkey for determinism
        validator_stakes.sort_by(|(pubkey1, staked1), (pubkey2, staked2)| {
            match staked2.cmp(staked1) {
                std::cmp::Ordering::Equal => pubkey2.cmp(pubkey1),
                other => other,
            }
        });

        let enforce_fix = self.no_overflow_rent_distribution_enabled();

        let mut rent_distributed_in_initial_round = 0;
        let validator_rent_shares = validator_stakes
            .into_iter()
            .map(|(pubkey, staked)| {
                let rent_share = if !enforce_fix {
                    (((staked * rent_to_be_distributed) as f64) / (total_staked as f64)) as u64
                } else {
                    (((staked as u128) * (rent_to_be_distributed as u128)) / (total_staked as u128))
                        .try_into()
                        .unwrap()
                };
                rent_distributed_in_initial_round += rent_share;
                (pubkey, rent_share)
            })
            .collect::<Vec<(Pubkey, u64)>>();

        // Leftover lamports after fraction calculation, will be paid to validators starting from highest stake
        // holder
        let mut leftover_lamports = rent_to_be_distributed - rent_distributed_in_initial_round;

        let mut rewards = vec![];
        validator_rent_shares
            .into_iter()
            .for_each(|(pubkey, rent_share)| {
                let rent_to_be_paid = if leftover_lamports > 0 {
                    leftover_lamports -= 1;
                    rent_share + 1
                } else {
                    rent_share
                };
                if !enforce_fix || rent_to_be_paid > 0 {
                    let mut account = self
                        .get_account_with_fixed_root(&pubkey)
                        .unwrap_or_default();
                    if account.checked_add_lamports(rent_to_be_paid).is_err() {
                        // overflow adding lamports
                        self.capitalization.fetch_sub(rent_to_be_paid, Relaxed);
                        error!(
                            "Burned {} rent lamports instead of sending to {}",
                            rent_to_be_paid, pubkey
                        );
                        inc_new_counter_error!(
                            "bank-burned_rent_lamports",
                            rent_to_be_paid as usize
                        );
                    } else {
                        self.store_account(&pubkey, &account);
                        rewards.push((
                            pubkey,
                            RewardInfo {
                                reward_type: RewardType::Rent,
                                lamports: rent_to_be_paid as i64,
                                post_balance: account.lamports(),
                                commission: None,
                            },
                        ));
                    }
                }
            });
        self.rewards.write().unwrap().append(&mut rewards);

        if enforce_fix {
            assert_eq!(leftover_lamports, 0);
        } else if leftover_lamports != 0 {
            warn!(
                "There was leftover from rent distribution: {}",
                leftover_lamports
            );
            self.capitalization.fetch_sub(leftover_lamports, Relaxed);
        }
    }

    fn distribute_rent(&self) {
        let total_rent_collected = self.collected_rent.load(Relaxed);

        let (burned_portion, rent_to_be_distributed) = self
            .rent_collector
            .rent
            .calculate_burn(total_rent_collected);

        debug!(
            "distributed rent: {} (rounded from: {}, burned: {})",
            rent_to_be_distributed, total_rent_collected, burned_portion
        );
        self.capitalization.fetch_sub(burned_portion, Relaxed);

        if rent_to_be_distributed == 0 {
            return;
        }

        self.distribute_rent_to_validators(self.vote_accounts(), rent_to_be_distributed);
    }

    fn collect_rent(
        &self,
        res: &[TransactionExecutionResult],
        loaded_txs: &mut [TransactionLoadResult],
    ) -> Vec<RentDebits> {
        let mut collected_rent: u64 = 0;
        let mut rent_debits: Vec<RentDebits> = Vec::with_capacity(loaded_txs.len());
        for (i, (raccs, _nonce_rollback)) in loaded_txs.iter_mut().enumerate() {
            let (res, _nonce_rollback) = &res[i];
            if res.is_err() || raccs.is_err() {
                rent_debits.push(RentDebits::default());
                continue;
            }

            let loaded_transaction = raccs.as_mut().unwrap();

            collected_rent += loaded_transaction.rent;
            rent_debits.push(mem::take(&mut loaded_transaction.rent_debits));
        }

        self.collected_rent.fetch_add(collected_rent, Relaxed);
        rent_debits
    }

    fn run_incinerator(&self) {
        if let Some((account, _)) =
            self.get_account_modified_since_parent_with_fixed_root(&incinerator::id())
        {
            self.capitalization.fetch_sub(account.lamports(), Relaxed);
            self.store_account(&incinerator::id(), &AccountSharedData::default());
        }
    }

    fn collect_rent_eagerly(&self) {
        if !self.enable_eager_rent_collection() {
            return;
        }

        let mut measure = Measure::start("collect_rent_eagerly-ms");
        for partition in self.rent_collection_partitions() {
            self.collect_rent_in_partition(partition);
        }
        measure.stop();
        inc_new_counter_info!("collect_rent_eagerly-ms", measure.as_ms() as usize);
    }

    #[cfg(test)]
    fn restore_old_behavior_for_fragile_tests(&self) {
        self.lazy_rent_collection.store(true, Relaxed);
        self.no_stake_rewrite.store(true, Relaxed);
    }

    fn enable_eager_rent_collection(&self) -> bool {
        if self.lazy_rent_collection.load(Relaxed) {
            return false;
        }

        true
    }

    fn rent_collection_partitions(&self) -> Vec<Partition> {
        if !self.use_fixed_collection_cycle() {
            // This mode is for production/development/testing.
            // In this mode, we iterate over the whole pubkey value range for each epochs
            // including warm-up epochs.
            // The only exception is the situation where normal epochs are relatively short
            // (currently less than 2 day). In that case, we arrange a single collection
            // cycle to be multiple of epochs so that a cycle could be greater than the 2 day.
            self.variable_cycle_partitions()
        } else {
            // This mode is mainly for benchmarking only.
            // In this mode, we always iterate over the whole pubkey value range with
            // <slot_count_in_two_day> slots as a collection cycle, regardless warm-up or
            // alignment between collection cycles and epochs.
            // Thus, we can simulate stable processing load of eager rent collection,
            // strictly proportional to the number of pubkeys since genesis.
            self.fixed_cycle_partitions()
        }
    }

    fn collect_rent_in_partition(&self, partition: Partition) {
        let subrange = Self::pubkey_range_from_partition(partition);

        let accounts = self
            .rc
            .accounts
            .load_to_collect_rent_eagerly(&self.ancestors, subrange);
        let account_count = accounts.len();

        // parallelize?
        let rent_for_sysvars = self.rent_for_sysvars();
        let mut total_rent = 0;
        let mut rent_debits = RentDebits::default();
        for (pubkey, mut account) in accounts {
            let rent = self.rent_collector.collect_from_existing_account(
                &pubkey,
                &mut account,
                rent_for_sysvars,
            );
            total_rent += rent;
            // Store all of them unconditionally to purge old AppendVec,
            // even if collected rent is 0 (= not updated).
            // Also, there's another subtle side-effect from this: this
            // ensures we verify the whole on-chain state (= all accounts)
            // via the account delta hash slowly once per an epoch.
            self.store_account(&pubkey, &account);
            rent_debits.push(&pubkey, rent, account.lamports());
        }
        self.collected_rent.fetch_add(total_rent, Relaxed);
        self.rewards.write().unwrap().append(&mut rent_debits.0);

        datapoint_info!("collect_rent_eagerly", ("accounts", account_count, i64));
    }

    // Mostly, the pair (start_index & end_index) is equivalent to this range:
    // start_index..=end_index. But it has some exceptional cases, including
    // this important and valid one:
    //   0..=0: the first partition in the new epoch when crossing epochs
    fn pubkey_range_from_partition(
        (start_index, end_index, partition_count): Partition,
    ) -> RangeInclusive<Pubkey> {
        assert!(start_index <= end_index);
        assert!(start_index < partition_count);
        assert!(end_index < partition_count);
        assert!(0 < partition_count);

        type Prefix = u64;
        const PREFIX_SIZE: usize = mem::size_of::<Prefix>();
        const PREFIX_MAX: Prefix = Prefix::max_value();

        let mut start_pubkey = [0x00u8; 32];
        let mut end_pubkey = [0xffu8; 32];

        if partition_count == 1 {
            assert_eq!(start_index, 0);
            assert_eq!(end_index, 0);
            return Pubkey::new_from_array(start_pubkey)..=Pubkey::new_from_array(end_pubkey);
        }

        // not-overflowing way of `(Prefix::max_value() + 1) / partition_count`
        let partition_width = (PREFIX_MAX - partition_count + 1) / partition_count + 1;
        let mut start_key_prefix = if start_index == 0 && end_index == 0 {
            0
        } else if start_index + 1 == partition_count {
            PREFIX_MAX
        } else {
            (start_index + 1) * partition_width
        };

        let mut end_key_prefix = if end_index + 1 == partition_count {
            PREFIX_MAX
        } else {
            (end_index + 1) * partition_width - 1
        };

        if start_index != 0 && start_index == end_index {
            // n..=n (n != 0): a noop pair across epochs without a gap under
            // multi_epoch_cycle, just nullify it.
            if end_key_prefix == PREFIX_MAX {
                start_key_prefix = end_key_prefix;
                start_pubkey = end_pubkey;
            } else {
                end_key_prefix = start_key_prefix;
                end_pubkey = start_pubkey;
            }
        }

        start_pubkey[0..PREFIX_SIZE].copy_from_slice(&start_key_prefix.to_be_bytes());
        end_pubkey[0..PREFIX_SIZE].copy_from_slice(&end_key_prefix.to_be_bytes());
        trace!(
            "pubkey_range_from_partition: ({}-{})/{} [{}]: {}-{}",
            start_index,
            end_index,
            partition_count,
            (end_key_prefix - start_key_prefix),
            start_pubkey.iter().map(|x| format!("{:02x}", x)).join(""),
            end_pubkey.iter().map(|x| format!("{:02x}", x)).join(""),
        );
        // should be an inclusive range (a closed interval) like this:
        // [0xgg00-0xhhff], [0xii00-0xjjff], ... (where 0xii00 == 0xhhff + 1)
        Pubkey::new_from_array(start_pubkey)..=Pubkey::new_from_array(end_pubkey)
    }

    fn fixed_cycle_partitions(&self) -> Vec<Partition> {
        let slot_count_in_two_day = self.slot_count_in_two_day();

        let parent_cycle = self.parent_slot() / slot_count_in_two_day;
        let current_cycle = self.slot() / slot_count_in_two_day;
        let mut parent_cycle_index = self.parent_slot() % slot_count_in_two_day;
        let current_cycle_index = self.slot() % slot_count_in_two_day;
        let mut partitions = vec![];
        if parent_cycle < current_cycle {
            if current_cycle_index > 0 {
                // generate and push gapped partitions because some slots are skipped
                let parent_last_cycle_index = slot_count_in_two_day - 1;

                // ... for parent cycle
                partitions.push((
                    parent_cycle_index,
                    parent_last_cycle_index,
                    slot_count_in_two_day,
                ));

                // ... for current cycle
                partitions.push((0, 0, slot_count_in_two_day));
            }
            parent_cycle_index = 0;
        }

        partitions.push((
            parent_cycle_index,
            current_cycle_index,
            slot_count_in_two_day,
        ));

        partitions
    }

    fn variable_cycle_partitions(&self) -> Vec<Partition> {
        let (current_epoch, current_slot_index) = self.get_epoch_and_slot_index(self.slot());
        let (parent_epoch, mut parent_slot_index) =
            self.get_epoch_and_slot_index(self.parent_slot());

        let mut partitions = vec![];
        if parent_epoch < current_epoch {
            let slot_skipped = (self.slot() - self.parent_slot()) > 1;
            if slot_skipped {
                // Generate special partitions because there are skipped slots
                // exactly at the epoch transition.

                let parent_last_slot_index = self.get_slots_in_epoch(parent_epoch) - 1;

                // ... for parent epoch
                partitions.push(self.partition_from_slot_indexes_with_gapped_epochs(
                    parent_slot_index,
                    parent_last_slot_index,
                    parent_epoch,
                ));

                if current_slot_index > 0 {
                    // ... for current epoch
                    partitions.push(self.partition_from_slot_indexes_with_gapped_epochs(
                        0,
                        0,
                        current_epoch,
                    ));
                }
            }
            parent_slot_index = 0;
        }

        partitions.push(self.partition_from_normal_slot_indexes(
            parent_slot_index,
            current_slot_index,
            current_epoch,
        ));

        partitions
    }

    fn do_partition_from_slot_indexes(
        &self,
        start_slot_index: SlotIndex,
        end_slot_index: SlotIndex,
        epoch: Epoch,
        generated_for_gapped_epochs: bool,
    ) -> Partition {
        let cycle_params = self.determine_collection_cycle_params(epoch);
        let (_, _, in_multi_epoch_cycle, _, _, partition_count) = cycle_params;

        // use common codepath for both very likely and very unlikely for the sake of minimized
        // risk of any miscalculation instead of negligibly faster computation per slot for the
        // likely case.
        let mut start_partition_index =
            Self::partition_index_from_slot_index(start_slot_index, cycle_params);
        let mut end_partition_index =
            Self::partition_index_from_slot_index(end_slot_index, cycle_params);

        // Adjust partition index for some edge cases
        let is_special_new_epoch = start_slot_index == 0 && end_slot_index != 1;
        let in_middle_of_cycle = start_partition_index > 0;
        if in_multi_epoch_cycle && is_special_new_epoch && in_middle_of_cycle {
            // Adjust slot indexes so that the final partition ranges are continuous!
            // This is need because the caller gives us off-by-one indexes when
            // an epoch boundary is crossed.
            // Usually there is no need for this adjustment because cycles are aligned
            // with epochs. But for multi-epoch cycles, adjust the indexes if it
            // happens in the middle of a cycle for both gapped and not-gapped cases:
            //
            // epoch (slot range)|slot idx.*1|raw part. idx.|adj. part. idx.|epoch boundary
            // ------------------+-----------+--------------+---------------+--------------
            // 3 (20..30)        | [7..8]    |   7.. 8      |   7.. 8
            //                   | [8..9]    |   8.. 9      |   8.. 9
            // 4 (30..40)        | [0..0]    |<10>..10      | <9>..10      <--- not gapped
            //                   | [0..1]    |  10..11      |  10..12
            //                   | [1..2]    |  11..12      |  11..12
            //                   | [2..9   *2|  12..19      |  12..19      <-+
            // 5 (40..50)        |  0..0   *2|<20>..<20>    |<19>..<19> *3 <-+- gapped
            //                   |  0..4]    |<20>..24      |<19>..24      <-+
            //                   | [4..5]    |  24..25      |  24..25
            //                   | [5..6]    |  25..26      |  25..26
            //
            // NOTE: <..> means the adjusted slots
            //
            // *1: The range of parent_bank.slot() and current_bank.slot() is firstly
            //     split by the epoch boundaries and then the split ones are given to us.
            //     The original ranges are denoted as [...]
            // *2: These are marked with generated_for_gapped_epochs = true.
            // *3: This becomes no-op partition
            start_partition_index -= 1;
            if generated_for_gapped_epochs {
                assert_eq!(start_slot_index, end_slot_index);
                end_partition_index -= 1;
            }
        }

        (start_partition_index, end_partition_index, partition_count)
    }

    fn partition_from_normal_slot_indexes(
        &self,
        start_slot_index: SlotIndex,
        end_slot_index: SlotIndex,
        epoch: Epoch,
    ) -> Partition {
        self.do_partition_from_slot_indexes(start_slot_index, end_slot_index, epoch, false)
    }

    fn partition_from_slot_indexes_with_gapped_epochs(
        &self,
        start_slot_index: SlotIndex,
        end_slot_index: SlotIndex,
        epoch: Epoch,
    ) -> Partition {
        self.do_partition_from_slot_indexes(start_slot_index, end_slot_index, epoch, true)
    }

    fn determine_collection_cycle_params(&self, epoch: Epoch) -> RentCollectionCycleParams {
        let slot_count_per_epoch = self.get_slots_in_epoch(epoch);

        if !self.use_multi_epoch_collection_cycle(epoch) {
            (
                epoch,
                slot_count_per_epoch,
                false,
                0,
                1,
                slot_count_per_epoch,
            )
        } else {
            let epoch_count_in_cycle = self.slot_count_in_two_day() / slot_count_per_epoch;
            let partition_count = slot_count_per_epoch * epoch_count_in_cycle;

            (
                epoch,
                slot_count_per_epoch,
                true,
                self.first_normal_epoch(),
                epoch_count_in_cycle,
                partition_count,
            )
        }
    }

    fn partition_index_from_slot_index(
        slot_index_in_epoch: SlotIndex,
        (
            epoch,
            slot_count_per_epoch,
            _,
            base_epoch,
            epoch_count_per_cycle,
            _,
        ): RentCollectionCycleParams,
    ) -> PartitionIndex {
        let epoch_offset = epoch - base_epoch;
        let epoch_index_in_cycle = epoch_offset % epoch_count_per_cycle;
        slot_index_in_epoch + epoch_index_in_cycle * slot_count_per_epoch
    }

    // Given short epochs, it's too costly to collect rent eagerly
    // within an epoch, so lower the frequency of it.
    // These logic isn't strictly eager anymore and should only be used
    // for development/performance purpose.
    // Absolutely not under ClusterType::MainnetBeta!!!!
    fn use_multi_epoch_collection_cycle(&self, epoch: Epoch) -> bool {
        // Force normal behavior, disabling multi epoch collection cycle for manual local testing
        #[cfg(not(test))]
        if self.slot_count_per_normal_epoch() == solana_sdk::epoch_schedule::MINIMUM_SLOTS_PER_EPOCH
        {
            return false;
        }

        epoch >= self.first_normal_epoch()
            && self.slot_count_per_normal_epoch() < self.slot_count_in_two_day()
    }

    fn use_fixed_collection_cycle(&self) -> bool {
        // Force normal behavior, disabling fixed collection cycle for manual local testing
        #[cfg(not(test))]
        if self.slot_count_per_normal_epoch() == solana_sdk::epoch_schedule::MINIMUM_SLOTS_PER_EPOCH
        {
            return false;
        }

        self.cluster_type() != ClusterType::MainnetBeta
            && self.slot_count_per_normal_epoch() < self.slot_count_in_two_day()
    }

    // This value is specially chosen to align with slots per epoch in mainnet-beta and testnet
    // Also, assume 500GB account data set as the extreme, then for 2 day (=48 hours) to collect
    // rent eagerly, we'll consume 5.7 MB/s IO bandwidth, bidirectionally.
    fn slot_count_in_two_day(&self) -> SlotCount {
        2 * DEFAULT_TICKS_PER_SECOND * SECONDS_PER_DAY / self.ticks_per_slot
    }

    fn slot_count_per_normal_epoch(&self) -> SlotCount {
        self.get_slots_in_epoch(self.first_normal_epoch())
    }

    pub fn cluster_type(&self) -> ClusterType {
        // unwrap is safe; self.cluster_type is ensured to be Some() always...
        // we only using Option here for ABI compatibility...
        self.cluster_type.unwrap()
    }

    /// Process a batch of transactions.
    #[must_use]
    pub fn load_execute_and_commit_transactions(
        &self,
        batch: &TransactionBatch,
        max_age: usize,
        collect_balances: bool,
        enable_cpi_recording: bool,
        enable_log_recording: bool,
        timings: &mut ExecuteTimings,
    ) -> (
        TransactionResults,
        TransactionBalancesSet,
        Vec<Option<InnerInstructionsList>>,
        Vec<Option<TransactionLogMessages>>,
    ) {
        let pre_balances = if collect_balances {
            self.collect_balances(batch)
        } else {
            vec![]
        };

        let (
            mut loaded_txs,
            executed,
            inner_instructions,
            transaction_logs,
            _,
            tx_count,
            signature_count,
        ) = self.load_and_execute_transactions(
            batch,
            max_age,
            enable_cpi_recording,
            enable_log_recording,
            timings,
        );

        let results = self.commit_transactions(
            batch.sanitized_transactions(),
            &mut loaded_txs,
            &executed,
            tx_count,
            signature_count,
            timings,
        );
        let post_balances = if collect_balances {
            self.collect_balances(batch)
        } else {
            vec![]
        };
        (
            results,
            TransactionBalancesSet::new(pre_balances, post_balances),
            inner_instructions,
            transaction_logs,
        )
    }

    /// Process a Transaction. This is used for unit tests and simply calls the vector
    /// Bank::process_transactions method.
    pub fn process_transaction(&self, tx: &Transaction) -> Result<()> {
        self.try_process_transactions(std::iter::once(tx))?[0].clone()?;
        tx.signatures
            .get(0)
            .map_or(Ok(()), |sig| self.get_signature_status(sig).unwrap())
    }

    /// Process multiple transaction in a single batch. This is used for benches and unit tests.
    ///
    /// # Panics
    ///
    /// Panics if any of the transactions do not pass sanitization checks.
    #[must_use]
    pub fn process_transactions<'a>(
        &self,
        txs: impl Iterator<Item = &'a Transaction>,
    ) -> Vec<Result<()>> {
        self.try_process_transactions(txs).unwrap()
    }

    /// Process multiple transaction in a single batch. This is used for benches and unit tests.
    /// Short circuits if any of the transactions do not pass sanitization checks.
    pub fn try_process_transactions<'a>(
        &self,
        txs: impl Iterator<Item = &'a Transaction>,
    ) -> Result<Vec<Result<()>>> {
        let batch = self.prepare_batch(txs)?;
        Ok(self.process_transaction_batch(&batch))
    }

    #[must_use]
    fn process_transaction_batch(&self, batch: &TransactionBatch) -> Vec<Result<()>> {
        self.load_execute_and_commit_transactions(
            batch,
            MAX_PROCESSING_AGE,
            false,
            false,
            false,
            &mut ExecuteTimings::default(),
        )
        .0
        .fee_collection_results
    }

    /// Create, sign, and process a Transaction from `keypair` to `to` of
    /// `n` lamports where `blockhash` is the last Entry ID observed by the client.
    pub fn transfer(&self, n: u64, keypair: &Keypair, to: &Pubkey) -> Result<Signature> {
        let blockhash = self.last_blockhash();
        let tx = system_transaction::transfer(keypair, to, n, blockhash);
        let signature = tx.signatures[0];
        self.process_transaction(&tx).map(|_| signature)
    }

    pub fn read_balance(account: &AccountSharedData) -> u64 {
        account.lamports()
    }
    /// Each program would need to be able to introspect its own state
    /// this is hard-coded to the Budget language
    pub fn get_balance(&self, pubkey: &Pubkey) -> u64 {
        self.get_account(pubkey)
            .map(|x| Self::read_balance(&x))
            .unwrap_or(0)
    }

    /// Compute all the parents of the bank in order
    pub fn parents(&self) -> Vec<Arc<Bank>> {
        let mut parents = vec![];
        let mut bank = self.parent();
        while let Some(parent) = bank {
            parents.push(parent.clone());
            bank = parent.parent();
        }
        parents
    }

    /// Compute all the parents of the bank including this bank itself
    pub fn parents_inclusive(self: Arc<Self>) -> Vec<Arc<Bank>> {
        let mut parents = self.parents();
        parents.insert(0, self);
        parents
    }

    pub fn store_account(&self, pubkey: &Pubkey, account: &AccountSharedData) {
        assert!(!self.freeze_started());
        self.rc
            .accounts
            .store_slow_cached(self.slot(), pubkey, account);

        if Stakes::is_stake(account) {
            self.stakes.write().unwrap().store(
                pubkey,
                account,
                self.stake_program_v2_enabled(),
                self.check_init_vote_data_enabled(),
            );
        }
    }

    pub fn force_flush_accounts_cache(&self) {
        self.rc
            .accounts
            .accounts_db
            .flush_accounts_cache(true, Some(self.slot()))
    }

    pub fn flush_accounts_cache_if_needed(&self) {
        self.rc
            .accounts
            .accounts_db
            .flush_accounts_cache(false, Some(self.slot()))
    }

    pub fn expire_old_recycle_stores(&self) {
        self.rc.accounts.accounts_db.expire_old_recycle_stores()
    }

    /// Technically this issues (or even burns!) new lamports,
    /// so be extra careful for its usage
    fn store_account_and_update_capitalization(
        &self,
        pubkey: &Pubkey,
        new_account: &AccountSharedData,
    ) {
        if let Some(old_account) = self.get_account_with_fixed_root(pubkey) {
            match new_account.lamports().cmp(&old_account.lamports()) {
                std::cmp::Ordering::Greater => {
                    let increased = new_account.lamports() - old_account.lamports();
                    trace!(
                        "store_account_and_update_capitalization: increased: {} {}",
                        pubkey,
                        increased
                    );
                    self.capitalization.fetch_add(increased, Relaxed);
                }
                std::cmp::Ordering::Less => {
                    let decreased = old_account.lamports() - new_account.lamports();
                    trace!(
                        "store_account_and_update_capitalization: decreased: {} {}",
                        pubkey,
                        decreased
                    );
                    self.capitalization.fetch_sub(decreased, Relaxed);
                }
                std::cmp::Ordering::Equal => {}
            }
        } else {
            trace!(
                "store_account_and_update_capitalization: created: {} {}",
                pubkey,
                new_account.lamports()
            );
            self.capitalization
                .fetch_add(new_account.lamports(), Relaxed);
        }

        self.store_account(pubkey, new_account);
    }

    fn withdraw(&self, pubkey: &Pubkey, lamports: u64) -> Result<()> {
        match self.get_account_with_fixed_root(pubkey) {
            Some(mut account) => {
                let min_balance = match get_system_account_kind(&account) {
                    Some(SystemAccountKind::Nonce) => self
                        .rent_collector
                        .rent
                        .minimum_balance(nonce::State::size()),
                    _ => 0,
                };

                lamports
                    .checked_add(min_balance)
                    .filter(|required_balance| *required_balance <= account.lamports())
                    .ok_or(TransactionError::InsufficientFundsForFee)?;
                account
                    .checked_sub_lamports(lamports)
                    .map_err(|_| TransactionError::InsufficientFundsForFee)?;
                self.store_account(pubkey, &account);

                Ok(())
            }
            None => Err(TransactionError::AccountNotFound),
        }
    }

    pub fn deposit(
        &self,
        pubkey: &Pubkey,
        lamports: u64,
    ) -> std::result::Result<u64, LamportsError> {
        // This doesn't collect rents intentionally.
        // Rents should only be applied to actual TXes
        let mut account = self.get_account_with_fixed_root(pubkey).unwrap_or_default();
        account.checked_add_lamports(lamports)?;
        self.store_account(pubkey, &account);
        Ok(account.lamports())
    }

    pub fn accounts(&self) -> Arc<Accounts> {
        self.rc.accounts.clone()
    }

    fn finish_init(
        &mut self,
        genesis_config: &GenesisConfig,
        additional_builtins: Option<&Builtins>,
        debug_do_not_add_builtins: bool,
    ) {
        self.rewards_pool_pubkeys =
            Arc::new(genesis_config.rewards_pools.keys().cloned().collect());

        let mut builtins = builtins::get();
        if let Some(additional_builtins) = additional_builtins {
            builtins
                .genesis_builtins
                .extend_from_slice(&additional_builtins.genesis_builtins);
            builtins
                .feature_builtins
                .extend_from_slice(&additional_builtins.feature_builtins);
        }
        if !debug_do_not_add_builtins {
            for builtin in builtins.genesis_builtins {
                self.add_builtin(
                    &builtin.name,
                    builtin.id,
                    builtin.process_instruction_with_context,
                );
            }
        }
        self.feature_builtins = Arc::new(builtins.feature_builtins);

        self.apply_feature_activations(true, debug_do_not_add_builtins);
    }

    pub fn set_inflation(&self, inflation: Inflation) {
        *self.inflation.write().unwrap() = inflation;
    }

    pub fn set_bpf_compute_budget(&mut self, bpf_compute_budget: Option<BpfComputeBudget>) {
        self.bpf_compute_budget = bpf_compute_budget;
    }

    pub fn hard_forks(&self) -> Arc<RwLock<HardForks>> {
        self.hard_forks.clone()
    }

    // Hi! leaky abstraction here....
    // try to use get_account_with_fixed_root() if it's called ONLY from on-chain runtime account
    // processing. That alternative fn provides more safety.
    pub fn get_account(&self, pubkey: &Pubkey) -> Option<AccountSharedData> {
        self.get_account_modified_slot(pubkey)
            .map(|(acc, _slot)| acc)
    }

    // Hi! leaky abstraction here....
    // use this over get_account() if it's called ONLY from on-chain runtime account
    // processing (i.e. from in-band replay/banking stage; that ensures root is *fixed* while
    // running).
    // pro: safer assertion can be enabled inside AccountsDb
    // con: panics!() if called from off-chain processing
    pub fn get_account_with_fixed_root(&self, pubkey: &Pubkey) -> Option<AccountSharedData> {
        self.load_slow_with_fixed_root(&self.ancestors, pubkey)
            .map(|(acc, _slot)| acc)
    }

    pub fn get_account_modified_slot(&self, pubkey: &Pubkey) -> Option<(AccountSharedData, Slot)> {
        self.load_slow(&self.ancestors, pubkey)
    }

    fn load_slow(
        &self,
        ancestors: &Ancestors,
        pubkey: &Pubkey,
    ) -> Option<(AccountSharedData, Slot)> {
        // get_account (= primary this fn caller) may be called from on-chain Bank code even if we
        // try hard to use get_account_with_fixed_root for that purpose...
        // so pass safer LoadHint:Unspecified here as a fallback
        self.rc.accounts.load_without_fixed_root(ancestors, pubkey)
    }

    fn load_slow_with_fixed_root(
        &self,
        ancestors: &Ancestors,
        pubkey: &Pubkey,
    ) -> Option<(AccountSharedData, Slot)> {
        self.rc.accounts.load_with_fixed_root(ancestors, pubkey)
    }

    // Exclude self to really fetch the parent Bank's account hash and data.
    //
    // Being idempotent is needed to make the lazy initialization possible,
    // especially for update_slot_hashes at the moment, which can be called
    // multiple times with the same parent_slot in the case of forking.
    //
    // Generally, all of sysvar update granularity should be slot boundaries.
    //
    // This behavior is deprecated... See comment in update_sysvar_account() for details
    fn get_sysvar_account_with_fixed_root(&self, pubkey: &Pubkey) -> Option<AccountSharedData> {
        let mut ancestors = self.ancestors.clone();
        ancestors.remove(&self.slot());
        self.rc
            .accounts
            .load_with_fixed_root(&ancestors, pubkey)
            .map(|(acc, _slot)| acc)
    }

    pub fn get_program_accounts(
        &self,
        program_id: &Pubkey,
    ) -> ScanResult<Vec<(Pubkey, AccountSharedData)>> {
        self.rc
            .accounts
            .load_by_program(&self.ancestors, self.bank_id, program_id)
    }

    pub fn get_filtered_program_accounts<F: Fn(&AccountSharedData) -> bool>(
        &self,
        program_id: &Pubkey,
        filter: F,
    ) -> ScanResult<Vec<(Pubkey, AccountSharedData)>> {
        self.rc.accounts.load_by_program_with_filter(
            &self.ancestors,
            self.bank_id,
            program_id,
            filter,
        )
    }

    pub fn get_filtered_indexed_accounts<F: Fn(&AccountSharedData) -> bool>(
        &self,
        index_key: &IndexKey,
        filter: F,
    ) -> ScanResult<Vec<(Pubkey, AccountSharedData)>> {
        self.rc.accounts.load_by_index_key_with_filter(
            &self.ancestors,
            self.bank_id,
            index_key,
            filter,
        )
    }

    pub fn account_indexes_include_key(&self, key: &Pubkey) -> bool {
        self.rc.accounts.account_indexes_include_key(key)
    }

    pub fn get_all_accounts_with_modified_slots(
        &self,
    ) -> ScanResult<Vec<(Pubkey, AccountSharedData, Slot)>> {
        self.rc.accounts.load_all(&self.ancestors, self.bank_id)
    }

    pub fn get_program_accounts_modified_since_parent(
        &self,
        program_id: &Pubkey,
    ) -> Vec<(Pubkey, AccountSharedData)> {
        self.rc
            .accounts
            .load_by_program_slot(self.slot(), Some(program_id))
    }

    pub fn get_transaction_logs(
        &self,
        address: Option<&Pubkey>,
    ) -> Option<Vec<TransactionLogInfo>> {
        let transaction_log_collector = self.transaction_log_collector.read().unwrap();

        match address {
            None => Some(transaction_log_collector.logs.clone()),
            Some(address) => transaction_log_collector
                .mentioned_address_map
                .get(address)
                .map(|log_indices| {
                    log_indices
                        .iter()
                        .map(|i| transaction_log_collector.logs[*i].clone())
                        .collect()
                }),
        }
    }

    pub fn get_all_accounts_modified_since_parent(&self) -> Vec<(Pubkey, AccountSharedData)> {
        self.rc.accounts.load_by_program_slot(self.slot(), None)
    }

    // if you want get_account_modified_since_parent without fixed_root, please define so...
    fn get_account_modified_since_parent_with_fixed_root(
        &self,
        pubkey: &Pubkey,
    ) -> Option<(AccountSharedData, Slot)> {
        let just_self: Ancestors = Ancestors::from(vec![self.slot()]);
        if let Some((account, slot)) = self.load_slow_with_fixed_root(&just_self, pubkey) {
            if slot == self.slot() {
                return Some((account, slot));
            }
        }
        None
    }

    pub fn get_largest_accounts(
        &self,
        num: usize,
        filter_by_address: &HashSet<Pubkey>,
        filter: AccountAddressFilter,
    ) -> ScanResult<Vec<(Pubkey, u64)>> {
        self.rc.accounts.load_largest_accounts(
            &self.ancestors,
            self.bank_id,
            num,
            filter_by_address,
            filter,
        )
    }

    pub fn transaction_count(&self) -> u64 {
        self.transaction_count.load(Relaxed)
    }

    pub fn transaction_error_count(&self) -> u64 {
        self.transaction_error_count.load(Relaxed)
    }

    pub fn transaction_entries_count(&self) -> u64 {
        self.transaction_entries_count.load(Relaxed)
    }

    pub fn transactions_per_entry_max(&self) -> u64 {
        self.transactions_per_entry_max.load(Relaxed)
    }

    fn increment_transaction_count(&self, tx_count: u64) {
        self.transaction_count.fetch_add(tx_count, Relaxed);
    }

    pub fn signature_count(&self) -> u64 {
        self.signature_count.load(Relaxed)
    }

    fn increment_signature_count(&self, signature_count: u64) {
        self.signature_count.fetch_add(signature_count, Relaxed);
    }

    pub fn get_signature_status_processed_since_parent(
        &self,
        signature: &Signature,
    ) -> Option<Result<()>> {
        if let Some((slot, status)) = self.get_signature_status_slot(signature) {
            if slot <= self.slot() {
                return Some(status);
            }
        }
        None
    }

    pub fn get_signature_status_with_blockhash(
        &self,
        signature: &Signature,
        blockhash: &Hash,
    ) -> Option<Result<()>> {
        let rcache = self.src.status_cache.read().unwrap();
        rcache
            .get_status(signature, blockhash, &self.ancestors)
            .map(|v| v.1)
    }

    pub fn get_signature_status_slot(&self, signature: &Signature) -> Option<(Slot, Result<()>)> {
        let rcache = self.src.status_cache.read().unwrap();
        rcache.get_status_any_blockhash(signature, &self.ancestors)
    }

    pub fn get_signature_status(&self, signature: &Signature) -> Option<Result<()>> {
        self.get_signature_status_slot(signature).map(|v| v.1)
    }

    pub fn has_signature(&self, signature: &Signature) -> bool {
        self.get_signature_status_slot(signature).is_some()
    }

    /// Hash the `accounts` HashMap. This represents a validator's interpretation
    ///  of the delta of the ledger since the last vote and up to now
    fn hash_internal_state(&self) -> Hash {
        // If there are no accounts, return the hash of the previous state and the latest blockhash
        let accounts_delta_hash = self.rc.accounts.bank_hash_info_at(self.slot());
        let mut signature_count_buf = [0u8; 8];
        LittleEndian::write_u64(&mut signature_count_buf[..], self.signature_count() as u64);

        let mut hash = hashv(&[
            self.parent_hash.as_ref(),
            accounts_delta_hash.hash.as_ref(),
            &signature_count_buf,
            self.last_blockhash().as_ref(),
        ]);

        if let Some(buf) = self
            .hard_forks
            .read()
            .unwrap()
            .get_hash_data(self.slot(), self.parent_slot())
        {
            info!("hard fork at bank {}", self.slot());
            hash = extend_and_hash(&hash, &buf)
        }

        info!(
            "bank frozen: {} hash: {} accounts_delta: {} signature_count: {} last_blockhash: {} capitalization: {}",
            self.slot(),
            hash,
            accounts_delta_hash.hash,
            self.signature_count(),
            self.last_blockhash(),
            self.capitalization(),
        );

        info!(
            "accounts hash slot: {} stats: {:?}",
            self.slot(),
            accounts_delta_hash.stats,
        );
        hash
    }

    /// Recalculate the hash_internal_state from the account stores. Would be used to verify a
    /// snapshot.
    #[must_use]
    fn verify_bank_hash(&self, test_hash_calculation: bool) -> bool {
        self.rc.accounts.verify_bank_hash_and_lamports(
            self.slot(),
            &self.ancestors,
            self.capitalization(),
            test_hash_calculation,
        )
    }

    pub fn get_snapshot_storages(&self) -> SnapshotStorages {
        self.rc.get_snapshot_storages(self.slot())
    }

    /// Get the snapshot storages _higher than_ the `full_snapshot_slot`.  This is used when making an
    /// incremental snapshot.
    pub fn get_incremental_snapshot_storages(&self, full_snapshot_slot: Slot) -> SnapshotStorages {
        self.get_snapshot_storages()
            .into_iter()
            .map(|storage| {
                storage
                    .into_iter()
                    .filter(|entry| entry.slot() > full_snapshot_slot)
                    .collect::<SnapshotStorage>()
            })
            .filter(|storage| !storage.is_empty())
            .collect()
    }

    #[must_use]
    fn verify_hash(&self) -> bool {
        assert!(self.is_frozen());
        let calculated_hash = self.hash_internal_state();
        let expected_hash = self.hash();

        if calculated_hash == expected_hash {
            true
        } else {
            warn!(
                "verify failed: slot: {}, {} (calculated) != {} (expected)",
                self.slot(),
                calculated_hash,
                expected_hash
            );
            false
        }
    }

    pub fn calculate_capitalization(&self, debug_verify: bool) -> u64 {
        let can_cached_slot_be_unflushed = true; // implied yes
        self.rc.accounts.calculate_capitalization(
            &self.ancestors,
            self.slot(),
            can_cached_slot_be_unflushed,
            debug_verify,
        )
    }

    pub fn calculate_and_verify_capitalization(&self, debug_verify: bool) -> bool {
        let calculated = self.calculate_capitalization(debug_verify);
        let expected = self.capitalization();
        if calculated == expected {
            true
        } else {
            warn!(
                "Capitalization mismatch: calculated: {} != expected: {}",
                calculated, expected
            );
            false
        }
    }

    /// Forcibly overwrites current capitalization by actually recalculating accounts' balances.
    /// This should only be used for developing purposes.
    pub fn set_capitalization(&self) -> u64 {
        let old = self.capitalization();
        let debug_verify = true;
        self.capitalization
            .store(self.calculate_capitalization(debug_verify), Relaxed);
        old
    }

    pub fn get_accounts_hash(&self) -> Hash {
        self.rc.accounts.accounts_db.get_accounts_hash(self.slot)
    }

    pub fn get_thread_pool(&self) -> &ThreadPool {
        &self.rc.accounts.accounts_db.thread_pool_clean
    }

    pub fn update_accounts_hash_with_index_option(
        &self,
        use_index: bool,
        debug_verify: bool,
    ) -> Hash {
        let (hash, total_lamports) = self
            .rc
            .accounts
            .accounts_db
            .update_accounts_hash_with_index_option(
                use_index,
                debug_verify,
                self.slot(),
                &self.ancestors,
                Some(self.capitalization()),
                false,
            );
        if total_lamports != self.capitalization() {
            datapoint_info!(
                "capitalization_mismatch",
                ("slot", self.slot(), i64),
                ("calculated_lamports", total_lamports, i64),
                ("capitalization", self.capitalization(), i64),
            );

            panic!(
                "capitalization_mismatch. slot: {}, calculated_lamports: {}, capitalization: {}",
                self.slot(),
                total_lamports,
                self.capitalization()
            );
        }
        hash
    }

    pub fn update_accounts_hash(&self) -> Hash {
        self.update_accounts_hash_with_index_option(true, false)
    }

    /// A snapshot bank should be purged of 0 lamport accounts which are not part of the hash
    /// calculation and could shield other real accounts.
    pub fn verify_snapshot_bank(&self, test_hash_calculation: bool) -> bool {
        info!("cleaning..");
        let mut clean_time = Measure::start("clean");
        if self.slot() > 0 {
            self.clean_accounts(true, true);
        }
        clean_time.stop();

        info!("shrinking..");
        let mut shrink_all_slots_time = Measure::start("shrink_all_slots");
        if self.slot() > 0 {
            self.shrink_all_slots(true);
        }
        shrink_all_slots_time.stop();

        info!("verify_bank_hash..");
        let mut verify_time = Measure::start("verify_bank_hash");
        let mut verify = self.verify_bank_hash(test_hash_calculation);
        verify_time.stop();

        info!("verify_hash..");
        let mut verify2_time = Measure::start("verify_hash");
        // Order and short-circuiting is significant; verify_hash requires a valid bank hash
        verify = verify && self.verify_hash();
        verify2_time.stop();

        datapoint_info!(
            "verify_snapshot_bank",
            ("clean_us", clean_time.as_us(), i64),
            ("shrink_all_slots_us", shrink_all_slots_time.as_us(), i64),
            ("verify_bank_hash_us", verify_time.as_us(), i64),
            ("verify_hash_us", verify2_time.as_us(), i64),
        );

        verify
    }

    /// Return the number of hashes per tick
    pub fn hashes_per_tick(&self) -> &Option<u64> {
        &self.hashes_per_tick
    }

    /// Return the number of ticks per slot
    pub fn ticks_per_slot(&self) -> u64 {
        self.ticks_per_slot
    }

    /// Return the number of slots per year
    pub fn slots_per_year(&self) -> f64 {
        self.slots_per_year
    }

    /// Return the number of ticks since genesis.
    pub fn tick_height(&self) -> u64 {
        self.tick_height.load(Relaxed)
    }

    /// Return the inflation parameters of the Bank
    pub fn inflation(&self) -> Inflation {
        *self.inflation.read().unwrap()
    }

    pub fn rent_collector(&self) -> RentCollector {
        self.rent_collector.clone()
    }

    /// Return the total capitalization of the Bank
    pub fn capitalization(&self) -> u64 {
        self.capitalization.load(Relaxed)
    }

    /// Return this bank's max_tick_height
    pub fn max_tick_height(&self) -> u64 {
        self.max_tick_height
    }

    /// Return the block_height of this bank
    pub fn block_height(&self) -> u64 {
        self.block_height
    }

    /// Return the number of slots per epoch for the given epoch
    pub fn get_slots_in_epoch(&self, epoch: Epoch) -> u64 {
        self.epoch_schedule.get_slots_in_epoch(epoch)
    }

    /// returns the epoch for which this bank's leader_schedule_slot_offset and slot would
    ///  need to cache leader_schedule
    pub fn get_leader_schedule_epoch(&self, slot: Slot) -> Epoch {
        self.epoch_schedule.get_leader_schedule_epoch(slot)
    }

    /// a bank-level cache of vote accounts
    fn update_cached_accounts<'a>(
        &self,
        txs: impl Iterator<Item = &'a Transaction>,
        res: &[TransactionExecutionResult],
        loaded_txs: &[TransactionLoadResult],
    ) -> Vec<OverwrittenVoteAccount> {
        let mut overwritten_vote_accounts = vec![];
        for (i, ((raccs, _load_nonce_rollback), tx)) in loaded_txs.iter().zip(txs).enumerate() {
            let (res, _res_nonce_rollback) = &res[i];
            if res.is_err() || raccs.is_err() {
                continue;
            }

            let message = &tx.message();
            let loaded_transaction = raccs.as_ref().unwrap();

            for (_i, (pubkey, account)) in (0..message.account_keys.len())
                .zip(loaded_transaction.accounts.iter())
                .filter(|(_i, (_pubkey, account))| (Stakes::is_stake(account)))
            {
                if Stakes::is_stake(account) {
                    if let Some(old_vote_account) = self.stakes.write().unwrap().store(
                        pubkey,
                        account,
                        self.stake_program_v2_enabled(),
                        self.check_init_vote_data_enabled(),
                    ) {
                        // TODO: one of the indices is redundant.
                        overwritten_vote_accounts.push(OverwrittenVoteAccount {
                            account: old_vote_account,
                            transaction_index: i,
                            transaction_result_index: i,
                        });
                    }
                }
            }
        }

        overwritten_vote_accounts
    }

    /// current stake delegations for this bank
    pub fn cloned_stake_delegations(&self) -> HashMap<Pubkey, Delegation> {
        self.stakes.read().unwrap().stake_delegations().clone()
    }

    pub fn staked_nodes(&self) -> HashMap<Pubkey, u64> {
        self.stakes.read().unwrap().staked_nodes()
    }

    /// current vote accounts for this bank along with the stake
    ///   attributed to each account
    /// Note: This clones the entire vote-accounts hashmap. For a single
    /// account lookup use get_vote_account instead.
    pub fn vote_accounts(&self) -> Vec<(Pubkey, (u64 /*stake*/, ArcVoteAccount))> {
        self.stakes
            .read()
            .unwrap()
            .vote_accounts()
            .iter()
            .map(|(k, v)| (*k, v.clone()))
            .collect()
    }

    /// Vote account for the given vote account pubkey along with the stake.
    pub fn get_vote_account(
        &self,
        vote_account: &Pubkey,
    ) -> Option<(u64 /*stake*/, ArcVoteAccount)> {
        self.stakes
            .read()
            .unwrap()
            .vote_accounts()
            .get(vote_account)
            .cloned()
    }

    /// Get the EpochStakes for a given epoch
    pub fn epoch_stakes(&self, epoch: Epoch) -> Option<&EpochStakes> {
        self.epoch_stakes.get(&epoch)
    }

    pub fn epoch_stakes_map(&self) -> &HashMap<Epoch, EpochStakes> {
        &self.epoch_stakes
    }

    pub fn epoch_staked_nodes(&self, epoch: Epoch) -> Option<HashMap<Pubkey, u64>> {
        Some(self.epoch_stakes.get(&epoch)?.stakes().staked_nodes())
    }

    /// vote accounts for the specific epoch along with the stake
    ///   attributed to each account
    pub fn epoch_vote_accounts(
        &self,
        epoch: Epoch,
    ) -> Option<&HashMap<Pubkey, (u64, ArcVoteAccount)>> {
        self.epoch_stakes
            .get(&epoch)
            .map(|epoch_stakes| Stakes::vote_accounts(epoch_stakes.stakes()))
    }

    /// Get the fixed authorized voter for the given vote account for the
    /// current epoch
    pub fn epoch_authorized_voter(&self, vote_account: &Pubkey) -> Option<&Pubkey> {
        self.epoch_stakes
            .get(&self.epoch)
            .expect("Epoch stakes for bank's own epoch must exist")
            .epoch_authorized_voters()
            .get(vote_account)
    }

    /// Get the fixed set of vote accounts for the given node id for the
    /// current epoch
    pub fn epoch_vote_accounts_for_node_id(&self, node_id: &Pubkey) -> Option<&NodeVoteAccounts> {
        self.epoch_stakes
            .get(&self.epoch)
            .expect("Epoch stakes for bank's own epoch must exist")
            .node_id_to_vote_accounts()
            .get(node_id)
    }

    /// Get the fixed total stake of all vote accounts for current epoch
    pub fn total_epoch_stake(&self) -> u64 {
        self.epoch_stakes
            .get(&self.epoch)
            .expect("Epoch stakes for bank's own epoch must exist")
            .total_stake()
    }

    /// Get the fixed stake of the given vote account for the current epoch
    pub fn epoch_vote_account_stake(&self, vote_account: &Pubkey) -> u64 {
        *self
            .epoch_vote_accounts(self.epoch())
            .expect("Bank epoch vote accounts must contain entry for the bank's own epoch")
            .get(vote_account)
            .map(|(stake, _)| stake)
            .unwrap_or(&0)
    }

    /// given a slot, return the epoch and offset into the epoch this slot falls
    /// e.g. with a fixed number for slots_per_epoch, the calculation is simply:
    ///
    ///  ( slot/slots_per_epoch, slot % slots_per_epoch )
    ///
    pub fn get_epoch_and_slot_index(&self, slot: Slot) -> (Epoch, SlotIndex) {
        self.epoch_schedule.get_epoch_and_slot_index(slot)
    }

    pub fn get_epoch_info(&self) -> EpochInfo {
        let absolute_slot = self.slot();
        let block_height = self.block_height();
        let (epoch, slot_index) = self.get_epoch_and_slot_index(absolute_slot);
        let slots_in_epoch = self.get_slots_in_epoch(epoch);
        let transaction_count = Some(self.transaction_count());
        EpochInfo {
            epoch,
            slot_index,
            slots_in_epoch,
            absolute_slot,
            block_height,
            transaction_count,
        }
    }

    pub fn is_empty(&self) -> bool {
        !self.is_delta.load(Relaxed)
    }

    /// Add an instruction processor to intercept instructions before the dynamic loader.
    pub fn add_builtin(
        &mut self,
        name: &str,
        program_id: Pubkey,
        process_instruction_with_context: ProcessInstructionWithContext,
    ) {
        debug!("Adding program {} under {:?}", name, program_id);
        self.add_native_program(name, &program_id, false);
        self.message_processor
            .add_program(program_id, process_instruction_with_context);
    }

    /// Replace a builtin instruction processor if it already exists
    pub fn replace_builtin(
        &mut self,
        name: &str,
        program_id: Pubkey,
        process_instruction_with_context: ProcessInstructionWithContext,
    ) {
        debug!("Replacing program {} under {:?}", name, program_id);
        self.add_native_program(name, &program_id, true);
        self.message_processor
            .add_program(program_id, process_instruction_with_context);
    }

    pub fn clean_accounts(&self, skip_last: bool, is_startup: bool) {
        let max_clean_slot = if skip_last {
            // Don't clean the slot we're snapshotting because it may have zero-lamport
            // accounts that were included in the bank delta hash when the bank was frozen,
            // and if we clean them here, any newly created snapshot's hash for this bank
            // may not match the frozen hash.
            Some(self.slot().saturating_sub(1))
        } else {
            None
        };
        self.rc
            .accounts
            .accounts_db
            .clean_accounts(max_clean_slot, is_startup);
    }

    pub fn shrink_all_slots(&self, is_startup: bool) {
        self.rc.accounts.accounts_db.shrink_all_slots(is_startup);
    }

    pub fn print_accounts_stats(&self) {
        self.rc.accounts.accounts_db.print_accounts_stats("");
    }

    pub fn process_stale_slot_with_budget(
        &self,
        mut consumed_budget: usize,
        budget_recovery_delta: usize,
    ) -> usize {
        if consumed_budget == 0 {
            let shrunken_account_count = self.rc.accounts.accounts_db.process_stale_slot_v1();
            if shrunken_account_count > 0 {
                datapoint_info!(
                    "stale_slot_shrink",
                    ("accounts", shrunken_account_count, i64)
                );
                consumed_budget += shrunken_account_count;
            }
        }
        consumed_budget.saturating_sub(budget_recovery_delta)
    }

    pub fn shrink_candidate_slots(&self) -> usize {
        self.rc.accounts.accounts_db.shrink_candidate_slots()
    }

    pub fn no_overflow_rent_distribution_enabled(&self) -> bool {
        self.feature_set
            .is_active(&feature_set::no_overflow_rent_distribution::id())
    }

    pub fn stake_program_v2_enabled(&self) -> bool {
        self.feature_set
            .is_active(&feature_set::stake_program_v2::id())
    }

    pub fn check_init_vote_data_enabled(&self) -> bool {
        self.feature_set
            .is_active(&feature_set::check_init_vote_data::id())
    }

    pub fn verify_tx_signatures_len_enabled(&self) -> bool {
        self.feature_set
            .is_active(&feature_set::verify_tx_signatures_len::id())
    }

    pub fn libsecp256k1_0_5_upgrade_enabled(&self) -> bool {
        self.feature_set
            .is_active(&feature_set::libsecp256k1_0_5_upgrade_enabled::id())
    }

    // Check if the wallclock time from bank creation to now has exceeded the allotted
    // time for transaction processing
    pub fn should_bank_still_be_processing_txs(
        bank_creation_time: &Instant,
        max_tx_ingestion_nanos: u128,
    ) -> bool {
        // Do this check outside of the poh lock, hence not a method on PohRecorder
        bank_creation_time.elapsed().as_nanos() <= max_tx_ingestion_nanos
    }

    pub fn deactivate_feature(&mut self, id: &Pubkey) {
        let mut feature_set = Arc::make_mut(&mut self.feature_set).clone();
        feature_set.active.remove(id);
        feature_set.inactive.insert(*id);
        self.feature_set = Arc::new(feature_set);
    }

    pub fn activate_feature(&mut self, id: &Pubkey) {
        let mut feature_set = Arc::make_mut(&mut self.feature_set).clone();
        feature_set.inactive.remove(id);
        feature_set.active.insert(*id, 0);
        self.feature_set = Arc::new(feature_set);
    }

    // This is called from snapshot restore AND for each epoch boundary
    // The entire code path herein must be idempotent
    fn apply_feature_activations(
        &mut self,
        init_finish_or_warp: bool,
        debug_do_not_add_builtins: bool,
    ) {
        let new_feature_activations = self.compute_active_feature_set(!init_finish_or_warp);

        if new_feature_activations.contains(&feature_set::pico_inflation::id()) {
            *self.inflation.write().unwrap() = Inflation::pico();
            self.fee_rate_governor.burn_percent = 50; // 50% fee burn
            self.rent_collector.rent.burn_percent = 50; // 50% rent burn
        }

        if !new_feature_activations.is_disjoint(&self.feature_set.full_inflation_features_enabled())
        {
            *self.inflation.write().unwrap() = Inflation::full();
            self.fee_rate_governor.burn_percent = 50; // 50% fee burn
            self.rent_collector.rent.burn_percent = 50; // 50% rent burn
        }

        if new_feature_activations.contains(&feature_set::spl_token_v2_self_transfer_fix::id()) {
            self.apply_spl_token_v2_self_transfer_fix();
        }
        // Remove me after a while around v1.6
        if !self.no_stake_rewrite.load(Relaxed)
            && new_feature_activations.contains(&feature_set::rewrite_stake::id())
        {
            // to avoid any potential risk of wrongly rewriting accounts in the future,
            // only do this once, taking small risk of unknown
            // bugs which again creates bad stake accounts..

            self.rewrite_stakes();
        }
        if new_feature_activations.contains(&feature_set::rent_for_sysvars::id()) {
            // when this feature is activated, immediately all of existing sysvars are susceptible
            // to rent collection and account data removal due to insufficient balance due to only
            // having 1 lamport.
            // so before any is accessed, reset the balance to be rent-exempt here at the same
            // timing when perpetual balance adjustment is started in update_sysvar_account().
            self.reset_all_sysvar_balances();
        }

        if !debug_do_not_add_builtins {
            self.ensure_feature_builtins(init_finish_or_warp, &new_feature_activations);
            self.reconfigure_token2_native_mint();
        }
        self.ensure_no_storage_rewards_pool();
    }

    fn reset_all_sysvar_balances(&self) {
        for sysvar_id in &[
            sysvar::clock::id(),
            sysvar::epoch_schedule::id(),
            sysvar::fees::id(),
            sysvar::recent_blockhashes::id(),
            sysvar::rent::id(),
            sysvar::rewards::id(),
            sysvar::slot_hashes::id(),
            sysvar::slot_history::id(),
            sysvar::stake_history::id(),
        ] {
            if let Some(mut account) = self.get_account(sysvar_id) {
                let (old_data_len, old_lamports) = (account.data().len(), account.lamports());
                self.adjust_sysvar_balance_for_rent(&mut account);
                info!(
                    "reset_all_sysvar_balances (slot: {}): {} ({} bytes) is reset from {} to {}",
                    self.slot(),
                    sysvar_id,
                    old_data_len,
                    old_lamports,
                    account.lamports()
                );
                self.store_account_and_update_capitalization(sysvar_id, &account);
            }
        }
    }

    fn adjust_sysvar_balance_for_rent(&self, account: &mut AccountSharedData) {
        account.set_lamports(
            self.get_minimum_balance_for_rent_exemption(account.data().len())
                .max(account.lamports()),
        );
    }

    // Compute the active feature set based on the current bank state, and return the set of newly activated features
    fn compute_active_feature_set(&mut self, allow_new_activations: bool) -> HashSet<Pubkey> {
        let mut active = self.feature_set.active.clone();
        let mut inactive = HashSet::new();
        let mut newly_activated = HashSet::new();
        let slot = self.slot();

        for feature_id in &self.feature_set.inactive {
            let mut activated = None;
            if let Some(mut account) = self.get_account_with_fixed_root(feature_id) {
                if let Some(mut feature) = feature::from_account(&account) {
                    match feature.activated_at {
                        None => {
                            if allow_new_activations {
                                // Feature has been requested, activate it now
                                feature.activated_at = Some(slot);
                                if feature::to_account(&feature, &mut account).is_some() {
                                    self.store_account(feature_id, &account);
                                }
                                newly_activated.insert(*feature_id);
                                activated = Some(slot);
                                info!("Feature {} activated at slot {}", feature_id, slot);
                            }
                        }
                        Some(activation_slot) => {
                            if slot >= activation_slot {
                                // Feature is already active
                                activated = Some(activation_slot);
                            }
                        }
                    }
                }
            }
            if let Some(slot) = activated {
                active.insert(*feature_id, slot);
            } else {
                inactive.insert(*feature_id);
            }
        }

        self.feature_set = Arc::new(FeatureSet { active, inactive });
        newly_activated
    }

    fn ensure_feature_builtins(
        &mut self,
        init_or_warp: bool,
        new_feature_activations: &HashSet<Pubkey>,
    ) {
        let feature_builtins = self.feature_builtins.clone();
        for (builtin, feature, activation_type) in feature_builtins.iter() {
            let should_populate = init_or_warp && self.feature_set.is_active(feature)
                || !init_or_warp && new_feature_activations.contains(feature);
            if should_populate {
                match activation_type {
                    ActivationType::NewProgram => self.add_builtin(
                        &builtin.name,
                        builtin.id,
                        builtin.process_instruction_with_context,
                    ),
                    ActivationType::NewVersion => self.replace_builtin(
                        &builtin.name,
                        builtin.id,
                        builtin.process_instruction_with_context,
                    ),
                }
            }
        }
    }

    fn apply_spl_token_v2_self_transfer_fix(&mut self) {
        if let Some(old_account) = self.get_account_with_fixed_root(&inline_spl_token_v2_0::id()) {
            if let Some(new_account) =
                self.get_account_with_fixed_root(&inline_spl_token_v2_0::new_token_program::id())
            {
                datapoint_info!(
                    "bank-apply_spl_token_v2_self_transfer_fix",
                    ("slot", self.slot, i64),
                );

                // Burn lamports in the old token account
                self.capitalization
                    .fetch_sub(old_account.lamports(), Relaxed);

                // Transfer new token account to old token account
                self.store_account(&inline_spl_token_v2_0::id(), &new_account);

                // Clear new token account
                self.store_account(
                    &inline_spl_token_v2_0::new_token_program::id(),
                    &AccountSharedData::default(),
                );

                self.remove_executor(&inline_spl_token_v2_0::id());
            }
        }
    }
    fn reconfigure_token2_native_mint(&mut self) {
        let reconfigure_token2_native_mint = match self.cluster_type() {
            ClusterType::Development => true,
            ClusterType::Devnet => true,
            ClusterType::Testnet => self.epoch() == 93,
            ClusterType::MainnetBeta => self.epoch() == 75,
        };

        if reconfigure_token2_native_mint {
            let mut native_mint_account = solana_sdk::account::AccountSharedData::from(Account {
                owner: inline_spl_token_v2_0::id(),
                data: inline_spl_token_v2_0::native_mint::ACCOUNT_DATA.to_vec(),
                lamports: sol_to_lamports(1.),
                executable: false,
                rent_epoch: self.epoch() + 1,
            });

            // As a workaround for
            // https://github.com/solana-labs/solana-program-library/issues/374, ensure that the
            // spl-token 2 native mint account is owned by the spl-token 2 program.
            let store = if let Some(existing_native_mint_account) =
                self.get_account_with_fixed_root(&inline_spl_token_v2_0::native_mint::id())
            {
                if existing_native_mint_account.owner() == &solana_sdk::system_program::id() {
                    native_mint_account.set_lamports(existing_native_mint_account.lamports());
                    true
                } else {
                    false
                }
            } else {
                self.capitalization
                    .fetch_add(native_mint_account.lamports(), Relaxed);
                true
            };

            if store {
                self.store_account(
                    &inline_spl_token_v2_0::native_mint::id(),
                    &native_mint_account,
                );
            }
        }
    }

    fn ensure_no_storage_rewards_pool(&mut self) {
        let purge_window_epoch = match self.cluster_type() {
            ClusterType::Development => false,
            // never do this for devnet; we're pristine here. :)
            ClusterType::Devnet => false,
            // schedule to remove at testnet/tds
            ClusterType::Testnet => self.epoch() == 93,
            // never do this for stable; we're pristine here. :)
            ClusterType::MainnetBeta => false,
        };

        if purge_window_epoch {
            for reward_pubkey in self.rewards_pool_pubkeys.iter() {
                if let Some(mut reward_account) = self.get_account_with_fixed_root(reward_pubkey) {
                    if reward_account.lamports() == u64::MAX {
                        reward_account.set_lamports(0);
                        self.store_account(reward_pubkey, &reward_account);
                        // Adjust capitalization.... it has been wrapping, reducing the real capitalization by 1-lamport
                        self.capitalization.fetch_add(1, Relaxed);
                        info!(
                            "purged rewards pool accont: {}, new capitalization: {}",
                            reward_pubkey,
                            self.capitalization()
                        );
                    }
                };
            }
        }
    }

    fn fix_recent_blockhashes_sysvar_delay(&self) -> bool {
        match self.cluster_type() {
            ClusterType::Development | ClusterType::Devnet | ClusterType::Testnet => true,
            ClusterType::MainnetBeta => self
                .feature_set
                .is_active(&feature_set::consistent_recent_blockhashes_sysvar::id()),
        }
    }

    fn rent_for_sysvars(&self) -> bool {
        self.feature_set
            .is_active(&feature_set::rent_for_sysvars::id())
    }
}

impl Drop for Bank {
    fn drop(&mut self) {
        if let Some(drop_callback) = self.drop_callback.read().unwrap().0.as_ref() {
            drop_callback.callback(self);
        } else {
            // Default case
            // 1. Tests
            // 2. At startup when replaying blockstore and there's no
            // AccountsBackgroundService to perform cleanups yet.
            self.rc
                .accounts
                .purge_slot(self.slot(), self.bank_id(), false);
        }
    }
}

pub fn goto_end_of_slot(bank: &mut Bank) {
    let mut tick_hash = bank.last_blockhash();
    loop {
        tick_hash = hashv(&[tick_hash.as_ref(), &[42]]);
        bank.register_tick(&tick_hash);
        if tick_hash == bank.last_blockhash() {
            bank.freeze();
            return;
        }
    }
}

fn is_simple_vote_transaction(transaction: &Transaction) -> bool {
    if transaction.message.instructions.len() == 1 {
        let instruction = &transaction.message.instructions[0];
        let program_pubkey =
            transaction.message.account_keys[instruction.program_id_index as usize];
        if program_pubkey == solana_vote_program::id() {
            if let Ok(vote_instruction) = limited_deserialize::<VoteInstruction>(&instruction.data)
            {
                return matches!(
                    vote_instruction,
                    VoteInstruction::Vote(_) | VoteInstruction::VoteSwitch(_, _)
                );
            }
        }
    }
    false
}

#[cfg(test)]
pub(crate) mod tests {
    use super::*;
    use crate::{
        accounts_background_service::{AbsRequestHandler, SendDroppedBankCallback},
        accounts_db::DEFAULT_ACCOUNTS_SHRINK_RATIO,
        accounts_index::{
            AccountIndex, AccountMap, AccountSecondaryIndexes, ScanError, ITER_BATCH_SIZE,
        },
        ancestors::Ancestors,
        genesis_utils::{
            activate_all_features, bootstrap_validator_stake_lamports,
            create_genesis_config_with_leader, create_genesis_config_with_vote_accounts,
            GenesisConfigInfo, ValidatorVoteKeypairs,
        },
        native_loader::NativeLoaderError,
        status_cache::MAX_CACHE_ENTRIES,
    };
    use crossbeam_channel::{bounded, unbounded};
    use solana_sdk::{
        account::Account,
        clock::{DEFAULT_SLOTS_PER_EPOCH, DEFAULT_TICKS_PER_SLOT},
        compute_budget,
        epoch_schedule::MINIMUM_SLOTS_PER_EPOCH,
        feature::Feature,
        genesis_config::create_genesis_config,
        instruction::{AccountMeta, CompiledInstruction, Instruction, InstructionError},
        message::{Message, MessageHeader},
        nonce,
        poh_config::PohConfig,
        process_instruction::InvokeContext,
        rent::Rent,
        signature::{keypair_from_seed, Keypair, Signer},
        stake::{
            instruction as stake_instruction,
            state::{Authorized, Delegation, Lockup, Stake},
        },
        system_instruction::{self, SystemError},
        system_program,
        sysvar::{fees::Fees, rewards::Rewards},
        timing::duration_as_s,
    };
    use solana_vote_program::{
        vote_instruction,
        vote_state::{
            self, BlockTimestamp, Vote, VoteInit, VoteState, VoteStateVersions, MAX_LOCKOUT_HISTORY,
        },
    };
    use std::{result, thread::Builder, time::Duration};

    #[test]
    fn test_nonce_rollback_info() {
        let nonce_authority = keypair_from_seed(&[0; 32]).unwrap();
        let nonce_address = nonce_authority.pubkey();
        let fee_calculator = FeeCalculator::new(42);
        let state =
            nonce::state::Versions::new_current(nonce::State::Initialized(nonce::state::Data {
                authority: Pubkey::default(),
                blockhash: Hash::new_unique(),
                fee_calculator: fee_calculator.clone(),
            }));
        let nonce_account = AccountSharedData::new_data(43, &state, &system_program::id()).unwrap();

        // NonceRollbackPartial create + NonceRollbackInfo impl
        let partial = NonceRollbackPartial::new(nonce_address, nonce_account.clone());
        assert_eq!(*partial.nonce_address(), nonce_address);
        assert_eq!(*partial.nonce_account(), nonce_account);
        assert_eq!(partial.fee_calculator(), Some(fee_calculator.clone()));
        assert_eq!(partial.fee_account(), None);

        let from = keypair_from_seed(&[1; 32]).unwrap();
        let from_address = from.pubkey();
        let to_address = Pubkey::new_unique();
        let instructions = vec![
            system_instruction::advance_nonce_account(&nonce_address, &nonce_authority.pubkey()),
            system_instruction::transfer(&from_address, &to_address, 42),
        ];
        let message = Message::new(&instructions, Some(&from_address));

        let from_account = AccountSharedData::new(44, 0, &Pubkey::default());
        let to_account = AccountSharedData::new(45, 0, &Pubkey::default());
        let recent_blockhashes_sysvar_account = AccountSharedData::new(4, 0, &Pubkey::default());
        let accounts = [
            (message.account_keys[0], from_account.clone()),
            (message.account_keys[1], nonce_account.clone()),
            (message.account_keys[2], to_account.clone()),
            (
                message.account_keys[3],
                recent_blockhashes_sysvar_account.clone(),
            ),
        ];

        // NonceRollbackFull create + NonceRollbackInfo impl
        let full = NonceRollbackFull::from_partial(partial.clone(), &message, &accounts).unwrap();
        assert_eq!(*full.nonce_address(), nonce_address);
        assert_eq!(*full.nonce_account(), nonce_account);
        assert_eq!(full.fee_calculator(), Some(fee_calculator));
        assert_eq!(full.fee_account(), Some(&from_account));

        let message = Message::new(&instructions, Some(&nonce_address));
        let accounts = [
            (message.account_keys[0], nonce_account),
            (message.account_keys[1], from_account),
            (message.account_keys[2], to_account),
            (message.account_keys[3], recent_blockhashes_sysvar_account),
        ];

        // Nonce account is fee-payer
        let full = NonceRollbackFull::from_partial(partial.clone(), &message, &accounts).unwrap();
        assert_eq!(full.fee_account(), None);

        // NonceRollbackFull create, fee-payer not in account_keys fails
        assert_eq!(
            NonceRollbackFull::from_partial(partial, &message, &[]).unwrap_err(),
            TransactionError::AccountNotFound,
        );
    }

    #[test]
    fn test_bank_unix_timestamp_from_genesis() {
        let (genesis_config, _mint_keypair) = create_genesis_config(1);
        let mut bank = Arc::new(Bank::new(&genesis_config));

        assert_eq!(
            genesis_config.creation_time,
            bank.unix_timestamp_from_genesis()
        );
        let slots_per_sec = 1.0
            / (duration_as_s(&genesis_config.poh_config.target_tick_duration)
                * genesis_config.ticks_per_slot as f32);

        for _i in 0..slots_per_sec as usize + 1 {
            bank = Arc::new(new_from_parent(&bank));
        }

        assert!(bank.unix_timestamp_from_genesis() - genesis_config.creation_time >= 1);
    }

    #[test]
    #[allow(clippy::float_cmp)]
    fn test_bank_new() {
        let dummy_leader_pubkey = solana_sdk::pubkey::new_rand();
        let dummy_leader_stake_lamports = bootstrap_validator_stake_lamports();
        let mint_lamports = 10_000;
        let GenesisConfigInfo {
            mut genesis_config,
            mint_keypair,
            voting_keypair,
            ..
        } = create_genesis_config_with_leader(
            mint_lamports,
            &dummy_leader_pubkey,
            dummy_leader_stake_lamports,
        );

        genesis_config.rent = Rent {
            lamports_per_byte_year: 5,
            exemption_threshold: 1.2,
            burn_percent: 5,
        };

        let bank = Bank::new(&genesis_config);
        assert_eq!(bank.get_balance(&mint_keypair.pubkey()), mint_lamports);
        assert_eq!(
            bank.get_balance(&voting_keypair.pubkey()),
            dummy_leader_stake_lamports /* 1 token goes to the vote account associated with dummy_leader_lamports */
        );

        let rent_account = bank.get_account(&sysvar::rent::id()).unwrap();
        let rent = from_account::<sysvar::rent::Rent, _>(&rent_account).unwrap();

        assert_eq!(rent.burn_percent, 5);
        assert_eq!(rent.exemption_threshold, 1.2);
        assert_eq!(rent.lamports_per_byte_year, 5);
    }

    #[test]
    fn test_bank_block_height() {
        let (genesis_config, _mint_keypair) = create_genesis_config(1);
        let bank0 = Arc::new(Bank::new(&genesis_config));
        assert_eq!(bank0.block_height(), 0);
        let bank1 = Arc::new(new_from_parent(&bank0));
        assert_eq!(bank1.block_height(), 1);
    }

    #[test]
    fn test_bank_update_epoch_stakes() {
        impl Bank {
            fn epoch_stake_keys(&self) -> Vec<Epoch> {
                let mut keys: Vec<Epoch> = self.epoch_stakes.keys().copied().collect();
                keys.sort_unstable();
                keys
            }

            fn epoch_stake_key_info(&self) -> (Epoch, Epoch, usize) {
                let mut keys: Vec<Epoch> = self.epoch_stakes.keys().copied().collect();
                keys.sort_unstable();
                (*keys.first().unwrap(), *keys.last().unwrap(), keys.len())
            }
        }

        let (genesis_config, _mint_keypair) = create_genesis_config(100_000);
        let mut bank = Bank::new(&genesis_config);

        let initial_epochs = bank.epoch_stake_keys();
        assert_eq!(initial_epochs, vec![0, 1]);

        for existing_epoch in &initial_epochs {
            bank.update_epoch_stakes(*existing_epoch);
            assert_eq!(bank.epoch_stake_keys(), initial_epochs);
        }

        for epoch in (initial_epochs.len() as Epoch)..MAX_LEADER_SCHEDULE_STAKES {
            bank.update_epoch_stakes(epoch);
            assert_eq!(bank.epoch_stakes.len() as Epoch, epoch + 1);
        }

        assert_eq!(
            bank.epoch_stake_key_info(),
            (
                0,
                MAX_LEADER_SCHEDULE_STAKES - 1,
                MAX_LEADER_SCHEDULE_STAKES as usize
            )
        );

        bank.update_epoch_stakes(MAX_LEADER_SCHEDULE_STAKES);
        assert_eq!(
            bank.epoch_stake_key_info(),
            (
                0,
                MAX_LEADER_SCHEDULE_STAKES,
                MAX_LEADER_SCHEDULE_STAKES as usize + 1
            )
        );

        bank.update_epoch_stakes(MAX_LEADER_SCHEDULE_STAKES + 1);
        assert_eq!(
            bank.epoch_stake_key_info(),
            (
                1,
                MAX_LEADER_SCHEDULE_STAKES + 1,
                MAX_LEADER_SCHEDULE_STAKES as usize + 1
            )
        );
    }

    #[test]
    fn test_bank_capitalization() {
        let bank0 = Arc::new(Bank::new(&GenesisConfig {
            accounts: (0..42)
                .map(|_| {
                    (
                        solana_sdk::pubkey::new_rand(),
                        Account::new(42, 0, &Pubkey::default()),
                    )
                })
                .collect(),
            cluster_type: ClusterType::MainnetBeta,
            ..GenesisConfig::default()
        }));
        let sysvar_and_native_proram_delta0 = 11;
        assert_eq!(
            bank0.capitalization(),
            42 * 42 + sysvar_and_native_proram_delta0
        );
        let bank1 = Bank::new_from_parent(&bank0, &Pubkey::default(), 1);
        let sysvar_and_native_proram_delta1 = 2;
        assert_eq!(
            bank1.capitalization(),
            42 * 42 + sysvar_and_native_proram_delta0 + sysvar_and_native_proram_delta1,
        );
    }

    #[test]
    fn test_credit_debit_rent_no_side_effect_on_hash() {
        solana_logger::setup();

        let (mut genesis_config, _mint_keypair) = create_genesis_config(10);
        let keypair1: Keypair = Keypair::new();
        let keypair2: Keypair = Keypair::new();
        let keypair3: Keypair = Keypair::new();
        let keypair4: Keypair = Keypair::new();

        // Transaction between these two keypairs will fail
        let keypair5: Keypair = Keypair::new();
        let keypair6: Keypair = Keypair::new();

        genesis_config.rent = Rent {
            lamports_per_byte_year: 1,
            exemption_threshold: 21.0,
            burn_percent: 10,
        };

        let root_bank = Arc::new(Bank::new(&genesis_config));
        let bank = Bank::new_from_parent(
            &root_bank,
            &Pubkey::default(),
            years_as_slots(
                2.0,
                &genesis_config.poh_config.target_tick_duration,
                genesis_config.ticks_per_slot,
            ) as u64,
        );

        let root_bank_2 = Arc::new(Bank::new(&genesis_config));
        let bank_with_success_txs = Bank::new_from_parent(
            &root_bank_2,
            &Pubkey::default(),
            years_as_slots(
                2.0,
                &genesis_config.poh_config.target_tick_duration,
                genesis_config.ticks_per_slot,
            ) as u64,
        );

        assert_eq!(bank.last_blockhash(), genesis_config.hash());

        // Initialize credit-debit and credit only accounts
        let account1 = AccountSharedData::new(264, 0, &Pubkey::default());
        let account2 = AccountSharedData::new(264, 1, &Pubkey::default());
        let account3 = AccountSharedData::new(264, 0, &Pubkey::default());
        let account4 = AccountSharedData::new(264, 1, &Pubkey::default());
        let account5 = AccountSharedData::new(10, 0, &Pubkey::default());
        let account6 = AccountSharedData::new(10, 1, &Pubkey::default());

        bank.store_account(&keypair1.pubkey(), &account1);
        bank.store_account(&keypair2.pubkey(), &account2);
        bank.store_account(&keypair3.pubkey(), &account3);
        bank.store_account(&keypair4.pubkey(), &account4);
        bank.store_account(&keypair5.pubkey(), &account5);
        bank.store_account(&keypair6.pubkey(), &account6);

        bank_with_success_txs.store_account(&keypair1.pubkey(), &account1);
        bank_with_success_txs.store_account(&keypair2.pubkey(), &account2);
        bank_with_success_txs.store_account(&keypair3.pubkey(), &account3);
        bank_with_success_txs.store_account(&keypair4.pubkey(), &account4);
        bank_with_success_txs.store_account(&keypair5.pubkey(), &account5);
        bank_with_success_txs.store_account(&keypair6.pubkey(), &account6);

        // Make native instruction loader rent exempt
        let system_program_id = system_program::id();
        let mut system_program_account = bank.get_account(&system_program_id).unwrap();
        system_program_account.set_lamports(
            bank.get_minimum_balance_for_rent_exemption(system_program_account.data().len()),
        );
        bank.store_account(&system_program_id, &system_program_account);
        bank_with_success_txs.store_account(&system_program_id, &system_program_account);

        let t1 =
            system_transaction::transfer(&keypair1, &keypair2.pubkey(), 1, genesis_config.hash());
        let t2 =
            system_transaction::transfer(&keypair3, &keypair4.pubkey(), 1, genesis_config.hash());
        let t3 =
            system_transaction::transfer(&keypair5, &keypair6.pubkey(), 1, genesis_config.hash());

        let txs = vec![t1.clone(), t2.clone(), t3];
        let res = bank.process_transactions(txs.iter());

        assert_eq!(res.len(), 3);
        assert_eq!(res[0], Ok(()));
        assert_eq!(res[1], Ok(()));
        assert_eq!(res[2], Err(TransactionError::AccountNotFound));

        bank.freeze();

        let rwlockguard_bank_hash = bank.hash.read().unwrap();
        let bank_hash = rwlockguard_bank_hash.as_ref();

        let txs = vec![t2, t1];
        let res = bank_with_success_txs.process_transactions(txs.iter());

        assert_eq!(res.len(), 2);
        assert_eq!(res[0], Ok(()));
        assert_eq!(res[1], Ok(()));

        bank_with_success_txs.freeze();

        let rwlockguard_bank_with_success_txs_hash = bank_with_success_txs.hash.read().unwrap();
        let bank_with_success_txs_hash = rwlockguard_bank_with_success_txs_hash.as_ref();

        assert_eq!(bank_with_success_txs_hash, bank_hash);
    }

    #[derive(Serialize, Deserialize)]
    enum MockInstruction {
        Deduction,
    }

    fn mock_process_instruction(
        _program_id: &Pubkey,
        data: &[u8],
        invoke_context: &mut dyn InvokeContext,
    ) -> result::Result<(), InstructionError> {
        let keyed_accounts = invoke_context.get_keyed_accounts()?;
        if let Ok(instruction) = bincode::deserialize(data) {
            match instruction {
                MockInstruction::Deduction => {
                    keyed_accounts[1]
                        .account
                        .borrow_mut()
                        .checked_add_lamports(1)?;
                    keyed_accounts[2]
                        .account
                        .borrow_mut()
                        .checked_sub_lamports(1)?;
                    Ok(())
                }
            }
        } else {
            Err(InstructionError::InvalidInstructionData)
        }
    }

    fn create_mock_transaction(
        payer: &Keypair,
        keypair1: &Keypair,
        keypair2: &Keypair,
        read_only_keypair: &Keypair,
        mock_program_id: Pubkey,
        recent_blockhash: Hash,
    ) -> Transaction {
        let account_metas = vec![
            AccountMeta::new(payer.pubkey(), true),
            AccountMeta::new(keypair1.pubkey(), true),
            AccountMeta::new(keypair2.pubkey(), true),
            AccountMeta::new_readonly(read_only_keypair.pubkey(), false),
        ];
        let deduct_instruction = Instruction::new_with_bincode(
            mock_program_id,
            &MockInstruction::Deduction,
            account_metas,
        );
        Transaction::new_signed_with_payer(
            &[deduct_instruction],
            Some(&payer.pubkey()),
            &[payer, keypair1, keypair2],
            recent_blockhash,
        )
    }

    fn store_accounts_for_rent_test(
        bank: &Bank,
        keypairs: &mut Vec<Keypair>,
        mock_program_id: Pubkey,
        generic_rent_due_for_system_account: u64,
    ) {
        let mut account_pairs: Vec<(Pubkey, AccountSharedData)> =
            Vec::with_capacity(keypairs.len() - 1);
        account_pairs.push((
            keypairs[0].pubkey(),
            AccountSharedData::new(
                generic_rent_due_for_system_account + 2,
                0,
                &Pubkey::default(),
            ),
        ));
        account_pairs.push((
            keypairs[1].pubkey(),
            AccountSharedData::new(
                generic_rent_due_for_system_account + 2,
                0,
                &Pubkey::default(),
            ),
        ));
        account_pairs.push((
            keypairs[2].pubkey(),
            AccountSharedData::new(
                generic_rent_due_for_system_account + 2,
                0,
                &Pubkey::default(),
            ),
        ));
        account_pairs.push((
            keypairs[3].pubkey(),
            AccountSharedData::new(
                generic_rent_due_for_system_account + 2,
                0,
                &Pubkey::default(),
            ),
        ));
        account_pairs.push((
            keypairs[4].pubkey(),
            AccountSharedData::new(10, 0, &Pubkey::default()),
        ));
        account_pairs.push((
            keypairs[5].pubkey(),
            AccountSharedData::new(10, 0, &Pubkey::default()),
        ));
        account_pairs.push((
            keypairs[6].pubkey(),
            AccountSharedData::new(
                (2 * generic_rent_due_for_system_account) + 24,
                0,
                &Pubkey::default(),
            ),
        ));

        account_pairs.push((
            keypairs[8].pubkey(),
            AccountSharedData::new(
                generic_rent_due_for_system_account + 2 + 929,
                0,
                &Pubkey::default(),
            ),
        ));
        account_pairs.push((
            keypairs[9].pubkey(),
            AccountSharedData::new(10, 0, &Pubkey::default()),
        ));

        // Feeding to MockProgram to test read only rent behaviour
        account_pairs.push((
            keypairs[10].pubkey(),
            AccountSharedData::new(
                generic_rent_due_for_system_account + 3,
                0,
                &Pubkey::default(),
            ),
        ));
        account_pairs.push((
            keypairs[11].pubkey(),
            AccountSharedData::new(generic_rent_due_for_system_account + 3, 0, &mock_program_id),
        ));
        account_pairs.push((
            keypairs[12].pubkey(),
            AccountSharedData::new(generic_rent_due_for_system_account + 3, 0, &mock_program_id),
        ));
        account_pairs.push((
            keypairs[13].pubkey(),
            AccountSharedData::new(14, 22, &mock_program_id),
        ));

        for account_pair in account_pairs.iter() {
            bank.store_account(&account_pair.0, &account_pair.1);
        }
    }

    fn create_child_bank_for_rent_test(
        root_bank: &Arc<Bank>,
        genesis_config: &GenesisConfig,
        mock_program_id: Pubkey,
    ) -> Bank {
        let mut bank = Bank::new_from_parent(
            root_bank,
            &Pubkey::default(),
            years_as_slots(
                2.0,
                &genesis_config.poh_config.target_tick_duration,
                genesis_config.ticks_per_slot,
            ) as u64,
        );
        bank.rent_collector.slots_per_year = 421_812.0;
        bank.add_builtin("mock_program", mock_program_id, mock_process_instruction);

        bank
    }

    fn assert_capitalization_diff(bank: &Bank, updater: impl Fn(), asserter: impl Fn(u64, u64)) {
        let old = bank.capitalization();
        updater();
        let new = bank.capitalization();
        asserter(old, new);
        assert_eq!(bank.capitalization(), bank.calculate_capitalization(true));
    }

    fn assert_capitalization_diff_with_new_bank(
        bank: &Bank,
        updater: impl Fn() -> Bank,
        asserter: impl Fn(u64, u64),
    ) -> Bank {
        let old = bank.capitalization();
        let bank = updater();
        let new = bank.capitalization();
        asserter(old, new);
        assert_eq!(bank.capitalization(), bank.calculate_capitalization(true));
        bank
    }

    #[test]
    fn test_store_account_and_update_capitalization_missing() {
        let (genesis_config, _mint_keypair) = create_genesis_config(0);
        let bank = Bank::new(&genesis_config);
        let pubkey = solana_sdk::pubkey::new_rand();

        let some_lamports = 400;
        let account = AccountSharedData::new(some_lamports, 0, &system_program::id());

        assert_capitalization_diff(
            &bank,
            || bank.store_account_and_update_capitalization(&pubkey, &account),
            |old, new| assert_eq!(old + some_lamports, new),
        );
        assert_eq!(account, bank.get_account(&pubkey).unwrap());
    }

    #[test]
    fn test_store_account_and_update_capitalization_increased() {
        let old_lamports = 400;
        let (genesis_config, mint_keypair) = create_genesis_config(old_lamports);
        let bank = Bank::new(&genesis_config);
        let pubkey = mint_keypair.pubkey();

        let new_lamports = 500;
        let account = AccountSharedData::new(new_lamports, 0, &system_program::id());

        assert_capitalization_diff(
            &bank,
            || bank.store_account_and_update_capitalization(&pubkey, &account),
            |old, new| assert_eq!(old + 100, new),
        );
        assert_eq!(account, bank.get_account(&pubkey).unwrap());
    }

    #[test]
    fn test_store_account_and_update_capitalization_decreased() {
        let old_lamports = 400;
        let (genesis_config, mint_keypair) = create_genesis_config(old_lamports);
        let bank = Bank::new(&genesis_config);
        let pubkey = mint_keypair.pubkey();

        let new_lamports = 100;
        let account = AccountSharedData::new(new_lamports, 0, &system_program::id());

        assert_capitalization_diff(
            &bank,
            || bank.store_account_and_update_capitalization(&pubkey, &account),
            |old, new| assert_eq!(old - 300, new),
        );
        assert_eq!(account, bank.get_account(&pubkey).unwrap());
    }

    #[test]
    fn test_store_account_and_update_capitalization_unchanged() {
        let lamports = 400;
        let (genesis_config, mint_keypair) = create_genesis_config(lamports);
        let bank = Bank::new(&genesis_config);
        let pubkey = mint_keypair.pubkey();

        let account = AccountSharedData::new(lamports, 1, &system_program::id());

        assert_capitalization_diff(
            &bank,
            || bank.store_account_and_update_capitalization(&pubkey, &account),
            |old, new| assert_eq!(old, new),
        );
        assert_eq!(account, bank.get_account(&pubkey).unwrap());
    }

    #[test]
    fn test_rent_distribution() {
        solana_logger::setup();

        let bootstrap_validator_pubkey = solana_sdk::pubkey::new_rand();
        let bootstrap_validator_stake_lamports = 30;
        let mut genesis_config = create_genesis_config_with_leader(
            10,
            &bootstrap_validator_pubkey,
            bootstrap_validator_stake_lamports,
        )
        .genesis_config;

        genesis_config.epoch_schedule = EpochSchedule::custom(
            MINIMUM_SLOTS_PER_EPOCH,
            genesis_config.epoch_schedule.leader_schedule_slot_offset,
            false,
        );

        genesis_config.rent = Rent {
            lamports_per_byte_year: 1,
            exemption_threshold: 2.0,
            burn_percent: 10,
        };

        let rent = Rent::free();

        let validator_1_pubkey = solana_sdk::pubkey::new_rand();
        let validator_1_stake_lamports = 20;
        let validator_1_staking_keypair = Keypair::new();
        let validator_1_voting_keypair = Keypair::new();

        let validator_1_vote_account = vote_state::create_account(
            &validator_1_voting_keypair.pubkey(),
            &validator_1_pubkey,
            0,
            validator_1_stake_lamports,
        );

        let validator_1_stake_account = stake_state::create_account(
            &validator_1_staking_keypair.pubkey(),
            &validator_1_voting_keypair.pubkey(),
            &validator_1_vote_account,
            &rent,
            validator_1_stake_lamports,
        );

        genesis_config.accounts.insert(
            validator_1_pubkey,
            Account::new(42, 0, &system_program::id()),
        );
        genesis_config.accounts.insert(
            validator_1_staking_keypair.pubkey(),
            Account::from(validator_1_stake_account),
        );
        genesis_config.accounts.insert(
            validator_1_voting_keypair.pubkey(),
            Account::from(validator_1_vote_account),
        );

        let validator_2_pubkey = solana_sdk::pubkey::new_rand();
        let validator_2_stake_lamports = 20;
        let validator_2_staking_keypair = Keypair::new();
        let validator_2_voting_keypair = Keypair::new();

        let validator_2_vote_account = vote_state::create_account(
            &validator_2_voting_keypair.pubkey(),
            &validator_2_pubkey,
            0,
            validator_2_stake_lamports,
        );

        let validator_2_stake_account = stake_state::create_account(
            &validator_2_staking_keypair.pubkey(),
            &validator_2_voting_keypair.pubkey(),
            &validator_2_vote_account,
            &rent,
            validator_2_stake_lamports,
        );

        genesis_config.accounts.insert(
            validator_2_pubkey,
            Account::new(42, 0, &system_program::id()),
        );
        genesis_config.accounts.insert(
            validator_2_staking_keypair.pubkey(),
            Account::from(validator_2_stake_account),
        );
        genesis_config.accounts.insert(
            validator_2_voting_keypair.pubkey(),
            Account::from(validator_2_vote_account),
        );

        let validator_3_pubkey = solana_sdk::pubkey::new_rand();
        let validator_3_stake_lamports = 30;
        let validator_3_staking_keypair = Keypair::new();
        let validator_3_voting_keypair = Keypair::new();

        let validator_3_vote_account = vote_state::create_account(
            &validator_3_voting_keypair.pubkey(),
            &validator_3_pubkey,
            0,
            validator_3_stake_lamports,
        );

        let validator_3_stake_account = stake_state::create_account(
            &validator_3_staking_keypair.pubkey(),
            &validator_3_voting_keypair.pubkey(),
            &validator_3_vote_account,
            &rent,
            validator_3_stake_lamports,
        );

        genesis_config.accounts.insert(
            validator_3_pubkey,
            Account::new(42, 0, &system_program::id()),
        );
        genesis_config.accounts.insert(
            validator_3_staking_keypair.pubkey(),
            Account::from(validator_3_stake_account),
        );
        genesis_config.accounts.insert(
            validator_3_voting_keypair.pubkey(),
            Account::from(validator_3_vote_account),
        );

        genesis_config.rent = Rent {
            lamports_per_byte_year: 1,
            exemption_threshold: 10.0,
            burn_percent: 10,
        };

        let mut bank = Bank::new(&genesis_config);
        // Enable rent collection
        bank.rent_collector.epoch = 5;
        bank.rent_collector.slots_per_year = 192.0;

        let payer = Keypair::new();
        let payer_account = AccountSharedData::new(400, 0, &system_program::id());
        bank.store_account_and_update_capitalization(&payer.pubkey(), &payer_account);

        let payee = Keypair::new();
        let payee_account = AccountSharedData::new(70, 1, &system_program::id());
        bank.store_account_and_update_capitalization(&payee.pubkey(), &payee_account);

        let bootstrap_validator_initial_balance = bank.get_balance(&bootstrap_validator_pubkey);

        let tx = system_transaction::transfer(&payer, &payee.pubkey(), 180, genesis_config.hash());

        let result = bank.process_transaction(&tx);
        assert_eq!(result, Ok(()));

        let mut total_rent_deducted = 0;

        // 400 - 128(Rent) - 180(Transfer)
        assert_eq!(bank.get_balance(&payer.pubkey()), 92);
        total_rent_deducted += 128;

        // 70 - 70(Rent) + 180(Transfer) - 21(Rent)
        assert_eq!(bank.get_balance(&payee.pubkey()), 159);
        total_rent_deducted += 70 + 21;

        let previous_capitalization = bank.capitalization.load(Relaxed);

        bank.freeze();

        assert_eq!(bank.collected_rent.load(Relaxed), total_rent_deducted);

        let burned_portion =
            total_rent_deducted * u64::from(bank.rent_collector.rent.burn_percent) / 100;
        let rent_to_be_distributed = total_rent_deducted - burned_portion;

        let bootstrap_validator_portion =
            ((bootstrap_validator_stake_lamports * rent_to_be_distributed) as f64 / 100.0) as u64
                + 1; // Leftover lamport
        assert_eq!(
            bank.get_balance(&bootstrap_validator_pubkey),
            bootstrap_validator_portion + bootstrap_validator_initial_balance
        );

        // Since, validator 1 and validator 2 has equal smallest stake, it comes down to comparison
        // between their pubkey.
        let tweak_1 = if validator_1_pubkey > validator_2_pubkey {
            1
        } else {
            0
        };
        let validator_1_portion =
            ((validator_1_stake_lamports * rent_to_be_distributed) as f64 / 100.0) as u64 + tweak_1;
        assert_eq!(
            bank.get_balance(&validator_1_pubkey),
            validator_1_portion + 42 - tweak_1,
        );

        // Since, validator 1 and validator 2 has equal smallest stake, it comes down to comparison
        // between their pubkey.
        let tweak_2 = if validator_2_pubkey > validator_1_pubkey {
            1
        } else {
            0
        };
        let validator_2_portion =
            ((validator_2_stake_lamports * rent_to_be_distributed) as f64 / 100.0) as u64 + tweak_2;
        assert_eq!(
            bank.get_balance(&validator_2_pubkey),
            validator_2_portion + 42 - tweak_2,
        );

        let validator_3_portion =
            ((validator_3_stake_lamports * rent_to_be_distributed) as f64 / 100.0) as u64 + 1;
        assert_eq!(
            bank.get_balance(&validator_3_pubkey),
            validator_3_portion + 42
        );

        let current_capitalization = bank.capitalization.load(Relaxed);

        // only slot history is newly created
        let sysvar_and_native_proram_delta =
            min_rent_excempt_balance_for_sysvars(&bank, &[sysvar::slot_history::id()]);
        assert_eq!(
            previous_capitalization - (current_capitalization - sysvar_and_native_proram_delta),
            burned_portion
        );

        assert!(bank.calculate_and_verify_capitalization(true));

        assert_eq!(
            rent_to_be_distributed,
            bank.rewards
                .read()
                .unwrap()
                .iter()
                .map(|(address, reward)| {
                    if reward.lamports > 0 {
                        assert_eq!(reward.reward_type, RewardType::Rent);
                        if *address == validator_2_pubkey {
                            assert_eq!(reward.post_balance, validator_2_portion + 42 - tweak_2);
                        } else if *address == validator_3_pubkey {
                            assert_eq!(reward.post_balance, validator_3_portion + 42);
                        }
                        reward.lamports as u64
                    } else {
                        0
                    }
                })
                .sum::<u64>()
        );
    }

    #[test]
    fn test_distribute_rent_to_validators_overflow() {
        solana_logger::setup();

        // These values are taken from the real cluster (testnet)
        const RENT_TO_BE_DISTRIBUTED: u64 = 120_525;
        const VALIDATOR_STAKE: u64 = 374_999_998_287_840;

        let validator_pubkey = solana_sdk::pubkey::new_rand();
        let mut genesis_config =
            create_genesis_config_with_leader(10, &validator_pubkey, VALIDATOR_STAKE)
                .genesis_config;

        let bank = Bank::new(&genesis_config);
        let old_validator_lamports = bank.get_balance(&validator_pubkey);
        bank.distribute_rent_to_validators(bank.vote_accounts(), RENT_TO_BE_DISTRIBUTED);
        let new_validator_lamports = bank.get_balance(&validator_pubkey);
        assert_eq!(
            new_validator_lamports,
            old_validator_lamports + RENT_TO_BE_DISTRIBUTED
        );

        genesis_config
            .accounts
            .remove(&feature_set::no_overflow_rent_distribution::id())
            .unwrap();
        let bank = std::panic::AssertUnwindSafe(Bank::new(&genesis_config));
        let old_validator_lamports = bank.get_balance(&validator_pubkey);
        let new_validator_lamports = std::panic::catch_unwind(|| {
            bank.distribute_rent_to_validators(bank.vote_accounts(), RENT_TO_BE_DISTRIBUTED);
            bank.get_balance(&validator_pubkey)
        });

        if let Ok(new_validator_lamports) = new_validator_lamports {
            info!("asserting overflowing incorrect rent distribution");
            assert_ne!(
                new_validator_lamports,
                old_validator_lamports + RENT_TO_BE_DISTRIBUTED
            );
        } else {
            info!("NOT-asserting overflowing incorrect rent distribution");
        }
    }

    #[test]
    fn test_rent_exempt_executable_account() {
        let (mut genesis_config, mint_keypair) = create_genesis_config(100_000);
        genesis_config.rent = Rent {
            lamports_per_byte_year: 1,
            exemption_threshold: 1000.0,
            burn_percent: 10,
        };

        let root_bank = Arc::new(Bank::new(&genesis_config));
        let bank = create_child_bank_for_rent_test(
            &root_bank,
            &genesis_config,
            solana_sdk::pubkey::new_rand(),
        );

        let account_pubkey = solana_sdk::pubkey::new_rand();
        let account_balance = 1;
        let mut account =
            AccountSharedData::new(account_balance, 0, &solana_sdk::pubkey::new_rand());
        account.set_executable(true);
        bank.store_account(&account_pubkey, &account);

        let transfer_lamports = 1;
        let tx = system_transaction::transfer(
            &mint_keypair,
            &account_pubkey,
            transfer_lamports,
            genesis_config.hash(),
        );

        assert_eq!(
            bank.process_transaction(&tx),
            Err(TransactionError::InstructionError(
                0,
                InstructionError::ExecutableLamportChange
            ))
        );
        assert_eq!(bank.get_balance(&account_pubkey), account_balance);
    }

    #[test]
    #[allow(clippy::cognitive_complexity)]
    fn test_rent_complex() {
        solana_logger::setup();
        let mock_program_id = Pubkey::new(&[2u8; 32]);

        let (mut genesis_config, _mint_keypair) = create_genesis_config(10);
        let mut keypairs: Vec<Keypair> = Vec::with_capacity(14);
        for _i in 0..14 {
            keypairs.push(Keypair::new());
        }

        genesis_config.rent = Rent {
            lamports_per_byte_year: 1,
            exemption_threshold: 1000.0,
            burn_percent: 10,
        };

        let root_bank = Bank::new(&genesis_config);
        // until we completely transition to the eager rent collection,
        // we must ensure lazy rent collection doens't get broken!
        root_bank.restore_old_behavior_for_fragile_tests();
        let root_bank = Arc::new(root_bank);
        let bank = create_child_bank_for_rent_test(&root_bank, &genesis_config, mock_program_id);

        assert_eq!(bank.last_blockhash(), genesis_config.hash());

        let slots_elapsed: u64 = (0..=bank.epoch)
            .map(|epoch| {
                bank.rent_collector
                    .epoch_schedule
                    .get_slots_in_epoch(epoch + 1)
            })
            .sum();
        let (generic_rent_due_for_system_account, _) = bank.rent_collector.rent.due(
            bank.get_minimum_balance_for_rent_exemption(0) - 1,
            0,
            slots_elapsed as f64 / bank.rent_collector.slots_per_year,
        );

        store_accounts_for_rent_test(
            &bank,
            &mut keypairs,
            mock_program_id,
            generic_rent_due_for_system_account,
        );

        let magic_rent_number = 131; // yuck, derive this value programmatically one day

        let t1 = system_transaction::transfer(
            &keypairs[0],
            &keypairs[1].pubkey(),
            1,
            genesis_config.hash(),
        );
        let t2 = system_transaction::transfer(
            &keypairs[2],
            &keypairs[3].pubkey(),
            1,
            genesis_config.hash(),
        );
        let t3 = system_transaction::transfer(
            &keypairs[4],
            &keypairs[5].pubkey(),
            1,
            genesis_config.hash(),
        );
        let t4 = system_transaction::transfer(
            &keypairs[6],
            &keypairs[7].pubkey(),
            generic_rent_due_for_system_account + 1,
            genesis_config.hash(),
        );
        let t5 = system_transaction::transfer(
            &keypairs[8],
            &keypairs[9].pubkey(),
            929,
            genesis_config.hash(),
        );

        let t6 = create_mock_transaction(
            &keypairs[10],
            &keypairs[11],
            &keypairs[12],
            &keypairs[13],
            mock_program_id,
            genesis_config.hash(),
        );

        let txs = vec![t6, t5, t1, t2, t3, t4];
        let res = bank.process_transactions(txs.iter());

        assert_eq!(res.len(), 6);
        assert_eq!(res[0], Ok(()));
        assert_eq!(res[1], Ok(()));
        assert_eq!(res[2], Ok(()));
        assert_eq!(res[3], Ok(()));
        assert_eq!(res[4], Err(TransactionError::AccountNotFound));
        assert_eq!(res[5], Ok(()));

        bank.freeze();

        let mut rent_collected = 0;

        // 48992 - generic_rent_due_for_system_account(Rent) - 1(transfer)
        assert_eq!(bank.get_balance(&keypairs[0].pubkey()), 1);
        rent_collected += generic_rent_due_for_system_account;

        // 48992 - generic_rent_due_for_system_account(Rent) + 1(transfer)
        assert_eq!(bank.get_balance(&keypairs[1].pubkey()), 3);
        rent_collected += generic_rent_due_for_system_account;

        // 48992 - generic_rent_due_for_system_account(Rent) - 1(transfer)
        assert_eq!(bank.get_balance(&keypairs[2].pubkey()), 1);
        rent_collected += generic_rent_due_for_system_account;

        // 48992 - generic_rent_due_for_system_account(Rent) + 1(transfer)
        assert_eq!(bank.get_balance(&keypairs[3].pubkey()), 3);
        rent_collected += generic_rent_due_for_system_account;

        // No rent deducted
        assert_eq!(bank.get_balance(&keypairs[4].pubkey()), 10);
        assert_eq!(bank.get_balance(&keypairs[5].pubkey()), 10);

        // 98004 - generic_rent_due_for_system_account(Rent) - 48991(transfer)
        assert_eq!(bank.get_balance(&keypairs[6].pubkey()), 23);
        rent_collected += generic_rent_due_for_system_account;

        // 0 + 48990(transfer) - magic_rent_number(Rent)
        assert_eq!(
            bank.get_balance(&keypairs[7].pubkey()),
            generic_rent_due_for_system_account + 1 - magic_rent_number
        );

        // Epoch should be updated
        // Rent deducted on store side
        let account8 = bank.get_account(&keypairs[7].pubkey()).unwrap();
        // Epoch should be set correctly.
        assert_eq!(account8.rent_epoch(), bank.epoch + 1);
        rent_collected += magic_rent_number;

        // 49921 - generic_rent_due_for_system_account(Rent) - 929(Transfer)
        assert_eq!(bank.get_balance(&keypairs[8].pubkey()), 2);
        rent_collected += generic_rent_due_for_system_account;

        let account10 = bank.get_account(&keypairs[9].pubkey()).unwrap();
        // Account was overwritten at load time, since it didn't have sufficient balance to pay rent
        // Then, at store time we deducted `magic_rent_number` rent for the current epoch, once it has balance
        assert_eq!(account10.rent_epoch(), bank.epoch + 1);
        // account data is blank now
        assert_eq!(account10.data().len(), 0);
        // 10 - 10(Rent) + 929(Transfer) - magic_rent_number(Rent)
        assert_eq!(account10.lamports(), 929 - magic_rent_number);
        rent_collected += magic_rent_number + 10;

        // 48993 - generic_rent_due_for_system_account(Rent)
        assert_eq!(bank.get_balance(&keypairs[10].pubkey()), 3);
        rent_collected += generic_rent_due_for_system_account;

        // 48993 - generic_rent_due_for_system_account(Rent) + 1(Addition by program)
        assert_eq!(bank.get_balance(&keypairs[11].pubkey()), 4);
        rent_collected += generic_rent_due_for_system_account;

        // 48993 - generic_rent_due_for_system_account(Rent) - 1(Deduction by program)
        assert_eq!(bank.get_balance(&keypairs[12].pubkey()), 2);
        rent_collected += generic_rent_due_for_system_account;

        // No rent for read-only account
        assert_eq!(bank.get_balance(&keypairs[13].pubkey()), 14);

        // Bank's collected rent should be sum of rent collected from all accounts
        assert_eq!(bank.collected_rent.load(Relaxed), rent_collected);
    }

    #[test]
    fn test_rent_eager_across_epoch_without_gap() {
        let (genesis_config, _mint_keypair) = create_genesis_config(1);

        let mut bank = Arc::new(Bank::new(&genesis_config));
        assert_eq!(bank.rent_collection_partitions(), vec![(0, 0, 32)]);

        bank = Arc::new(new_from_parent(&bank));
        assert_eq!(bank.rent_collection_partitions(), vec![(0, 1, 32)]);
        for _ in 2..32 {
            bank = Arc::new(new_from_parent(&bank));
        }
        assert_eq!(bank.rent_collection_partitions(), vec![(30, 31, 32)]);
        bank = Arc::new(new_from_parent(&bank));
        assert_eq!(bank.rent_collection_partitions(), vec![(0, 0, 64)]);
    }

    #[test]
    fn test_rent_eager_across_epoch_with_full_gap() {
        let (mut genesis_config, _mint_keypair) = create_genesis_config(1);
        activate_all_features(&mut genesis_config);

        let mut bank = Arc::new(Bank::new(&genesis_config));
        assert_eq!(bank.rent_collection_partitions(), vec![(0, 0, 32)]);

        bank = Arc::new(new_from_parent(&bank));
        assert_eq!(bank.rent_collection_partitions(), vec![(0, 1, 32)]);
        for _ in 2..15 {
            bank = Arc::new(new_from_parent(&bank));
        }
        assert_eq!(bank.rent_collection_partitions(), vec![(13, 14, 32)]);
        bank = Arc::new(Bank::new_from_parent(&bank, &Pubkey::default(), 49));
        assert_eq!(
            bank.rent_collection_partitions(),
            vec![(14, 31, 32), (0, 0, 64), (0, 17, 64)]
        );
        bank = Arc::new(new_from_parent(&bank));
        assert_eq!(bank.rent_collection_partitions(), vec![(17, 18, 64)]);
    }

    #[test]
    fn test_rent_eager_across_epoch_with_half_gap() {
        let (mut genesis_config, _mint_keypair) = create_genesis_config(1);
        activate_all_features(&mut genesis_config);

        let mut bank = Arc::new(Bank::new(&genesis_config));
        assert_eq!(bank.rent_collection_partitions(), vec![(0, 0, 32)]);

        bank = Arc::new(new_from_parent(&bank));
        assert_eq!(bank.rent_collection_partitions(), vec![(0, 1, 32)]);
        for _ in 2..15 {
            bank = Arc::new(new_from_parent(&bank));
        }
        assert_eq!(bank.rent_collection_partitions(), vec![(13, 14, 32)]);
        bank = Arc::new(Bank::new_from_parent(&bank, &Pubkey::default(), 32));
        assert_eq!(
            bank.rent_collection_partitions(),
            vec![(14, 31, 32), (0, 0, 64)]
        );
        bank = Arc::new(new_from_parent(&bank));
        assert_eq!(bank.rent_collection_partitions(), vec![(0, 1, 64)]);
    }

    #[test]
    #[allow(clippy::cognitive_complexity)]
    fn test_rent_eager_across_epoch_without_gap_under_multi_epoch_cycle() {
        let leader_pubkey = solana_sdk::pubkey::new_rand();
        let leader_lamports = 3;
        let mut genesis_config =
            create_genesis_config_with_leader(5, &leader_pubkey, leader_lamports).genesis_config;
        genesis_config.cluster_type = ClusterType::MainnetBeta;

        const SLOTS_PER_EPOCH: u64 = MINIMUM_SLOTS_PER_EPOCH as u64;
        const LEADER_SCHEDULE_SLOT_OFFSET: u64 = SLOTS_PER_EPOCH * 3 - 3;
        genesis_config.epoch_schedule =
            EpochSchedule::custom(SLOTS_PER_EPOCH, LEADER_SCHEDULE_SLOT_OFFSET, false);

        let mut bank = Arc::new(Bank::new(&genesis_config));
        assert_eq!(DEFAULT_SLOTS_PER_EPOCH, 432_000);
        assert_eq!(bank.get_slots_in_epoch(bank.epoch()), 32);
        assert_eq!(bank.get_epoch_and_slot_index(bank.slot()), (0, 0));
        assert_eq!(bank.rent_collection_partitions(), vec![(0, 0, 432_000)]);

        bank = Arc::new(new_from_parent(&bank));
        assert_eq!(bank.get_slots_in_epoch(bank.epoch()), 32);
        assert_eq!(bank.get_epoch_and_slot_index(bank.slot()), (0, 1));
        assert_eq!(bank.rent_collection_partitions(), vec![(0, 1, 432_000)]);

        for _ in 2..32 {
            bank = Arc::new(new_from_parent(&bank));
        }
        assert_eq!(bank.get_slots_in_epoch(bank.epoch()), 32);
        assert_eq!(bank.get_epoch_and_slot_index(bank.slot()), (0, 31));
        assert_eq!(bank.rent_collection_partitions(), vec![(30, 31, 432_000)]);

        bank = Arc::new(new_from_parent(&bank));
        assert_eq!(bank.get_slots_in_epoch(bank.epoch()), 32);
        assert_eq!(bank.get_epoch_and_slot_index(bank.slot()), (1, 0));
        assert_eq!(bank.rent_collection_partitions(), vec![(31, 32, 432_000)]);

        bank = Arc::new(new_from_parent(&bank));
        assert_eq!(bank.get_slots_in_epoch(bank.epoch()), 32);
        assert_eq!(bank.get_epoch_and_slot_index(bank.slot()), (1, 1));
        assert_eq!(bank.rent_collection_partitions(), vec![(32, 33, 432_000)]);

        bank = Arc::new(Bank::new_from_parent(&bank, &Pubkey::default(), 1000));
        bank = Arc::new(Bank::new_from_parent(&bank, &Pubkey::default(), 1001));
        assert_eq!(bank.get_slots_in_epoch(bank.epoch()), 32);
        assert_eq!(bank.get_epoch_and_slot_index(bank.slot()), (31, 9));
        assert_eq!(
            bank.rent_collection_partitions(),
            vec![(1000, 1001, 432_000)]
        );

        bank = Arc::new(Bank::new_from_parent(&bank, &Pubkey::default(), 431_998));
        bank = Arc::new(Bank::new_from_parent(&bank, &Pubkey::default(), 431_999));
        assert_eq!(bank.get_slots_in_epoch(bank.epoch()), 32);
        assert_eq!(bank.get_epoch_and_slot_index(bank.slot()), (13499, 31));
        assert_eq!(
            bank.rent_collection_partitions(),
            vec![(431_998, 431_999, 432_000)]
        );

        bank = Arc::new(new_from_parent(&bank));
        assert_eq!(bank.get_slots_in_epoch(bank.epoch()), 32);
        assert_eq!(bank.get_epoch_and_slot_index(bank.slot()), (13500, 0));
        assert_eq!(bank.rent_collection_partitions(), vec![(0, 0, 432_000)]);

        bank = Arc::new(new_from_parent(&bank));
        assert_eq!(bank.get_slots_in_epoch(bank.epoch()), 32);
        assert_eq!(bank.get_epoch_and_slot_index(bank.slot()), (13500, 1));
        assert_eq!(bank.rent_collection_partitions(), vec![(0, 1, 432_000)]);
    }

    #[test]
    fn test_rent_eager_across_epoch_with_gap_under_multi_epoch_cycle() {
        let leader_pubkey = solana_sdk::pubkey::new_rand();
        let leader_lamports = 3;
        let mut genesis_config =
            create_genesis_config_with_leader(5, &leader_pubkey, leader_lamports).genesis_config;
        genesis_config.cluster_type = ClusterType::MainnetBeta;

        const SLOTS_PER_EPOCH: u64 = MINIMUM_SLOTS_PER_EPOCH as u64;
        const LEADER_SCHEDULE_SLOT_OFFSET: u64 = SLOTS_PER_EPOCH * 3 - 3;
        genesis_config.epoch_schedule =
            EpochSchedule::custom(SLOTS_PER_EPOCH, LEADER_SCHEDULE_SLOT_OFFSET, false);

        let mut bank = Arc::new(Bank::new(&genesis_config));
        assert_eq!(DEFAULT_SLOTS_PER_EPOCH, 432_000);
        assert_eq!(bank.get_slots_in_epoch(bank.epoch()), 32);
        assert_eq!(bank.get_epoch_and_slot_index(bank.slot()), (0, 0));
        assert_eq!(bank.rent_collection_partitions(), vec![(0, 0, 432_000)]);

        bank = Arc::new(new_from_parent(&bank));
        assert_eq!(bank.get_slots_in_epoch(bank.epoch()), 32);
        assert_eq!(bank.get_epoch_and_slot_index(bank.slot()), (0, 1));
        assert_eq!(bank.rent_collection_partitions(), vec![(0, 1, 432_000)]);

        for _ in 2..19 {
            bank = Arc::new(new_from_parent(&bank));
        }
        assert_eq!(bank.get_slots_in_epoch(bank.epoch()), 32);
        assert_eq!(bank.get_epoch_and_slot_index(bank.slot()), (0, 18));
        assert_eq!(bank.rent_collection_partitions(), vec![(17, 18, 432_000)]);

        bank = Arc::new(Bank::new_from_parent(&bank, &Pubkey::default(), 44));
        assert_eq!(bank.get_slots_in_epoch(bank.epoch()), 32);
        assert_eq!(bank.get_epoch_and_slot_index(bank.slot()), (1, 12));
        assert_eq!(
            bank.rent_collection_partitions(),
            vec![(18, 31, 432_000), (31, 31, 432_000), (31, 44, 432_000)]
        );

        bank = Arc::new(new_from_parent(&bank));
        assert_eq!(bank.get_slots_in_epoch(bank.epoch()), 32);
        assert_eq!(bank.get_epoch_and_slot_index(bank.slot()), (1, 13));
        assert_eq!(bank.rent_collection_partitions(), vec![(44, 45, 432_000)]);

        bank = Arc::new(Bank::new_from_parent(&bank, &Pubkey::default(), 431_993));
        bank = Arc::new(Bank::new_from_parent(&bank, &Pubkey::default(), 432_011));
        assert_eq!(bank.get_slots_in_epoch(bank.epoch()), 32);
        assert_eq!(bank.get_epoch_and_slot_index(bank.slot()), (13500, 11));
        assert_eq!(
            bank.rent_collection_partitions(),
            vec![
                (431_993, 431_999, 432_000),
                (0, 0, 432_000),
                (0, 11, 432_000)
            ]
        );
    }

    #[test]
    fn test_rent_eager_with_warmup_epochs_under_multi_epoch_cycle() {
        let leader_pubkey = solana_sdk::pubkey::new_rand();
        let leader_lamports = 3;
        let mut genesis_config =
            create_genesis_config_with_leader(5, &leader_pubkey, leader_lamports).genesis_config;
        genesis_config.cluster_type = ClusterType::MainnetBeta;

        const SLOTS_PER_EPOCH: u64 = MINIMUM_SLOTS_PER_EPOCH as u64 * 8;
        const LEADER_SCHEDULE_SLOT_OFFSET: u64 = SLOTS_PER_EPOCH * 3 - 3;
        genesis_config.epoch_schedule =
            EpochSchedule::custom(SLOTS_PER_EPOCH, LEADER_SCHEDULE_SLOT_OFFSET, true);

        let mut bank = Arc::new(Bank::new(&genesis_config));
        assert_eq!(DEFAULT_SLOTS_PER_EPOCH, 432_000);
        assert_eq!(bank.get_slots_in_epoch(bank.epoch()), 32);
        assert_eq!(bank.first_normal_epoch(), 3);
        assert_eq!(bank.get_epoch_and_slot_index(bank.slot()), (0, 0));
        assert_eq!(bank.rent_collection_partitions(), vec![(0, 0, 32)]);

        bank = Arc::new(Bank::new_from_parent(&bank, &Pubkey::default(), 222));
        bank = Arc::new(new_from_parent(&bank));
        assert_eq!(bank.get_slots_in_epoch(bank.epoch()), 128);
        assert_eq!(bank.get_epoch_and_slot_index(bank.slot()), (2, 127));
        assert_eq!(bank.rent_collection_partitions(), vec![(126, 127, 128)]);

        bank = Arc::new(new_from_parent(&bank));
        assert_eq!(bank.get_slots_in_epoch(bank.epoch()), 256);
        assert_eq!(bank.get_epoch_and_slot_index(bank.slot()), (3, 0));
        assert_eq!(bank.rent_collection_partitions(), vec![(0, 0, 431_872)]);
        assert_eq!(431_872 % bank.get_slots_in_epoch(bank.epoch()), 0);

        bank = Arc::new(new_from_parent(&bank));
        assert_eq!(bank.get_slots_in_epoch(bank.epoch()), 256);
        assert_eq!(bank.get_epoch_and_slot_index(bank.slot()), (3, 1));
        assert_eq!(bank.rent_collection_partitions(), vec![(0, 1, 431_872)]);

        bank = Arc::new(Bank::new_from_parent(
            &bank,
            &Pubkey::default(),
            431_872 + 223 - 1,
        ));
        bank = Arc::new(new_from_parent(&bank));
        assert_eq!(bank.get_slots_in_epoch(bank.epoch()), 256);
        assert_eq!(bank.get_epoch_and_slot_index(bank.slot()), (1689, 255));
        assert_eq!(
            bank.rent_collection_partitions(),
            vec![(431_870, 431_871, 431_872)]
        );

        bank = Arc::new(new_from_parent(&bank));
        assert_eq!(bank.get_slots_in_epoch(bank.epoch()), 256);
        assert_eq!(bank.get_epoch_and_slot_index(bank.slot()), (1690, 0));
        assert_eq!(bank.rent_collection_partitions(), vec![(0, 0, 431_872)]);
    }

    #[test]
    fn test_rent_eager_under_fixed_cycle_for_development() {
        solana_logger::setup();
        let leader_pubkey = solana_sdk::pubkey::new_rand();
        let leader_lamports = 3;
        let mut genesis_config =
            create_genesis_config_with_leader(5, &leader_pubkey, leader_lamports).genesis_config;

        const SLOTS_PER_EPOCH: u64 = MINIMUM_SLOTS_PER_EPOCH as u64 * 8;
        const LEADER_SCHEDULE_SLOT_OFFSET: u64 = SLOTS_PER_EPOCH * 3 - 3;
        genesis_config.epoch_schedule =
            EpochSchedule::custom(SLOTS_PER_EPOCH, LEADER_SCHEDULE_SLOT_OFFSET, true);

        let mut bank = Arc::new(Bank::new(&genesis_config));
        assert_eq!(bank.get_slots_in_epoch(bank.epoch()), 32);
        assert_eq!(bank.first_normal_epoch(), 3);
        assert_eq!(bank.get_epoch_and_slot_index(bank.slot()), (0, 0));
        assert_eq!(bank.rent_collection_partitions(), vec![(0, 0, 432_000)]);

        bank = Arc::new(Bank::new_from_parent(&bank, &Pubkey::default(), 222));
        bank = Arc::new(new_from_parent(&bank));
        assert_eq!(bank.get_slots_in_epoch(bank.epoch()), 128);
        assert_eq!(bank.get_epoch_and_slot_index(bank.slot()), (2, 127));
        assert_eq!(bank.rent_collection_partitions(), vec![(222, 223, 432_000)]);

        bank = Arc::new(new_from_parent(&bank));
        assert_eq!(bank.get_slots_in_epoch(bank.epoch()), 256);
        assert_eq!(bank.get_epoch_and_slot_index(bank.slot()), (3, 0));
        assert_eq!(bank.rent_collection_partitions(), vec![(223, 224, 432_000)]);

        bank = Arc::new(new_from_parent(&bank));
        assert_eq!(bank.get_slots_in_epoch(bank.epoch()), 256);
        assert_eq!(bank.get_epoch_and_slot_index(bank.slot()), (3, 1));
        assert_eq!(bank.rent_collection_partitions(), vec![(224, 225, 432_000)]);

        bank = Arc::new(Bank::new_from_parent(
            &bank,
            &Pubkey::default(),
            432_000 - 2,
        ));
        bank = Arc::new(new_from_parent(&bank));
        assert_eq!(
            bank.rent_collection_partitions(),
            vec![(431_998, 431_999, 432_000)]
        );
        bank = Arc::new(new_from_parent(&bank));
        assert_eq!(bank.rent_collection_partitions(), vec![(0, 0, 432_000)]);
        bank = Arc::new(new_from_parent(&bank));
        assert_eq!(bank.rent_collection_partitions(), vec![(0, 1, 432_000)]);

        bank = Arc::new(Bank::new_from_parent(
            &bank,
            &Pubkey::default(),
            864_000 - 20,
        ));
        bank = Arc::new(Bank::new_from_parent(
            &bank,
            &Pubkey::default(),
            864_000 + 39,
        ));
        assert_eq!(
            bank.rent_collection_partitions(),
            vec![
                (431_980, 431_999, 432_000),
                (0, 0, 432_000),
                (0, 39, 432_000)
            ]
        );
    }

    #[test]
    fn test_rent_eager_pubkey_range_minimal() {
        let range = Bank::pubkey_range_from_partition((0, 0, 1));
        assert_eq!(
            range,
            Pubkey::new_from_array([0x00; 32])..=Pubkey::new_from_array([0xff; 32])
        );
    }

    #[test]
    fn test_rent_eager_pubkey_range_maximum() {
        let max = !0;

        let range = Bank::pubkey_range_from_partition((0, 0, max));
        assert_eq!(
            range,
            Pubkey::new_from_array([0x00; 32])
                ..=Pubkey::new_from_array([
                    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff, 0xff,
                    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                    0xff, 0xff, 0xff, 0xff, 0xff, 0xff
                ])
        );
        let range = Bank::pubkey_range_from_partition((0, 1, max));
        assert_eq!(
            range,
            Pubkey::new_from_array([
                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                0x00, 0x00, 0x00, 0x00,
            ])
                ..=Pubkey::new_from_array([
                    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0xff, 0xff, 0xff, 0xff, 0xff,
                    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                    0xff, 0xff, 0xff, 0xff, 0xff, 0xff
                ])
        );
        let range = Bank::pubkey_range_from_partition((max - 3, max - 2, max));
        assert_eq!(
            range,
            Pubkey::new_from_array([
                0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfd, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                0x00, 0x00, 0x00, 0x00,
            ])
                ..=Pubkey::new_from_array([
                    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfd, 0xff, 0xff, 0xff, 0xff, 0xff,
                    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                    0xff, 0xff, 0xff, 0xff, 0xff, 0xff
                ])
        );
        let range = Bank::pubkey_range_from_partition((max - 2, max - 1, max));
        assert_eq!(
            range,
            Pubkey::new_from_array([
                0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfe, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                0x00, 0x00, 0x00, 0x00,
            ])
                ..=Pubkey::new_from_array([
                    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                    0xff, 0xff, 0xff, 0xff, 0xff, 0xff
                ])
        );

        fn should_cause_overflow(partition_count: u64) -> bool {
            // Check `partition_width = (u64::max_value() + 1) / partition_count` is exact and
            // does not have a remainder.
            // This way, `partition_width * partition_count == (u64::max_value() + 1)`,
            // so the test actually tests for overflow
            (u64::max_value() - partition_count + 1) % partition_count == 0
        }

        let max_exact = 64;
        // Make sure `max_exact` divides evenly when calculating `calculate_partition_width`
        assert!(should_cause_overflow(max_exact));
        // Make sure `max_inexact` doesn't divide evenly when calculating `calculate_partition_width`
        let max_inexact = 10;
        assert!(!should_cause_overflow(max_inexact));

        for max in &[max_exact, max_inexact] {
            let range = Bank::pubkey_range_from_partition((max - 1, max - 1, *max));
            assert_eq!(
                range,
                Pubkey::new_from_array([
                    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                    0xff, 0xff, 0xff, 0xff, 0xff, 0xff
                ])
                    ..=Pubkey::new_from_array([
                        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff
                    ])
            );
        }
    }

    fn map_to_test_bad_range() -> AccountMap<Pubkey, i8> {
        let mut map: AccountMap<Pubkey, i8> = AccountMap::new();
        // when empty, AccountMap (= std::collections::BTreeMap) doesn't sanitize given range...
        map.insert(solana_sdk::pubkey::new_rand(), 1);
        map
    }

    #[test]
    #[should_panic(expected = "range start is greater than range end in BTreeMap")]
    fn test_rent_eager_bad_range() {
        let test_map = map_to_test_bad_range();
        test_map.range(
            Pubkey::new_from_array([
                0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                0x00, 0x00, 0x00, 0x01,
            ])
                ..=Pubkey::new_from_array([
                    0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0x00, 0x00, 0x00, 0x00, 0x00,
                    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                    0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                ]),
        );
    }

    #[test]
    fn test_rent_eager_pubkey_range_noop_range() {
        let test_map = map_to_test_bad_range();

        let range = Bank::pubkey_range_from_partition((0, 0, 3));
        assert_eq!(
            range,
            Pubkey::new_from_array([
                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                0x00, 0x00, 0x00, 0x00
            ])
                ..=Pubkey::new_from_array([
                    0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x54, 0xff, 0xff, 0xff, 0xff, 0xff,
                    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                    0xff, 0xff, 0xff, 0xff, 0xff, 0xff
                ])
        );
        test_map.range(range);

        let range = Bank::pubkey_range_from_partition((1, 1, 3));
        assert_eq!(
            range,
            Pubkey::new_from_array([
                0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                0x00, 0x00, 0x00, 0x00
            ])
                ..=Pubkey::new_from_array([
                    0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0x00, 0x00, 0x00, 0x00, 0x00,
                    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                    0x00, 0x00, 0x00, 0x00, 0x00, 0x00
                ])
        );
        test_map.range(range);

        let range = Bank::pubkey_range_from_partition((2, 2, 3));
        assert_eq!(
            range,
            Pubkey::new_from_array([
                0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                0xff, 0xff, 0xff, 0xff
            ])
                ..=Pubkey::new_from_array([
                    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                    0xff, 0xff, 0xff, 0xff, 0xff, 0xff
                ])
        );
        test_map.range(range);
    }

    #[test]
    fn test_rent_eager_pubkey_range_dividable() {
        let test_map = map_to_test_bad_range();
        let range = Bank::pubkey_range_from_partition((0, 0, 2));

        assert_eq!(
            range,
            Pubkey::new_from_array([
                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                0x00, 0x00, 0x00, 0x00
            ])
                ..=Pubkey::new_from_array([
                    0x7f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                    0xff, 0xff, 0xff, 0xff, 0xff, 0xff
                ])
        );
        test_map.range(range);

        let range = Bank::pubkey_range_from_partition((0, 1, 2));
        assert_eq!(
            range,
            Pubkey::new_from_array([
                0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                0x00, 0x00, 0x00, 0x00
            ])
                ..=Pubkey::new_from_array([
                    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                    0xff, 0xff, 0xff, 0xff, 0xff, 0xff
                ])
        );
        test_map.range(range);
    }

    #[test]
    fn test_rent_eager_pubkey_range_not_dividable() {
        solana_logger::setup();

        let test_map = map_to_test_bad_range();
        let range = Bank::pubkey_range_from_partition((0, 0, 3));
        assert_eq!(
            range,
            Pubkey::new_from_array([
                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                0x00, 0x00, 0x00, 0x00
            ])
                ..=Pubkey::new_from_array([
                    0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x54, 0xff, 0xff, 0xff, 0xff, 0xff,
                    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                    0xff, 0xff, 0xff, 0xff, 0xff, 0xff
                ])
        );
        test_map.range(range);

        let range = Bank::pubkey_range_from_partition((0, 1, 3));
        assert_eq!(
            range,
            Pubkey::new_from_array([
                0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                0x00, 0x00, 0x00, 0x00
            ])
                ..=Pubkey::new_from_array([
                    0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xa9, 0xff, 0xff, 0xff, 0xff, 0xff,
                    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                    0xff, 0xff, 0xff, 0xff, 0xff, 0xff
                ])
        );
        test_map.range(range);

        let range = Bank::pubkey_range_from_partition((1, 2, 3));
        assert_eq!(
            range,
            Pubkey::new_from_array([
                0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                0x00, 0x00, 0x00, 0x00
            ])
                ..=Pubkey::new_from_array([
                    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                    0xff, 0xff, 0xff, 0xff, 0xff, 0xff
                ])
        );
        test_map.range(range);
    }

    #[test]
    fn test_rent_eager_pubkey_range_gap() {
        solana_logger::setup();

        let test_map = map_to_test_bad_range();
        let range = Bank::pubkey_range_from_partition((120, 1023, 12345));
        assert_eq!(
            range,
            Pubkey::new_from_array([
                0x02, 0x82, 0x5a, 0x89, 0xd1, 0xac, 0x58, 0x9c, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                0x00, 0x00, 0x00, 0x00
            ])
                ..=Pubkey::new_from_array([
                    0x15, 0x3c, 0x1d, 0xf1, 0xc6, 0x39, 0xef, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                    0xff, 0xff, 0xff, 0xff, 0xff, 0xff
                ])
        );
        test_map.range(range);
    }

    impl Bank {
        fn slots_by_pubkey(&self, pubkey: &Pubkey, ancestors: &Ancestors) -> Vec<Slot> {
            let (locked_entry, _) = self
                .rc
                .accounts
                .accounts_db
                .accounts_index
                .get(pubkey, Some(ancestors), None)
                .unwrap();
            locked_entry
                .slot_list()
                .iter()
                .map(|(slot, _)| *slot)
                .collect::<Vec<Slot>>()
        }

        fn first_slot_in_next_epoch(&self) -> Slot {
            self.epoch_schedule()
                .get_first_slot_in_epoch(self.epoch() + 1)
        }
    }

    #[test]
    fn test_rent_eager_collect_rent_in_partition() {
        solana_logger::setup();

        let (mut genesis_config, _mint_keypair) = create_genesis_config(1);
        activate_all_features(&mut genesis_config);

        let zero_lamport_pubkey = solana_sdk::pubkey::new_rand();
        let rent_due_pubkey = solana_sdk::pubkey::new_rand();
        let rent_exempt_pubkey = solana_sdk::pubkey::new_rand();

        let mut bank = Arc::new(Bank::new(&genesis_config));
        let zero_lamports = 0;
        let little_lamports = 1234;
        let large_lamports = 123_456_789;
        let rent_collected = 22;

        bank.store_account(
            &zero_lamport_pubkey,
            &AccountSharedData::new(zero_lamports, 0, &Pubkey::default()),
        );
        bank.store_account(
            &rent_due_pubkey,
            &AccountSharedData::new(little_lamports, 0, &Pubkey::default()),
        );
        bank.store_account(
            &rent_exempt_pubkey,
            &AccountSharedData::new(large_lamports, 0, &Pubkey::default()),
        );

        let genesis_slot = 0;
        let some_slot = 1000;
        let ancestors = vec![(some_slot, 0), (0, 1)].into_iter().collect();

        bank = Arc::new(Bank::new_from_parent(&bank, &Pubkey::default(), some_slot));

        assert_eq!(bank.collected_rent.load(Relaxed), 0);
        assert_eq!(
            bank.get_account(&rent_due_pubkey).unwrap().lamports(),
            little_lamports
        );
        assert_eq!(bank.get_account(&rent_due_pubkey).unwrap().rent_epoch(), 0);
        assert_eq!(
            bank.slots_by_pubkey(&rent_due_pubkey, &ancestors),
            vec![genesis_slot]
        );
        assert_eq!(
            bank.slots_by_pubkey(&rent_exempt_pubkey, &ancestors),
            vec![genesis_slot]
        );
        assert_eq!(
            bank.slots_by_pubkey(&zero_lamport_pubkey, &ancestors),
            vec![genesis_slot]
        );

        bank.collect_rent_in_partition((0, 0, 1)); // all range

        // unrelated 1-lamport account exists
        assert_eq!(bank.collected_rent.load(Relaxed), rent_collected + 1);
        assert_eq!(
            bank.get_account(&rent_due_pubkey).unwrap().lamports(),
            little_lamports - rent_collected
        );
        assert_eq!(bank.get_account(&rent_due_pubkey).unwrap().rent_epoch(), 6);
        assert_eq!(
            bank.get_account(&rent_exempt_pubkey).unwrap().lamports(),
            large_lamports
        );
        assert_eq!(
            bank.get_account(&rent_exempt_pubkey).unwrap().rent_epoch(),
            5
        );
        assert_eq!(
            bank.slots_by_pubkey(&rent_due_pubkey, &ancestors),
            vec![genesis_slot, some_slot]
        );
        assert_eq!(
            bank.slots_by_pubkey(&rent_exempt_pubkey, &ancestors),
            vec![genesis_slot, some_slot]
        );
        assert_eq!(
            bank.slots_by_pubkey(&zero_lamport_pubkey, &ancestors),
            vec![genesis_slot]
        );
    }

    #[test]
    fn test_rent_eager_collect_rent_zero_lamport_deterministic() {
        solana_logger::setup();

        let (genesis_config, _mint_keypair) = create_genesis_config(1);

        let zero_lamport_pubkey = solana_sdk::pubkey::new_rand();

        let genesis_bank1 = Arc::new(Bank::new(&genesis_config));
        let genesis_bank2 = Arc::new(Bank::new(&genesis_config));
        let bank1_with_zero = Arc::new(new_from_parent(&genesis_bank1));
        let bank1_without_zero = Arc::new(new_from_parent(&genesis_bank2));
        let zero_lamports = 0;

        let account = AccountSharedData::new(zero_lamports, 0, &Pubkey::default());
        bank1_with_zero.store_account(&zero_lamport_pubkey, &account);
        bank1_without_zero.store_account(&zero_lamport_pubkey, &account);

        bank1_without_zero
            .rc
            .accounts
            .accounts_db
            .accounts_index
            .add_root(genesis_bank1.slot() + 1, false);
        bank1_without_zero
            .rc
            .accounts
            .accounts_db
            .accounts_index
            .purge_roots(&zero_lamport_pubkey);

        let some_slot = 1000;
        let bank2_with_zero = Arc::new(Bank::new_from_parent(
            &bank1_with_zero,
            &Pubkey::default(),
            some_slot,
        ));
        let bank2_without_zero = Arc::new(Bank::new_from_parent(
            &bank1_without_zero,
            &Pubkey::default(),
            some_slot,
        ));
        let hash1_with_zero = bank1_with_zero.hash();
        let hash1_without_zero = bank1_without_zero.hash();
        assert_eq!(hash1_with_zero, hash1_without_zero);
        assert_ne!(hash1_with_zero, Hash::default());

        bank2_with_zero.collect_rent_in_partition((0, 0, 1)); // all
        bank2_without_zero.collect_rent_in_partition((0, 0, 1)); // all

        bank2_with_zero.freeze();
        let hash2_with_zero = bank2_with_zero.hash();
        bank2_without_zero.freeze();
        let hash2_without_zero = bank2_without_zero.hash();

        assert_eq!(hash2_with_zero, hash2_without_zero);
        assert_ne!(hash2_with_zero, Hash::default());
    }

    #[test]
    fn test_bank_update_vote_stake_rewards() {
        solana_logger::setup();

        // create a bank that ticks really slowly...
        let bank0 = Arc::new(Bank::new(&GenesisConfig {
            accounts: (0..42)
                .map(|_| {
                    (
                        solana_sdk::pubkey::new_rand(),
                        Account::new(1_000_000_000, 0, &Pubkey::default()),
                    )
                })
                .collect(),
            // set it up so the first epoch is a full year long
            poh_config: PohConfig {
                target_tick_duration: Duration::from_secs(
                    SECONDS_PER_YEAR as u64
                        / MINIMUM_SLOTS_PER_EPOCH as u64
                        / DEFAULT_TICKS_PER_SLOT,
                ),
                hashes_per_tick: None,
                target_tick_count: None,
            },
            cluster_type: ClusterType::MainnetBeta,

            ..GenesisConfig::default()
        }));

        // enable lazy rent collection because this test depends on rent-due accounts
        // not being eagerly-collected for exact rewards calculation
        bank0.restore_old_behavior_for_fragile_tests();

        let sysvar_and_native_program_delta0 = 11;
        assert_eq!(
            bank0.capitalization(),
            42 * 1_000_000_000 + sysvar_and_native_program_delta0
        );
        assert!(bank0.rewards.read().unwrap().is_empty());

        let ((vote_id, mut vote_account), (stake_id, stake_account)) =
            crate::stakes::tests::create_staked_node_accounts(1_0000);

        // set up accounts
        bank0.store_account_and_update_capitalization(&stake_id, &stake_account);

        // generate some rewards
        let mut vote_state = Some(VoteState::from(&vote_account).unwrap());
        for i in 0..MAX_LOCKOUT_HISTORY + 42 {
            if let Some(v) = vote_state.as_mut() {
                v.process_slot_vote_unchecked(i as u64)
            }
            let versioned = VoteStateVersions::Current(Box::new(vote_state.take().unwrap()));
            VoteState::to(&versioned, &mut vote_account).unwrap();
            bank0.store_account_and_update_capitalization(&vote_id, &vote_account);
            match versioned {
                VoteStateVersions::Current(v) => {
                    vote_state = Some(*v);
                }
                _ => panic!("Has to be of type Current"),
            };
        }
        bank0.store_account_and_update_capitalization(&vote_id, &vote_account);

        let validator_points: u128 = bank0
            .stake_delegation_accounts(&mut null_tracer())
            .iter()
            .flat_map(|(_vote_pubkey, (stake_group, vote_account))| {
                stake_group
                    .iter()
                    .map(move |(_stake_pubkey, stake_account)| (stake_account, vote_account))
            })
            .map(|(stake_account, vote_account)| {
                stake_state::calculate_points(stake_account, vote_account, None, true).unwrap_or(0)
            })
            .sum();

        // put a child bank in epoch 1, which calls update_rewards()...
        let bank1 = Bank::new_from_parent(
            &bank0,
            &Pubkey::default(),
            bank0.get_slots_in_epoch(bank0.epoch()) + 1,
        );
        // verify that there's inflation
        assert_ne!(bank1.capitalization(), bank0.capitalization());

        // verify the inflation is represented in validator_points *
        let sysvar_and_native_proram_delta1 = 2;
        let paid_rewards =
            bank1.capitalization() - bank0.capitalization() - sysvar_and_native_proram_delta1;

        let rewards = bank1
            .get_account(&sysvar::rewards::id())
            .map(|account| from_account::<Rewards, _>(&account).unwrap())
            .unwrap();

        // verify the stake and vote accounts are the right size
        assert!(
            ((bank1.get_balance(&stake_id) - stake_account.lamports() + bank1.get_balance(&vote_id)
                - vote_account.lamports()) as f64
                - rewards.validator_point_value * validator_points as f64)
                .abs()
                < 1.0
        );

        // verify the rewards are the right size
        let allocated_rewards = rewards.validator_point_value * validator_points as f64;
        assert!((allocated_rewards - paid_rewards as f64).abs() < 1.0); // rounding, truncating

        // verify validator rewards show up in bank1.rewards vector
        assert_eq!(
            *bank1.rewards.read().unwrap(),
            vec![(
                stake_id,
                RewardInfo {
                    reward_type: RewardType::Staking,
                    lamports: (rewards.validator_point_value * validator_points as f64) as i64,
                    post_balance: bank1.get_balance(&stake_id),
                    commission: Some(0),
                }
            )]
        );
        bank1.freeze();
        assert!(bank1.calculate_and_verify_capitalization(true));
    }

    fn do_test_bank_update_rewards_determinism() -> u64 {
        // create a bank that ticks really slowly...
        let bank = Arc::new(Bank::new(&GenesisConfig {
            accounts: (0..42)
                .map(|_| {
                    (
                        solana_sdk::pubkey::new_rand(),
                        Account::new(1_000_000_000, 0, &Pubkey::default()),
                    )
                })
                .collect(),
            // set it up so the first epoch is a full year long
            poh_config: PohConfig {
                target_tick_duration: Duration::from_secs(
                    SECONDS_PER_YEAR as u64
                        / MINIMUM_SLOTS_PER_EPOCH as u64
                        / DEFAULT_TICKS_PER_SLOT,
                ),
                hashes_per_tick: None,
                target_tick_count: None,
            },
            cluster_type: ClusterType::MainnetBeta,

            ..GenesisConfig::default()
        }));

        // enable lazy rent collection because this test depends on rent-due accounts
        // not being eagerly-collected for exact rewards calculation
        bank.restore_old_behavior_for_fragile_tests();

        let sysvar_and_native_proram_delta = 11;
        assert_eq!(
            bank.capitalization(),
            42 * 1_000_000_000 + sysvar_and_native_proram_delta
        );
        assert!(bank.rewards.read().unwrap().is_empty());

        let vote_id = solana_sdk::pubkey::new_rand();
        let mut vote_account =
            vote_state::create_account(&vote_id, &solana_sdk::pubkey::new_rand(), 50, 100);
        let (stake_id1, stake_account1) = crate::stakes::tests::create_stake_account(123, &vote_id);
        let (stake_id2, stake_account2) = crate::stakes::tests::create_stake_account(456, &vote_id);

        // set up accounts
        bank.store_account_and_update_capitalization(&stake_id1, &stake_account1);
        bank.store_account_and_update_capitalization(&stake_id2, &stake_account2);

        // generate some rewards
        let mut vote_state = Some(VoteState::from(&vote_account).unwrap());
        for i in 0..MAX_LOCKOUT_HISTORY + 42 {
            if let Some(v) = vote_state.as_mut() {
                v.process_slot_vote_unchecked(i as u64)
            }
            let versioned = VoteStateVersions::Current(Box::new(vote_state.take().unwrap()));
            VoteState::to(&versioned, &mut vote_account).unwrap();
            bank.store_account_and_update_capitalization(&vote_id, &vote_account);
            match versioned {
                VoteStateVersions::Current(v) => {
                    vote_state = Some(*v);
                }
                _ => panic!("Has to be of type Current"),
            };
        }
        bank.store_account_and_update_capitalization(&vote_id, &vote_account);

        // put a child bank in epoch 1, which calls update_rewards()...
        let bank1 = Bank::new_from_parent(
            &bank,
            &Pubkey::default(),
            bank.get_slots_in_epoch(bank.epoch()) + 1,
        );
        // verify that there's inflation
        assert_ne!(bank1.capitalization(), bank.capitalization());

        bank1.freeze();
        assert!(bank1.calculate_and_verify_capitalization(true));

        // verify voting and staking rewards are recorded
        let rewards = bank1.rewards.read().unwrap();
        rewards
            .iter()
            .find(|(_address, reward)| reward.reward_type == RewardType::Voting)
            .unwrap();
        rewards
            .iter()
            .find(|(_address, reward)| reward.reward_type == RewardType::Staking)
            .unwrap();

        bank1.capitalization()
    }

    #[test]
    fn test_bank_update_rewards_determinism() {
        solana_logger::setup();

        // The same reward should be distributed given same credits
        let expected_capitalization = do_test_bank_update_rewards_determinism();
        // Repeat somewhat large number of iterations to expose possible different behavior
        // depending on the randomly-seeded HashMap ordering
        for _ in 0..30 {
            let actual_capitalization = do_test_bank_update_rewards_determinism();
            assert_eq!(actual_capitalization, expected_capitalization);
        }
    }

    // Test that purging 0 lamports accounts works.
    #[test]
    fn test_purge_empty_accounts() {
        solana_logger::setup();
        let (genesis_config, mint_keypair) = create_genesis_config(500_000);
        let parent = Arc::new(Bank::new(&genesis_config));
        let mut bank = parent;
        for _ in 0..10 {
            let blockhash = bank.last_blockhash();
            let pubkey = solana_sdk::pubkey::new_rand();
            let tx = system_transaction::transfer(&mint_keypair, &pubkey, 0, blockhash);
            bank.process_transaction(&tx).unwrap();
            bank.freeze();
            bank.squash();
            bank = Arc::new(new_from_parent(&bank));
        }

        bank.freeze();
        bank.squash();
        bank.force_flush_accounts_cache();
        let hash = bank.update_accounts_hash();
        bank.clean_accounts(false, false);
        assert_eq!(bank.update_accounts_hash(), hash);

        let bank0 = Arc::new(new_from_parent(&bank));
        let blockhash = bank.last_blockhash();
        let keypair = Keypair::new();
        let tx = system_transaction::transfer(&mint_keypair, &keypair.pubkey(), 10, blockhash);
        bank0.process_transaction(&tx).unwrap();

        let bank1 = Arc::new(new_from_parent(&bank0));
        let pubkey = solana_sdk::pubkey::new_rand();
        let blockhash = bank.last_blockhash();
        let tx = system_transaction::transfer(&keypair, &pubkey, 10, blockhash);
        bank1.process_transaction(&tx).unwrap();

        assert_eq!(bank0.get_account(&keypair.pubkey()).unwrap().lamports(), 10);
        assert_eq!(bank1.get_account(&keypair.pubkey()), None);

        info!("bank0 purge");
        let hash = bank0.update_accounts_hash();
        bank0.clean_accounts(false, false);
        assert_eq!(bank0.update_accounts_hash(), hash);

        assert_eq!(bank0.get_account(&keypair.pubkey()).unwrap().lamports(), 10);
        assert_eq!(bank1.get_account(&keypair.pubkey()), None);

        info!("bank1 purge");
        bank1.clean_accounts(false, false);

        assert_eq!(bank0.get_account(&keypair.pubkey()).unwrap().lamports(), 10);
        assert_eq!(bank1.get_account(&keypair.pubkey()), None);

        assert!(bank0.verify_bank_hash(true));

        // Squash and then verify hash_internal value
        bank0.freeze();
        bank0.squash();
        assert!(bank0.verify_bank_hash(true));

        bank1.freeze();
        bank1.squash();
        bank1.update_accounts_hash();
        assert!(bank1.verify_bank_hash(true));

        // keypair should have 0 tokens on both forks
        assert_eq!(bank0.get_account(&keypair.pubkey()), None);
        assert_eq!(bank1.get_account(&keypair.pubkey()), None);
        bank1.force_flush_accounts_cache();
        bank1.clean_accounts(false, false);

        assert!(bank1.verify_bank_hash(true));
    }

    #[test]
    fn test_two_payments_to_one_party() {
        let (genesis_config, mint_keypair) = create_genesis_config(10_000);
        let pubkey = solana_sdk::pubkey::new_rand();
        let bank = Bank::new(&genesis_config);
        assert_eq!(bank.last_blockhash(), genesis_config.hash());

        bank.transfer(1_000, &mint_keypair, &pubkey).unwrap();
        assert_eq!(bank.get_balance(&pubkey), 1_000);

        bank.transfer(500, &mint_keypair, &pubkey).unwrap();
        assert_eq!(bank.get_balance(&pubkey), 1_500);
        assert_eq!(bank.transaction_count(), 2);
    }

    #[test]
    fn test_one_source_two_tx_one_batch() {
        let (genesis_config, mint_keypair) = create_genesis_config(1);
        let key1 = solana_sdk::pubkey::new_rand();
        let key2 = solana_sdk::pubkey::new_rand();
        let bank = Bank::new(&genesis_config);
        assert_eq!(bank.last_blockhash(), genesis_config.hash());

        let t1 = system_transaction::transfer(&mint_keypair, &key1, 1, genesis_config.hash());
        let t2 = system_transaction::transfer(&mint_keypair, &key2, 1, genesis_config.hash());
        let txs = vec![t1.clone(), t2.clone()];
        let res = bank.process_transactions(txs.iter());

        assert_eq!(res.len(), 2);
        assert_eq!(res[0], Ok(()));
        assert_eq!(res[1], Err(TransactionError::AccountInUse));
        assert_eq!(bank.get_balance(&mint_keypair.pubkey()), 0);
        assert_eq!(bank.get_balance(&key1), 1);
        assert_eq!(bank.get_balance(&key2), 0);
        assert_eq!(bank.get_signature_status(&t1.signatures[0]), Some(Ok(())));
        // TODO: Transactions that fail to pay a fee could be dropped silently.
        // Non-instruction errors don't get logged in the signature cache
        assert_eq!(bank.get_signature_status(&t2.signatures[0]), None);
    }

    #[test]
    fn test_one_tx_two_out_atomic_fail() {
        let (genesis_config, mint_keypair) = create_genesis_config(1);
        let key1 = solana_sdk::pubkey::new_rand();
        let key2 = solana_sdk::pubkey::new_rand();
        let bank = Bank::new(&genesis_config);
        let instructions =
            system_instruction::transfer_many(&mint_keypair.pubkey(), &[(key1, 1), (key2, 1)]);
        let message = Message::new(&instructions, Some(&mint_keypair.pubkey()));
        let tx = Transaction::new(&[&mint_keypair], message, genesis_config.hash());
        assert_eq!(
            bank.process_transaction(&tx).unwrap_err(),
            TransactionError::InstructionError(1, SystemError::ResultWithNegativeLamports.into())
        );
        assert_eq!(bank.get_balance(&mint_keypair.pubkey()), 1);
        assert_eq!(bank.get_balance(&key1), 0);
        assert_eq!(bank.get_balance(&key2), 0);
    }

    #[test]
    fn test_one_tx_two_out_atomic_pass() {
        let (genesis_config, mint_keypair) = create_genesis_config(2);
        let key1 = solana_sdk::pubkey::new_rand();
        let key2 = solana_sdk::pubkey::new_rand();
        let bank = Bank::new(&genesis_config);
        let instructions =
            system_instruction::transfer_many(&mint_keypair.pubkey(), &[(key1, 1), (key2, 1)]);
        let message = Message::new(&instructions, Some(&mint_keypair.pubkey()));
        let tx = Transaction::new(&[&mint_keypair], message, genesis_config.hash());
        bank.process_transaction(&tx).unwrap();
        assert_eq!(bank.get_balance(&mint_keypair.pubkey()), 0);
        assert_eq!(bank.get_balance(&key1), 1);
        assert_eq!(bank.get_balance(&key2), 1);
    }

    // This test demonstrates that fees are paid even when a program fails.
    #[test]
    fn test_detect_failed_duplicate_transactions() {
        let (mut genesis_config, mint_keypair) = create_genesis_config(2);
        genesis_config.fee_rate_governor = FeeRateGovernor::new(1, 0);
        let bank = Bank::new(&genesis_config);

        let dest = Keypair::new();

        // source with 0 program context
        let tx =
            system_transaction::transfer(&mint_keypair, &dest.pubkey(), 2, genesis_config.hash());
        let signature = tx.signatures[0];
        assert!(!bank.has_signature(&signature));

        assert_eq!(
            bank.process_transaction(&tx),
            Err(TransactionError::InstructionError(
                0,
                SystemError::ResultWithNegativeLamports.into(),
            ))
        );

        // The lamports didn't move, but the from address paid the transaction fee.
        assert_eq!(bank.get_balance(&dest.pubkey()), 0);

        // This should be the original balance minus the transaction fee.
        assert_eq!(bank.get_balance(&mint_keypair.pubkey()), 1);
    }

    #[test]
    fn test_account_not_found() {
        solana_logger::setup();
        let (genesis_config, mint_keypair) = create_genesis_config(0);
        let bank = Bank::new(&genesis_config);
        let keypair = Keypair::new();
        assert_eq!(
            bank.transfer(1, &keypair, &mint_keypair.pubkey()),
            Err(TransactionError::AccountNotFound)
        );
        assert_eq!(bank.transaction_count(), 0);
    }

    #[test]
    fn test_insufficient_funds() {
        let (genesis_config, mint_keypair) = create_genesis_config(11_000);
        let bank = Bank::new(&genesis_config);
        let pubkey = solana_sdk::pubkey::new_rand();
        bank.transfer(1_000, &mint_keypair, &pubkey).unwrap();
        assert_eq!(bank.transaction_count(), 1);
        assert_eq!(bank.get_balance(&pubkey), 1_000);
        assert_eq!(
            bank.transfer(10_001, &mint_keypair, &pubkey),
            Err(TransactionError::InstructionError(
                0,
                SystemError::ResultWithNegativeLamports.into(),
            ))
        );
        assert_eq!(bank.transaction_count(), 1);

        let mint_pubkey = mint_keypair.pubkey();
        assert_eq!(bank.get_balance(&mint_pubkey), 10_000);
        assert_eq!(bank.get_balance(&pubkey), 1_000);
    }

    #[test]
    fn test_transfer_to_newb() {
        solana_logger::setup();
        let (genesis_config, mint_keypair) = create_genesis_config(10_000);
        let bank = Bank::new(&genesis_config);
        let pubkey = solana_sdk::pubkey::new_rand();
        bank.transfer(500, &mint_keypair, &pubkey).unwrap();
        assert_eq!(bank.get_balance(&pubkey), 500);
    }

    #[test]
    fn test_transfer_to_sysvar() {
        solana_logger::setup();
        let (genesis_config, mint_keypair) = create_genesis_config(10_000);
        let bank = Arc::new(Bank::new(&genesis_config));

        let normal_pubkey = solana_sdk::pubkey::new_rand();
        let sysvar_pubkey = sysvar::clock::id();
        assert_eq!(bank.get_balance(&normal_pubkey), 0);
        assert_eq!(bank.get_balance(&sysvar_pubkey), 1);

        bank.transfer(500, &mint_keypair, &normal_pubkey).unwrap();
        bank.transfer(500, &mint_keypair, &sysvar_pubkey)
            .unwrap_err();
        assert_eq!(bank.get_balance(&normal_pubkey), 500);
        assert_eq!(bank.get_balance(&sysvar_pubkey), 1);

        let bank = Arc::new(new_from_parent(&bank));
        assert_eq!(bank.get_balance(&normal_pubkey), 500);
        assert_eq!(bank.get_balance(&sysvar_pubkey), 1);
    }

    #[test]
    fn test_bank_deposit() {
        let (genesis_config, _mint_keypair) = create_genesis_config(100);
        let bank = Bank::new(&genesis_config);

        // Test new account
        let key = Keypair::new();
        let new_balance = bank.deposit(&key.pubkey(), 10).unwrap();
        assert_eq!(new_balance, 10);
        assert_eq!(bank.get_balance(&key.pubkey()), 10);

        // Existing account
        let new_balance = bank.deposit(&key.pubkey(), 3).unwrap();
        assert_eq!(new_balance, 13);
        assert_eq!(bank.get_balance(&key.pubkey()), 13);
    }

    #[test]
    fn test_bank_withdraw() {
        let (genesis_config, _mint_keypair) = create_genesis_config(100);
        let bank = Bank::new(&genesis_config);

        // Test no account
        let key = Keypair::new();
        assert_eq!(
            bank.withdraw(&key.pubkey(), 10),
            Err(TransactionError::AccountNotFound)
        );

        bank.deposit(&key.pubkey(), 3).unwrap();
        assert_eq!(bank.get_balance(&key.pubkey()), 3);

        // Low balance
        assert_eq!(
            bank.withdraw(&key.pubkey(), 10),
            Err(TransactionError::InsufficientFundsForFee)
        );

        // Enough balance
        assert_eq!(bank.withdraw(&key.pubkey(), 2), Ok(()));
        assert_eq!(bank.get_balance(&key.pubkey()), 1);
    }

    #[test]
    fn test_bank_withdraw_from_nonce_account() {
        let (mut genesis_config, _mint_keypair) = create_genesis_config(100_000);
        genesis_config.rent.lamports_per_byte_year = 42;
        let bank = Bank::new(&genesis_config);

        let min_balance = bank.get_minimum_balance_for_rent_exemption(nonce::State::size());
        let nonce = Keypair::new();
        let nonce_account = AccountSharedData::new_data(
            min_balance + 42,
            &nonce::state::Versions::new_current(nonce::State::Initialized(
                nonce::state::Data::default(),
            )),
            &system_program::id(),
        )
        .unwrap();
        bank.store_account(&nonce.pubkey(), &nonce_account);
        assert_eq!(bank.get_balance(&nonce.pubkey()), min_balance + 42);

        // Resulting in non-zero, but sub-min_balance balance fails
        assert_eq!(
            bank.withdraw(&nonce.pubkey(), min_balance / 2),
            Err(TransactionError::InsufficientFundsForFee)
        );
        assert_eq!(bank.get_balance(&nonce.pubkey()), min_balance + 42);

        // Resulting in exactly rent-exempt balance succeeds
        bank.withdraw(&nonce.pubkey(), 42).unwrap();
        assert_eq!(bank.get_balance(&nonce.pubkey()), min_balance);

        // Account closure fails
        assert_eq!(
            bank.withdraw(&nonce.pubkey(), min_balance),
            Err(TransactionError::InsufficientFundsForFee),
        );
    }

    #[test]
    fn test_bank_tx_fee() {
        solana_logger::setup();

        let arbitrary_transfer_amount = 42;
        let mint = arbitrary_transfer_amount * 100;
        let leader = solana_sdk::pubkey::new_rand();
        let GenesisConfigInfo {
            mut genesis_config,
            mint_keypair,
            ..
        } = create_genesis_config_with_leader(mint, &leader, 3);
        genesis_config.fee_rate_governor = FeeRateGovernor::new(4, 0); // something divisible by 2

        let expected_fee_paid = genesis_config
            .fee_rate_governor
            .create_fee_calculator()
            .lamports_per_signature;
        let (expected_fee_collected, expected_fee_burned) =
            genesis_config.fee_rate_governor.burn(expected_fee_paid);

        let mut bank = Bank::new(&genesis_config);

        let capitalization = bank.capitalization();

        let key = Keypair::new();
        let tx = system_transaction::transfer(
            &mint_keypair,
            &key.pubkey(),
            arbitrary_transfer_amount,
            bank.last_blockhash(),
        );

        let initial_balance = bank.get_balance(&leader);
        assert_eq!(bank.process_transaction(&tx), Ok(()));
        assert_eq!(bank.get_balance(&key.pubkey()), arbitrary_transfer_amount);
        assert_eq!(
            bank.get_balance(&mint_keypair.pubkey()),
            mint - arbitrary_transfer_amount - expected_fee_paid
        );

        assert_eq!(bank.get_balance(&leader), initial_balance);
        goto_end_of_slot(&mut bank);
        assert_eq!(bank.signature_count(), 1);
        assert_eq!(
            bank.get_balance(&leader),
            initial_balance + expected_fee_collected
        ); // Leader collects fee after the bank is frozen

        // verify capitalization
        let sysvar_and_native_proram_delta = 1;
        assert_eq!(
            capitalization - expected_fee_burned + sysvar_and_native_proram_delta,
            bank.capitalization()
        );

        assert_eq!(
            *bank.rewards.read().unwrap(),
            vec![(
                leader,
                RewardInfo {
                    reward_type: RewardType::Fee,
                    lamports: expected_fee_collected as i64,
                    post_balance: initial_balance + expected_fee_collected,
                    commission: None,
                }
            )]
        );

        // Verify that an InstructionError collects fees, too
        let mut bank = Bank::new_from_parent(&Arc::new(bank), &leader, 1);
        let mut tx =
            system_transaction::transfer(&mint_keypair, &key.pubkey(), 1, bank.last_blockhash());
        // Create a bogus instruction to system_program to cause an instruction error
        tx.message.instructions[0].data[0] = 40;

        bank.process_transaction(&tx)
            .expect_err("instruction error");
        assert_eq!(bank.get_balance(&key.pubkey()), arbitrary_transfer_amount); // no change
        assert_eq!(
            bank.get_balance(&mint_keypair.pubkey()),
            mint - arbitrary_transfer_amount - 2 * expected_fee_paid
        ); // mint_keypair still pays a fee
        goto_end_of_slot(&mut bank);
        assert_eq!(bank.signature_count(), 1);

        // Profit! 2 transaction signatures processed at 3 lamports each
        assert_eq!(
            bank.get_balance(&leader),
            initial_balance + 2 * expected_fee_collected
        );

        assert_eq!(
            *bank.rewards.read().unwrap(),
            vec![(
                leader,
                RewardInfo {
                    reward_type: RewardType::Fee,
                    lamports: expected_fee_collected as i64,
                    post_balance: initial_balance + 2 * expected_fee_collected,
                    commission: None,
                }
            )]
        );
    }

    #[test]
    fn test_bank_blockhash_fee_schedule() {
        //solana_logger::setup();

        let leader = solana_sdk::pubkey::new_rand();
        let GenesisConfigInfo {
            mut genesis_config,
            mint_keypair,
            ..
        } = create_genesis_config_with_leader(1_000_000, &leader, 3);
        genesis_config
            .fee_rate_governor
            .target_lamports_per_signature = 1000;
        genesis_config.fee_rate_governor.target_signatures_per_slot = 1;

        let mut bank = Bank::new(&genesis_config);
        goto_end_of_slot(&mut bank);
        let (cheap_blockhash, cheap_fee_calculator) = bank.last_blockhash_with_fee_calculator();
        assert_eq!(cheap_fee_calculator.lamports_per_signature, 0);

        let mut bank = Bank::new_from_parent(&Arc::new(bank), &leader, 1);
        goto_end_of_slot(&mut bank);
        let (expensive_blockhash, expensive_fee_calculator) =
            bank.last_blockhash_with_fee_calculator();
        assert!(
            cheap_fee_calculator.lamports_per_signature
                < expensive_fee_calculator.lamports_per_signature
        );

        let bank = Bank::new_from_parent(&Arc::new(bank), &leader, 2);

        // Send a transfer using cheap_blockhash
        let key = Keypair::new();
        let initial_mint_balance = bank.get_balance(&mint_keypair.pubkey());
        let tx = system_transaction::transfer(&mint_keypair, &key.pubkey(), 1, cheap_blockhash);
        assert_eq!(bank.process_transaction(&tx), Ok(()));
        assert_eq!(bank.get_balance(&key.pubkey()), 1);
        assert_eq!(
            bank.get_balance(&mint_keypair.pubkey()),
            initial_mint_balance - 1 - cheap_fee_calculator.lamports_per_signature
        );

        // Send a transfer using expensive_blockhash
        let key = Keypair::new();
        let initial_mint_balance = bank.get_balance(&mint_keypair.pubkey());
        let tx = system_transaction::transfer(&mint_keypair, &key.pubkey(), 1, expensive_blockhash);
        assert_eq!(bank.process_transaction(&tx), Ok(()));
        assert_eq!(bank.get_balance(&key.pubkey()), 1);
        assert_eq!(
            bank.get_balance(&mint_keypair.pubkey()),
            initial_mint_balance - 1 - expensive_fee_calculator.lamports_per_signature
        );
    }

    #[test]
    fn test_filter_program_errors_and_collect_fee() {
        let leader = solana_sdk::pubkey::new_rand();
        let GenesisConfigInfo {
            mut genesis_config,
            mint_keypair,
            ..
        } = create_genesis_config_with_leader(100, &leader, 3);
        genesis_config.fee_rate_governor = FeeRateGovernor::new(2, 0);
        let bank = Bank::new(&genesis_config);

        let key = Keypair::new();
        let tx1 =
            system_transaction::transfer(&mint_keypair, &key.pubkey(), 2, genesis_config.hash());
        let tx2 =
            system_transaction::transfer(&mint_keypair, &key.pubkey(), 5, genesis_config.hash());

        let results = vec![
            (Ok(()), None),
            (
                Err(TransactionError::InstructionError(
                    1,
                    SystemError::ResultWithNegativeLamports.into(),
                )),
                None,
            ),
        ];
        let initial_balance = bank.get_balance(&leader);

        let results = bank.filter_program_errors_and_collect_fee([tx1, tx2].iter(), &results);
        bank.freeze();
        assert_eq!(
            bank.get_balance(&leader),
            initial_balance
                + bank
                    .fee_rate_governor
                    .burn(bank.fee_calculator.lamports_per_signature * 2)
                    .0
        );
        assert_eq!(results[0], Ok(()));
        assert_eq!(results[1], Ok(()));
    }

    #[test]
    fn test_debits_before_credits() {
        let (genesis_config, mint_keypair) = create_genesis_config(2);
        let bank = Bank::new(&genesis_config);
        let keypair = Keypair::new();
        let tx0 = system_transaction::transfer(
            &mint_keypair,
            &keypair.pubkey(),
            2,
            genesis_config.hash(),
        );
        let tx1 = system_transaction::transfer(
            &keypair,
            &mint_keypair.pubkey(),
            1,
            genesis_config.hash(),
        );
        let txs = vec![tx0, tx1];
        let results = bank.process_transactions(txs.iter());
        assert!(results[1].is_err());

        // Assert bad transactions aren't counted.
        assert_eq!(bank.transaction_count(), 1);
    }

    #[test]
    fn test_readonly_accounts() {
        let GenesisConfigInfo {
            genesis_config,
            mint_keypair,
            ..
        } = create_genesis_config_with_leader(500, &solana_sdk::pubkey::new_rand(), 0);
        let bank = Bank::new(&genesis_config);

        let vote_pubkey0 = solana_sdk::pubkey::new_rand();
        let vote_pubkey1 = solana_sdk::pubkey::new_rand();
        let vote_pubkey2 = solana_sdk::pubkey::new_rand();
        let authorized_voter = Keypair::new();
        let payer0 = Keypair::new();
        let payer1 = Keypair::new();

        // Create vote accounts
        let vote_account0 =
            vote_state::create_account(&vote_pubkey0, &authorized_voter.pubkey(), 0, 100);
        let vote_account1 =
            vote_state::create_account(&vote_pubkey1, &authorized_voter.pubkey(), 0, 100);
        let vote_account2 =
            vote_state::create_account(&vote_pubkey2, &authorized_voter.pubkey(), 0, 100);
        bank.store_account(&vote_pubkey0, &vote_account0);
        bank.store_account(&vote_pubkey1, &vote_account1);
        bank.store_account(&vote_pubkey2, &vote_account2);

        // Fund payers
        bank.transfer(10, &mint_keypair, &payer0.pubkey()).unwrap();
        bank.transfer(10, &mint_keypair, &payer1.pubkey()).unwrap();
        bank.transfer(1, &mint_keypair, &authorized_voter.pubkey())
            .unwrap();

        let vote = Vote::new(vec![1], Hash::default());
        let ix0 = vote_instruction::vote(&vote_pubkey0, &authorized_voter.pubkey(), vote.clone());
        let tx0 = Transaction::new_signed_with_payer(
            &[ix0],
            Some(&payer0.pubkey()),
            &[&payer0, &authorized_voter],
            bank.last_blockhash(),
        );
        let ix1 = vote_instruction::vote(&vote_pubkey1, &authorized_voter.pubkey(), vote.clone());
        let tx1 = Transaction::new_signed_with_payer(
            &[ix1],
            Some(&payer1.pubkey()),
            &[&payer1, &authorized_voter],
            bank.last_blockhash(),
        );
        let txs = vec![tx0, tx1];
        let results = bank.process_transactions(txs.iter());

        // If multiple transactions attempt to read the same account, they should succeed.
        // Vote authorized_voter and sysvar accounts are given read-only handling
        assert_eq!(results[0], Ok(()));
        assert_eq!(results[1], Ok(()));

        let ix0 = vote_instruction::vote(&vote_pubkey2, &authorized_voter.pubkey(), vote);
        let tx0 = Transaction::new_signed_with_payer(
            &[ix0],
            Some(&payer0.pubkey()),
            &[&payer0, &authorized_voter],
            bank.last_blockhash(),
        );
        let tx1 = system_transaction::transfer(
            &authorized_voter,
            &solana_sdk::pubkey::new_rand(),
            1,
            bank.last_blockhash(),
        );
        let txs = vec![tx0, tx1];
        let results = bank.process_transactions(txs.iter());
        // However, an account may not be locked as read-only and writable at the same time.
        assert_eq!(results[0], Ok(()));
        assert_eq!(results[1], Err(TransactionError::AccountInUse));
    }

    #[test]
    fn test_interleaving_locks() {
        let (genesis_config, mint_keypair) = create_genesis_config(3);
        let bank = Bank::new(&genesis_config);
        let alice = Keypair::new();
        let bob = Keypair::new();

        let tx1 =
            system_transaction::transfer(&mint_keypair, &alice.pubkey(), 1, genesis_config.hash());
        let pay_alice = vec![tx1];

        let lock_result = bank.prepare_batch(pay_alice.iter()).unwrap();
        let results_alice = bank
            .load_execute_and_commit_transactions(
                &lock_result,
                MAX_PROCESSING_AGE,
                false,
                false,
                false,
                &mut ExecuteTimings::default(),
            )
            .0
            .fee_collection_results;
        assert_eq!(results_alice[0], Ok(()));

        // try executing an interleaved transfer twice
        assert_eq!(
            bank.transfer(1, &mint_keypair, &bob.pubkey()),
            Err(TransactionError::AccountInUse)
        );
        // the second time should fail as well
        // this verifies that `unlock_accounts` doesn't unlock `AccountInUse` accounts
        assert_eq!(
            bank.transfer(1, &mint_keypair, &bob.pubkey()),
            Err(TransactionError::AccountInUse)
        );

        drop(lock_result);

        assert!(bank.transfer(2, &mint_keypair, &bob.pubkey()).is_ok());
    }

    #[test]
    fn test_readonly_relaxed_locks() {
        let (genesis_config, _) = create_genesis_config(3);
        let bank = Bank::new(&genesis_config);
        let key0 = Keypair::new();
        let key1 = Keypair::new();
        let key2 = Keypair::new();
        let key3 = solana_sdk::pubkey::new_rand();

        let message = Message {
            header: MessageHeader {
                num_required_signatures: 1,
                num_readonly_signed_accounts: 0,
                num_readonly_unsigned_accounts: 1,
            },
            account_keys: vec![key0.pubkey(), key3],
            recent_blockhash: Hash::default(),
            instructions: vec![],
        };
        let tx = Transaction::new(&[&key0], message, genesis_config.hash());
        let txs = vec![tx];

        let batch0 = bank.prepare_batch(txs.iter()).unwrap();
        assert!(batch0.lock_results()[0].is_ok());

        // Try locking accounts, locking a previously read-only account as writable
        // should fail
        let message = Message {
            header: MessageHeader {
                num_required_signatures: 1,
                num_readonly_signed_accounts: 0,
                num_readonly_unsigned_accounts: 0,
            },
            account_keys: vec![key1.pubkey(), key3],
            recent_blockhash: Hash::default(),
            instructions: vec![],
        };
        let tx = Transaction::new(&[&key1], message, genesis_config.hash());
        let txs = vec![tx];

        let batch1 = bank.prepare_batch(txs.iter()).unwrap();
        assert!(batch1.lock_results()[0].is_err());

        // Try locking a previously read-only account a 2nd time; should succeed
        let message = Message {
            header: MessageHeader {
                num_required_signatures: 1,
                num_readonly_signed_accounts: 0,
                num_readonly_unsigned_accounts: 1,
            },
            account_keys: vec![key2.pubkey(), key3],
            recent_blockhash: Hash::default(),
            instructions: vec![],
        };
        let tx = Transaction::new(&[&key2], message, genesis_config.hash());
        let txs = vec![tx];

        let batch2 = bank.prepare_batch(txs.iter()).unwrap();
        assert!(batch2.lock_results()[0].is_ok());
    }

    #[test]
    fn test_bank_invalid_account_index() {
        let (genesis_config, mint_keypair) = create_genesis_config(1);
        let keypair = Keypair::new();
        let bank = Bank::new(&genesis_config);

        let tx = system_transaction::transfer(
            &mint_keypair,
            &keypair.pubkey(),
            1,
            genesis_config.hash(),
        );

        let mut tx_invalid_program_index = tx.clone();
        tx_invalid_program_index.message.instructions[0].program_id_index = 42;
        assert_eq!(
            bank.process_transaction(&tx_invalid_program_index),
            Err(TransactionError::SanitizeFailure)
        );

        let mut tx_invalid_account_index = tx;
        tx_invalid_account_index.message.instructions[0].accounts[0] = 42;
        assert_eq!(
            bank.process_transaction(&tx_invalid_account_index),
            Err(TransactionError::SanitizeFailure)
        );
    }

    #[test]
    fn test_bank_pay_to_self() {
        let (genesis_config, mint_keypair) = create_genesis_config(1);
        let key1 = Keypair::new();
        let bank = Bank::new(&genesis_config);

        bank.transfer(1, &mint_keypair, &key1.pubkey()).unwrap();
        assert_eq!(bank.get_balance(&key1.pubkey()), 1);
        let tx = system_transaction::transfer(&key1, &key1.pubkey(), 1, genesis_config.hash());
        let _res = bank.process_transaction(&tx);

        assert_eq!(bank.get_balance(&key1.pubkey()), 1);
        bank.get_signature_status(&tx.signatures[0])
            .unwrap()
            .unwrap();
    }

    fn new_from_parent(parent: &Arc<Bank>) -> Bank {
        Bank::new_from_parent(parent, &Pubkey::default(), parent.slot() + 1)
    }

    /// Verify that the parent's vector is computed correctly
    #[test]
    fn test_bank_parents() {
        let (genesis_config, _) = create_genesis_config(1);
        let parent = Arc::new(Bank::new(&genesis_config));

        let bank = new_from_parent(&parent);
        assert!(Arc::ptr_eq(&bank.parents()[0], &parent));
    }

    /// Verifies that transactions are dropped if they have already been processed
    #[test]
    fn test_tx_already_processed() {
        let (genesis_config, mint_keypair) = create_genesis_config(2);
        let bank = Bank::new(&genesis_config);

        let key1 = Keypair::new();
        let mut tx =
            system_transaction::transfer(&mint_keypair, &key1.pubkey(), 1, genesis_config.hash());

        // First process `tx` so that the status cache is updated
        assert_eq!(bank.process_transaction(&tx), Ok(()));

        // Ensure that signature check works
        assert_eq!(
            bank.process_transaction(&tx),
            Err(TransactionError::AlreadyProcessed)
        );

        // Change transaction signature to simulate processing a transaction with a different signature
        // for the same message.
        tx.signatures[0] = Signature::default();

        // Ensure that message hash check works
        assert_eq!(
            bank.process_transaction(&tx),
            Err(TransactionError::AlreadyProcessed)
        );
    }

    /// Verifies that last ids and status cache are correctly referenced from parent
    #[test]
    fn test_bank_parent_already_processed() {
        let (genesis_config, mint_keypair) = create_genesis_config(2);
        let key1 = Keypair::new();
        let parent = Arc::new(Bank::new(&genesis_config));

        let tx =
            system_transaction::transfer(&mint_keypair, &key1.pubkey(), 1, genesis_config.hash());
        assert_eq!(parent.process_transaction(&tx), Ok(()));
        let bank = new_from_parent(&parent);
        assert_eq!(
            bank.process_transaction(&tx),
            Err(TransactionError::AlreadyProcessed)
        );
    }

    /// Verifies that last ids and accounts are correctly referenced from parent
    #[test]
    fn test_bank_parent_account_spend() {
        let (genesis_config, mint_keypair) = create_genesis_config(2);
        let key1 = Keypair::new();
        let key2 = Keypair::new();
        let parent = Arc::new(Bank::new(&genesis_config));

        let tx =
            system_transaction::transfer(&mint_keypair, &key1.pubkey(), 1, genesis_config.hash());
        assert_eq!(parent.process_transaction(&tx), Ok(()));
        let bank = new_from_parent(&parent);
        let tx = system_transaction::transfer(&key1, &key2.pubkey(), 1, genesis_config.hash());
        assert_eq!(bank.process_transaction(&tx), Ok(()));
        assert_eq!(parent.get_signature_status(&tx.signatures[0]), None);
    }

    #[test]
    fn test_bank_hash_internal_state() {
        let (genesis_config, mint_keypair) = create_genesis_config(2_000);
        let bank0 = Bank::new(&genesis_config);
        let bank1 = Bank::new(&genesis_config);
        let initial_state = bank0.hash_internal_state();
        assert_eq!(bank1.hash_internal_state(), initial_state);

        let pubkey = solana_sdk::pubkey::new_rand();
        bank0.transfer(1_000, &mint_keypair, &pubkey).unwrap();
        assert_ne!(bank0.hash_internal_state(), initial_state);
        bank1.transfer(1_000, &mint_keypair, &pubkey).unwrap();
        assert_eq!(bank0.hash_internal_state(), bank1.hash_internal_state());

        // Checkpointing should always result in a new state
        let bank2 = new_from_parent(&Arc::new(bank1));
        assert_ne!(bank0.hash_internal_state(), bank2.hash_internal_state());

        let pubkey2 = solana_sdk::pubkey::new_rand();
        info!("transfer 2 {}", pubkey2);
        bank2.transfer(10, &mint_keypair, &pubkey2).unwrap();
        bank2.update_accounts_hash();
        assert!(bank2.verify_bank_hash(true));
    }

    #[test]
    fn test_bank_hash_internal_state_verify() {
        solana_logger::setup();
        let (genesis_config, mint_keypair) = create_genesis_config(2_000);
        let bank0 = Bank::new(&genesis_config);

        let pubkey = solana_sdk::pubkey::new_rand();
        info!("transfer 0 {} mint: {}", pubkey, mint_keypair.pubkey());
        bank0.transfer(1_000, &mint_keypair, &pubkey).unwrap();

        let bank0_state = bank0.hash_internal_state();
        let bank0 = Arc::new(bank0);
        // Checkpointing should result in a new state while freezing the parent
        let bank2 = Bank::new_from_parent(&bank0, &solana_sdk::pubkey::new_rand(), 1);
        assert_ne!(bank0_state, bank2.hash_internal_state());
        // Checkpointing should modify the checkpoint's state when freezed
        assert_ne!(bank0_state, bank0.hash_internal_state());

        // Checkpointing should never modify the checkpoint's state once frozen
        let bank0_state = bank0.hash_internal_state();
        bank2.update_accounts_hash();
        assert!(bank2.verify_bank_hash(true));
        let bank3 = Bank::new_from_parent(&bank0, &solana_sdk::pubkey::new_rand(), 2);
        assert_eq!(bank0_state, bank0.hash_internal_state());
        assert!(bank2.verify_bank_hash(true));
        bank3.update_accounts_hash();
        assert!(bank3.verify_bank_hash(true));

        let pubkey2 = solana_sdk::pubkey::new_rand();
        info!("transfer 2 {}", pubkey2);
        bank2.transfer(10, &mint_keypair, &pubkey2).unwrap();
        bank2.update_accounts_hash();
        assert!(bank2.verify_bank_hash(true));
        assert!(bank3.verify_bank_hash(true));
    }

    #[test]
    #[should_panic(expected = "assertion failed: self.is_frozen()")]
    fn test_verify_hash_unfrozen() {
        let (genesis_config, _mint_keypair) = create_genesis_config(2_000);
        let bank = Bank::new(&genesis_config);
        assert!(bank.verify_hash());
    }

    #[test]
    fn test_verify_snapshot_bank() {
        solana_logger::setup();
        let pubkey = solana_sdk::pubkey::new_rand();
        let (genesis_config, mint_keypair) = create_genesis_config(2_000);
        let bank = Bank::new(&genesis_config);
        bank.transfer(1_000, &mint_keypair, &pubkey).unwrap();
        bank.freeze();
        bank.update_accounts_hash();
        assert!(bank.verify_snapshot_bank(true));

        // tamper the bank after freeze!
        bank.increment_signature_count(1);
        assert!(!bank.verify_snapshot_bank(true));
    }

    // Test that two bank forks with the same accounts should not hash to the same value.
    #[test]
    fn test_bank_hash_internal_state_same_account_different_fork() {
        solana_logger::setup();
        let (genesis_config, mint_keypair) = create_genesis_config(2_000);
        let bank0 = Arc::new(Bank::new(&genesis_config));
        let initial_state = bank0.hash_internal_state();
        let bank1 = Bank::new_from_parent(&bank0, &Pubkey::default(), 1);
        assert_ne!(bank1.hash_internal_state(), initial_state);

        info!("transfer bank1");
        let pubkey = solana_sdk::pubkey::new_rand();
        bank1.transfer(1_000, &mint_keypair, &pubkey).unwrap();
        assert_ne!(bank1.hash_internal_state(), initial_state);

        info!("transfer bank2");
        // bank2 should not hash the same as bank1
        let bank2 = Bank::new_from_parent(&bank0, &Pubkey::default(), 2);
        bank2.transfer(1_000, &mint_keypair, &pubkey).unwrap();
        assert_ne!(bank2.hash_internal_state(), initial_state);
        assert_ne!(bank1.hash_internal_state(), bank2.hash_internal_state());
    }

    #[test]
    fn test_hash_internal_state_genesis() {
        let bank0 = Bank::new(&create_genesis_config(10).0);
        let bank1 = Bank::new(&create_genesis_config(20).0);
        assert_ne!(bank0.hash_internal_state(), bank1.hash_internal_state());
    }

    // See that the order of two transfers does not affect the result
    // of hash_internal_state
    #[test]
    fn test_hash_internal_state_order() {
        let (genesis_config, mint_keypair) = create_genesis_config(100);
        let bank0 = Bank::new(&genesis_config);
        let bank1 = Bank::new(&genesis_config);
        assert_eq!(bank0.hash_internal_state(), bank1.hash_internal_state());
        let key0 = solana_sdk::pubkey::new_rand();
        let key1 = solana_sdk::pubkey::new_rand();
        bank0.transfer(10, &mint_keypair, &key0).unwrap();
        bank0.transfer(20, &mint_keypair, &key1).unwrap();

        bank1.transfer(20, &mint_keypair, &key1).unwrap();
        bank1.transfer(10, &mint_keypair, &key0).unwrap();

        assert_eq!(bank0.hash_internal_state(), bank1.hash_internal_state());
    }

    #[test]
    fn test_hash_internal_state_error() {
        solana_logger::setup();
        let (genesis_config, mint_keypair) = create_genesis_config(100);
        let bank = Bank::new(&genesis_config);
        let key0 = solana_sdk::pubkey::new_rand();
        bank.transfer(10, &mint_keypair, &key0).unwrap();
        let orig = bank.hash_internal_state();

        // Transfer will error but still take a fee
        assert!(bank.transfer(1000, &mint_keypair, &key0).is_err());
        assert_ne!(orig, bank.hash_internal_state());

        let orig = bank.hash_internal_state();
        let empty_keypair = Keypair::new();
        assert!(bank.transfer(1000, &empty_keypair, &key0).is_err());
        assert_eq!(orig, bank.hash_internal_state());
    }

    #[test]
    fn test_bank_hash_internal_state_squash() {
        let collector_id = Pubkey::default();
        let bank0 = Arc::new(Bank::new(&create_genesis_config(10).0));
        let hash0 = bank0.hash_internal_state();
        // save hash0 because new_from_parent
        // updates sysvar entries

        let bank1 = Bank::new_from_parent(&bank0, &collector_id, 1);

        // no delta in bank1, hashes should always update
        assert_ne!(hash0, bank1.hash_internal_state());

        // remove parent
        bank1.squash();
        assert!(bank1.parents().is_empty());
    }

    /// Verifies that last ids and accounts are correctly referenced from parent
    #[test]
    fn test_bank_squash() {
        solana_logger::setup();
        let (genesis_config, mint_keypair) = create_genesis_config(2);
        let key1 = Keypair::new();
        let key2 = Keypair::new();
        let parent = Arc::new(Bank::new(&genesis_config));

        let tx_transfer_mint_to_1 =
            system_transaction::transfer(&mint_keypair, &key1.pubkey(), 1, genesis_config.hash());
        trace!("parent process tx ");
        assert_eq!(parent.process_transaction(&tx_transfer_mint_to_1), Ok(()));
        trace!("done parent process tx ");
        assert_eq!(parent.transaction_count(), 1);
        assert_eq!(
            parent.get_signature_status(&tx_transfer_mint_to_1.signatures[0]),
            Some(Ok(()))
        );

        trace!("new from parent");
        let bank = new_from_parent(&parent);
        trace!("done new from parent");
        assert_eq!(
            bank.get_signature_status(&tx_transfer_mint_to_1.signatures[0]),
            Some(Ok(()))
        );

        assert_eq!(bank.transaction_count(), parent.transaction_count());
        let tx_transfer_1_to_2 =
            system_transaction::transfer(&key1, &key2.pubkey(), 1, genesis_config.hash());
        assert_eq!(bank.process_transaction(&tx_transfer_1_to_2), Ok(()));
        assert_eq!(bank.transaction_count(), 2);
        assert_eq!(parent.transaction_count(), 1);
        assert_eq!(
            parent.get_signature_status(&tx_transfer_1_to_2.signatures[0]),
            None
        );

        for _ in 0..3 {
            // first time these should match what happened above, assert that parents are ok
            assert_eq!(bank.get_balance(&key1.pubkey()), 0);
            assert_eq!(bank.get_account(&key1.pubkey()), None);
            assert_eq!(bank.get_balance(&key2.pubkey()), 1);
            trace!("start");
            assert_eq!(
                bank.get_signature_status(&tx_transfer_mint_to_1.signatures[0]),
                Some(Ok(()))
            );
            assert_eq!(
                bank.get_signature_status(&tx_transfer_1_to_2.signatures[0]),
                Some(Ok(()))
            );

            // works iteration 0, no-ops on iteration 1 and 2
            trace!("SQUASH");
            bank.squash();

            assert_eq!(parent.transaction_count(), 1);
            assert_eq!(bank.transaction_count(), 2);
        }
    }

    #[test]
    fn test_bank_get_account_in_parent_after_squash() {
        let (genesis_config, mint_keypair) = create_genesis_config(500);
        let parent = Arc::new(Bank::new(&genesis_config));

        let key1 = Keypair::new();

        parent.transfer(1, &mint_keypair, &key1.pubkey()).unwrap();
        assert_eq!(parent.get_balance(&key1.pubkey()), 1);
        let bank = new_from_parent(&parent);
        bank.squash();
        assert_eq!(parent.get_balance(&key1.pubkey()), 1);
    }

    #[test]
    fn test_bank_get_account_in_parent_after_squash2() {
        solana_logger::setup();
        let (genesis_config, mint_keypair) = create_genesis_config(500);
        let bank0 = Arc::new(Bank::new(&genesis_config));

        let key1 = Keypair::new();

        bank0.transfer(1, &mint_keypair, &key1.pubkey()).unwrap();
        assert_eq!(bank0.get_balance(&key1.pubkey()), 1);

        let bank1 = Arc::new(Bank::new_from_parent(&bank0, &Pubkey::default(), 1));
        bank1.transfer(3, &mint_keypair, &key1.pubkey()).unwrap();
        let bank2 = Arc::new(Bank::new_from_parent(&bank0, &Pubkey::default(), 2));
        bank2.transfer(2, &mint_keypair, &key1.pubkey()).unwrap();
        let bank3 = Arc::new(Bank::new_from_parent(&bank1, &Pubkey::default(), 3));
        bank1.squash();

        // This picks up the values from 1 which is the highest root:
        // TODO: if we need to access rooted banks older than this,
        // need to fix the lookup.
        assert_eq!(bank0.get_balance(&key1.pubkey()), 4);
        assert_eq!(bank3.get_balance(&key1.pubkey()), 4);
        assert_eq!(bank2.get_balance(&key1.pubkey()), 3);
        bank3.squash();
        assert_eq!(bank1.get_balance(&key1.pubkey()), 4);

        let bank4 = Arc::new(Bank::new_from_parent(&bank3, &Pubkey::default(), 4));
        bank4.transfer(4, &mint_keypair, &key1.pubkey()).unwrap();
        assert_eq!(bank4.get_balance(&key1.pubkey()), 8);
        assert_eq!(bank3.get_balance(&key1.pubkey()), 4);
        bank4.squash();
        let bank5 = Arc::new(Bank::new_from_parent(&bank4, &Pubkey::default(), 5));
        bank5.squash();
        let bank6 = Arc::new(Bank::new_from_parent(&bank5, &Pubkey::default(), 6));
        bank6.squash();

        // This picks up the values from 4 which is the highest root:
        // TODO: if we need to access rooted banks older than this,
        // need to fix the lookup.
        assert_eq!(bank3.get_balance(&key1.pubkey()), 8);
        assert_eq!(bank2.get_balance(&key1.pubkey()), 8);

        assert_eq!(bank4.get_balance(&key1.pubkey()), 8);
    }

    #[test]
    fn test_bank_get_account_modified_since_parent_with_fixed_root() {
        let pubkey = solana_sdk::pubkey::new_rand();

        let (genesis_config, mint_keypair) = create_genesis_config(500);
        let bank1 = Arc::new(Bank::new(&genesis_config));
        bank1.transfer(1, &mint_keypair, &pubkey).unwrap();
        let result = bank1.get_account_modified_since_parent_with_fixed_root(&pubkey);
        assert!(result.is_some());
        let (account, slot) = result.unwrap();
        assert_eq!(account.lamports(), 1);
        assert_eq!(slot, 0);

        let bank2 = Arc::new(Bank::new_from_parent(&bank1, &Pubkey::default(), 1));
        assert!(bank2
            .get_account_modified_since_parent_with_fixed_root(&pubkey)
            .is_none());
        bank2.transfer(100, &mint_keypair, &pubkey).unwrap();
        let result = bank1.get_account_modified_since_parent_with_fixed_root(&pubkey);
        assert!(result.is_some());
        let (account, slot) = result.unwrap();
        assert_eq!(account.lamports(), 1);
        assert_eq!(slot, 0);
        let result = bank2.get_account_modified_since_parent_with_fixed_root(&pubkey);
        assert!(result.is_some());
        let (account, slot) = result.unwrap();
        assert_eq!(account.lamports(), 101);
        assert_eq!(slot, 1);

        bank1.squash();

        let bank3 = Bank::new_from_parent(&bank2, &Pubkey::default(), 3);
        assert_eq!(
            None,
            bank3.get_account_modified_since_parent_with_fixed_root(&pubkey)
        );
    }

    #[test]
    fn test_bank_update_sysvar_account() {
        use sysvar::clock::Clock;

        let dummy_clock_id = solana_sdk::pubkey::new_rand();
        let dummy_rent_epoch = 44;
        let (mut genesis_config, _mint_keypair) = create_genesis_config(500);

        let expected_previous_slot = 3;
        let mut expected_next_slot = expected_previous_slot + 1;

        // First, initialize the clock sysvar
        activate_all_features(&mut genesis_config);
        let bank1 = Arc::new(Bank::new(&genesis_config));
        assert_eq!(bank1.calculate_capitalization(true), bank1.capitalization());

        assert_capitalization_diff(
            &bank1,
            || {
                bank1.update_sysvar_account(&dummy_clock_id, |optional_account| {
                    assert!(optional_account.is_none());

                    let mut account = create_account(
                        &Clock {
                            slot: expected_previous_slot,
                            ..Clock::default()
                        },
                        bank1.inherit_specially_retained_account_fields(optional_account),
                    );
                    account.set_rent_epoch(dummy_rent_epoch);
                    account
                });
                let current_account = bank1.get_account(&dummy_clock_id).unwrap();
                assert_eq!(
                    expected_previous_slot,
                    from_account::<Clock, _>(&current_account).unwrap().slot
                );
                assert_eq!(dummy_rent_epoch, current_account.rent_epoch());
            },
            |old, new| {
                assert_eq!(
                    old + min_rent_excempt_balance_for_sysvars(&bank1, &[sysvar::clock::id()]),
                    new
                );
            },
        );

        assert_capitalization_diff(
            &bank1,
            || {
                bank1.update_sysvar_account(&dummy_clock_id, |optional_account| {
                    assert!(optional_account.is_some());

                    create_account(
                        &Clock {
                            slot: expected_previous_slot,
                            ..Clock::default()
                        },
                        bank1.inherit_specially_retained_account_fields(optional_account),
                    )
                })
            },
            |old, new| {
                // creating new sysvar twice in a slot shouldn't increment capitalization twice
                assert_eq!(old, new);
            },
        );

        // Updating should increment the clock's slot
        let bank2 = Arc::new(Bank::new_from_parent(&bank1, &Pubkey::default(), 1));
        assert_capitalization_diff(
            &bank2,
            || {
                bank2.update_sysvar_account(&dummy_clock_id, |optional_account| {
                    let slot = from_account::<Clock, _>(optional_account.as_ref().unwrap())
                        .unwrap()
                        .slot
                        + 1;

                    create_account(
                        &Clock {
                            slot,
                            ..Clock::default()
                        },
                        bank2.inherit_specially_retained_account_fields(optional_account),
                    )
                });
                let current_account = bank2.get_account(&dummy_clock_id).unwrap();
                assert_eq!(
                    expected_next_slot,
                    from_account::<Clock, _>(&current_account).unwrap().slot
                );
                // inherit_specially_retained_account_fields() now starts to inherit rent_epoch too
                // with rent_for_sysvars
                assert_eq!(dummy_rent_epoch, current_account.rent_epoch());
            },
            |old, new| {
                // if existing, capitalization shouldn't change
                assert_eq!(old, new);
            },
        );

        // Updating again should give bank2's sysvar to the closure not bank1's.
        // Thus, increment expected_next_slot accordingly
        expected_next_slot += 1;
        assert_capitalization_diff(
            &bank2,
            || {
                bank2.update_sysvar_account(&dummy_clock_id, |optional_account| {
                    let slot = from_account::<Clock, _>(optional_account.as_ref().unwrap())
                        .unwrap()
                        .slot
                        + 1;

                    create_account(
                        &Clock {
                            slot,
                            ..Clock::default()
                        },
                        bank2.inherit_specially_retained_account_fields(optional_account),
                    )
                });
                let current_account = bank2.get_account(&dummy_clock_id).unwrap();
                assert_eq!(
                    expected_next_slot,
                    from_account::<Clock, _>(&current_account).unwrap().slot
                );
            },
            |old, new| {
                // updating twice in a slot shouldn't increment capitalization twice
                assert_eq!(old, new);
            },
        );
    }

    #[test]
    fn test_bank_epoch_vote_accounts() {
        let leader_pubkey = solana_sdk::pubkey::new_rand();
        let leader_lamports = 3;
        let mut genesis_config =
            create_genesis_config_with_leader(5, &leader_pubkey, leader_lamports).genesis_config;

        // set this up weird, forces future generation, odd mod(), etc.
        //  this says: "vote_accounts for epoch X should be generated at slot index 3 in epoch X-2...
        const SLOTS_PER_EPOCH: u64 = MINIMUM_SLOTS_PER_EPOCH as u64;
        const LEADER_SCHEDULE_SLOT_OFFSET: u64 = SLOTS_PER_EPOCH * 3 - 3;
        // no warmup allows me to do the normal division stuff below
        genesis_config.epoch_schedule =
            EpochSchedule::custom(SLOTS_PER_EPOCH, LEADER_SCHEDULE_SLOT_OFFSET, false);

        let parent = Arc::new(Bank::new(&genesis_config));
        let mut leader_vote_stake: Vec<_> = parent
            .epoch_vote_accounts(0)
            .map(|accounts| {
                accounts
                    .iter()
                    .filter_map(|(pubkey, (stake, account))| {
                        if let Ok(vote_state) = account.vote_state().as_ref() {
                            if vote_state.node_pubkey == leader_pubkey {
                                Some((*pubkey, *stake))
                            } else {
                                None
                            }
                        } else {
                            None
                        }
                    })
                    .collect()
            })
            .unwrap();
        assert_eq!(leader_vote_stake.len(), 1);
        let (leader_vote_account, leader_stake) = leader_vote_stake.pop().unwrap();
        assert!(leader_stake > 0);

        let leader_stake = Stake {
            delegation: Delegation {
                stake: leader_lamports,
                activation_epoch: std::u64::MAX, // bootstrap
                ..Delegation::default()
            },
            ..Stake::default()
        };

        let mut epoch = 1;
        loop {
            if epoch > LEADER_SCHEDULE_SLOT_OFFSET / SLOTS_PER_EPOCH {
                break;
            }
            let vote_accounts = parent.epoch_vote_accounts(epoch);
            assert!(vote_accounts.is_some());

            // epoch_stakes are a snapshot at the leader_schedule_slot_offset boundary
            //   in the prior epoch (0 in this case)
            assert_eq!(
                leader_stake.stake(0, None, true),
                vote_accounts.unwrap().get(&leader_vote_account).unwrap().0
            );

            epoch += 1;
        }

        // child crosses epoch boundary and is the first slot in the epoch
        let child = Bank::new_from_parent(
            &parent,
            &leader_pubkey,
            SLOTS_PER_EPOCH - (LEADER_SCHEDULE_SLOT_OFFSET % SLOTS_PER_EPOCH),
        );

        assert!(child.epoch_vote_accounts(epoch).is_some());
        assert_eq!(
            leader_stake.stake(child.epoch(), None, true),
            child
                .epoch_vote_accounts(epoch)
                .unwrap()
                .get(&leader_vote_account)
                .unwrap()
                .0
        );

        // child crosses epoch boundary but isn't the first slot in the epoch, still
        //  makes an epoch stakes snapshot at 1
        let child = Bank::new_from_parent(
            &parent,
            &leader_pubkey,
            SLOTS_PER_EPOCH - (LEADER_SCHEDULE_SLOT_OFFSET % SLOTS_PER_EPOCH) + 1,
        );
        assert!(child.epoch_vote_accounts(epoch).is_some());
        assert_eq!(
            leader_stake.stake(child.epoch(), None, true),
            child
                .epoch_vote_accounts(epoch)
                .unwrap()
                .get(&leader_vote_account)
                .unwrap()
                .0
        );
    }

    #[test]
    fn test_zero_signatures() {
        solana_logger::setup();
        let (genesis_config, mint_keypair) = create_genesis_config(500);
        let mut bank = Bank::new(&genesis_config);
        bank.fee_calculator.lamports_per_signature = 2;
        let key = Keypair::new();

        let mut transfer_instruction =
            system_instruction::transfer(&mint_keypair.pubkey(), &key.pubkey(), 0);
        transfer_instruction.accounts[0].is_signer = false;
        let message = Message::new(&[transfer_instruction], None);
        let tx = Transaction::new(&[&Keypair::new(); 0], message, bank.last_blockhash());

        assert_eq!(
            bank.process_transaction(&tx),
            Err(TransactionError::SanitizeFailure)
        );
        assert_eq!(bank.get_balance(&key.pubkey()), 0);
    }

    #[test]
    fn test_bank_get_slots_in_epoch() {
        let (genesis_config, _) = create_genesis_config(500);

        let bank = Bank::new(&genesis_config);

        assert_eq!(bank.get_slots_in_epoch(0), MINIMUM_SLOTS_PER_EPOCH as u64);
        assert_eq!(
            bank.get_slots_in_epoch(2),
            (MINIMUM_SLOTS_PER_EPOCH * 4) as u64
        );
        assert_eq!(
            bank.get_slots_in_epoch(5000),
            genesis_config.epoch_schedule.slots_per_epoch
        );
    }

    #[test]
    fn test_is_delta_true() {
        let (genesis_config, mint_keypair) = create_genesis_config(500);
        let bank = Arc::new(Bank::new(&genesis_config));
        let key1 = Keypair::new();
        let tx_transfer_mint_to_1 =
            system_transaction::transfer(&mint_keypair, &key1.pubkey(), 1, genesis_config.hash());
        assert_eq!(bank.process_transaction(&tx_transfer_mint_to_1), Ok(()));
        assert!(bank.is_delta.load(Relaxed));

        let bank1 = new_from_parent(&bank);
        let hash1 = bank1.hash_internal_state();
        assert!(!bank1.is_delta.load(Relaxed));
        assert_ne!(hash1, bank.hash());
        // ticks don't make a bank into a delta or change its state unless a block boundary is crossed
        bank1.register_tick(&Hash::default());
        assert!(!bank1.is_delta.load(Relaxed));
        assert_eq!(bank1.hash_internal_state(), hash1);
    }

    #[test]
    fn test_is_empty() {
        let (genesis_config, mint_keypair) = create_genesis_config(500);
        let bank0 = Arc::new(Bank::new(&genesis_config));
        let key1 = Keypair::new();

        // The zeroth bank is empty becasue there are no transactions
        assert!(bank0.is_empty());

        // Set is_delta to true, bank is no longer empty
        let tx_transfer_mint_to_1 =
            system_transaction::transfer(&mint_keypair, &key1.pubkey(), 1, genesis_config.hash());
        assert_eq!(bank0.process_transaction(&tx_transfer_mint_to_1), Ok(()));
        assert!(!bank0.is_empty());
    }

    #[test]
    fn test_bank_inherit_tx_count() {
        let (genesis_config, mint_keypair) = create_genesis_config(500);
        let bank0 = Arc::new(Bank::new(&genesis_config));

        // Bank 1
        let bank1 = Arc::new(Bank::new_from_parent(
            &bank0,
            &solana_sdk::pubkey::new_rand(),
            1,
        ));
        // Bank 2
        let bank2 = Bank::new_from_parent(&bank0, &solana_sdk::pubkey::new_rand(), 2);

        // transfer a token
        assert_eq!(
            bank1.process_transaction(&system_transaction::transfer(
                &mint_keypair,
                &Keypair::new().pubkey(),
                1,
                genesis_config.hash(),
            )),
            Ok(())
        );

        assert_eq!(bank0.transaction_count(), 0);
        assert_eq!(bank2.transaction_count(), 0);
        assert_eq!(bank1.transaction_count(), 1);

        bank1.squash();

        assert_eq!(bank0.transaction_count(), 0);
        assert_eq!(bank2.transaction_count(), 0);
        assert_eq!(bank1.transaction_count(), 1);

        let bank6 = Bank::new_from_parent(&bank1, &solana_sdk::pubkey::new_rand(), 3);
        assert_eq!(bank1.transaction_count(), 1);
        assert_eq!(bank6.transaction_count(), 1);

        bank6.squash();
        assert_eq!(bank6.transaction_count(), 1);
    }

    #[test]
    fn test_bank_inherit_fee_rate_governor() {
        let (mut genesis_config, _mint_keypair) = create_genesis_config(500);
        genesis_config
            .fee_rate_governor
            .target_lamports_per_signature = 123;

        let bank0 = Arc::new(Bank::new(&genesis_config));
        let bank1 = Arc::new(new_from_parent(&bank0));
        assert_eq!(
            bank0.fee_rate_governor.target_lamports_per_signature / 2,
            bank1
                .fee_rate_governor
                .create_fee_calculator()
                .lamports_per_signature
        );
    }

    #[test]
    fn test_bank_vote_accounts() {
        let GenesisConfigInfo {
            genesis_config,
            mint_keypair,
            ..
        } = create_genesis_config_with_leader(500, &solana_sdk::pubkey::new_rand(), 1);
        let bank = Arc::new(Bank::new(&genesis_config));

        let vote_accounts = bank.vote_accounts();
        assert_eq!(vote_accounts.len(), 1); // bootstrap validator has
                                            // to have a vote account

        let vote_keypair = Keypair::new();
        let instructions = vote_instruction::create_account(
            &mint_keypair.pubkey(),
            &vote_keypair.pubkey(),
            &VoteInit {
                node_pubkey: mint_keypair.pubkey(),
                authorized_voter: vote_keypair.pubkey(),
                authorized_withdrawer: vote_keypair.pubkey(),
                commission: 0,
            },
            10,
        );

        let message = Message::new(&instructions, Some(&mint_keypair.pubkey()));
        let transaction = Transaction::new(
            &[&mint_keypair, &vote_keypair],
            message,
            bank.last_blockhash(),
        );

        bank.process_transaction(&transaction).unwrap();

        let vote_accounts = bank.vote_accounts().into_iter().collect::<HashMap<_, _>>();

        assert_eq!(vote_accounts.len(), 2);

        assert!(vote_accounts.get(&vote_keypair.pubkey()).is_some());

        assert!(bank.withdraw(&vote_keypair.pubkey(), 10).is_ok());

        let vote_accounts = bank.vote_accounts();

        assert_eq!(vote_accounts.len(), 1);
    }

    #[test]
    fn test_bank_cloned_stake_delegations() {
        let GenesisConfigInfo {
            genesis_config,
            mint_keypair,
            ..
        } = create_genesis_config_with_leader(500, &solana_sdk::pubkey::new_rand(), 1);
        let bank = Arc::new(Bank::new(&genesis_config));

        let stake_delegations = bank.cloned_stake_delegations();
        assert_eq!(stake_delegations.len(), 1); // bootstrap validator has
                                                // to have a stake delegation

        let vote_keypair = Keypair::new();
        let mut instructions = vote_instruction::create_account(
            &mint_keypair.pubkey(),
            &vote_keypair.pubkey(),
            &VoteInit {
                node_pubkey: mint_keypair.pubkey(),
                authorized_voter: vote_keypair.pubkey(),
                authorized_withdrawer: vote_keypair.pubkey(),
                commission: 0,
            },
            10,
        );

        let stake_keypair = Keypair::new();
        instructions.extend(stake_instruction::create_account_and_delegate_stake(
            &mint_keypair.pubkey(),
            &stake_keypair.pubkey(),
            &vote_keypair.pubkey(),
            &Authorized::auto(&stake_keypair.pubkey()),
            &Lockup::default(),
            10,
        ));

        let message = Message::new(&instructions, Some(&mint_keypair.pubkey()));
        let transaction = Transaction::new(
            &[&mint_keypair, &vote_keypair, &stake_keypair],
            message,
            bank.last_blockhash(),
        );

        bank.process_transaction(&transaction).unwrap();

        let stake_delegations = bank.cloned_stake_delegations();
        assert_eq!(stake_delegations.len(), 2);
        assert!(stake_delegations.get(&stake_keypair.pubkey()).is_some());
    }

    #[test]
    fn test_bank_fees_account() {
        let (mut genesis_config, _) = create_genesis_config(500);
        genesis_config.fee_rate_governor = FeeRateGovernor::new(12345, 0);
        let bank = Arc::new(Bank::new(&genesis_config));

        let fees_account = bank.get_account(&sysvar::fees::id()).unwrap();
        let fees = from_account::<Fees, _>(&fees_account).unwrap();
        assert_eq!(
            bank.fee_calculator.lamports_per_signature,
            fees.fee_calculator.lamports_per_signature
        );
        assert_eq!(fees.fee_calculator.lamports_per_signature, 12345);
    }

    #[test]
    fn test_is_delta_with_no_committables() {
        let (genesis_config, mint_keypair) = create_genesis_config(8000);
        let bank = Bank::new(&genesis_config);
        bank.is_delta.store(false, Relaxed);

        let keypair1 = Keypair::new();
        let keypair2 = Keypair::new();
        let fail_tx =
            system_transaction::transfer(&keypair1, &keypair2.pubkey(), 1, bank.last_blockhash());

        // Should fail with TransactionError::AccountNotFound, which means
        // the account which this tx operated on will not be committed. Thus
        // the bank is_delta should still be false
        assert_eq!(
            bank.process_transaction(&fail_tx),
            Err(TransactionError::AccountNotFound)
        );

        // Check the bank is_delta is still false
        assert!(!bank.is_delta.load(Relaxed));

        // Should fail with InstructionError, but InstructionErrors are committable,
        // so is_delta should be true
        assert_eq!(
            bank.transfer(10_001, &mint_keypair, &solana_sdk::pubkey::new_rand()),
            Err(TransactionError::InstructionError(
                0,
                SystemError::ResultWithNegativeLamports.into(),
            ))
        );

        assert!(bank.is_delta.load(Relaxed));
    }

    #[test]
    fn test_bank_get_program_accounts() {
        let (genesis_config, mint_keypair) = create_genesis_config(500);
        let parent = Arc::new(Bank::new(&genesis_config));
        parent.restore_old_behavior_for_fragile_tests();

        let genesis_accounts: Vec<_> = parent.get_all_accounts_with_modified_slots().unwrap();
        assert!(
            genesis_accounts
                .iter()
                .any(|(pubkey, _, _)| *pubkey == mint_keypair.pubkey()),
            "mint pubkey not found"
        );
        assert!(
            genesis_accounts
                .iter()
                .any(|(pubkey, _, _)| solana_sdk::sysvar::is_sysvar_id(pubkey)),
            "no sysvars found"
        );

        let bank0 = Arc::new(new_from_parent(&parent));
        let pubkey0 = solana_sdk::pubkey::new_rand();
        let program_id = Pubkey::new(&[2; 32]);
        let account0 = AccountSharedData::new(1, 0, &program_id);
        bank0.store_account(&pubkey0, &account0);

        assert_eq!(
            bank0.get_program_accounts_modified_since_parent(&program_id),
            vec![(pubkey0, account0.clone())]
        );

        let bank1 = Arc::new(new_from_parent(&bank0));
        bank1.squash();
        assert_eq!(
            bank0.get_program_accounts(&program_id).unwrap(),
            vec![(pubkey0, account0.clone())]
        );
        assert_eq!(
            bank1.get_program_accounts(&program_id).unwrap(),
            vec![(pubkey0, account0)]
        );
        assert_eq!(
            bank1.get_program_accounts_modified_since_parent(&program_id),
            vec![]
        );

        let bank2 = Arc::new(new_from_parent(&bank1));
        let pubkey1 = solana_sdk::pubkey::new_rand();
        let account1 = AccountSharedData::new(3, 0, &program_id);
        bank2.store_account(&pubkey1, &account1);
        // Accounts with 0 lamports should be filtered out by Accounts::load_by_program()
        let pubkey2 = solana_sdk::pubkey::new_rand();
        let account2 = AccountSharedData::new(0, 0, &program_id);
        bank2.store_account(&pubkey2, &account2);

        let bank3 = Arc::new(new_from_parent(&bank2));
        bank3.squash();
        assert_eq!(bank1.get_program_accounts(&program_id).unwrap().len(), 2);
        assert_eq!(bank3.get_program_accounts(&program_id).unwrap().len(), 2);
    }

    #[test]
    fn test_get_filtered_indexed_accounts() {
        let (genesis_config, _mint_keypair) = create_genesis_config(500);
        let mut account_indexes = AccountSecondaryIndexes::default();
        account_indexes.indexes.insert(AccountIndex::ProgramId);
        let bank = Arc::new(Bank::new_with_config(
            &genesis_config,
            account_indexes,
            false,
            AccountShrinkThreshold::default(),
        ));

        let address = Pubkey::new_unique();
        let program_id = Pubkey::new_unique();
        let account = AccountSharedData::new(1, 0, &program_id);
        bank.store_account(&address, &account);

        let indexed_accounts = bank
            .get_filtered_indexed_accounts(&IndexKey::ProgramId(program_id), |_| true)
            .unwrap();
        assert_eq!(indexed_accounts.len(), 1);
        assert_eq!(indexed_accounts[0], (address, account));

        // Even though the account is re-stored in the bank (and the index) under a new program id,
        // it is still present in the index under the original program id as well. This
        // demonstrates the need for a redundant post-processing filter.
        let another_program_id = Pubkey::new_unique();
        let new_account = AccountSharedData::new(1, 0, &another_program_id);
        let bank = Arc::new(new_from_parent(&bank));
        bank.store_account(&address, &new_account);
        let indexed_accounts = bank
            .get_filtered_indexed_accounts(&IndexKey::ProgramId(program_id), |_| true)
            .unwrap();
        assert_eq!(indexed_accounts.len(), 1);
        assert_eq!(indexed_accounts[0], (address, new_account.clone()));
        let indexed_accounts = bank
            .get_filtered_indexed_accounts(&IndexKey::ProgramId(another_program_id), |_| true)
            .unwrap();
        assert_eq!(indexed_accounts.len(), 1);
        assert_eq!(indexed_accounts[0], (address, new_account.clone()));

        // Post-processing filter
        let indexed_accounts = bank
            .get_filtered_indexed_accounts(&IndexKey::ProgramId(program_id), |account| {
                account.owner() == &program_id
            })
            .unwrap();
        assert!(indexed_accounts.is_empty());
        let indexed_accounts = bank
            .get_filtered_indexed_accounts(&IndexKey::ProgramId(another_program_id), |account| {
                account.owner() == &another_program_id
            })
            .unwrap();
        assert_eq!(indexed_accounts.len(), 1);
        assert_eq!(indexed_accounts[0], (address, new_account));
    }

    #[test]
    fn test_status_cache_ancestors() {
        solana_logger::setup();
        let (genesis_config, _mint_keypair) = create_genesis_config(500);
        let parent = Arc::new(Bank::new(&genesis_config));
        let bank1 = Arc::new(new_from_parent(&parent));
        let mut bank = bank1;
        for _ in 0..MAX_CACHE_ENTRIES * 2 {
            bank = Arc::new(new_from_parent(&bank));
            bank.squash();
        }

        let bank = new_from_parent(&bank);
        assert_eq!(
            bank.status_cache_ancestors(),
            (bank.slot() - MAX_CACHE_ENTRIES as u64..=bank.slot()).collect::<Vec<_>>()
        );
    }

    #[test]
    fn test_add_builtin() {
        let (genesis_config, mint_keypair) = create_genesis_config(500);
        let mut bank = Bank::new(&genesis_config);

        fn mock_vote_program_id() -> Pubkey {
            Pubkey::new(&[42u8; 32])
        }
        fn mock_vote_processor(
            program_id: &Pubkey,
            _instruction_data: &[u8],
            _invoke_context: &mut dyn InvokeContext,
        ) -> std::result::Result<(), InstructionError> {
            if mock_vote_program_id() != *program_id {
                return Err(InstructionError::IncorrectProgramId);
            }
            Err(InstructionError::Custom(42))
        }

        assert!(bank.get_account(&mock_vote_program_id()).is_none());
        bank.add_builtin(
            "mock_vote_program",
            mock_vote_program_id(),
            mock_vote_processor,
        );
        assert!(bank.get_account(&mock_vote_program_id()).is_some());

        let mock_account = Keypair::new();
        let mock_validator_identity = Keypair::new();
        let mut instructions = vote_instruction::create_account(
            &mint_keypair.pubkey(),
            &mock_account.pubkey(),
            &VoteInit {
                node_pubkey: mock_validator_identity.pubkey(),
                ..VoteInit::default()
            },
            1,
        );
        instructions[1].program_id = mock_vote_program_id();

        let message = Message::new(&instructions, Some(&mint_keypair.pubkey()));
        let transaction = Transaction::new(
            &[&mint_keypair, &mock_account, &mock_validator_identity],
            message,
            bank.last_blockhash(),
        );

        assert_eq!(
            bank.process_transaction(&transaction),
            Err(TransactionError::InstructionError(
                1,
                InstructionError::Custom(42)
            ))
        );
    }

    #[test]
    fn test_add_duplicate_static_program() {
        let GenesisConfigInfo {
            genesis_config,
            mint_keypair,
            ..
        } = create_genesis_config_with_leader(500, &solana_sdk::pubkey::new_rand(), 0);
        let mut bank = Bank::new(&genesis_config);

        fn mock_vote_processor(
            _pubkey: &Pubkey,
            _data: &[u8],
            _invoke_context: &mut dyn InvokeContext,
        ) -> std::result::Result<(), InstructionError> {
            Err(InstructionError::Custom(42))
        }

        let mock_account = Keypair::new();
        let mock_validator_identity = Keypair::new();
        let instructions = vote_instruction::create_account(
            &mint_keypair.pubkey(),
            &mock_account.pubkey(),
            &VoteInit {
                node_pubkey: mock_validator_identity.pubkey(),
                ..VoteInit::default()
            },
            1,
        );

        let message = Message::new(&instructions, Some(&mint_keypair.pubkey()));
        let transaction = Transaction::new(
            &[&mint_keypair, &mock_account, &mock_validator_identity],
            message,
            bank.last_blockhash(),
        );

        let vote_loader_account = bank.get_account(&solana_vote_program::id()).unwrap();
        bank.add_builtin(
            "solana_vote_program",
            solana_vote_program::id(),
            mock_vote_processor,
        );
        let new_vote_loader_account = bank.get_account(&solana_vote_program::id()).unwrap();
        // Vote loader account should not be updated since it was included in the genesis config.
        assert_eq!(vote_loader_account.data(), new_vote_loader_account.data());
        assert_eq!(
            bank.process_transaction(&transaction),
            Err(TransactionError::InstructionError(
                1,
                InstructionError::Custom(42)
            ))
        );
    }

    #[test]
    fn test_add_instruction_processor_for_existing_unrelated_accounts() {
        let (genesis_config, _mint_keypair) = create_genesis_config(500);
        let mut bank = Bank::new(&genesis_config);

        fn mock_ix_processor(
            _pubkey: &Pubkey,
            _data: &[u8],
            _invoke_context: &mut dyn InvokeContext,
        ) -> std::result::Result<(), InstructionError> {
            Err(InstructionError::Custom(42))
        }

        // Non-native loader accounts can not be used for instruction processing
        assert!(bank.stakes.read().unwrap().vote_accounts().is_empty());
        assert!(bank.stakes.read().unwrap().stake_delegations().is_empty());
        assert_eq!(bank.calculate_capitalization(true), bank.capitalization());

        let ((vote_id, vote_account), (stake_id, stake_account)) =
            crate::stakes::tests::create_staked_node_accounts(1_0000);
        bank.capitalization
            .fetch_add(vote_account.lamports() + stake_account.lamports(), Relaxed);
        bank.store_account(&vote_id, &vote_account);
        bank.store_account(&stake_id, &stake_account);
        assert!(!bank.stakes.read().unwrap().vote_accounts().is_empty());
        assert!(!bank.stakes.read().unwrap().stake_delegations().is_empty());
        assert_eq!(bank.calculate_capitalization(true), bank.capitalization());

        bank.add_builtin("mock_program1", vote_id, mock_ix_processor);
        bank.add_builtin("mock_program2", stake_id, mock_ix_processor);
        assert!(bank.stakes.read().unwrap().vote_accounts().is_empty());
        assert!(bank.stakes.read().unwrap().stake_delegations().is_empty());
        assert_eq!(bank.calculate_capitalization(true), bank.capitalization());
        assert_eq!(
            "mock_program1",
            String::from_utf8_lossy(bank.get_account(&vote_id).unwrap_or_default().data())
        );
        assert_eq!(
            "mock_program2",
            String::from_utf8_lossy(bank.get_account(&stake_id).unwrap_or_default().data())
        );

        // Re-adding builtin programs should be no-op
        bank.update_accounts_hash();
        let old_hash = bank.get_accounts_hash();
        bank.add_builtin("mock_program1", vote_id, mock_ix_processor);
        bank.add_builtin("mock_program2", stake_id, mock_ix_processor);
        bank.update_accounts_hash();
        let new_hash = bank.get_accounts_hash();
        assert_eq!(old_hash, new_hash);
        assert!(bank.stakes.read().unwrap().vote_accounts().is_empty());
        assert!(bank.stakes.read().unwrap().stake_delegations().is_empty());
        assert_eq!(bank.calculate_capitalization(true), bank.capitalization());
        assert_eq!(
            "mock_program1",
            String::from_utf8_lossy(bank.get_account(&vote_id).unwrap_or_default().data())
        );
        assert_eq!(
            "mock_program2",
            String::from_utf8_lossy(bank.get_account(&stake_id).unwrap_or_default().data())
        );
    }

    #[test]
    fn test_recent_blockhashes_sysvar() {
        let (genesis_config, _mint_keypair) = create_genesis_config(500);
        let mut bank = Arc::new(Bank::new(&genesis_config));
        for i in 1..5 {
            let bhq_account = bank.get_account(&sysvar::recent_blockhashes::id()).unwrap();
            let recent_blockhashes =
                from_account::<sysvar::recent_blockhashes::RecentBlockhashes, _>(&bhq_account)
                    .unwrap();
            // Check length
            assert_eq!(recent_blockhashes.len(), i);
            let most_recent_hash = recent_blockhashes.iter().next().unwrap().blockhash;
            // Check order
            assert_eq!(Some(true), bank.check_hash_age(&most_recent_hash, 0));
            goto_end_of_slot(Arc::get_mut(&mut bank).unwrap());
            bank = Arc::new(new_from_parent(&bank));
        }
    }

    #[test]
    fn test_blockhash_queue_sysvar_consistency() {
        let (genesis_config, _mint_keypair) = create_genesis_config(100_000);
        let mut bank = Arc::new(Bank::new(&genesis_config));
        goto_end_of_slot(Arc::get_mut(&mut bank).unwrap());

        let bhq_account = bank.get_account(&sysvar::recent_blockhashes::id()).unwrap();
        let recent_blockhashes =
            from_account::<sysvar::recent_blockhashes::RecentBlockhashes, _>(&bhq_account).unwrap();

        let sysvar_recent_blockhash = recent_blockhashes[0].blockhash;
        let bank_last_blockhash = bank.last_blockhash();
        assert_eq!(sysvar_recent_blockhash, bank_last_blockhash);
    }

    #[test]
    fn test_bank_inherit_last_vote_sync() {
        let (genesis_config, _) = create_genesis_config(500);
        let bank0 = Arc::new(Bank::new(&genesis_config));
        let last_ts = bank0.last_vote_sync.load(Relaxed);
        assert_eq!(last_ts, 0);
        bank0.last_vote_sync.store(1, Relaxed);
        let bank1 =
            Bank::new_from_parent(&bank0, &Pubkey::default(), bank0.get_slots_in_epoch(0) - 1);
        let last_ts = bank1.last_vote_sync.load(Relaxed);
        assert_eq!(last_ts, 1);
    }

    #[test]
    fn test_hash_internal_state_unchanged() {
        let (genesis_config, _) = create_genesis_config(500);
        let bank0 = Arc::new(Bank::new(&genesis_config));
        bank0.freeze();
        let bank0_hash = bank0.hash();
        let bank1 = Bank::new_from_parent(&bank0, &Pubkey::default(), 1);
        bank1.freeze();
        let bank1_hash = bank1.hash();
        // Checkpointing should always result in a new state
        assert_ne!(bank0_hash, bank1_hash);
    }

    #[test]
    fn test_ticks_change_state() {
        let (genesis_config, _) = create_genesis_config(500);
        let bank = Arc::new(Bank::new(&genesis_config));
        let bank1 = new_from_parent(&bank);
        let hash1 = bank1.hash_internal_state();
        // ticks don't change its state unless a block boundary is crossed
        for _ in 0..genesis_config.ticks_per_slot {
            assert_eq!(bank1.hash_internal_state(), hash1);
            bank1.register_tick(&Hash::default());
        }
        assert_ne!(bank1.hash_internal_state(), hash1);
    }

    #[ignore]
    #[test]
    fn test_banks_leak() {
        fn add_lotsa_stake_accounts(genesis_config: &mut GenesisConfig) {
            const LOTSA: usize = 4_096;

            (0..LOTSA).for_each(|_| {
                let pubkey = solana_sdk::pubkey::new_rand();
                genesis_config.add_account(
                    pubkey,
                    stake_state::create_lockup_stake_account(
                        &Authorized::auto(&pubkey),
                        &Lockup::default(),
                        &Rent::default(),
                        50_000_000,
                    ),
                );
            });
        }
        solana_logger::setup();
        let (mut genesis_config, _) = create_genesis_config(100_000_000_000_000);
        add_lotsa_stake_accounts(&mut genesis_config);
        let mut bank = std::sync::Arc::new(Bank::new(&genesis_config));
        let mut num_banks = 0;
        let pid = std::process::id();
        #[cfg(not(target_os = "linux"))]
        error!(
            "\nYou can run this to watch RAM:\n   while read -p 'banks: '; do echo $(( $(ps -o vsize= -p {})/$REPLY));done", pid
        );
        loop {
            num_banks += 1;
            bank = std::sync::Arc::new(new_from_parent(&bank));
            if num_banks % 100 == 0 {
                #[cfg(target_os = "linux")]
                {
                    let pages_consumed = std::fs::read_to_string(format!("/proc/{}/statm", pid))
                        .unwrap()
                        .split_whitespace()
                        .next()
                        .unwrap()
                        .parse::<usize>()
                        .unwrap();
                    error!(
                        "at {} banks: {} mem or {}kB/bank",
                        num_banks,
                        pages_consumed * 4096,
                        (pages_consumed * 4) / num_banks
                    );
                }
                #[cfg(not(target_os = "linux"))]
                {
                    error!("{} banks, sleeping for 5 sec", num_banks);
                    std::thread::sleep(Duration::new(5, 0));
                }
            }
        }
    }

    fn get_nonce_account(bank: &Bank, nonce_pubkey: &Pubkey) -> Option<Hash> {
        bank.get_account(nonce_pubkey).and_then(|acc| {
            let state =
                StateMut::<nonce::state::Versions>::state(&acc).map(|v| v.convert_to_current());
            match state {
                Ok(nonce::State::Initialized(ref data)) => Some(data.blockhash),
                _ => None,
            }
        })
    }

    fn nonce_setup(
        bank: &mut Arc<Bank>,
        mint_keypair: &Keypair,
        custodian_lamports: u64,
        nonce_lamports: u64,
        nonce_authority: Option<Pubkey>,
    ) -> Result<(Keypair, Keypair)> {
        let custodian_keypair = Keypair::new();
        let nonce_keypair = Keypair::new();
        /* Setup accounts */
        let mut setup_ixs = vec![system_instruction::transfer(
            &mint_keypair.pubkey(),
            &custodian_keypair.pubkey(),
            custodian_lamports,
        )];
        let nonce_authority = nonce_authority.unwrap_or_else(|| nonce_keypair.pubkey());
        setup_ixs.extend_from_slice(&system_instruction::create_nonce_account(
            &custodian_keypair.pubkey(),
            &nonce_keypair.pubkey(),
            &nonce_authority,
            nonce_lamports,
        ));
        let message = Message::new(&setup_ixs, Some(&mint_keypair.pubkey()));
        let setup_tx = Transaction::new(
            &[mint_keypair, &custodian_keypair, &nonce_keypair],
            message,
            bank.last_blockhash(),
        );
        bank.process_transaction(&setup_tx)?;
        Ok((custodian_keypair, nonce_keypair))
    }

    fn setup_nonce_with_bank<F>(
        supply_lamports: u64,
        mut genesis_cfg_fn: F,
        custodian_lamports: u64,
        nonce_lamports: u64,
        nonce_authority: Option<Pubkey>,
    ) -> Result<(Arc<Bank>, Keypair, Keypair, Keypair)>
    where
        F: FnMut(&mut GenesisConfig),
    {
        let (mut genesis_config, mint_keypair) = create_genesis_config(supply_lamports);
        genesis_config.rent.lamports_per_byte_year = 0;
        genesis_cfg_fn(&mut genesis_config);
        let mut bank = Arc::new(Bank::new(&genesis_config));

        // Banks 0 and 1 have no fees, wait two blocks before
        // initializing our nonce accounts
        for _ in 0..2 {
            goto_end_of_slot(Arc::get_mut(&mut bank).unwrap());
            bank = Arc::new(new_from_parent(&bank));
        }

        let (custodian_keypair, nonce_keypair) = nonce_setup(
            &mut bank,
            &mint_keypair,
            custodian_lamports,
            nonce_lamports,
            nonce_authority,
        )?;
        Ok((bank, mint_keypair, custodian_keypair, nonce_keypair))
    }

    #[test]
    fn test_check_tx_durable_nonce_ok() {
        let (bank, _mint_keypair, custodian_keypair, nonce_keypair) =
            setup_nonce_with_bank(10_000_000, |_| {}, 5_000_000, 250_000, None).unwrap();
        let custodian_pubkey = custodian_keypair.pubkey();
        let nonce_pubkey = nonce_keypair.pubkey();

        let nonce_hash = get_nonce_account(&bank, &nonce_pubkey).unwrap();
        let tx = Transaction::new_signed_with_payer(
            &[
                system_instruction::advance_nonce_account(&nonce_pubkey, &nonce_pubkey),
                system_instruction::transfer(&custodian_pubkey, &nonce_pubkey, 100_000),
            ],
            Some(&custodian_pubkey),
            &[&custodian_keypair, &nonce_keypair],
            nonce_hash,
        );
        let nonce_account = bank.get_account(&nonce_pubkey).unwrap();
        assert_eq!(
            bank.check_tx_durable_nonce(&tx),
            Some((nonce_pubkey, nonce_account))
        );
    }

    #[test]
    fn test_check_tx_durable_nonce_not_durable_nonce_fail() {
        let (bank, _mint_keypair, custodian_keypair, nonce_keypair) =
            setup_nonce_with_bank(10_000_000, |_| {}, 5_000_000, 250_000, None).unwrap();
        let custodian_pubkey = custodian_keypair.pubkey();
        let nonce_pubkey = nonce_keypair.pubkey();

        let nonce_hash = get_nonce_account(&bank, &nonce_pubkey).unwrap();
        let tx = Transaction::new_signed_with_payer(
            &[
                system_instruction::transfer(&custodian_pubkey, &nonce_pubkey, 100_000),
                system_instruction::advance_nonce_account(&nonce_pubkey, &nonce_pubkey),
            ],
            Some(&custodian_pubkey),
            &[&custodian_keypair, &nonce_keypair],
            nonce_hash,
        );
        assert!(bank.check_tx_durable_nonce(&tx).is_none());
    }

    #[test]
    fn test_check_tx_durable_nonce_missing_ix_pubkey_fail() {
        let (bank, _mint_keypair, custodian_keypair, nonce_keypair) =
            setup_nonce_with_bank(10_000_000, |_| {}, 5_000_000, 250_000, None).unwrap();
        let custodian_pubkey = custodian_keypair.pubkey();
        let nonce_pubkey = nonce_keypair.pubkey();

        let nonce_hash = get_nonce_account(&bank, &nonce_pubkey).unwrap();
        let mut tx = Transaction::new_signed_with_payer(
            &[
                system_instruction::advance_nonce_account(&nonce_pubkey, &nonce_pubkey),
                system_instruction::transfer(&custodian_pubkey, &nonce_pubkey, 100_000),
            ],
            Some(&custodian_pubkey),
            &[&custodian_keypair, &nonce_keypair],
            nonce_hash,
        );
        tx.message.instructions[0].accounts.clear();
        assert!(bank.check_tx_durable_nonce(&tx).is_none());
    }

    #[test]
    fn test_check_tx_durable_nonce_nonce_acc_does_not_exist_fail() {
        let (bank, _mint_keypair, custodian_keypair, nonce_keypair) =
            setup_nonce_with_bank(10_000_000, |_| {}, 5_000_000, 250_000, None).unwrap();
        let custodian_pubkey = custodian_keypair.pubkey();
        let nonce_pubkey = nonce_keypair.pubkey();
        let missing_keypair = Keypair::new();
        let missing_pubkey = missing_keypair.pubkey();

        let nonce_hash = get_nonce_account(&bank, &nonce_pubkey).unwrap();
        let tx = Transaction::new_signed_with_payer(
            &[
                system_instruction::advance_nonce_account(&missing_pubkey, &nonce_pubkey),
                system_instruction::transfer(&custodian_pubkey, &nonce_pubkey, 100_000),
            ],
            Some(&custodian_pubkey),
            &[&custodian_keypair, &nonce_keypair],
            nonce_hash,
        );
        assert!(bank.check_tx_durable_nonce(&tx).is_none());
    }

    #[test]
    fn test_check_tx_durable_nonce_bad_tx_hash_fail() {
        let (bank, _mint_keypair, custodian_keypair, nonce_keypair) =
            setup_nonce_with_bank(10_000_000, |_| {}, 5_000_000, 250_000, None).unwrap();
        let custodian_pubkey = custodian_keypair.pubkey();
        let nonce_pubkey = nonce_keypair.pubkey();

        let tx = Transaction::new_signed_with_payer(
            &[
                system_instruction::advance_nonce_account(&nonce_pubkey, &nonce_pubkey),
                system_instruction::transfer(&custodian_pubkey, &nonce_pubkey, 100_000),
            ],
            Some(&custodian_pubkey),
            &[&custodian_keypair, &nonce_keypair],
            Hash::default(),
        );
        assert!(bank.check_tx_durable_nonce(&tx).is_none());
    }

    #[test]
    fn test_assign_from_nonce_account_fail() {
        let (genesis_config, _mint_keypair) = create_genesis_config(100_000_000);
        let bank = Arc::new(Bank::new(&genesis_config));
        let nonce = Keypair::new();
        let nonce_account = AccountSharedData::new_data(
            42_424_242,
            &nonce::state::Versions::new_current(nonce::State::Initialized(
                nonce::state::Data::default(),
            )),
            &system_program::id(),
        )
        .unwrap();
        let blockhash = bank.last_blockhash();
        bank.store_account(&nonce.pubkey(), &nonce_account);

        let ix = system_instruction::assign(&nonce.pubkey(), &Pubkey::new(&[9u8; 32]));
        let message = Message::new(&[ix], Some(&nonce.pubkey()));
        let tx = Transaction::new(&[&nonce], message, blockhash);

        let expect = Err(TransactionError::InstructionError(
            0,
            InstructionError::ModifiedProgramId,
        ));
        assert_eq!(bank.process_transaction(&tx), expect);
    }

    #[test]
    fn test_durable_nonce_transaction() {
        let (mut bank, _mint_keypair, custodian_keypair, nonce_keypair) =
            setup_nonce_with_bank(10_000_000, |_| {}, 5_000_000, 250_000, None).unwrap();
        let alice_keypair = Keypair::new();
        let alice_pubkey = alice_keypair.pubkey();
        let custodian_pubkey = custodian_keypair.pubkey();
        let nonce_pubkey = nonce_keypair.pubkey();

        assert_eq!(bank.get_balance(&custodian_pubkey), 4_750_000);
        assert_eq!(bank.get_balance(&nonce_pubkey), 250_000);

        /* Grab the hash stored in the nonce account */
        let nonce_hash = get_nonce_account(&bank, &nonce_pubkey).unwrap();

        /* Kick nonce hash off the blockhash_queue */
        for _ in 0..MAX_RECENT_BLOCKHASHES + 1 {
            goto_end_of_slot(Arc::get_mut(&mut bank).unwrap());
            bank = Arc::new(new_from_parent(&bank));
        }

        /* Expect a non-Durable Nonce transfer to fail */
        assert_eq!(
            bank.process_transaction(&system_transaction::transfer(
                &custodian_keypair,
                &alice_pubkey,
                100_000,
                nonce_hash
            ),),
            Err(TransactionError::BlockhashNotFound),
        );
        /* Check fee not charged */
        assert_eq!(bank.get_balance(&custodian_pubkey), 4_750_000);

        /* Durable Nonce transfer */
        let durable_tx = Transaction::new_signed_with_payer(
            &[
                system_instruction::advance_nonce_account(&nonce_pubkey, &nonce_pubkey),
                system_instruction::transfer(&custodian_pubkey, &alice_pubkey, 100_000),
            ],
            Some(&custodian_pubkey),
            &[&custodian_keypair, &nonce_keypair],
            nonce_hash,
        );
        assert_eq!(bank.process_transaction(&durable_tx), Ok(()));

        /* Check balances */
        assert_eq!(bank.get_balance(&custodian_pubkey), 4_640_000);
        assert_eq!(bank.get_balance(&nonce_pubkey), 250_000);
        assert_eq!(bank.get_balance(&alice_pubkey), 100_000);

        /* Confirm stored nonce has advanced */
        let new_nonce = get_nonce_account(&bank, &nonce_pubkey).unwrap();
        assert_ne!(nonce_hash, new_nonce);

        /* Durable Nonce re-use fails */
        let durable_tx = Transaction::new_signed_with_payer(
            &[
                system_instruction::advance_nonce_account(&nonce_pubkey, &nonce_pubkey),
                system_instruction::transfer(&custodian_pubkey, &alice_pubkey, 100_000),
            ],
            Some(&custodian_pubkey),
            &[&custodian_keypair, &nonce_keypair],
            nonce_hash,
        );
        assert_eq!(
            bank.process_transaction(&durable_tx),
            Err(TransactionError::BlockhashNotFound)
        );
        /* Check fee not charged and nonce not advanced */
        assert_eq!(bank.get_balance(&custodian_pubkey), 4_640_000);
        assert_eq!(new_nonce, get_nonce_account(&bank, &nonce_pubkey).unwrap());

        let nonce_hash = new_nonce;

        /* Kick nonce hash off the blockhash_queue */
        for _ in 0..MAX_RECENT_BLOCKHASHES + 1 {
            goto_end_of_slot(Arc::get_mut(&mut bank).unwrap());
            bank = Arc::new(new_from_parent(&bank));
        }

        let durable_tx = Transaction::new_signed_with_payer(
            &[
                system_instruction::advance_nonce_account(&nonce_pubkey, &nonce_pubkey),
                system_instruction::transfer(&custodian_pubkey, &alice_pubkey, 100_000_000),
            ],
            Some(&custodian_pubkey),
            &[&custodian_keypair, &nonce_keypair],
            nonce_hash,
        );
        assert_eq!(
            bank.process_transaction(&durable_tx),
            Err(TransactionError::InstructionError(
                1,
                system_instruction::SystemError::ResultWithNegativeLamports.into(),
            ))
        );
        /* Check fee charged and nonce has advanced */
        assert_eq!(bank.get_balance(&custodian_pubkey), 4_630_000);
        assert_ne!(nonce_hash, get_nonce_account(&bank, &nonce_pubkey).unwrap());
        /* Confirm replaying a TX that failed with InstructionError::* now
         * fails with TransactionError::BlockhashNotFound
         */
        assert_eq!(
            bank.process_transaction(&durable_tx),
            Err(TransactionError::BlockhashNotFound),
        );
    }

    #[test]
    fn test_nonce_payer() {
        solana_logger::setup();
        let (mut bank, _mint_keypair, custodian_keypair, nonce_keypair) =
            setup_nonce_with_bank(10_000_000, |_| {}, 5_000_000, 250_000, None).unwrap();
        let alice_keypair = Keypair::new();
        let alice_pubkey = alice_keypair.pubkey();
        let custodian_pubkey = custodian_keypair.pubkey();
        let nonce_pubkey = nonce_keypair.pubkey();

        debug!("alice: {}", alice_pubkey);
        debug!("custodian: {}", custodian_pubkey);
        debug!("nonce: {}", nonce_pubkey);
        debug!("nonce account: {:?}", bank.get_account(&nonce_pubkey));
        debug!("cust: {:?}", bank.get_account(&custodian_pubkey));
        let nonce_hash = get_nonce_account(&bank, &nonce_pubkey).unwrap();

        for _ in 0..MAX_RECENT_BLOCKHASHES + 1 {
            goto_end_of_slot(Arc::get_mut(&mut bank).unwrap());
            bank = Arc::new(new_from_parent(&bank));
        }

        let durable_tx = Transaction::new_signed_with_payer(
            &[
                system_instruction::advance_nonce_account(&nonce_pubkey, &nonce_pubkey),
                system_instruction::transfer(&custodian_pubkey, &alice_pubkey, 100_000_000),
            ],
            Some(&nonce_pubkey),
            &[&custodian_keypair, &nonce_keypair],
            nonce_hash,
        );
        debug!("{:?}", durable_tx);
        assert_eq!(
            bank.process_transaction(&durable_tx),
            Err(TransactionError::InstructionError(
                1,
                system_instruction::SystemError::ResultWithNegativeLamports.into(),
            ))
        );
        /* Check fee charged and nonce has advanced */
        assert_eq!(bank.get_balance(&nonce_pubkey), 240_000);
        assert_ne!(nonce_hash, get_nonce_account(&bank, &nonce_pubkey).unwrap());
    }

    #[test]
    fn test_nonce_fee_calculator_updates() {
        let (mut genesis_config, mint_keypair) = create_genesis_config(1_000_000);
        genesis_config.rent.lamports_per_byte_year = 0;
        let mut bank = Arc::new(Bank::new(&genesis_config));

        // Deliberately use bank 0 to initialize nonce account, so that nonce account fee_calculator indicates 0 fees
        let (custodian_keypair, nonce_keypair) =
            nonce_setup(&mut bank, &mint_keypair, 500_000, 100_000, None).unwrap();
        let custodian_pubkey = custodian_keypair.pubkey();
        let nonce_pubkey = nonce_keypair.pubkey();

        // Grab the hash and fee_calculator stored in the nonce account
        let (stored_nonce_hash, stored_fee_calculator) = bank
            .get_account(&nonce_pubkey)
            .and_then(|acc| {
                let state =
                    StateMut::<nonce::state::Versions>::state(&acc).map(|v| v.convert_to_current());
                match state {
                    Ok(nonce::State::Initialized(ref data)) => {
                        Some((data.blockhash, data.fee_calculator.clone()))
                    }
                    _ => None,
                }
            })
            .unwrap();

        // Kick nonce hash off the blockhash_queue
        for _ in 0..MAX_RECENT_BLOCKHASHES + 1 {
            goto_end_of_slot(Arc::get_mut(&mut bank).unwrap());
            bank = Arc::new(new_from_parent(&bank));
        }

        // Durable Nonce transfer
        let nonce_tx = Transaction::new_signed_with_payer(
            &[
                system_instruction::advance_nonce_account(&nonce_pubkey, &nonce_pubkey),
                system_instruction::transfer(
                    &custodian_pubkey,
                    &solana_sdk::pubkey::new_rand(),
                    100_000,
                ),
            ],
            Some(&custodian_pubkey),
            &[&custodian_keypair, &nonce_keypair],
            stored_nonce_hash,
        );
        bank.process_transaction(&nonce_tx).unwrap();

        // Grab the new hash and fee_calculator; both should be updated
        let (nonce_hash, fee_calculator) = bank
            .get_account(&nonce_pubkey)
            .and_then(|acc| {
                let state =
                    StateMut::<nonce::state::Versions>::state(&acc).map(|v| v.convert_to_current());
                match state {
                    Ok(nonce::State::Initialized(ref data)) => {
                        Some((data.blockhash, data.fee_calculator.clone()))
                    }
                    _ => None,
                }
            })
            .unwrap();

        assert_ne!(stored_nonce_hash, nonce_hash);
        assert_ne!(stored_fee_calculator, fee_calculator);
    }

    #[test]
    fn test_collect_balances() {
        let (genesis_config, _mint_keypair) = create_genesis_config(500);
        let parent = Arc::new(Bank::new(&genesis_config));
        let bank0 = Arc::new(new_from_parent(&parent));

        let keypair = Keypair::new();
        let pubkey0 = solana_sdk::pubkey::new_rand();
        let pubkey1 = solana_sdk::pubkey::new_rand();
        let program_id = Pubkey::new(&[2; 32]);
        let keypair_account = AccountSharedData::new(8, 0, &program_id);
        let account0 = AccountSharedData::new(11, 0, &program_id);
        let program_account = AccountSharedData::new(1, 10, &Pubkey::default());
        bank0.store_account(&keypair.pubkey(), &keypair_account);
        bank0.store_account(&pubkey0, &account0);
        bank0.store_account(&program_id, &program_account);

        let instructions = vec![CompiledInstruction::new(1, &(), vec![0])];
        let tx0 = Transaction::new_with_compiled_instructions(
            &[&keypair],
            &[pubkey0],
            Hash::default(),
            vec![program_id],
            instructions,
        );
        let instructions = vec![CompiledInstruction::new(1, &(), vec![0])];
        let tx1 = Transaction::new_with_compiled_instructions(
            &[&keypair],
            &[pubkey1],
            Hash::default(),
            vec![program_id],
            instructions,
        );
        let txs = vec![tx0, tx1];
        let batch = bank0.prepare_batch(txs.iter()).unwrap();
        let balances = bank0.collect_balances(&batch);
        assert_eq!(balances.len(), 2);
        assert_eq!(balances[0], vec![8, 11, 1]);
        assert_eq!(balances[1], vec![8, 0, 1]);

        let txs: Vec<_> = txs.iter().rev().cloned().collect();
        let batch = bank0.prepare_batch(txs.iter()).unwrap();
        let balances = bank0.collect_balances(&batch);
        assert_eq!(balances.len(), 2);
        assert_eq!(balances[0], vec![8, 0, 1]);
        assert_eq!(balances[1], vec![8, 11, 1]);
    }

    #[test]
    fn test_pre_post_transaction_balances() {
        let (mut genesis_config, _mint_keypair) = create_genesis_config(500);
        let fee_rate_governor = FeeRateGovernor::new(1, 0);
        genesis_config.fee_rate_governor = fee_rate_governor;
        let parent = Arc::new(Bank::new(&genesis_config));
        let bank0 = Arc::new(new_from_parent(&parent));

        let keypair0 = Keypair::new();
        let keypair1 = Keypair::new();
        let pubkey0 = solana_sdk::pubkey::new_rand();
        let pubkey1 = solana_sdk::pubkey::new_rand();
        let pubkey2 = solana_sdk::pubkey::new_rand();
        let keypair0_account = AccountSharedData::new(8, 0, &Pubkey::default());
        let keypair1_account = AccountSharedData::new(9, 0, &Pubkey::default());
        let account0 = AccountSharedData::new(11, 0, &Pubkey::default());
        bank0.store_account(&keypair0.pubkey(), &keypair0_account);
        bank0.store_account(&keypair1.pubkey(), &keypair1_account);
        bank0.store_account(&pubkey0, &account0);

        let blockhash = bank0.last_blockhash();

        let tx0 = system_transaction::transfer(&keypair0, &pubkey0, 2, blockhash);
        let tx1 = system_transaction::transfer(&Keypair::new(), &pubkey1, 2, blockhash);
        let tx2 = system_transaction::transfer(&keypair1, &pubkey2, 12, blockhash);
        let txs = vec![tx0, tx1, tx2];

        let lock_result = bank0.prepare_batch(txs.iter()).unwrap();
        let (transaction_results, transaction_balances_set, inner_instructions, transaction_logs) =
            bank0.load_execute_and_commit_transactions(
                &lock_result,
                MAX_PROCESSING_AGE,
                true,
                false,
                false,
                &mut ExecuteTimings::default(),
            );

        assert!(inner_instructions.iter().all(Option::is_none));
        assert!(transaction_logs.iter().all(Option::is_none));

        assert_eq!(inner_instructions.len(), 3);
        assert_eq!(transaction_logs.len(), 3);
        assert_eq!(transaction_balances_set.pre_balances.len(), 3);
        assert_eq!(transaction_balances_set.post_balances.len(), 3);

        assert!(transaction_results.execution_results[0].0.is_ok());
        assert_eq!(transaction_balances_set.pre_balances[0], vec![8, 11, 1]);
        assert_eq!(transaction_balances_set.post_balances[0], vec![5, 13, 1]);

        // Failed transactions still produce balance sets
        // This is a TransactionError - not possible to charge fees
        assert!(transaction_results.execution_results[1].0.is_err());
        assert_eq!(transaction_balances_set.pre_balances[1], vec![0, 0, 1]);
        assert_eq!(transaction_balances_set.post_balances[1], vec![0, 0, 1]);

        // Failed transactions still produce balance sets
        // This is an InstructionError - fees charged
        assert!(transaction_results.execution_results[2].0.is_err());
        assert_eq!(transaction_balances_set.pre_balances[2], vec![9, 0, 1]);
        assert_eq!(transaction_balances_set.post_balances[2], vec![8, 0, 1]);
    }

    #[test]
    fn test_transaction_with_duplicate_accounts_in_instruction() {
        let (genesis_config, mint_keypair) = create_genesis_config(500);
        let mut bank = Bank::new(&genesis_config);

        fn mock_process_instruction(
            _program_id: &Pubkey,
            data: &[u8],
            invoke_context: &mut dyn InvokeContext,
        ) -> result::Result<(), InstructionError> {
            let keyed_accounts = invoke_context.get_keyed_accounts()?;
            let lamports = data[0] as u64;
            {
                let mut to_account = keyed_accounts[1].try_account_ref_mut()?;
                let mut dup_account = keyed_accounts[2].try_account_ref_mut()?;
                dup_account.checked_sub_lamports(lamports)?;
                to_account.checked_add_lamports(lamports)?;
            }
            keyed_accounts[0]
                .try_account_ref_mut()?
                .checked_sub_lamports(lamports)?;
            keyed_accounts[1]
                .try_account_ref_mut()?
                .checked_add_lamports(lamports)?;
            Ok(())
        }

        let mock_program_id = Pubkey::new(&[2u8; 32]);
        bank.add_builtin("mock_program", mock_program_id, mock_process_instruction);

        let from_pubkey = solana_sdk::pubkey::new_rand();
        let to_pubkey = solana_sdk::pubkey::new_rand();
        let dup_pubkey = from_pubkey;
        let from_account = AccountSharedData::new(100, 1, &mock_program_id);
        let to_account = AccountSharedData::new(0, 1, &mock_program_id);
        bank.store_account(&from_pubkey, &from_account);
        bank.store_account(&to_pubkey, &to_account);

        let account_metas = vec![
            AccountMeta::new(from_pubkey, false),
            AccountMeta::new(to_pubkey, false),
            AccountMeta::new(dup_pubkey, false),
        ];
        let instruction = Instruction::new_with_bincode(mock_program_id, &10, account_metas);
        let tx = Transaction::new_signed_with_payer(
            &[instruction],
            Some(&mint_keypair.pubkey()),
            &[&mint_keypair],
            bank.last_blockhash(),
        );

        let result = bank.process_transaction(&tx);
        assert_eq!(result, Ok(()));
        assert_eq!(bank.get_balance(&from_pubkey), 80);
        assert_eq!(bank.get_balance(&to_pubkey), 20);
    }

    #[test]
    fn test_transaction_with_program_ids_passed_to_programs() {
        let (genesis_config, mint_keypair) = create_genesis_config(500);
        let mut bank = Bank::new(&genesis_config);

        #[allow(clippy::unnecessary_wraps)]
        fn mock_process_instruction(
            _program_id: &Pubkey,
            _data: &[u8],
            _invoke_context: &mut dyn InvokeContext,
        ) -> result::Result<(), InstructionError> {
            Ok(())
        }

        let mock_program_id = Pubkey::new(&[2u8; 32]);
        bank.add_builtin("mock_program", mock_program_id, mock_process_instruction);

        let from_pubkey = solana_sdk::pubkey::new_rand();
        let to_pubkey = solana_sdk::pubkey::new_rand();
        let dup_pubkey = from_pubkey;
        let from_account = AccountSharedData::new(100, 1, &mock_program_id);
        let to_account = AccountSharedData::new(0, 1, &mock_program_id);
        bank.store_account(&from_pubkey, &from_account);
        bank.store_account(&to_pubkey, &to_account);

        let account_metas = vec![
            AccountMeta::new(from_pubkey, false),
            AccountMeta::new(to_pubkey, false),
            AccountMeta::new(dup_pubkey, false),
            AccountMeta::new(mock_program_id, false),
        ];
        let instruction = Instruction::new_with_bincode(mock_program_id, &10, account_metas);
        let tx = Transaction::new_signed_with_payer(
            &[instruction],
            Some(&mint_keypair.pubkey()),
            &[&mint_keypair],
            bank.last_blockhash(),
        );

        let result = bank.process_transaction(&tx);
        assert_eq!(result, Ok(()));
    }

    #[test]
    fn test_account_ids_after_program_ids() {
        solana_logger::setup();
        let (genesis_config, mint_keypair) = create_genesis_config(500);
        let mut bank = Bank::new(&genesis_config);

        let from_pubkey = solana_sdk::pubkey::new_rand();
        let to_pubkey = solana_sdk::pubkey::new_rand();

        let account_metas = vec![
            AccountMeta::new(from_pubkey, false),
            AccountMeta::new(to_pubkey, false),
        ];

        let instruction =
            Instruction::new_with_bincode(solana_vote_program::id(), &10, account_metas);
        let mut tx = Transaction::new_signed_with_payer(
            &[instruction],
            Some(&mint_keypair.pubkey()),
            &[&mint_keypair],
            bank.last_blockhash(),
        );

        tx.message.account_keys.push(solana_sdk::pubkey::new_rand());

        bank.add_builtin(
            "mock_vote",
            solana_vote_program::id(),
            mock_ok_vote_processor,
        );
        let result = bank.process_transaction(&tx);
        assert_eq!(result, Ok(()));
        let account = bank.get_account(&solana_vote_program::id()).unwrap();
        info!("account: {:?}", account);
        assert!(account.executable());
    }

    #[test]
    fn test_incinerator() {
        let (genesis_config, mint_keypair) = create_genesis_config(1_000_000_000_000);
        let bank0 = Arc::new(Bank::new(&genesis_config));

        // Move to the first normal slot so normal rent behaviour applies
        let bank = Bank::new_from_parent(
            &bank0,
            &Pubkey::default(),
            genesis_config.epoch_schedule.first_normal_slot,
        );
        let pre_capitalization = bank.capitalization();

        // Burn a non-rent exempt amount
        let burn_amount = bank.get_minimum_balance_for_rent_exemption(0) - 1;

        assert_eq!(bank.get_balance(&incinerator::id()), 0);
        bank.transfer(burn_amount, &mint_keypair, &incinerator::id())
            .unwrap();
        assert_eq!(bank.get_balance(&incinerator::id()), burn_amount);
        bank.freeze();
        assert_eq!(bank.get_balance(&incinerator::id()), 0);

        // Ensure that no rent was collected, and the entire burn amount was removed from bank
        // capitalization
        assert_eq!(bank.capitalization(), pre_capitalization - burn_amount);
    }

    #[test]
    fn test_duplicate_account_key() {
        solana_logger::setup();
        let (genesis_config, mint_keypair) = create_genesis_config(500);
        let mut bank = Bank::new(&genesis_config);

        let from_pubkey = solana_sdk::pubkey::new_rand();
        let to_pubkey = solana_sdk::pubkey::new_rand();

        let account_metas = vec![
            AccountMeta::new(from_pubkey, false),
            AccountMeta::new(to_pubkey, false),
        ];

        bank.add_builtin(
            "mock_vote",
            solana_vote_program::id(),
            mock_ok_vote_processor,
        );

        let instruction =
            Instruction::new_with_bincode(solana_vote_program::id(), &10, account_metas);
        let mut tx = Transaction::new_signed_with_payer(
            &[instruction],
            Some(&mint_keypair.pubkey()),
            &[&mint_keypair],
            bank.last_blockhash(),
        );
        tx.message.account_keys.push(from_pubkey);

        let result = bank.process_transaction(&tx);
        assert_eq!(result, Err(TransactionError::AccountLoadedTwice));
    }

    #[test]
    fn test_program_id_as_payer() {
        solana_logger::setup();
        let (genesis_config, mint_keypair) = create_genesis_config(500);
        let mut bank = Bank::new(&genesis_config);

        let from_pubkey = solana_sdk::pubkey::new_rand();
        let to_pubkey = solana_sdk::pubkey::new_rand();

        let account_metas = vec![
            AccountMeta::new(from_pubkey, false),
            AccountMeta::new(to_pubkey, false),
        ];

        bank.add_builtin(
            "mock_vote",
            solana_vote_program::id(),
            mock_ok_vote_processor,
        );

        let instruction =
            Instruction::new_with_bincode(solana_vote_program::id(), &10, account_metas);
        let mut tx = Transaction::new_signed_with_payer(
            &[instruction],
            Some(&mint_keypair.pubkey()),
            &[&mint_keypair],
            bank.last_blockhash(),
        );

        info!(
            "mint: {} account keys: {:?}",
            mint_keypair.pubkey(),
            tx.message.account_keys
        );
        assert_eq!(tx.message.account_keys.len(), 4);
        tx.message.account_keys.clear();
        tx.message.account_keys.push(solana_vote_program::id());
        tx.message.account_keys.push(mint_keypair.pubkey());
        tx.message.account_keys.push(from_pubkey);
        tx.message.account_keys.push(to_pubkey);
        tx.message.instructions[0].program_id_index = 0;
        tx.message.instructions[0].accounts.clear();
        tx.message.instructions[0].accounts.push(2);
        tx.message.instructions[0].accounts.push(3);

        let result = bank.process_transaction(&tx);
        assert_eq!(result, Err(TransactionError::SanitizeFailure));
    }

    #[allow(clippy::unnecessary_wraps)]
    fn mock_ok_vote_processor(
        _pubkey: &Pubkey,
        _data: &[u8],
        _invoke_context: &mut dyn InvokeContext,
    ) -> std::result::Result<(), InstructionError> {
        Ok(())
    }

    #[test]
    fn test_ref_account_key_after_program_id() {
        let (genesis_config, mint_keypair) = create_genesis_config(500);
        let mut bank = Bank::new(&genesis_config);

        let from_pubkey = solana_sdk::pubkey::new_rand();
        let to_pubkey = solana_sdk::pubkey::new_rand();

        let account_metas = vec![
            AccountMeta::new(from_pubkey, false),
            AccountMeta::new(to_pubkey, false),
        ];

        bank.add_builtin(
            "mock_vote",
            solana_vote_program::id(),
            mock_ok_vote_processor,
        );

        let instruction =
            Instruction::new_with_bincode(solana_vote_program::id(), &10, account_metas);
        let mut tx = Transaction::new_signed_with_payer(
            &[instruction],
            Some(&mint_keypair.pubkey()),
            &[&mint_keypair],
            bank.last_blockhash(),
        );

        tx.message.account_keys.push(solana_sdk::pubkey::new_rand());
        assert_eq!(tx.message.account_keys.len(), 5);
        tx.message.instructions[0].accounts.remove(0);
        tx.message.instructions[0].accounts.push(4);

        let result = bank.process_transaction(&tx);
        assert_eq!(result, Ok(()));
    }

    #[test]
    fn test_fuzz_instructions() {
        solana_logger::setup();
        use rand::{thread_rng, Rng};
        let (genesis_config, _mint_keypair) = create_genesis_config(1_000_000_000);
        let mut bank = Bank::new(&genesis_config);

        let max_programs = 5;
        let program_keys: Vec<_> = (0..max_programs)
            .enumerate()
            .map(|i| {
                let key = solana_sdk::pubkey::new_rand();
                let name = format!("program{:?}", i);
                bank.add_builtin(&name, key, mock_ok_vote_processor);
                (key, name.as_bytes().to_vec())
            })
            .collect();
        let max_keys = 100;
        let keys: Vec<_> = (0..max_keys)
            .enumerate()
            .map(|_| {
                let key = solana_sdk::pubkey::new_rand();
                let balance = if thread_rng().gen_ratio(9, 10) {
                    let lamports = if thread_rng().gen_ratio(1, 5) {
                        thread_rng().gen_range(0, 10)
                    } else {
                        thread_rng().gen_range(20, 100)
                    };
                    let space = thread_rng().gen_range(0, 10);
                    let owner = Pubkey::default();
                    let account = AccountSharedData::new(lamports, space, &owner);
                    bank.store_account(&key, &account);
                    lamports
                } else {
                    0
                };
                (key, balance)
            })
            .collect();
        let mut results = HashMap::new();
        for _ in 0..2_000 {
            let num_keys = if thread_rng().gen_ratio(1, 5) {
                thread_rng().gen_range(0, max_keys)
            } else {
                thread_rng().gen_range(1, 4)
            };
            let num_instructions = thread_rng().gen_range(0, max_keys - num_keys);

            let mut account_keys: Vec<_> = if thread_rng().gen_ratio(1, 5) {
                (0..num_keys)
                    .map(|_| {
                        let idx = thread_rng().gen_range(0, keys.len());
                        keys[idx].0
                    })
                    .collect()
            } else {
                let mut inserted = HashSet::new();
                (0..num_keys)
                    .map(|_| {
                        let mut idx;
                        loop {
                            idx = thread_rng().gen_range(0, keys.len());
                            if !inserted.contains(&idx) {
                                break;
                            }
                        }
                        inserted.insert(idx);
                        keys[idx].0
                    })
                    .collect()
            };

            let instructions: Vec<_> = if num_keys > 0 {
                (0..num_instructions)
                    .map(|_| {
                        let num_accounts_to_pass = thread_rng().gen_range(0, num_keys);
                        let account_indexes = (0..num_accounts_to_pass)
                            .map(|_| thread_rng().gen_range(0, num_keys))
                            .collect();
                        let program_index: u8 = thread_rng().gen_range(0, num_keys) as u8;
                        if thread_rng().gen_ratio(4, 5) {
                            let programs_index = thread_rng().gen_range(0, program_keys.len());
                            account_keys[program_index as usize] = program_keys[programs_index].0;
                        }
                        CompiledInstruction::new(program_index, &10, account_indexes)
                    })
                    .collect()
            } else {
                vec![]
            };

            let account_keys_len = std::cmp::max(account_keys.len(), 2);
            let num_signatures = if thread_rng().gen_ratio(1, 5) {
                thread_rng().gen_range(0, account_keys_len + 10)
            } else {
                thread_rng().gen_range(1, account_keys_len)
            };

            let num_required_signatures = if thread_rng().gen_ratio(1, 5) {
                thread_rng().gen_range(0, account_keys_len + 10) as u8
            } else {
                thread_rng().gen_range(1, std::cmp::max(2, num_signatures)) as u8
            };
            let num_readonly_signed_accounts = if thread_rng().gen_ratio(1, 5) {
                thread_rng().gen_range(0, account_keys_len) as u8
            } else {
                let max = if num_required_signatures > 1 {
                    num_required_signatures - 1
                } else {
                    1
                };
                thread_rng().gen_range(0, max) as u8
            };

            let num_readonly_unsigned_accounts = if thread_rng().gen_ratio(1, 5)
                || (num_required_signatures as usize) >= account_keys_len
            {
                thread_rng().gen_range(0, account_keys_len) as u8
            } else {
                thread_rng().gen_range(0, account_keys_len - num_required_signatures as usize) as u8
            };

            let header = MessageHeader {
                num_required_signatures,
                num_readonly_signed_accounts,
                num_readonly_unsigned_accounts,
            };
            let message = Message {
                header,
                account_keys,
                recent_blockhash: bank.last_blockhash(),
                instructions,
            };

            let tx = Transaction {
                signatures: vec![Signature::default(); num_signatures],
                message,
            };

            let result = bank.process_transaction(&tx);
            for (key, balance) in &keys {
                assert_eq!(bank.get_balance(key), *balance);
            }
            for (key, name) in &program_keys {
                let account = bank.get_account(key).unwrap();
                assert!(account.executable());
                assert_eq!(account.data(), name);
            }
            info!("result: {:?}", result);
            let result_key = format!("{:?}", result);
            *results.entry(result_key).or_insert(0) += 1;
        }
        info!("results: {:?}", results);
    }

    #[test]
    fn test_bank_hash_consistency() {
        solana_logger::setup();

        let mut genesis_config = GenesisConfig::new(
            &[(
                Pubkey::new(&[42; 32]),
                AccountSharedData::new(1_000_000_000_000, 0, &system_program::id()),
            )],
            &[],
        );
        genesis_config.creation_time = 0;
        genesis_config.cluster_type = ClusterType::MainnetBeta;
        genesis_config.rent.burn_percent = 100;
        let mut bank = Arc::new(Bank::new(&genesis_config));
        // Check a few slots, cross an epoch boundary
        assert_eq!(bank.get_slots_in_epoch(0), 32);
        loop {
            goto_end_of_slot(Arc::get_mut(&mut bank).unwrap());
            if bank.slot == 0 {
                assert_eq!(
                    bank.hash().to_string(),
                    "BfvaoHkrQwrkQo7T1mW6jmJXveRy11rut8bva2H1Rt5H"
                );
            }
            if bank.slot == 32 {
                assert_eq!(
                    bank.hash().to_string(),
                    "JBGPApnSMPKZaYiR16v46XSSGcKxy8kCbVtN1CG1XDxW"
                );
            }
            if bank.slot == 64 {
                assert_eq!(
                    bank.hash().to_string(),
                    "BDCt9cGPfxpgJXzp8Tq1nX1zSqpbs8xrkAFyRhmXKiuX"
                );
            }
            if bank.slot == 128 {
                assert_eq!(
                    bank.hash().to_string(),
                    "4zUpK4VUhKLaPUgeMMSeDR2w827goriRL5NndJxGDVmz"
                );
                break;
            }
            bank = Arc::new(new_from_parent(&bank));
        }
    }

    #[test]
    fn test_same_program_id_uses_unqiue_executable_accounts() {
        fn nested_processor(
            _program_id: &Pubkey,
            _data: &[u8],
            invoke_context: &mut dyn InvokeContext,
        ) -> result::Result<(), InstructionError> {
            let keyed_accounts = invoke_context.get_keyed_accounts()?;
            assert_eq!(42, keyed_accounts[0].lamports().unwrap());
            let mut account = keyed_accounts[0].try_account_ref_mut()?;
            account.checked_add_lamports(1)?;
            Ok(())
        }

        let (genesis_config, mint_keypair) = create_genesis_config(50000);
        let mut bank = Bank::new(&genesis_config);

        // Add a new program
        let program1_pubkey = solana_sdk::pubkey::new_rand();
        bank.add_builtin("program", program1_pubkey, nested_processor);

        // Add a new program owned by the first
        let program2_pubkey = solana_sdk::pubkey::new_rand();
        let mut program2_account = AccountSharedData::new(42, 1, &program1_pubkey);
        program2_account.set_executable(true);
        bank.store_account(&program2_pubkey, &program2_account);

        let instruction = Instruction::new_with_bincode(program2_pubkey, &10, vec![]);
        let tx = Transaction::new_signed_with_payer(
            &[instruction.clone(), instruction],
            Some(&mint_keypair.pubkey()),
            &[&mint_keypair],
            bank.last_blockhash(),
        );
        assert!(bank.process_transaction(&tx).is_ok());
        assert_eq!(1, bank.get_balance(&program1_pubkey));
        assert_eq!(42, bank.get_balance(&program2_pubkey));
    }

    fn get_shrink_account_size() -> usize {
        let (genesis_config, _mint_keypair) = create_genesis_config(1_000_000_000);

        // Set root for bank 0, with caching disabled so we can get the size
        // of the storage for this slot
        let mut bank0 = Arc::new(Bank::new_with_config(
            &genesis_config,
            AccountSecondaryIndexes::default(),
            false,
            AccountShrinkThreshold::default(),
        ));
        bank0.restore_old_behavior_for_fragile_tests();
        goto_end_of_slot(Arc::<Bank>::get_mut(&mut bank0).unwrap());
        bank0.freeze();
        bank0.squash();

        let sizes = bank0
            .rc
            .accounts
            .scan_slot(0, |stored_account| Some(stored_account.stored_size()));

        // Create an account such that it takes DEFAULT_ACCOUNTS_SHRINK_RATIO of the total account space for
        // the slot, so when it gets pruned, the storage entry will become a shrink candidate.
        let bank0_total_size: usize = sizes.into_iter().sum();
        let pubkey0_size = (bank0_total_size as f64 / (1.0 - DEFAULT_ACCOUNTS_SHRINK_RATIO)).ceil();
        assert!(
            pubkey0_size / (pubkey0_size + bank0_total_size as f64) > DEFAULT_ACCOUNTS_SHRINK_RATIO
        );
        pubkey0_size as usize
    }

    #[test]
    fn test_shrink_candidate_slots_cached() {
        solana_logger::setup();

        let (genesis_config, _mint_keypair) = create_genesis_config(1_000_000_000);
        let pubkey0 = solana_sdk::pubkey::new_rand();
        let pubkey1 = solana_sdk::pubkey::new_rand();
        let pubkey2 = solana_sdk::pubkey::new_rand();

        // Set root for bank 0, with caching enabled
        let mut bank0 = Arc::new(Bank::new_with_config(
            &genesis_config,
            AccountSecondaryIndexes::default(),
            true,
            AccountShrinkThreshold::default(),
        ));
        bank0.restore_old_behavior_for_fragile_tests();

        let pubkey0_size = get_shrink_account_size();

        let account0 = AccountSharedData::new(1000, pubkey0_size as usize, &Pubkey::new_unique());
        bank0.store_account(&pubkey0, &account0);

        goto_end_of_slot(Arc::<Bank>::get_mut(&mut bank0).unwrap());
        bank0.freeze();
        bank0.squash();
        // Flush now so that accounts cache cleaning doesn't clean up bank 0 when later
        // slots add updates to the cache
        bank0.force_flush_accounts_cache();

        // Store some lamports in bank 1
        let some_lamports = 123;
        let mut bank1 = Arc::new(new_from_parent(&bank0));
        bank1.deposit(&pubkey1, some_lamports).unwrap();
        bank1.deposit(&pubkey2, some_lamports).unwrap();
        goto_end_of_slot(Arc::<Bank>::get_mut(&mut bank1).unwrap());
        bank1.freeze();
        bank1.squash();
        // Flush now so that accounts cache cleaning doesn't clean up bank 0 when later
        // slots add updates to the cache
        bank1.force_flush_accounts_cache();

        // Store some lamports for pubkey1 in bank 2, root bank 2
        let mut bank2 = Arc::new(new_from_parent(&bank1));
        bank2.deposit(&pubkey1, some_lamports).unwrap();
        bank2.store_account(&pubkey0, &account0);
        goto_end_of_slot(Arc::<Bank>::get_mut(&mut bank2).unwrap());
        bank2.freeze();
        bank2.squash();
        bank2.force_flush_accounts_cache();

        // Clean accounts, which should add earlier slots to the shrink
        // candidate set
        bank2.clean_accounts(false, false);

        // Slots 0 and 1 should be candidates for shrinking, but slot 2
        // shouldn't because none of its accounts are outdated by a later
        // root
        assert_eq!(bank2.shrink_candidate_slots(), 2);
        let alive_counts: Vec<usize> = (0..3)
            .map(|slot| {
                bank2
                    .rc
                    .accounts
                    .accounts_db
                    .alive_account_count_in_slot(slot)
            })
            .collect();

        // No more slots should be shrunk
        assert_eq!(bank2.shrink_candidate_slots(), 0);
        // alive_counts represents the count of alive accounts in the three slots 0,1,2
        assert_eq!(alive_counts, vec![10, 1, 7]);
    }

    #[test]
    fn test_process_stale_slot_with_budget() {
        solana_logger::setup();

        let (genesis_config, _mint_keypair) = create_genesis_config(1_000_000_000);
        let pubkey1 = solana_sdk::pubkey::new_rand();
        let pubkey2 = solana_sdk::pubkey::new_rand();

        let mut bank = Arc::new(Bank::new(&genesis_config));
        bank.restore_old_behavior_for_fragile_tests();
        assert_eq!(bank.process_stale_slot_with_budget(0, 0), 0);
        assert_eq!(bank.process_stale_slot_with_budget(133, 0), 133);

        assert_eq!(bank.process_stale_slot_with_budget(0, 100), 0);
        assert_eq!(bank.process_stale_slot_with_budget(33, 100), 0);
        assert_eq!(bank.process_stale_slot_with_budget(133, 100), 33);

        goto_end_of_slot(Arc::<Bank>::get_mut(&mut bank).unwrap());

        bank.squash();

        let some_lamports = 123;
        let mut bank = Arc::new(new_from_parent(&bank));
        bank.deposit(&pubkey1, some_lamports).unwrap();
        bank.deposit(&pubkey2, some_lamports).unwrap();

        goto_end_of_slot(Arc::<Bank>::get_mut(&mut bank).unwrap());

        let mut bank = Arc::new(new_from_parent(&bank));
        bank.deposit(&pubkey1, some_lamports).unwrap();

        goto_end_of_slot(Arc::<Bank>::get_mut(&mut bank).unwrap());

        bank.squash();
        bank.clean_accounts(false, false);
        let force_to_return_alive_account = 0;
        assert_eq!(
            bank.process_stale_slot_with_budget(22, force_to_return_alive_account),
            22
        );

        let consumed_budgets: usize = (0..3)
            .map(|_| bank.process_stale_slot_with_budget(0, force_to_return_alive_account))
            .sum();
        // consumed_budgets represents the count of alive accounts in the three slots 0,1,2
        assert_eq!(consumed_budgets, 11);
    }

    #[test]
    fn test_upgrade_epoch() {
        solana_logger::setup();
        let GenesisConfigInfo {
            mut genesis_config,
            mint_keypair,
            ..
        } = create_genesis_config_with_leader(500, &solana_sdk::pubkey::new_rand(), 0);
        genesis_config.fee_rate_governor = FeeRateGovernor::new(1, 0);
        let bank = Arc::new(Bank::new(&genesis_config));
        // Jump to the test-only upgrade epoch -- see `Bank::upgrade_epoch()`
        let bank = Bank::new_from_parent(
            &bank,
            &Pubkey::default(),
            genesis_config
                .epoch_schedule
                .get_first_slot_in_epoch(0xdead),
        );

        assert_eq!(bank.get_balance(&mint_keypair.pubkey()), 500);

        // Normal transfers are not allowed
        assert_eq!(
            bank.transfer(2, &mint_keypair, &mint_keypair.pubkey()),
            Err(TransactionError::ClusterMaintenance)
        );
        assert_eq!(bank.get_balance(&mint_keypair.pubkey()), 500); // no transaction fee charged

        let vote_pubkey = solana_sdk::pubkey::new_rand();
        let authorized_voter = Keypair::new();

        // VoteInstruction::Vote is allowed.  The transaction fails with a vote program instruction
        // error because the vote account is not actually setup
        let tx = Transaction::new_signed_with_payer(
            &[vote_instruction::vote(
                &vote_pubkey,
                &authorized_voter.pubkey(),
                Vote::new(vec![1], Hash::default()),
            )],
            Some(&mint_keypair.pubkey()),
            &[&mint_keypair, &authorized_voter],
            bank.last_blockhash(),
        );
        assert_eq!(
            bank.process_transaction(&tx),
            Err(TransactionError::InstructionError(
                0,
                InstructionError::InvalidAccountOwner
            ))
        );
        assert_eq!(bank.get_balance(&mint_keypair.pubkey()), 498); // transaction fee charged

        // VoteInstruction::VoteSwitch is allowed.  The transaction fails with a vote program
        // instruction error because the vote account is not actually setup
        let tx = Transaction::new_signed_with_payer(
            &[vote_instruction::vote_switch(
                &vote_pubkey,
                &authorized_voter.pubkey(),
                Vote::new(vec![1], Hash::default()),
                Hash::default(),
            )],
            Some(&mint_keypair.pubkey()),
            &[&mint_keypair, &authorized_voter],
            bank.last_blockhash(),
        );
        assert_eq!(
            bank.process_transaction(&tx),
            Err(TransactionError::InstructionError(
                0,
                InstructionError::InvalidAccountOwner
            ))
        );
        assert_eq!(bank.get_balance(&mint_keypair.pubkey()), 496); // transaction fee charged

        // Other vote program instructions, like VoteInstruction::UpdateCommission are not allowed
        let tx = Transaction::new_signed_with_payer(
            &[vote_instruction::update_commission(
                &vote_pubkey,
                &authorized_voter.pubkey(),
                123,
            )],
            Some(&mint_keypair.pubkey()),
            &[&mint_keypair, &authorized_voter],
            bank.last_blockhash(),
        );
        assert_eq!(
            bank.process_transaction(&tx),
            Err(TransactionError::ClusterMaintenance)
        );
        assert_eq!(bank.get_balance(&mint_keypair.pubkey()), 496); // no transaction fee charged
    }

    #[test]
    fn test_add_builtin_no_overwrite() {
        let (genesis_config, _mint_keypair) = create_genesis_config(100_000);

        #[allow(clippy::unnecessary_wraps)]
        fn mock_ix_processor(
            _pubkey: &Pubkey,
            _data: &[u8],
            _invoke_context: &mut dyn InvokeContext,
        ) -> std::result::Result<(), InstructionError> {
            Ok(())
        }

        let slot = 123;
        let program_id = solana_sdk::pubkey::new_rand();

        let mut bank = Arc::new(Bank::new_from_parent(
            &Arc::new(Bank::new(&genesis_config)),
            &Pubkey::default(),
            slot,
        ));
        assert_eq!(bank.get_account_modified_slot(&program_id), None);

        Arc::get_mut(&mut bank)
            .unwrap()
            .add_builtin("mock_program", program_id, mock_ix_processor);
        assert_eq!(bank.get_account_modified_slot(&program_id).unwrap().1, slot);

        let mut bank = Arc::new(new_from_parent(&bank));
        Arc::get_mut(&mut bank)
            .unwrap()
            .add_builtin("mock_program", program_id, mock_ix_processor);
        assert_eq!(bank.get_account_modified_slot(&program_id).unwrap().1, slot);

        Arc::get_mut(&mut bank).unwrap().replace_builtin(
            "mock_program v2",
            program_id,
            mock_ix_processor,
        );
        assert_eq!(
            bank.get_account_modified_slot(&program_id).unwrap().1,
            bank.slot()
        );
    }

    #[test]
    fn test_add_builtin_loader_no_overwrite() {
        let (genesis_config, _mint_keypair) = create_genesis_config(100_000);

        #[allow(clippy::unnecessary_wraps)]
        fn mock_ix_processor(
            _pubkey: &Pubkey,
            _data: &[u8],
            _context: &mut dyn InvokeContext,
        ) -> std::result::Result<(), InstructionError> {
            Ok(())
        }

        let slot = 123;
        let loader_id = solana_sdk::pubkey::new_rand();

        let mut bank = Arc::new(Bank::new_from_parent(
            &Arc::new(Bank::new(&genesis_config)),
            &Pubkey::default(),
            slot,
        ));
        assert_eq!(bank.get_account_modified_slot(&loader_id), None);

        Arc::get_mut(&mut bank)
            .unwrap()
            .add_builtin("mock_program", loader_id, mock_ix_processor);
        assert_eq!(bank.get_account_modified_slot(&loader_id).unwrap().1, slot);

        let mut bank = Arc::new(new_from_parent(&bank));
        Arc::get_mut(&mut bank)
            .unwrap()
            .add_builtin("mock_program", loader_id, mock_ix_processor);
        assert_eq!(bank.get_account_modified_slot(&loader_id).unwrap().1, slot);
    }

    #[test]
    fn test_add_native_program() {
        let (mut genesis_config, _mint_keypair) = create_genesis_config(100_000);
        activate_all_features(&mut genesis_config);

        let slot = 123;
        let program_id = solana_sdk::pubkey::new_rand();

        let bank = Arc::new(Bank::new_from_parent(
            &Arc::new(Bank::new(&genesis_config)),
            &Pubkey::default(),
            slot,
        ));
        assert_eq!(bank.get_account_modified_slot(&program_id), None);

        assert_capitalization_diff(
            &bank,
            || bank.add_native_program("mock_program", &program_id, false),
            |old, new| {
                assert_eq!(old + 1, new);
            },
        );

        assert_eq!(bank.get_account_modified_slot(&program_id).unwrap().1, slot);

        let bank = Arc::new(new_from_parent(&bank));
        assert_capitalization_diff(
            &bank,
            || bank.add_native_program("mock_program", &program_id, false),
            |old, new| assert_eq!(old, new),
        );

        assert_eq!(bank.get_account_modified_slot(&program_id).unwrap().1, slot);

        let bank = Arc::new(new_from_parent(&bank));
        // When replacing native_program, name must change to disambiguate from repeated
        // invocations.
        assert_capitalization_diff(
            &bank,
            || bank.add_native_program("mock_program v2", &program_id, true),
            |old, new| assert_eq!(old, new),
        );

        assert_eq!(
            bank.get_account_modified_slot(&program_id).unwrap().1,
            bank.slot()
        );

        let bank = Arc::new(new_from_parent(&bank));
        assert_capitalization_diff(
            &bank,
            || bank.add_native_program("mock_program v2", &program_id, true),
            |old, new| assert_eq!(old, new),
        );

        // replacing with same name shouldn't update account
        assert_eq!(
            bank.get_account_modified_slot(&program_id).unwrap().1,
            bank.parent_slot()
        );
    }

    #[test]
    fn test_add_native_program_inherited_cap_while_replacing() {
        let (genesis_config, mint_keypair) = create_genesis_config(100_000);
        let bank = Bank::new(&genesis_config);
        let program_id = solana_sdk::pubkey::new_rand();

        bank.add_native_program("mock_program", &program_id, false);
        assert_eq!(bank.capitalization(), bank.calculate_capitalization(true));

        // someone mess with program_id's balance
        bank.withdraw(&mint_keypair.pubkey(), 10).unwrap();
        assert_ne!(bank.capitalization(), bank.calculate_capitalization(true));
        bank.deposit(&program_id, 10).unwrap();
        assert_eq!(bank.capitalization(), bank.calculate_capitalization(true));

        bank.add_native_program("mock_program v2", &program_id, true);
        assert_eq!(bank.capitalization(), bank.calculate_capitalization(true));
    }

    #[test]
    fn test_add_native_program_squatted_while_not_replacing() {
        let (genesis_config, mint_keypair) = create_genesis_config(100_000);
        let bank = Bank::new(&genesis_config);
        let program_id = solana_sdk::pubkey::new_rand();

        // someone managed to squat at program_id!
        bank.withdraw(&mint_keypair.pubkey(), 10).unwrap();
        assert_ne!(bank.capitalization(), bank.calculate_capitalization(true));
        bank.deposit(&program_id, 10).unwrap();
        assert_eq!(bank.capitalization(), bank.calculate_capitalization(true));

        bank.add_native_program("mock_program", &program_id, false);
        assert_eq!(bank.capitalization(), bank.calculate_capitalization(true));
    }

    #[test]
    #[should_panic(
        expected = "Can't change frozen bank by adding not-existing new native \
                   program (mock_program, CiXgo2KHKSDmDnV1F6B69eWFgNAPiSBjjYvfB4cvRNre). \
                   Maybe, inconsistent program activation is detected on snapshot restore?"
    )]
    fn test_add_native_program_after_frozen() {
        use std::str::FromStr;
        let (genesis_config, _mint_keypair) = create_genesis_config(100_000);

        let slot = 123;
        let program_id = Pubkey::from_str("CiXgo2KHKSDmDnV1F6B69eWFgNAPiSBjjYvfB4cvRNre").unwrap();

        let bank = Bank::new_from_parent(
            &Arc::new(Bank::new(&genesis_config)),
            &Pubkey::default(),
            slot,
        );
        bank.freeze();

        bank.add_native_program("mock_program", &program_id, false);
    }

    #[test]
    #[should_panic(
        expected = "There is no account to replace with native program (mock_program, \
                    CiXgo2KHKSDmDnV1F6B69eWFgNAPiSBjjYvfB4cvRNre)."
    )]
    fn test_add_native_program_replace_none() {
        use std::str::FromStr;
        let (genesis_config, _mint_keypair) = create_genesis_config(100_000);

        let slot = 123;
        let program_id = Pubkey::from_str("CiXgo2KHKSDmDnV1F6B69eWFgNAPiSBjjYvfB4cvRNre").unwrap();

        let bank = Bank::new_from_parent(
            &Arc::new(Bank::new(&genesis_config)),
            &Pubkey::default(),
            slot,
        );

        bank.add_native_program("mock_program", &program_id, true);
    }

    #[test]
    fn test_reconfigure_token2_native_mint() {
        solana_logger::setup();

        let mut genesis_config =
            create_genesis_config_with_leader(5, &solana_sdk::pubkey::new_rand(), 0).genesis_config;

        // ClusterType::Development - Native mint exists immediately
        assert_eq!(genesis_config.cluster_type, ClusterType::Development);
        let bank = Arc::new(Bank::new(&genesis_config));
        assert_eq!(
            bank.get_balance(&inline_spl_token_v2_0::native_mint::id()),
            1000000000
        );

        // Testnet - Native mint blinks into existence at epoch 93
        genesis_config.cluster_type = ClusterType::Testnet;
        let bank = Arc::new(Bank::new(&genesis_config));
        assert_eq!(
            bank.get_balance(&inline_spl_token_v2_0::native_mint::id()),
            0
        );
        bank.deposit(&inline_spl_token_v2_0::native_mint::id(), 4200000000)
            .unwrap();

        let bank = Bank::new_from_parent(
            &bank,
            &Pubkey::default(),
            genesis_config.epoch_schedule.get_first_slot_in_epoch(93),
        );

        let native_mint_account = bank
            .get_account(&inline_spl_token_v2_0::native_mint::id())
            .unwrap();
        assert_eq!(native_mint_account.data().len(), 82);
        assert_eq!(
            bank.get_balance(&inline_spl_token_v2_0::native_mint::id()),
            4200000000
        );
        assert_eq!(native_mint_account.owner(), &inline_spl_token_v2_0::id());

        // MainnetBeta - Native mint blinks into existence at epoch 75
        genesis_config.cluster_type = ClusterType::MainnetBeta;
        let bank = Arc::new(Bank::new(&genesis_config));
        assert_eq!(
            bank.get_balance(&inline_spl_token_v2_0::native_mint::id()),
            0
        );
        bank.deposit(&inline_spl_token_v2_0::native_mint::id(), 4200000000)
            .unwrap();

        let bank = Bank::new_from_parent(
            &bank,
            &Pubkey::default(),
            genesis_config.epoch_schedule.get_first_slot_in_epoch(75),
        );

        let native_mint_account = bank
            .get_account(&inline_spl_token_v2_0::native_mint::id())
            .unwrap();
        assert_eq!(native_mint_account.data().len(), 82);
        assert_eq!(
            bank.get_balance(&inline_spl_token_v2_0::native_mint::id()),
            4200000000
        );
        assert_eq!(native_mint_account.owner(), &inline_spl_token_v2_0::id());
    }

    #[test]
    fn test_ensure_no_storage_rewards_pool() {
        solana_logger::setup();

        let mut genesis_config =
            create_genesis_config_with_leader(5, &solana_sdk::pubkey::new_rand(), 0).genesis_config;

        // Testnet - Storage rewards pool is purged at epoch 93
        // Also this is with bad capitalization
        genesis_config.cluster_type = ClusterType::Testnet;
        genesis_config.inflation = Inflation::default();
        let reward_pubkey = solana_sdk::pubkey::new_rand();
        genesis_config.rewards_pools.insert(
            reward_pubkey,
            Account::new(u64::MAX, 0, &solana_sdk::pubkey::new_rand()),
        );
        let bank0 = Bank::new(&genesis_config);
        // because capitalization has been reset with bogus capitalization calculation allowing overflows,
        // deliberately substract 1 lamport to simulate it
        bank0.capitalization.fetch_sub(1, Relaxed);
        let bank0 = Arc::new(bank0);
        assert_eq!(bank0.get_balance(&reward_pubkey), u64::MAX,);

        let bank1 = Bank::new_from_parent(
            &bank0,
            &Pubkey::default(),
            genesis_config.epoch_schedule.get_first_slot_in_epoch(93),
        );

        // assert that everything gets in order....
        assert!(bank1.get_account(&reward_pubkey).is_none());
        let sysvar_and_native_proram_delta = 1;
        assert_eq!(
            bank0.capitalization() + 1 + 1_000_000_000 + sysvar_and_native_proram_delta,
            bank1.capitalization()
        );
        assert_eq!(bank1.capitalization(), bank1.calculate_capitalization(true));

        // Depending on RUSTFLAGS, this test exposes rust's checked math behavior or not...
        // So do some convolted setup; anyway this test itself will just be temporary
        let bank0 = std::panic::AssertUnwindSafe(bank0);
        let overflowing_capitalization =
            std::panic::catch_unwind(|| bank0.calculate_capitalization(true));
        if let Ok(overflowing_capitalization) = overflowing_capitalization {
            info!("asserting overflowing capitalization for bank0");
            assert_eq!(overflowing_capitalization, bank0.capitalization());
        } else {
            info!("NOT-asserting overflowing capitalization for bank0");
        }
    }

    #[derive(Debug)]
    struct TestExecutor {}
    impl Executor for TestExecutor {
        fn execute(
            &self,
            _loader_id: &Pubkey,
            _program_id: &Pubkey,
            _instruction_data: &[u8],
            _invoke_context: &mut dyn InvokeContext,
            _use_jit: bool,
        ) -> std::result::Result<(), InstructionError> {
            Ok(())
        }
    }

    #[test]
    fn test_cached_executors() {
        let key1 = solana_sdk::pubkey::new_rand();
        let key2 = solana_sdk::pubkey::new_rand();
        let key3 = solana_sdk::pubkey::new_rand();
        let key4 = solana_sdk::pubkey::new_rand();
        let executor: Arc<dyn Executor> = Arc::new(TestExecutor {});
        let mut cache = CachedExecutors::new(3, 0);

        cache.put(&key1, executor.clone());
        cache.put(&key2, executor.clone());
        cache.put(&key3, executor.clone());
        assert!(cache.get(&key1).is_some());
        assert!(cache.get(&key2).is_some());
        assert!(cache.get(&key3).is_some());

        assert!(cache.get(&key1).is_some());
        assert!(cache.get(&key1).is_some());
        assert!(cache.get(&key2).is_some());
        cache.put(&key4, executor.clone());
        assert!(cache.get(&key1).is_some());
        assert!(cache.get(&key2).is_some());
        assert!(cache.get(&key3).is_none());
        assert!(cache.get(&key4).is_some());

        assert!(cache.get(&key4).is_some());
        assert!(cache.get(&key4).is_some());
        assert!(cache.get(&key4).is_some());
        cache.put(&key3, executor.clone());
        assert!(cache.get(&key1).is_some());
        assert!(cache.get(&key2).is_none());
        assert!(cache.get(&key3).is_some());
        assert!(cache.get(&key4).is_some());
    }

    #[test]
    fn test_cached_executors_eviction() {
        let key1 = solana_sdk::pubkey::new_rand();
        let key2 = solana_sdk::pubkey::new_rand();
        let key3 = solana_sdk::pubkey::new_rand();
        let key4 = solana_sdk::pubkey::new_rand();
        let executor: Arc<dyn Executor> = Arc::new(TestExecutor {});
        let mut cache = CachedExecutors::new(3, 0);
        assert!(cache.current_epoch == 0);

        cache.put(&key1, executor.clone());
        cache.put(&key2, executor.clone());
        cache.put(&key3, executor.clone());
        assert!(cache.get(&key1).is_some());
        assert!(cache.get(&key1).is_some());
        assert!(cache.get(&key1).is_some());

        cache = cache.clone_with_epoch(1);
        assert!(cache.current_epoch == 1);

        assert!(cache.get(&key2).is_some());
        assert!(cache.get(&key2).is_some());
        assert!(cache.get(&key3).is_some());
        cache.put(&key4, executor.clone());

        assert!(cache.get(&key4).is_some());
        assert!(cache.get(&key3).is_none());

        cache = cache.clone_with_epoch(2);
        assert!(cache.current_epoch == 2);

        cache.put(&key3, executor.clone());
        assert!(cache.get(&key3).is_some());
    }

    #[test]
    fn test_bank_executor_cache() {
        solana_logger::setup();

        let (genesis_config, _) = create_genesis_config(1);
        let bank = Bank::new(&genesis_config);

        let key1 = solana_sdk::pubkey::new_rand();
        let key2 = solana_sdk::pubkey::new_rand();
        let key3 = solana_sdk::pubkey::new_rand();
        let key4 = solana_sdk::pubkey::new_rand();
        let executor: Arc<dyn Executor> = Arc::new(TestExecutor {});

        let message = Message {
            header: MessageHeader {
                num_required_signatures: 1,
                num_readonly_signed_accounts: 0,
                num_readonly_unsigned_accounts: 1,
            },
            account_keys: vec![key1, key2],
            recent_blockhash: Hash::default(),
            instructions: vec![],
        };

        let loaders = &[
            vec![
                (key3, AccountSharedData::default()),
                (key4, AccountSharedData::default()),
            ],
            vec![(key1, AccountSharedData::default())],
        ];

        // don't do any work if not dirty
        let mut executors = Executors::default();
        executors.insert(key1, executor.clone());
        executors.insert(key2, executor.clone());
        executors.insert(key3, executor.clone());
        executors.insert(key4, executor.clone());
        let executors = Rc::new(RefCell::new(executors));
        executors.borrow_mut().is_dirty = false;
        bank.update_executors(executors);
        let executors = bank.get_executors(&message, loaders);
        assert_eq!(executors.borrow().executors.len(), 0);

        // do work
        let mut executors = Executors::default();
        executors.insert(key1, executor.clone());
        executors.insert(key2, executor.clone());
        executors.insert(key3, executor.clone());
        executors.insert(key4, executor.clone());
        let executors = Rc::new(RefCell::new(executors));
        bank.update_executors(executors);
        let executors = bank.get_executors(&message, loaders);
        assert_eq!(executors.borrow().executors.len(), 4);
        assert!(executors.borrow().executors.contains_key(&key1));
        assert!(executors.borrow().executors.contains_key(&key2));
        assert!(executors.borrow().executors.contains_key(&key3));
        assert!(executors.borrow().executors.contains_key(&key4));

        // Check inheritance
        let bank = Bank::new_from_parent(&Arc::new(bank), &solana_sdk::pubkey::new_rand(), 1);
        let executors = bank.get_executors(&message, loaders);
        assert_eq!(executors.borrow().executors.len(), 4);
        assert!(executors.borrow().executors.contains_key(&key1));
        assert!(executors.borrow().executors.contains_key(&key2));
        assert!(executors.borrow().executors.contains_key(&key3));
        assert!(executors.borrow().executors.contains_key(&key4));

        bank.remove_executor(&key1);
        bank.remove_executor(&key2);
        bank.remove_executor(&key3);
        bank.remove_executor(&key4);
        let executors = bank.get_executors(&message, loaders);
        assert_eq!(executors.borrow().executors.len(), 0);
        assert!(!executors.borrow().executors.contains_key(&key1));
        assert!(!executors.borrow().executors.contains_key(&key2));
        assert!(!executors.borrow().executors.contains_key(&key3));
        assert!(!executors.borrow().executors.contains_key(&key4));
    }

    #[test]
    fn test_bank_executor_cow() {
        solana_logger::setup();

        let (genesis_config, _) = create_genesis_config(1);
        let root = Arc::new(Bank::new(&genesis_config));

        let key1 = solana_sdk::pubkey::new_rand();
        let key2 = solana_sdk::pubkey::new_rand();
        let executor: Arc<dyn Executor> = Arc::new(TestExecutor {});

        let loaders = &[vec![
            (key1, AccountSharedData::default()),
            (key2, AccountSharedData::default()),
        ]];

        // add one to root bank
        let mut executors = Executors::default();
        executors.insert(key1, executor.clone());
        let executors = Rc::new(RefCell::new(executors));
        root.update_executors(executors);
        let executors = root.get_executors(&Message::default(), loaders);
        assert_eq!(executors.borrow().executors.len(), 1);

        let fork1 = Bank::new_from_parent(&root, &Pubkey::default(), 1);
        let fork2 = Bank::new_from_parent(&root, &Pubkey::default(), 1);

        let executors = fork1.get_executors(&Message::default(), loaders);
        assert_eq!(executors.borrow().executors.len(), 1);
        let executors = fork2.get_executors(&Message::default(), loaders);
        assert_eq!(executors.borrow().executors.len(), 1);

        let mut executors = Executors::default();
        executors.insert(key2, executor.clone());
        let executors = Rc::new(RefCell::new(executors));
        fork1.update_executors(executors);

        let executors = fork1.get_executors(&Message::default(), loaders);
        assert_eq!(executors.borrow().executors.len(), 2);
        let executors = fork2.get_executors(&Message::default(), loaders);
        assert_eq!(executors.borrow().executors.len(), 1);

        fork1.remove_executor(&key1);

        let executors = fork1.get_executors(&Message::default(), loaders);
        assert_eq!(executors.borrow().executors.len(), 1);
        let executors = fork2.get_executors(&Message::default(), loaders);
        assert_eq!(executors.borrow().executors.len(), 1);
    }

    #[test]
    fn test_compute_active_feature_set() {
        let (genesis_config, _mint_keypair) = create_genesis_config(100_000);
        let bank0 = Arc::new(Bank::new(&genesis_config));
        let mut bank = Bank::new_from_parent(&bank0, &Pubkey::default(), 1);

        let test_feature = "TestFeature11111111111111111111111111111111"
            .parse::<Pubkey>()
            .unwrap();
        let mut feature_set = FeatureSet::default();
        feature_set.inactive.insert(test_feature);
        bank.feature_set = Arc::new(feature_set.clone());

        let new_activations = bank.compute_active_feature_set(true);
        assert!(new_activations.is_empty());
        assert!(!bank.feature_set.is_active(&test_feature));

        // Depositing into the `test_feature` account should do nothing
        bank.deposit(&test_feature, 42).unwrap();
        let new_activations = bank.compute_active_feature_set(true);
        assert!(new_activations.is_empty());
        assert!(!bank.feature_set.is_active(&test_feature));

        // Request `test_feature` activation
        let feature = Feature::default();
        assert_eq!(feature.activated_at, None);
        bank.store_account(&test_feature, &feature::create_account(&feature, 42));

        // Run `compute_active_feature_set` disallowing new activations
        let new_activations = bank.compute_active_feature_set(false);
        assert!(new_activations.is_empty());
        assert!(!bank.feature_set.is_active(&test_feature));
        let feature = feature::from_account(&bank.get_account(&test_feature).expect("get_account"))
            .expect("from_account");
        assert_eq!(feature.activated_at, None);

        // Run `compute_active_feature_set` allowing new activations
        let new_activations = bank.compute_active_feature_set(true);
        assert_eq!(new_activations.len(), 1);
        assert!(bank.feature_set.is_active(&test_feature));
        let feature = feature::from_account(&bank.get_account(&test_feature).expect("get_account"))
            .expect("from_account");
        assert_eq!(feature.activated_at, Some(1));

        // Reset the bank's feature set
        bank.feature_set = Arc::new(feature_set);
        assert!(!bank.feature_set.is_active(&test_feature));

        // Running `compute_active_feature_set` will not cause new activations, but
        // `test_feature` is now be active
        let new_activations = bank.compute_active_feature_set(true);
        assert!(new_activations.is_empty());
        assert!(bank.feature_set.is_active(&test_feature));
    }

    #[test]
    fn test_spl_token_v2_self_transfer_fix() {
        let (genesis_config, _mint_keypair) = create_genesis_config(0);
        let mut bank = Bank::new(&genesis_config);

        // Setup original token account
        bank.store_account_and_update_capitalization(
            &inline_spl_token_v2_0::id(),
            &AccountSharedData::from(Account {
                lamports: 100,
                ..Account::default()
            }),
        );
        assert_eq!(bank.get_balance(&inline_spl_token_v2_0::id()), 100);

        // Setup new token account
        let new_token_account = AccountSharedData::from(Account {
            lamports: 123,
            ..Account::default()
        });
        bank.store_account_and_update_capitalization(
            &inline_spl_token_v2_0::new_token_program::id(),
            &new_token_account,
        );
        assert_eq!(
            bank.get_balance(&inline_spl_token_v2_0::new_token_program::id()),
            123
        );

        let original_capitalization = bank.capitalization();

        bank.apply_spl_token_v2_self_transfer_fix();

        // New token account is now empty
        assert_eq!(
            bank.get_balance(&inline_spl_token_v2_0::new_token_program::id()),
            0
        );

        // Old token account holds the new token account
        assert_eq!(
            bank.get_account(&inline_spl_token_v2_0::id()),
            Some(new_token_account)
        );

        // Lamports in the old token account were burnt
        assert_eq!(bank.capitalization(), original_capitalization - 100);
    }

    pub fn update_vote_account_timestamp(
        timestamp: BlockTimestamp,
        bank: &Bank,
        vote_pubkey: &Pubkey,
    ) {
        let mut vote_account = bank.get_account(vote_pubkey).unwrap_or_default();
        let mut vote_state = VoteState::from(&vote_account).unwrap_or_default();
        vote_state.last_timestamp = timestamp;
        let versioned = VoteStateVersions::new_current(vote_state);
        VoteState::to(&versioned, &mut vote_account).unwrap();
        bank.store_account(vote_pubkey, &vote_account);
    }

    fn min_rent_excempt_balance_for_sysvars(bank: &Bank, sysvar_ids: &[Pubkey]) -> u64 {
        sysvar_ids
            .iter()
            .map(|sysvar_id| {
                trace!("min_rent_excempt_balance_for_sysvars: {}", sysvar_id);
                bank.get_minimum_balance_for_rent_exemption(
                    bank.get_account(sysvar_id).unwrap().data().len(),
                )
            })
            .sum()
    }

    fn expected_cap_delta_after_sysvar_reset(bank: &Bank, sysvar_ids: &[Pubkey]) -> u64 {
        min_rent_excempt_balance_for_sysvars(bank, sysvar_ids) - sysvar_ids.len() as u64
    }

    #[test]
    fn test_adjust_sysvar_balance_for_rent() {
        let (genesis_config, _mint_keypair) = create_genesis_config(0);
        let bank = Bank::new(&genesis_config);
        let mut smaller_sample_sysvar = bank.get_account(&sysvar::clock::id()).unwrap();
        assert_eq!(smaller_sample_sysvar.lamports(), 1);
        bank.adjust_sysvar_balance_for_rent(&mut smaller_sample_sysvar);
        assert_eq!(
            smaller_sample_sysvar.lamports(),
            bank.get_minimum_balance_for_rent_exemption(smaller_sample_sysvar.data().len()),
        );

        let mut bigger_sample_sysvar = AccountSharedData::new(
            1,
            smaller_sample_sysvar.data().len() + 1,
            &Pubkey::default(),
        );
        bank.adjust_sysvar_balance_for_rent(&mut bigger_sample_sysvar);
        assert!(smaller_sample_sysvar.lamports() < bigger_sample_sysvar.lamports());

        // excess lamports shouldn't be reduced by adjust_sysvar_balance_for_rent()
        let excess_lamports = smaller_sample_sysvar.lamports() + 999;
        smaller_sample_sysvar.set_lamports(excess_lamports);
        bank.adjust_sysvar_balance_for_rent(&mut smaller_sample_sysvar);
        assert_eq!(smaller_sample_sysvar.lamports(), excess_lamports);
    }

    // this test can be removed after rent_for_sysvars activation on mainnet-beta
    #[test]
    fn test_no_deletion_due_to_rent_upon_rent_for_sysvar_activation() {
        solana_logger::setup();

        let (mut genesis_config, _mint_keypair) = create_genesis_config(0);
        let feature_balance =
            std::cmp::max(genesis_config.rent.minimum_balance(Feature::size_of()), 1);

        // activate all features but rent_for_sysvars
        activate_all_features(&mut genesis_config);
        genesis_config
            .accounts
            .remove(&feature_set::rent_for_sysvars::id());
        let bank0 = Bank::new(&genesis_config);
        let bank1 = Arc::new(new_from_parent(&Arc::new(bank0)));

        // schedule activation of simple capitalization
        bank1.store_account_and_update_capitalization(
            &feature_set::rent_for_sysvars::id(),
            &feature::create_account(&Feature { activated_at: None }, feature_balance),
        );

        let bank2 =
            Bank::new_from_parent(&bank1, &Pubkey::default(), bank1.first_slot_in_next_epoch());
        assert_eq!(bank2.get_program_accounts(&sysvar::id()).unwrap().len(), 8);

        // force rent collection for sysvars
        bank2.collect_rent_in_partition((0, 0, 1)); // all range

        // no sysvar should be deleted due to rent
        assert_eq!(bank2.get_program_accounts(&sysvar::id()).unwrap().len(), 8);
    }

    // this test can be removed after rent_for_sysvars activation on mainnet-beta
    #[test]
    fn test_rent_for_sysvars_adjustment_minimum_genesis_set() {
        solana_logger::setup();

        let (mut genesis_config, _mint_keypair) = create_genesis_config(0);
        let feature_balance =
            std::cmp::max(genesis_config.rent.minimum_balance(Feature::size_of()), 1);

        // inhibit deprecated rewards sysvar creation altogether
        genesis_config.accounts.insert(
            feature_set::deprecate_rewards_sysvar::id(),
            Account::from(feature::create_account(
                &Feature {
                    activated_at: Some(0),
                },
                feature_balance,
            )),
        );

        let bank0 = Bank::new(&genesis_config);
        let bank1 = Arc::new(new_from_parent(&Arc::new(bank0)));

        // schedule activation of rent_for_sysvars
        bank1.store_account_and_update_capitalization(
            &feature_set::rent_for_sysvars::id(),
            &feature::create_account(&Feature { activated_at: None }, feature_balance),
        );

        {
            let sysvars = bank1.get_program_accounts(&sysvar::id()).unwrap();
            assert_eq!(sysvars.len(), 8);
            assert!(sysvars
                .iter()
                .map(|(_pubkey, account)| account.lamports())
                .all(|lamports| lamports == 1));
        }

        // 8 sysvars should be reset by reset_all_sysvar_balances()
        let bank2 = assert_capitalization_diff_with_new_bank(
            &bank1,
            || Bank::new_from_parent(&bank1, &Pubkey::default(), bank1.first_slot_in_next_epoch()),
            |old, new| {
                assert_eq!(
                    old + expected_cap_delta_after_sysvar_reset(
                        &bank1,
                        &[
                            sysvar::clock::id(),
                            sysvar::epoch_schedule::id(),
                            sysvar::fees::id(),
                            sysvar::recent_blockhashes::id(),
                            sysvar::rent::id(),
                            sysvar::slot_hashes::id(),
                            sysvar::slot_history::id(),
                            sysvar::stake_history::id(),
                        ]
                    ),
                    new
                )
            },
        );

        {
            let sysvars = bank2.get_program_accounts(&sysvar::id()).unwrap();
            assert_eq!(sysvars.len(), 8);
            assert!(sysvars
                .iter()
                .map(|(_pubkey, account)| account.lamports())
                .all(|lamports| lamports > 1));
        }
    }

    // this test can be removed after rent_for_sysvars activation on mainnet-beta
    #[test]
    fn test_rent_for_sysvars_adjustment_full_set() {
        solana_logger::setup();

        let (mut genesis_config, _mint_keypair) = create_genesis_config(0);
        let feature_balance =
            std::cmp::max(genesis_config.rent.minimum_balance(Feature::size_of()), 1);

        // activate all features but rent_for_sysvars
        activate_all_features(&mut genesis_config);
        genesis_config
            .accounts
            .remove(&feature_set::rent_for_sysvars::id());
        // intentionally create deprecated rewards sysvar creation
        genesis_config
            .accounts
            .remove(&feature_set::deprecate_rewards_sysvar::id());

        // intentionally create bogus native programs
        #[allow(clippy::unnecessary_wraps)]
        fn mock_process_instruction(
            _program_id: &Pubkey,
            _data: &[u8],
            _invoke_context: &mut dyn InvokeContext,
        ) -> std::result::Result<(), solana_sdk::instruction::InstructionError> {
            Ok(())
        }
        let builtins = Builtins {
            genesis_builtins: vec![
                Builtin::new(
                    "mock bpf",
                    solana_sdk::bpf_loader::id(),
                    mock_process_instruction,
                ),
                Builtin::new(
                    "mock bpf",
                    solana_sdk::bpf_loader_deprecated::id(),
                    mock_process_instruction,
                ),
            ],
            feature_builtins: (vec![]),
        };

        let bank0 = Arc::new(Bank::new_with_paths(
            &genesis_config,
            Vec::new(),
            &[],
            None,
            Some(&builtins),
            AccountSecondaryIndexes::default(),
            false,
            AccountShrinkThreshold::default(),
            false,
        ));
        // move to next epoch to create now deprecated rewards sysvar intentionally
        let bank1 = Arc::new(Bank::new_from_parent(
            &bank0,
            &Pubkey::default(),
            bank0.first_slot_in_next_epoch(),
        ));

        // schedule activation of simple capitalization
        bank1.store_account_and_update_capitalization(
            &feature_set::rent_for_sysvars::id(),
            &feature::create_account(&Feature { activated_at: None }, feature_balance),
        );
        {
            let sysvars = bank1.get_program_accounts(&sysvar::id()).unwrap();
            assert_eq!(sysvars.len(), 9);
            assert!(sysvars
                .iter()
                .map(|(_pubkey, account)| account.lamports())
                .all(|lamports| lamports == 1));
        }

        // 9 sysvars should be reset by reset_all_sysvar_balances()
        let bank2 = assert_capitalization_diff_with_new_bank(
            &bank1,
            || Bank::new_from_parent(&bank1, &Pubkey::default(), bank1.first_slot_in_next_epoch()),
            |old, new| {
                assert_eq!(
                    old + expected_cap_delta_after_sysvar_reset(
                        &bank1,
                        &[
                            sysvar::clock::id(),
                            sysvar::epoch_schedule::id(),
                            sysvar::fees::id(),
                            sysvar::recent_blockhashes::id(),
                            sysvar::rent::id(),
                            sysvar::rewards::id(),
                            sysvar::slot_hashes::id(),
                            sysvar::slot_history::id(),
                            sysvar::stake_history::id(),
                        ]
                    ),
                    new
                )
            },
        );
        {
            let sysvars = bank2.get_program_accounts(&sysvar::id()).unwrap();
            assert_eq!(sysvars.len(), 9);
            assert!(sysvars
                .iter()
                .map(|(_pubkey, account)| account.lamports())
                .all(|lamports| lamports > 1));
        }
    }

    #[test]
    fn test_update_clock_timestamp() {
        let leader_pubkey = solana_sdk::pubkey::new_rand();
        let GenesisConfigInfo {
            genesis_config,
            voting_keypair,
            ..
        } = create_genesis_config_with_leader(5, &leader_pubkey, 3);
        let mut bank = Bank::new(&genesis_config);
        // Advance past slot 0, which has special handling.
        bank = new_from_parent(&Arc::new(bank));
        bank = new_from_parent(&Arc::new(bank));
        assert_eq!(
            bank.clock().unix_timestamp,
            bank.unix_timestamp_from_genesis()
        );

        bank.update_clock(None);
        assert_eq!(
            bank.clock().unix_timestamp,
            bank.unix_timestamp_from_genesis()
        );

        update_vote_account_timestamp(
            BlockTimestamp {
                slot: bank.slot(),
                timestamp: bank.unix_timestamp_from_genesis() - 1,
            },
            &bank,
            &voting_keypair.pubkey(),
        );
        bank.update_clock(None);
        assert_eq!(
            bank.clock().unix_timestamp,
            bank.unix_timestamp_from_genesis()
        );

        update_vote_account_timestamp(
            BlockTimestamp {
                slot: bank.slot(),
                timestamp: bank.unix_timestamp_from_genesis(),
            },
            &bank,
            &voting_keypair.pubkey(),
        );
        bank.update_clock(None);
        assert_eq!(
            bank.clock().unix_timestamp,
            bank.unix_timestamp_from_genesis()
        );

        update_vote_account_timestamp(
            BlockTimestamp {
                slot: bank.slot(),
                timestamp: bank.unix_timestamp_from_genesis() + 1,
            },
            &bank,
            &voting_keypair.pubkey(),
        );
        bank.update_clock(None);
        assert_eq!(
            bank.clock().unix_timestamp,
            bank.unix_timestamp_from_genesis() + 1
        );

        // Timestamp cannot go backward from ancestor Bank to child
        bank = new_from_parent(&Arc::new(bank));
        update_vote_account_timestamp(
            BlockTimestamp {
                slot: bank.slot(),
                timestamp: bank.unix_timestamp_from_genesis() - 1,
            },
            &bank,
            &voting_keypair.pubkey(),
        );
        bank.update_clock(None);
        assert_eq!(
            bank.clock().unix_timestamp,
            bank.unix_timestamp_from_genesis()
        );
    }

    fn poh_estimate_offset(bank: &Bank) -> Duration {
        let mut epoch_start_slot = bank.epoch_schedule.get_first_slot_in_epoch(bank.epoch());
        if epoch_start_slot == bank.slot() {
            epoch_start_slot = bank
                .epoch_schedule
                .get_first_slot_in_epoch(bank.epoch() - 1);
        }
        bank.slot().saturating_sub(epoch_start_slot) as u32
            * Duration::from_nanos(bank.ns_per_slot as u64)
    }

    #[test]
    fn test_warp_timestamp_again_feature_slow() {
        fn max_allowable_delta_since_epoch(bank: &Bank, max_allowable_drift: u32) -> i64 {
            let poh_estimate_offset = poh_estimate_offset(bank);
            (poh_estimate_offset.as_secs()
                + (poh_estimate_offset * max_allowable_drift / 100).as_secs()) as i64
        }

        let leader_pubkey = solana_sdk::pubkey::new_rand();
        let GenesisConfigInfo {
            mut genesis_config,
            voting_keypair,
            ..
        } = create_genesis_config_with_leader(5, &leader_pubkey, 3);
        let slots_in_epoch = 32;
        genesis_config
            .accounts
            .remove(&feature_set::warp_timestamp_again::id())
            .unwrap();
        genesis_config.epoch_schedule = EpochSchedule::new(slots_in_epoch);
        let mut bank = Bank::new(&genesis_config);

        let recent_timestamp: UnixTimestamp = bank.unix_timestamp_from_genesis();
        let additional_secs = 8; // Greater than MAX_ALLOWABLE_DRIFT_PERCENTAGE for full epoch
        update_vote_account_timestamp(
            BlockTimestamp {
                slot: bank.slot(),
                timestamp: recent_timestamp + additional_secs,
            },
            &bank,
            &voting_keypair.pubkey(),
        );

        // additional_secs greater than MAX_ALLOWABLE_DRIFT_PERCENTAGE for an epoch
        // timestamp bounded to 50% deviation
        for _ in 0..31 {
            bank = new_from_parent(&Arc::new(bank));
            assert_eq!(
                bank.clock().unix_timestamp,
                bank.clock().epoch_start_timestamp
                    + max_allowable_delta_since_epoch(&bank, MAX_ALLOWABLE_DRIFT_PERCENTAGE),
            );
            assert_eq!(bank.clock().epoch_start_timestamp, recent_timestamp);
        }

        // Request `warp_timestamp_again` activation
        let feature = Feature { activated_at: None };
        bank.store_account(
            &feature_set::warp_timestamp_again::id(),
            &feature::create_account(&feature, 42),
        );
        let previous_epoch_timestamp = bank.clock().epoch_start_timestamp;
        let previous_timestamp = bank.clock().unix_timestamp;

        // Advance to epoch boundary to activate; time is warped to estimate with no bounding
        bank = new_from_parent(&Arc::new(bank));
        assert_ne!(bank.clock().epoch_start_timestamp, previous_timestamp);
        assert!(
            bank.clock().epoch_start_timestamp
                > previous_epoch_timestamp
                    + max_allowable_delta_since_epoch(&bank, MAX_ALLOWABLE_DRIFT_PERCENTAGE)
        );

        // Refresh vote timestamp
        let recent_timestamp: UnixTimestamp = bank.clock().unix_timestamp;
        let additional_secs = 8;
        update_vote_account_timestamp(
            BlockTimestamp {
                slot: bank.slot(),
                timestamp: recent_timestamp + additional_secs,
            },
            &bank,
            &voting_keypair.pubkey(),
        );

        // additional_secs greater than MAX_ALLOWABLE_DRIFT_PERCENTAGE for 22 slots
        // timestamp bounded to 80% deviation
        for _ in 0..23 {
            bank = new_from_parent(&Arc::new(bank));
            assert_eq!(
                bank.clock().unix_timestamp,
                bank.clock().epoch_start_timestamp
                    + max_allowable_delta_since_epoch(&bank, MAX_ALLOWABLE_DRIFT_PERCENTAGE_SLOW),
            );
            assert_eq!(bank.clock().epoch_start_timestamp, recent_timestamp);
        }
        for _ in 0..8 {
            bank = new_from_parent(&Arc::new(bank));
            assert_eq!(
                bank.clock().unix_timestamp,
                bank.clock().epoch_start_timestamp
                    + poh_estimate_offset(&bank).as_secs() as i64
                    + additional_secs,
            );
            assert_eq!(bank.clock().epoch_start_timestamp, recent_timestamp);
        }
    }

    #[test]
    fn test_timestamp_fast() {
        fn max_allowable_delta_since_epoch(bank: &Bank, max_allowable_drift: u32) -> i64 {
            let poh_estimate_offset = poh_estimate_offset(bank);
            (poh_estimate_offset.as_secs()
                - (poh_estimate_offset * max_allowable_drift / 100).as_secs()) as i64
        }

        let leader_pubkey = solana_sdk::pubkey::new_rand();
        let GenesisConfigInfo {
            mut genesis_config,
            voting_keypair,
            ..
        } = create_genesis_config_with_leader(5, &leader_pubkey, 3);
        let slots_in_epoch = 32;
        genesis_config.epoch_schedule = EpochSchedule::new(slots_in_epoch);
        let mut bank = Bank::new(&genesis_config);

        let recent_timestamp: UnixTimestamp = bank.unix_timestamp_from_genesis();
        let additional_secs = 5; // Greater than MAX_ALLOWABLE_DRIFT_PERCENTAGE_FAST for full epoch
        update_vote_account_timestamp(
            BlockTimestamp {
                slot: bank.slot(),
                timestamp: recent_timestamp - additional_secs,
            },
            &bank,
            &voting_keypair.pubkey(),
        );

        // additional_secs greater than MAX_ALLOWABLE_DRIFT_PERCENTAGE_FAST for an epoch
        // timestamp bounded to 25% deviation
        for _ in 0..31 {
            bank = new_from_parent(&Arc::new(bank));
            assert_eq!(
                bank.clock().unix_timestamp,
                bank.clock().epoch_start_timestamp
                    + max_allowable_delta_since_epoch(&bank, MAX_ALLOWABLE_DRIFT_PERCENTAGE_FAST),
            );
            assert_eq!(bank.clock().epoch_start_timestamp, recent_timestamp);
        }
    }

    #[test]
    fn test_program_is_native_loader() {
        let (genesis_config, mint_keypair) = create_genesis_config(50000);
        let bank = Bank::new(&genesis_config);

        let tx = Transaction::new_signed_with_payer(
            &[Instruction::new_with_bincode(
                native_loader::id(),
                &(),
                vec![],
            )],
            Some(&mint_keypair.pubkey()),
            &[&mint_keypair],
            bank.last_blockhash(),
        );
        assert_eq!(
            bank.process_transaction(&tx),
            Err(TransactionError::InstructionError(
                0,
                InstructionError::UnsupportedProgramId
            ))
        );
    }

    #[test]
    fn test_bad_native_loader() {
        let (genesis_config, mint_keypair) = create_genesis_config(50000);
        let bank = Bank::new(&genesis_config);
        let to_keypair = Keypair::new();

        let tx = Transaction::new_signed_with_payer(
            &[
                system_instruction::create_account(
                    &mint_keypair.pubkey(),
                    &to_keypair.pubkey(),
                    10000,
                    0,
                    &native_loader::id(),
                ),
                Instruction::new_with_bincode(
                    native_loader::id(),
                    &(),
                    vec![AccountMeta::new(to_keypair.pubkey(), false)],
                ),
            ],
            Some(&mint_keypair.pubkey()),
            &[&mint_keypair, &to_keypair],
            bank.last_blockhash(),
        );
        assert_eq!(
            bank.process_transaction(&tx),
            Err(TransactionError::InstructionError(
                1,
                InstructionError::Custom(NativeLoaderError::InvalidAccountData as u32)
            ))
        );

        let tx = Transaction::new_signed_with_payer(
            &[
                system_instruction::create_account(
                    &mint_keypair.pubkey(),
                    &to_keypair.pubkey(),
                    10000,
                    100,
                    &native_loader::id(),
                ),
                Instruction::new_with_bincode(
                    native_loader::id(),
                    &(),
                    vec![AccountMeta::new(to_keypair.pubkey(), false)],
                ),
            ],
            Some(&mint_keypair.pubkey()),
            &[&mint_keypair, &to_keypair],
            bank.last_blockhash(),
        );
        assert_eq!(
            bank.process_transaction(&tx),
            Err(TransactionError::InstructionError(
                1,
                InstructionError::Custom(NativeLoaderError::InvalidAccountData as u32)
            ))
        );
    }

    #[test]
    fn test_debug_bank() {
        let (genesis_config, _mint_keypair) = create_genesis_config(50000);
        let mut bank = Bank::new(&genesis_config);
        bank.finish_init(&genesis_config, None, false);
        let debug = format!("{:#?}", bank);
        assert!(!debug.is_empty());
    }

    #[derive(Debug)]
    enum AcceptableScanResults {
        DroppedSlotError,
        NoFailure,
        Both,
    }

    fn test_store_scan_consistency<F: 'static>(
        accounts_db_caching_enabled: bool,
        update_f: F,
        drop_callback: Option<Box<dyn DropCallback + Send + Sync>>,
        acceptable_scan_results: AcceptableScanResults,
    ) where
        F: Fn(
                Arc<Bank>,
                crossbeam_channel::Sender<Arc<Bank>>,
                crossbeam_channel::Receiver<BankId>,
                Arc<HashSet<Pubkey>>,
                Pubkey,
                u64,
            ) + std::marker::Send,
    {
        // Set up initial bank
        let mut genesis_config = create_genesis_config_with_leader(
            10,
            &solana_sdk::pubkey::new_rand(),
            374_999_998_287_840,
        )
        .genesis_config;
        genesis_config.rent = Rent::free();
        let bank0 = Arc::new(Bank::new_with_config(
            &genesis_config,
            AccountSecondaryIndexes::default(),
            accounts_db_caching_enabled,
            AccountShrinkThreshold::default(),
        ));
        bank0.set_callback(drop_callback);

        // Set up pubkeys to write to
        let total_pubkeys = ITER_BATCH_SIZE * 10;
        let total_pubkeys_to_modify = 10;
        let all_pubkeys: Vec<Pubkey> = std::iter::repeat_with(solana_sdk::pubkey::new_rand)
            .take(total_pubkeys)
            .collect();
        let program_id = system_program::id();
        let starting_lamports = 1;
        let starting_account = AccountSharedData::new(starting_lamports, 0, &program_id);

        // Write accounts to the store
        for key in &all_pubkeys {
            bank0.store_account(key, &starting_account);
        }

        // Set aside a subset of accounts to modify
        let pubkeys_to_modify: Arc<HashSet<Pubkey>> = Arc::new(
            all_pubkeys
                .into_iter()
                .take(total_pubkeys_to_modify)
                .collect(),
        );
        let exit = Arc::new(AtomicBool::new(false));

        // Thread that runs scan and constantly checks for
        // consistency
        let pubkeys_to_modify_ = pubkeys_to_modify.clone();

        // Channel over which the bank to scan is sent
        let (bank_to_scan_sender, bank_to_scan_receiver): (
            crossbeam_channel::Sender<Arc<Bank>>,
            crossbeam_channel::Receiver<Arc<Bank>>,
        ) = bounded(1);

        let (scan_finished_sender, scan_finished_receiver): (
            crossbeam_channel::Sender<BankId>,
            crossbeam_channel::Receiver<BankId>,
        ) = unbounded();
        let num_banks_scanned = Arc::new(AtomicU64::new(0));
        let scan_thread = {
            let exit = exit.clone();
            let num_banks_scanned = num_banks_scanned.clone();
            Builder::new()
                .name("scan".to_string())
                .spawn(move || {
                    loop {
                        info!("starting scan iteration");
                        if exit.load(Relaxed) {
                            info!("scan exiting");
                            return;
                        }
                        if let Ok(bank_to_scan) =
                            bank_to_scan_receiver.recv_timeout(Duration::from_millis(10))
                        {
                            info!("scanning program accounts for slot {}", bank_to_scan.slot());
                            let accounts_result = bank_to_scan.get_program_accounts(&program_id);
                            let _ = scan_finished_sender.send(bank_to_scan.bank_id());
                            num_banks_scanned.fetch_add(1, Relaxed);
                            match (&acceptable_scan_results, accounts_result.is_err()) {
                                (AcceptableScanResults::DroppedSlotError, _)
                                | (AcceptableScanResults::Both, true) => {
                                    assert_eq!(
                                        accounts_result,
                                        Err(ScanError::SlotRemoved {
                                            slot: bank_to_scan.slot(),
                                            bank_id: bank_to_scan.bank_id()
                                        })
                                    );
                                }
                                (AcceptableScanResults::NoFailure, _)
                                | (AcceptableScanResults::Both, false) => {
                                    assert!(accounts_result.is_ok())
                                }
                            }

                            // Should never see empty accounts because no slot ever deleted
                            // any of the original accounts, and the scan should reflect the
                            // account state at some frozen slot `X` (no partial updates).
                            if let Ok(accounts) = accounts_result {
                                assert!(!accounts.is_empty());
                                let mut expected_lamports = None;
                                let mut target_accounts_found = HashSet::new();
                                for (pubkey, account) in accounts {
                                    let account_balance = account.lamports();
                                    if pubkeys_to_modify_.contains(&pubkey) {
                                        target_accounts_found.insert(pubkey);
                                        if let Some(expected_lamports) = expected_lamports {
                                            assert_eq!(account_balance, expected_lamports);
                                        } else {
                                            // All pubkeys in the specified set should have the same balance
                                            expected_lamports = Some(account_balance);
                                        }
                                    }
                                }

                                // Should've found all the accounts, i.e. no partial cleans should
                                // be detected
                                assert_eq!(target_accounts_found.len(), total_pubkeys_to_modify);
                            }
                        }
                    }
                })
                .unwrap()
        };

        // Thread that constantly updates the accounts, sets
        // roots, and cleans
        let update_thread = Builder::new()
            .name("update".to_string())
            .spawn(move || {
                update_f(
                    bank0,
                    bank_to_scan_sender,
                    scan_finished_receiver,
                    pubkeys_to_modify,
                    program_id,
                    starting_lamports,
                );
            })
            .unwrap();

        // Let threads run for a while, check the scans didn't see any mixed slots
        let min_expected_number_of_scans = 5;
        std::thread::sleep(Duration::new(5, 0));
        loop {
            if num_banks_scanned.load(Relaxed) > min_expected_number_of_scans {
                break;
            } else {
                std::thread::sleep(Duration::from_millis(100));
            }
        }
        exit.store(true, Relaxed);
        scan_thread.join().unwrap();
        update_thread.join().unwrap();
    }

    #[test]
    fn test_store_scan_consistency_unrooted() {
        for accounts_db_caching_enabled in &[false, true] {
            let (pruned_banks_sender, pruned_banks_receiver) = unbounded();
            let abs_request_handler = AbsRequestHandler {
                snapshot_request_handler: None,
                pruned_banks_receiver,
            };
            test_store_scan_consistency(
                *accounts_db_caching_enabled,
                move |bank0,
                      bank_to_scan_sender,
                      _scan_finished_receiver,
                      pubkeys_to_modify,
                      program_id,
                      starting_lamports| {
                    let mut current_major_fork_bank = bank0;
                    loop {
                        let mut current_minor_fork_bank = current_major_fork_bank.clone();
                        let num_new_banks = 2;
                        let lamports = current_minor_fork_bank.slot() + starting_lamports + 1;
                        // Modify banks on the two banks on the minor fork
                        for pubkeys_to_modify in &pubkeys_to_modify
                            .iter()
                            .chunks(pubkeys_to_modify.len() / num_new_banks)
                        {
                            current_minor_fork_bank = Arc::new(Bank::new_from_parent(
                                &current_minor_fork_bank,
                                &solana_sdk::pubkey::new_rand(),
                                current_minor_fork_bank.slot() + 2,
                            ));
                            let account = AccountSharedData::new(lamports, 0, &program_id);
                            // Write partial updates to each of the banks in the minor fork so if any of them
                            // get cleaned up, there will be keys with the wrong account value/missing.
                            for key in pubkeys_to_modify {
                                current_minor_fork_bank.store_account(key, &account);
                            }
                            current_minor_fork_bank.freeze();
                        }

                        // All the parent banks made in this iteration of the loop
                        // are currently discoverable, previous parents should have
                        // been squashed
                        assert_eq!(
                            current_minor_fork_bank.clone().parents_inclusive().len(),
                            num_new_banks + 1,
                        );

                        // `next_major_bank` needs to be sandwiched between the minor fork banks
                        // That way, after the squash(), the minor fork has the potential to see a
                        // *partial* clean of the banks < `next_major_bank`.
                        current_major_fork_bank = Arc::new(Bank::new_from_parent(
                            &current_major_fork_bank,
                            &solana_sdk::pubkey::new_rand(),
                            current_minor_fork_bank.slot() - 1,
                        ));
                        let lamports = current_major_fork_bank.slot() + starting_lamports + 1;
                        let account = AccountSharedData::new(lamports, 0, &program_id);
                        for key in pubkeys_to_modify.iter() {
                            // Store rooted updates to these pubkeys such that the minor
                            // fork updates to the same keys will be deleted by clean
                            current_major_fork_bank.store_account(key, &account);
                        }

                        // Send the last new bank to the scan thread to perform the scan.
                        // Meanwhile this thread will continually set roots on a separate fork
                        // and squash/clean, purging the account entries from the minor forks
                        /*
                                    bank 0
                                /         \
                        minor bank 1       \
                            /         current_major_fork_bank
                        minor bank 2

                        */
                        // The capacity of the channel is 1 so that this thread will wait for the scan to finish before starting
                        // the next iteration, allowing the scan to stay in sync with these updates
                        // such that every scan will see this interruption.
                        if bank_to_scan_sender.send(current_minor_fork_bank).is_err() {
                            // Channel was disconnected, exit
                            return;
                        }
                        current_major_fork_bank.freeze();
                        current_major_fork_bank.squash();
                        // Try to get cache flush/clean to overlap with the scan
                        current_major_fork_bank.force_flush_accounts_cache();
                        current_major_fork_bank.clean_accounts(false, false);
                        // Move purge here so that Bank::drop()->purge_slots() doesn't race
                        // with clean. Simulates the call from AccountsBackgroundService
                        let is_abs_service = true;
                        abs_request_handler
                            .handle_pruned_banks(&current_major_fork_bank, is_abs_service);
                    }
                },
                Some(Box::new(SendDroppedBankCallback::new(
                    pruned_banks_sender.clone(),
                ))),
                AcceptableScanResults::NoFailure,
            )
        }
    }

    #[test]
    fn test_store_scan_consistency_root() {
        for accounts_db_caching_enabled in &[false, true] {
            test_store_scan_consistency(
                *accounts_db_caching_enabled,
                |bank0,
                 bank_to_scan_sender,
                 _scan_finished_receiver,
                 pubkeys_to_modify,
                 program_id,
                 starting_lamports| {
                    let mut current_bank = bank0.clone();
                    let mut prev_bank = bank0;
                    loop {
                        let lamports_this_round = current_bank.slot() + starting_lamports + 1;
                        let account = AccountSharedData::new(lamports_this_round, 0, &program_id);
                        for key in pubkeys_to_modify.iter() {
                            current_bank.store_account(key, &account);
                        }
                        current_bank.freeze();
                        // Send the previous bank to the scan thread to perform the scan.
                        // Meanwhile this thread will squash and update roots immediately after
                        // so the roots will update while scanning.
                        //
                        // The capacity of the channel is 1 so that this thread will wait for the scan to finish before starting
                        // the next iteration, allowing the scan to stay in sync with these updates
                        // such that every scan will see this interruption.
                        if bank_to_scan_sender.send(prev_bank).is_err() {
                            // Channel was disconnected, exit
                            return;
                        }
                        current_bank.squash();
                        if current_bank.slot() % 2 == 0 {
                            current_bank.force_flush_accounts_cache();
                            current_bank.clean_accounts(true, false);
                        }
                        prev_bank = current_bank.clone();
                        current_bank = Arc::new(Bank::new_from_parent(
                            &current_bank,
                            &solana_sdk::pubkey::new_rand(),
                            current_bank.slot() + 1,
                        ));
                    }
                },
                None,
                AcceptableScanResults::NoFailure,
            );
        }
    }

    fn setup_banks_on_fork_to_remove(
        bank0: Arc<Bank>,
        pubkeys_to_modify: Arc<HashSet<Pubkey>>,
        program_id: &Pubkey,
        starting_lamports: u64,
        num_banks_on_fork: usize,
        step_size: usize,
    ) -> (Arc<Bank>, Vec<(Slot, BankId)>, Ancestors) {
        // Need at least 2 keys to create inconsistency in account balances when deleting
        // slots
        assert!(pubkeys_to_modify.len() > 1);

        // Tracks the bank at the tip of the to be created fork
        let mut bank_at_fork_tip = bank0;

        // All the slots on the fork except slot 0
        let mut slots_on_fork = Vec::with_capacity(num_banks_on_fork);

        // All accounts in each set of `step_size` slots will have the same account balances.
        // The account balances of the accounts changes every `step_size` banks. Thus if you
        // delete any one of the latest `step_size` slots, then you will see varying account
        // balances when loading the accounts.
        assert!(num_banks_on_fork >= 2);
        assert!(step_size >= 2);
        let pubkeys_to_modify: Vec<Pubkey> = pubkeys_to_modify.iter().cloned().collect();
        let pubkeys_to_modify_per_slot = (pubkeys_to_modify.len() / step_size).max(1);
        for _ in (0..num_banks_on_fork).step_by(step_size) {
            let mut lamports_this_round = 0;
            for i in 0..step_size {
                bank_at_fork_tip = Arc::new(Bank::new_from_parent(
                    &bank_at_fork_tip,
                    &solana_sdk::pubkey::new_rand(),
                    bank_at_fork_tip.slot() + 1,
                ));
                if lamports_this_round == 0 {
                    lamports_this_round = bank_at_fork_tip.bank_id() + starting_lamports + 1;
                }
                let pubkey_to_modify_starting_index = i * pubkeys_to_modify_per_slot;
                let account = AccountSharedData::new(lamports_this_round, 0, program_id);
                for pubkey_index_to_modify in pubkey_to_modify_starting_index
                    ..pubkey_to_modify_starting_index + pubkeys_to_modify_per_slot
                {
                    let key = pubkeys_to_modify[pubkey_index_to_modify % pubkeys_to_modify.len()];
                    bank_at_fork_tip.store_account(&key, &account);
                }
                bank_at_fork_tip.freeze();
                slots_on_fork.push((bank_at_fork_tip.slot(), bank_at_fork_tip.bank_id()));
            }
        }

        let ancestors: Vec<(Slot, usize)> = slots_on_fork.iter().map(|(s, _)| (*s, 0)).collect();
        let ancestors = Ancestors::from(ancestors);

        (bank_at_fork_tip, slots_on_fork, ancestors)
    }

    #[test]
    fn test_remove_unrooted_before_scan() {
        for accounts_db_caching_enabled in &[false, true] {
            test_store_scan_consistency(
                *accounts_db_caching_enabled,
                |bank0,
                 bank_to_scan_sender,
                 scan_finished_receiver,
                 pubkeys_to_modify,
                 program_id,
                 starting_lamports| {
                    loop {
                        let (bank_at_fork_tip, slots_on_fork, ancestors) =
                            setup_banks_on_fork_to_remove(
                                bank0.clone(),
                                pubkeys_to_modify.clone(),
                                &program_id,
                                starting_lamports,
                                10,
                                2,
                            );
                        // Test removing the slot before the scan starts, should cause
                        // SlotRemoved error every time
                        for k in pubkeys_to_modify.iter() {
                            assert!(bank_at_fork_tip.load_slow(&ancestors, k).is_some());
                        }
                        bank_at_fork_tip.remove_unrooted_slots(&slots_on_fork);

                        // Accounts on this fork should not be found after removal
                        for k in pubkeys_to_modify.iter() {
                            assert!(bank_at_fork_tip.load_slow(&ancestors, k).is_none());
                        }
                        if bank_to_scan_sender.send(bank_at_fork_tip.clone()).is_err() {
                            return;
                        }

                        // Wait for scan to finish before starting next iteration
                        let finished_scan_bank_id = scan_finished_receiver.recv();
                        if finished_scan_bank_id.is_err() {
                            return;
                        }
                        assert_eq!(finished_scan_bank_id.unwrap(), bank_at_fork_tip.bank_id());
                    }
                },
                None,
                // Test removing the slot before the scan starts, should error every time
                AcceptableScanResults::DroppedSlotError,
            );
        }
    }

    #[test]
    fn test_remove_unrooted_scan_then_recreate_same_slot_before_scan() {
        for accounts_db_caching_enabled in &[false, true] {
            test_store_scan_consistency(
                *accounts_db_caching_enabled,
                |bank0,
                 bank_to_scan_sender,
                 scan_finished_receiver,
                 pubkeys_to_modify,
                 program_id,
                 starting_lamports| {
                    let mut prev_bank = bank0.clone();
                    loop {
                        let start = Instant::now();
                        let (bank_at_fork_tip, slots_on_fork, ancestors) =
                            setup_banks_on_fork_to_remove(
                                bank0.clone(),
                                pubkeys_to_modify.clone(),
                                &program_id,
                                starting_lamports,
                                10,
                                2,
                            );
                        info!("setting up banks elapsed: {}", start.elapsed().as_millis());
                        // Remove the fork. Then we'll recreate the slots and only after we've
                        // recreated the slots, do we send this old bank for scanning.
                        // Skip scanning bank 0 on first iteration of loop, since those accounts
                        // aren't being removed
                        if prev_bank.slot() != 0 {
                            info!(
                                "sending bank with slot: {:?}, elapsed: {}",
                                prev_bank.slot(),
                                start.elapsed().as_millis()
                            );
                            // Although we dumped the slots last iteration via `remove_unrooted_slots()`,
                            // we've recreated those slots this iteration, so they should be findable
                            // again
                            for k in pubkeys_to_modify.iter() {
                                assert!(bank_at_fork_tip.load_slow(&ancestors, k).is_some());
                            }

                            // Now after we've recreated the slots removed in the previous loop
                            // iteration, send the previous bank, should fail even though the
                            // same slots were recreated
                            if bank_to_scan_sender.send(prev_bank.clone()).is_err() {
                                return;
                            }

                            let finished_scan_bank_id = scan_finished_receiver.recv();
                            if finished_scan_bank_id.is_err() {
                                return;
                            }
                            // Wait for scan to finish before starting next iteration
                            assert_eq!(finished_scan_bank_id.unwrap(), prev_bank.bank_id());
                        }
                        bank_at_fork_tip.remove_unrooted_slots(&slots_on_fork);
                        prev_bank = bank_at_fork_tip;
                    }
                },
                None,
                // Test removing the slot before the scan starts, should error every time
                AcceptableScanResults::DroppedSlotError,
            );
        }
    }

    #[test]
    fn test_remove_unrooted_scan_interleaved_with_remove_unrooted_slots() {
        for accounts_db_caching_enabled in &[false, true] {
            test_store_scan_consistency(
                *accounts_db_caching_enabled,
                |bank0,
                 bank_to_scan_sender,
                 scan_finished_receiver,
                 pubkeys_to_modify,
                 program_id,
                 starting_lamports| {
                    loop {
                        let step_size = 2;
                        let (bank_at_fork_tip, slots_on_fork, ancestors) =
                            setup_banks_on_fork_to_remove(
                                bank0.clone(),
                                pubkeys_to_modify.clone(),
                                &program_id,
                                starting_lamports,
                                10,
                                step_size,
                            );
                        // Although we dumped the slots last iteration via `remove_unrooted_slots()`,
                        // we've recreated those slots this iteration, so they should be findable
                        // again
                        for k in pubkeys_to_modify.iter() {
                            assert!(bank_at_fork_tip.load_slow(&ancestors, k).is_some());
                        }

                        // Now after we've recreated the slots removed in the previous loop
                        // iteration, send the previous bank, should fail even though the
                        // same slots were recreated
                        if bank_to_scan_sender.send(bank_at_fork_tip.clone()).is_err() {
                            return;
                        }

                        // Remove 1 < `step_size` of the *latest* slots while the scan is happening.
                        // This should create inconsistency between the account balances of accounts
                        // stored in that slot, and the accounts stored in earlier slots
                        let slot_to_remove = *slots_on_fork.last().unwrap();
                        bank_at_fork_tip.remove_unrooted_slots(&[slot_to_remove]);

                        // Wait for scan to finish before starting next iteration
                        let finished_scan_bank_id = scan_finished_receiver.recv();
                        if finished_scan_bank_id.is_err() {
                            return;
                        }
                        assert_eq!(finished_scan_bank_id.unwrap(), bank_at_fork_tip.bank_id());

                        // Remove the rest of the slots before the next iteration
                        for (slot, bank_id) in slots_on_fork {
                            bank_at_fork_tip.remove_unrooted_slots(&[(slot, bank_id)]);
                        }
                    }
                },
                None,
                // Test removing the slot before the scan starts, should error every time
                AcceptableScanResults::Both,
            );
        }
    }

    #[test]
    fn test_stake_rewrite() {
        let GenesisConfigInfo { genesis_config, .. } =
            create_genesis_config_with_leader(500, &solana_sdk::pubkey::new_rand(), 1);
        let bank = Arc::new(Bank::new(&genesis_config));

        // quickest way of creting bad stake account
        let bootstrap_stake_pubkey = bank
            .cloned_stake_delegations()
            .keys()
            .next()
            .copied()
            .unwrap();
        let mut bootstrap_stake_account = bank.get_account(&bootstrap_stake_pubkey).unwrap();
        bootstrap_stake_account.set_lamports(10000000);
        bank.store_account(&bootstrap_stake_pubkey, &bootstrap_stake_account);

        assert_eq!(bank.rewrite_stakes(), (1, 1));
    }

    #[test]
    fn test_get_inflation_start_slot_devnet_testnet() {
        let GenesisConfigInfo {
            mut genesis_config, ..
        } = create_genesis_config_with_leader(42, &solana_sdk::pubkey::new_rand(), 42);
        genesis_config
            .accounts
            .remove(&feature_set::pico_inflation::id())
            .unwrap();
        genesis_config
            .accounts
            .remove(&feature_set::full_inflation::devnet_and_testnet::id())
            .unwrap();
        for pair in feature_set::FULL_INFLATION_FEATURE_PAIRS.iter() {
            genesis_config.accounts.remove(&pair.vote_id).unwrap();
            genesis_config.accounts.remove(&pair.enable_id).unwrap();
        }

        let bank = Bank::new(&genesis_config);

        // Advance slot
        let mut bank = new_from_parent(&Arc::new(bank));
        bank = new_from_parent(&Arc::new(bank));
        assert_eq!(bank.get_inflation_start_slot(), 0);
        assert_eq!(bank.slot(), 2);

        // Request `pico_inflation` activation
        bank.store_account(
            &feature_set::pico_inflation::id(),
            &feature::create_account(
                &Feature {
                    activated_at: Some(1),
                },
                42,
            ),
        );
        bank.compute_active_feature_set(true);
        assert_eq!(bank.get_inflation_start_slot(), 1);

        // Advance slot
        bank = new_from_parent(&Arc::new(bank));
        assert_eq!(bank.slot(), 3);

        // Request `full_inflation::devnet_and_testnet` activation,
        // which takes priority over pico_inflation
        bank.store_account(
            &feature_set::full_inflation::devnet_and_testnet::id(),
            &feature::create_account(
                &Feature {
                    activated_at: Some(2),
                },
                42,
            ),
        );
        bank.compute_active_feature_set(true);
        assert_eq!(bank.get_inflation_start_slot(), 2);

        // Request `full_inflation::mainnet::certusone` activation,
        // which should have no effect on `get_inflation_start_slot`
        bank.store_account(
            &feature_set::full_inflation::mainnet::certusone::vote::id(),
            &feature::create_account(
                &Feature {
                    activated_at: Some(3),
                },
                42,
            ),
        );
        bank.store_account(
            &feature_set::full_inflation::mainnet::certusone::enable::id(),
            &feature::create_account(
                &Feature {
                    activated_at: Some(3),
                },
                42,
            ),
        );
        bank.compute_active_feature_set(true);
        assert_eq!(bank.get_inflation_start_slot(), 2);
    }

    #[test]
    fn test_get_inflation_start_slot_mainnet() {
        let GenesisConfigInfo {
            mut genesis_config, ..
        } = create_genesis_config_with_leader(42, &solana_sdk::pubkey::new_rand(), 42);
        genesis_config
            .accounts
            .remove(&feature_set::pico_inflation::id())
            .unwrap();
        genesis_config
            .accounts
            .remove(&feature_set::full_inflation::devnet_and_testnet::id())
            .unwrap();
        for pair in feature_set::FULL_INFLATION_FEATURE_PAIRS.iter() {
            genesis_config.accounts.remove(&pair.vote_id).unwrap();
            genesis_config.accounts.remove(&pair.enable_id).unwrap();
        }

        let bank = Bank::new(&genesis_config);

        // Advance slot
        let mut bank = new_from_parent(&Arc::new(bank));
        bank = new_from_parent(&Arc::new(bank));
        assert_eq!(bank.get_inflation_start_slot(), 0);
        assert_eq!(bank.slot(), 2);

        // Request `pico_inflation` activation
        bank.store_account(
            &feature_set::pico_inflation::id(),
            &feature::create_account(
                &Feature {
                    activated_at: Some(1),
                },
                42,
            ),
        );
        bank.compute_active_feature_set(true);
        assert_eq!(bank.get_inflation_start_slot(), 1);

        // Advance slot
        bank = new_from_parent(&Arc::new(bank));
        assert_eq!(bank.slot(), 3);

        // Request `full_inflation::mainnet::certusone` activation,
        // which takes priority over pico_inflation
        bank.store_account(
            &feature_set::full_inflation::mainnet::certusone::vote::id(),
            &feature::create_account(
                &Feature {
                    activated_at: Some(2),
                },
                42,
            ),
        );
        bank.store_account(
            &feature_set::full_inflation::mainnet::certusone::enable::id(),
            &feature::create_account(
                &Feature {
                    activated_at: Some(2),
                },
                42,
            ),
        );
        bank.compute_active_feature_set(true);
        assert_eq!(bank.get_inflation_start_slot(), 2);

        // Advance slot
        bank = new_from_parent(&Arc::new(bank));
        assert_eq!(bank.slot(), 4);

        // Request `full_inflation::devnet_and_testnet` activation,
        // which should have no effect on `get_inflation_start_slot`
        bank.store_account(
            &feature_set::full_inflation::devnet_and_testnet::id(),
            &feature::create_account(
                &Feature {
                    activated_at: Some(bank.slot()),
                },
                42,
            ),
        );
        bank.compute_active_feature_set(true);
        assert_eq!(bank.get_inflation_start_slot(), 2);
    }

    #[test]
    fn test_get_inflation_num_slots_with_activations() {
        let GenesisConfigInfo {
            mut genesis_config, ..
        } = create_genesis_config_with_leader(42, &solana_sdk::pubkey::new_rand(), 42);
        let slots_per_epoch = 32;
        genesis_config.epoch_schedule = EpochSchedule::new(slots_per_epoch);
        genesis_config
            .accounts
            .remove(&feature_set::pico_inflation::id())
            .unwrap();
        genesis_config
            .accounts
            .remove(&feature_set::full_inflation::devnet_and_testnet::id())
            .unwrap();
        for pair in feature_set::FULL_INFLATION_FEATURE_PAIRS.iter() {
            genesis_config.accounts.remove(&pair.vote_id).unwrap();
            genesis_config.accounts.remove(&pair.enable_id).unwrap();
        }

        let mut bank = Bank::new(&genesis_config);
        assert_eq!(bank.get_inflation_num_slots(), 0);
        for _ in 0..2 * slots_per_epoch {
            bank = new_from_parent(&Arc::new(bank));
        }
        assert_eq!(bank.get_inflation_num_slots(), 2 * slots_per_epoch);

        // Activate pico_inflation
        let pico_inflation_activation_slot = bank.slot();
        bank.store_account(
            &feature_set::pico_inflation::id(),
            &feature::create_account(
                &Feature {
                    activated_at: Some(pico_inflation_activation_slot),
                },
                42,
            ),
        );
        bank.compute_active_feature_set(true);
        assert_eq!(bank.get_inflation_num_slots(), slots_per_epoch);
        for _ in 0..slots_per_epoch {
            bank = new_from_parent(&Arc::new(bank));
        }
        assert_eq!(bank.get_inflation_num_slots(), 2 * slots_per_epoch);

        // Activate full_inflation::devnet_and_testnet
        let full_inflation_activation_slot = bank.slot();
        bank.store_account(
            &feature_set::full_inflation::devnet_and_testnet::id(),
            &feature::create_account(
                &Feature {
                    activated_at: Some(full_inflation_activation_slot),
                },
                42,
            ),
        );
        bank.compute_active_feature_set(true);
        assert_eq!(bank.get_inflation_num_slots(), slots_per_epoch);
        for _ in 0..slots_per_epoch {
            bank = new_from_parent(&Arc::new(bank));
        }
        assert_eq!(bank.get_inflation_num_slots(), 2 * slots_per_epoch);
    }

    #[test]
    fn test_get_inflation_num_slots_already_activated() {
        let GenesisConfigInfo {
            mut genesis_config, ..
        } = create_genesis_config_with_leader(42, &solana_sdk::pubkey::new_rand(), 42);
        let slots_per_epoch = 32;
        genesis_config.epoch_schedule = EpochSchedule::new(slots_per_epoch);
        let mut bank = Bank::new(&genesis_config);
        assert_eq!(bank.get_inflation_num_slots(), 0);
        for _ in 0..slots_per_epoch {
            bank = new_from_parent(&Arc::new(bank));
        }
        assert_eq!(bank.get_inflation_num_slots(), slots_per_epoch);
        for _ in 0..slots_per_epoch {
            bank = new_from_parent(&Arc::new(bank));
        }
        assert_eq!(bank.get_inflation_num_slots(), 2 * slots_per_epoch);
    }

    #[test]
    fn test_stake_vote_account_validity() {
        let validator_vote_keypairs0 = ValidatorVoteKeypairs::new_rand();
        let validator_vote_keypairs1 = ValidatorVoteKeypairs::new_rand();
        let validator_keypairs = vec![&validator_vote_keypairs0, &validator_vote_keypairs1];
        let GenesisConfigInfo {
            genesis_config,
            mint_keypair: _,
            voting_keypair: _,
        } = create_genesis_config_with_vote_accounts(
            1_000_000_000,
            &validator_keypairs,
            vec![10_000; 2],
        );
        let bank = Arc::new(Bank::new(&genesis_config));
        let stake_delegation_accounts = bank.stake_delegation_accounts(&mut null_tracer());
        assert_eq!(stake_delegation_accounts.len(), 2);

        let mut vote_account = bank
            .get_account(&validator_vote_keypairs0.vote_keypair.pubkey())
            .unwrap_or_default();
        let original_lamports = vote_account.lamports();
        vote_account.set_lamports(0);
        // Simulate vote account removal via full withdrawal
        bank.store_account(
            &validator_vote_keypairs0.vote_keypair.pubkey(),
            &vote_account,
        );

        // Modify staked vote account owner; a vote account owned by another program could be
        // freely modified with malicious data
        let bogus_vote_program = Pubkey::new_unique();
        vote_account.set_lamports(original_lamports);
        vote_account.set_owner(bogus_vote_program);
        bank.store_account(
            &validator_vote_keypairs0.vote_keypair.pubkey(),
            &vote_account,
        );

        assert_eq!(bank.vote_accounts().len(), 1);

        // Modify stake account owner; a stake account owned by another program could be freely
        // modified with malicious data
        let bogus_stake_program = Pubkey::new_unique();
        let mut stake_account = bank
            .get_account(&validator_vote_keypairs1.stake_keypair.pubkey())
            .unwrap_or_default();
        stake_account.set_owner(bogus_stake_program);
        bank.store_account(
            &validator_vote_keypairs1.stake_keypair.pubkey(),
            &stake_account,
        );

        // Accounts must be valid stake and vote accounts
        let stake_delegation_accounts = bank.stake_delegation_accounts(&mut null_tracer());
        assert_eq!(stake_delegation_accounts.len(), 0);
    }

    #[test]
    fn test_vote_epoch_panic() {
        let GenesisConfigInfo {
            genesis_config,
            mint_keypair,
            ..
        } = create_genesis_config_with_leader(
            1_000_000_000_000_000,
            &Pubkey::new_unique(),
            bootstrap_validator_stake_lamports(),
        );
        let bank = Arc::new(Bank::new(&genesis_config));

        let vote_keypair = keypair_from_seed(&[1u8; 32]).unwrap();
        let stake_keypair = keypair_from_seed(&[2u8; 32]).unwrap();

        let mut setup_ixs = Vec::new();
        setup_ixs.extend(
            vote_instruction::create_account(
                &mint_keypair.pubkey(),
                &vote_keypair.pubkey(),
                &VoteInit {
                    node_pubkey: mint_keypair.pubkey(),
                    authorized_voter: vote_keypair.pubkey(),
                    authorized_withdrawer: mint_keypair.pubkey(),
                    commission: 0,
                },
                1_000_000_000,
            )
            .into_iter(),
        );
        setup_ixs.extend(
            stake_instruction::create_account_and_delegate_stake(
                &mint_keypair.pubkey(),
                &stake_keypair.pubkey(),
                &vote_keypair.pubkey(),
                &Authorized::auto(&mint_keypair.pubkey()),
                &Lockup::default(),
                1_000_000_000_000,
            )
            .into_iter(),
        );
        setup_ixs.push(vote_instruction::withdraw(
            &vote_keypair.pubkey(),
            &mint_keypair.pubkey(),
            1_000_000_000,
            &mint_keypair.pubkey(),
        ));
        setup_ixs.push(system_instruction::transfer(
            &mint_keypair.pubkey(),
            &vote_keypair.pubkey(),
            1_000_000_000,
        ));

        let result = bank.process_transaction(&Transaction::new(
            &[&mint_keypair, &vote_keypair, &stake_keypair],
            Message::new(&setup_ixs, Some(&mint_keypair.pubkey())),
            bank.last_blockhash(),
        ));
        assert!(result.is_ok());

        let _bank = Bank::new_from_parent(
            &bank,
            &mint_keypair.pubkey(),
            genesis_config.epoch_schedule.get_first_slot_in_epoch(1),
        );
    }

    #[test]
    fn test_tx_log_order() {
        let GenesisConfigInfo {
            genesis_config,
            mint_keypair,
            ..
        } = create_genesis_config_with_leader(
            1_000_000_000_000_000,
            &Pubkey::new_unique(),
            bootstrap_validator_stake_lamports(),
        );
        let bank = Arc::new(Bank::new(&genesis_config));
        *bank.transaction_log_collector_config.write().unwrap() = TransactionLogCollectorConfig {
            mentioned_addresses: HashSet::new(),
            filter: TransactionLogCollectorFilter::All,
        };
        let blockhash = bank.last_blockhash();

        let sender0 = Keypair::new();
        let sender1 = Keypair::new();
        bank.transfer(100, &mint_keypair, &sender0.pubkey())
            .unwrap();
        bank.transfer(100, &mint_keypair, &sender1.pubkey())
            .unwrap();

        let recipient0 = Pubkey::new_unique();
        let recipient1 = Pubkey::new_unique();
        let tx0 = system_transaction::transfer(&sender0, &recipient0, 10, blockhash);
        let success_sig = tx0.signatures[0];
        let tx1 = system_transaction::transfer(&sender1, &recipient1, 110, blockhash); // Should produce insufficient funds log
        let failure_sig = tx1.signatures[0];
        let tx2 = system_transaction::transfer(&sender0, &recipient0, 1, blockhash);
        let txs = vec![tx0, tx1, tx2];
        let batch = bank.prepare_batch(txs.iter()).unwrap();

        let log_results = bank
            .load_execute_and_commit_transactions(
                &batch,
                MAX_PROCESSING_AGE,
                false,
                false,
                true,
                &mut ExecuteTimings::default(),
            )
            .3;
        assert_eq!(log_results.len(), 3);
        assert!(log_results[0].as_ref().unwrap()[1].contains(&"success".to_string()));
        assert!(log_results[1].as_ref().unwrap()[2].contains(&"failed".to_string()));
        assert!(log_results[2].as_ref().is_none());

        let stored_logs = &bank.transaction_log_collector.read().unwrap().logs;
        let success_log_info = stored_logs
            .iter()
            .find(|transaction_log_info| transaction_log_info.signature == success_sig)
            .unwrap();
        assert!(success_log_info.result.is_ok());
        let success_log = success_log_info.log_messages.clone().pop().unwrap();
        assert!(success_log.contains(&"success".to_string()));
        let failure_log_info = stored_logs
            .iter()
            .find(|transaction_log_info| transaction_log_info.signature == failure_sig)
            .unwrap();
        assert!(failure_log_info.result.is_err());
        let failure_log = failure_log_info.log_messages.clone().pop().unwrap();
        assert!(failure_log.contains(&"failed".to_string()));
    }

    #[test]
    fn test_get_largest_accounts() {
        let GenesisConfigInfo { genesis_config, .. } =
            create_genesis_config_with_leader(42, &solana_sdk::pubkey::new_rand(), 42);
        let bank = Bank::new(&genesis_config);

        let pubkeys: Vec<_> = (0..5).map(|_| Pubkey::new_unique()).collect();
        let pubkeys_hashset: HashSet<_> = pubkeys.iter().cloned().collect();

        let pubkeys_balances: Vec<_> = pubkeys
            .iter()
            .cloned()
            .zip(vec![
                sol_to_lamports(2.0),
                sol_to_lamports(3.0),
                sol_to_lamports(3.0),
                sol_to_lamports(4.0),
                sol_to_lamports(5.0),
            ])
            .collect();

        // Initialize accounts; all have larger SOL balances than current Bank built-ins
        let account0 = AccountSharedData::new(pubkeys_balances[0].1, 0, &Pubkey::default());
        bank.store_account(&pubkeys_balances[0].0, &account0);
        let account1 = AccountSharedData::new(pubkeys_balances[1].1, 0, &Pubkey::default());
        bank.store_account(&pubkeys_balances[1].0, &account1);
        let account2 = AccountSharedData::new(pubkeys_balances[2].1, 0, &Pubkey::default());
        bank.store_account(&pubkeys_balances[2].0, &account2);
        let account3 = AccountSharedData::new(pubkeys_balances[3].1, 0, &Pubkey::default());
        bank.store_account(&pubkeys_balances[3].0, &account3);
        let account4 = AccountSharedData::new(pubkeys_balances[4].1, 0, &Pubkey::default());
        bank.store_account(&pubkeys_balances[4].0, &account4);

        // Create HashSet to exclude an account
        let exclude4: HashSet<_> = pubkeys[4..].iter().cloned().collect();

        let mut sorted_accounts = pubkeys_balances.clone();
        sorted_accounts.sort_by(|a, b| a.1.cmp(&b.1).reverse());

        // Return only one largest account
        assert_eq!(
            bank.get_largest_accounts(1, &pubkeys_hashset, AccountAddressFilter::Include)
                .unwrap(),
            vec![(pubkeys[4], sol_to_lamports(5.0))]
        );
        assert_eq!(
            bank.get_largest_accounts(1, &HashSet::new(), AccountAddressFilter::Exclude)
                .unwrap(),
            vec![(pubkeys[4], sol_to_lamports(5.0))]
        );
        assert_eq!(
            bank.get_largest_accounts(1, &exclude4, AccountAddressFilter::Exclude)
                .unwrap(),
            vec![(pubkeys[3], sol_to_lamports(4.0))]
        );

        // Return all added accounts
        let results = bank
            .get_largest_accounts(10, &pubkeys_hashset, AccountAddressFilter::Include)
            .unwrap();
        assert_eq!(results.len(), sorted_accounts.len());
        for pubkey_balance in sorted_accounts.iter() {
            assert!(results.contains(pubkey_balance));
        }
        let mut sorted_results = results.clone();
        sorted_results.sort_by(|a, b| a.1.cmp(&b.1).reverse());
        assert_eq!(sorted_results, results);

        let expected_accounts = sorted_accounts[1..].to_vec();
        let results = bank
            .get_largest_accounts(10, &exclude4, AccountAddressFilter::Exclude)
            .unwrap();
        // results include 5 Bank builtins
        assert_eq!(results.len(), 10);
        for pubkey_balance in expected_accounts.iter() {
            assert!(results.contains(pubkey_balance));
        }
        let mut sorted_results = results.clone();
        sorted_results.sort_by(|a, b| a.1.cmp(&b.1).reverse());
        assert_eq!(sorted_results, results);

        // Return 3 added accounts
        let expected_accounts = sorted_accounts[0..4].to_vec();
        let results = bank
            .get_largest_accounts(4, &pubkeys_hashset, AccountAddressFilter::Include)
            .unwrap();
        assert_eq!(results.len(), expected_accounts.len());
        for pubkey_balance in expected_accounts.iter() {
            assert!(results.contains(pubkey_balance));
        }

        let expected_accounts = expected_accounts[1..4].to_vec();
        let results = bank
            .get_largest_accounts(3, &exclude4, AccountAddressFilter::Exclude)
            .unwrap();
        assert_eq!(results.len(), expected_accounts.len());
        for pubkey_balance in expected_accounts.iter() {
            assert!(results.contains(pubkey_balance));
        }

        // Exclude more, and non-sequential, accounts
        let exclude: HashSet<_> = vec![pubkeys[0], pubkeys[2], pubkeys[4]]
            .iter()
            .cloned()
            .collect();
        assert_eq!(
            bank.get_largest_accounts(2, &exclude, AccountAddressFilter::Exclude)
                .unwrap(),
            vec![pubkeys_balances[3], pubkeys_balances[1]]
        );
    }

    #[test]
    fn test_transfer_sysvar() {
        solana_logger::setup();
        let GenesisConfigInfo {
            genesis_config,
            mint_keypair,
            ..
        } = create_genesis_config_with_leader(
            1_000_000_000_000_000,
            &Pubkey::new_unique(),
            bootstrap_validator_stake_lamports(),
        );
        let mut bank = Bank::new(&genesis_config);

        fn mock_ix_processor(
            _pubkey: &Pubkey,
            _data: &[u8],
            invoke_context: &mut dyn InvokeContext,
        ) -> std::result::Result<(), InstructionError> {
            use solana_sdk::account::WritableAccount;
            let keyed_accounts = invoke_context.get_keyed_accounts()?;
            let mut data = keyed_accounts[1].try_account_ref_mut()?;
            data.data_as_mut_slice()[0] = 5;
            Ok(())
        }

        let program_id = solana_sdk::pubkey::new_rand();
        bank.add_builtin("mock_program1", program_id, mock_ix_processor);

        let blockhash = bank.last_blockhash();
        let blockhash_sysvar = sysvar::recent_blockhashes::id();
        let orig_lamports = bank
            .get_account(&sysvar::recent_blockhashes::id())
            .unwrap()
            .lamports();
        info!("{:?}", bank.get_account(&sysvar::recent_blockhashes::id()));
        let tx = system_transaction::transfer(&mint_keypair, &blockhash_sysvar, 10, blockhash);
        assert_eq!(
            bank.process_transaction(&tx),
            Err(TransactionError::InstructionError(
                0,
                InstructionError::ReadonlyLamportChange
            ))
        );
        assert_eq!(
            bank.get_account(&sysvar::recent_blockhashes::id())
                .unwrap()
                .lamports(),
            orig_lamports
        );
        info!("{:?}", bank.get_account(&sysvar::recent_blockhashes::id()));

        let accounts = vec![
            AccountMeta::new(mint_keypair.pubkey(), true),
            AccountMeta::new(blockhash_sysvar, false),
        ];
        let ix = Instruction::new_with_bincode(program_id, &0, accounts);
        let message = Message::new(&[ix], Some(&mint_keypair.pubkey()));
        let tx = Transaction::new(&[&mint_keypair], message, blockhash);
        assert_eq!(
            bank.process_transaction(&tx),
            Err(TransactionError::InstructionError(
                0,
                InstructionError::ReadonlyDataModified
            ))
        );
    }

    #[test]
    fn test_clean_dropped_unrooted_frozen_banks() {
        solana_logger::setup();
        do_test_clean_dropped_unrooted_banks(FreezeBank1::Yes);
    }

    #[test]
    fn test_clean_dropped_unrooted_unfrozen_banks() {
        solana_logger::setup();
        do_test_clean_dropped_unrooted_banks(FreezeBank1::No);
    }

    /// A simple enum to toggle freezing Bank1 or not.  Used in the clean_dropped_unrooted tests.
    enum FreezeBank1 {
        No,
        Yes,
    }

    fn do_test_clean_dropped_unrooted_banks(freeze_bank1: FreezeBank1) {
        //! Test that dropped unrooted banks are cleaned up properly
        //!
        //! slot 0:       bank0 (rooted)
        //!               /   \
        //! slot 1:      /   bank1 (unrooted and dropped)
        //!             /
        //! slot 2:  bank2 (rooted)
        //!
        //! In the scenario above, when `clean_accounts()` is called on bank2, the keys that exist
        //! _only_ in bank1 should be cleaned up, since those keys are unreachable.
        //!
        //! The following scenarios are tested:
        //!
        //! 1. A key is written _only_ in an unrooted bank (key1)
        //!     - In this case, key1 should be cleaned up
        //! 2. A key is written in both an unrooted _and_ rooted bank (key3)
        //!     - In this case, key3's ref-count should be decremented correctly
        //! 3. A key with zero lamports is _only_ in an unrooted bank (key4)
        //!     - In this case, key4 should be cleaned up
        //! 4. A key with zero lamports is in both an unrooted _and_ rooted bank (key5)
        //!     - In this case, key5's ref-count should be decremented correctly

        let (genesis_config, mint_keypair) = create_genesis_config(100);
        let bank0 = Arc::new(Bank::new(&genesis_config));

        let collector = Pubkey::new_unique();
        let owner = Pubkey::new_unique();

        let key1 = Keypair::new(); // only touched in bank1
        let key2 = Keypair::new(); // only touched in bank2
        let key3 = Keypair::new(); // touched in both bank1 and bank2
        let key4 = Keypair::new(); // in only bank1, and has zero lamports
        let key5 = Keypair::new(); // in both bank1 and bank2, and has zero lamports
        bank0.transfer(2, &mint_keypair, &key2.pubkey()).unwrap();
        bank0.freeze();

        let slot = 1;
        let bank1 = Bank::new_from_parent(&bank0, &collector, slot);
        bank1.transfer(3, &mint_keypair, &key1.pubkey()).unwrap();
        bank1.store_account(&key4.pubkey(), &AccountSharedData::new(0, 0, &owner));
        bank1.store_account(&key5.pubkey(), &AccountSharedData::new(0, 0, &owner));

        if let FreezeBank1::Yes = freeze_bank1 {
            bank1.freeze();
        }

        let slot = slot + 1;
        let bank2 = Bank::new_from_parent(&bank0, &collector, slot);
        bank2.transfer(4, &mint_keypair, &key2.pubkey()).unwrap();
        bank2.transfer(6, &mint_keypair, &key3.pubkey()).unwrap();
        bank2.store_account(&key5.pubkey(), &AccountSharedData::new(0, 0, &owner));

        bank2.freeze(); // the freeze here is not strictly necessary, but more for illustration
        bank2.squash();

        drop(bank1);
        bank2.clean_accounts(false, false);

        let expected_ref_count_for_cleaned_up_keys = 0;
        let expected_ref_count_for_keys_in_both_slot1_and_slot2 = 1;

        assert_eq!(
            bank2
                .rc
                .accounts
                .accounts_db
                .accounts_index
                .ref_count_from_storage(&key1.pubkey()),
            expected_ref_count_for_cleaned_up_keys
        );
        assert_ne!(
            bank2
                .rc
                .accounts
                .accounts_db
                .accounts_index
                .ref_count_from_storage(&key3.pubkey()),
            expected_ref_count_for_cleaned_up_keys
        );
        assert_eq!(
            bank2
                .rc
                .accounts
                .accounts_db
                .accounts_index
                .ref_count_from_storage(&key4.pubkey()),
            expected_ref_count_for_cleaned_up_keys
        );
        assert_eq!(
            bank2
                .rc
                .accounts
                .accounts_db
                .accounts_index
                .ref_count_from_storage(&key5.pubkey()),
            expected_ref_count_for_keys_in_both_slot1_and_slot2,
        );

        assert_eq!(
            bank2.rc.accounts.accounts_db.alive_account_count_in_slot(1),
            0
        );
    }

    #[test]
    fn test_rent_debits() {
        let mut rent_debits = RentDebits::default();

        // No entry for 0 rewards
        rent_debits.push(&Pubkey::default(), 0, 0);
        assert_eq!(rent_debits.0.len(), 0);

        // Doesn't fit an `i64`, no entry. (we'll die elsewhere)
        rent_debits.push(&Pubkey::default(), u64::MAX, 0);
        assert_eq!(rent_debits.0.len(), 0);

        // Since we're casting from `u64` the `i64::checked_neg()` is infallible

        // Some that actually work
        rent_debits.push(&Pubkey::default(), 1, 0);
        assert_eq!(rent_debits.0.len(), 1);
        rent_debits.push(&Pubkey::default(), i64::MAX as u64, 0);
        assert_eq!(rent_debits.0.len(), 2);
    }

    #[test]
    fn test_compute_request_instruction() {
        solana_logger::setup();
        let GenesisConfigInfo {
            genesis_config,
            mint_keypair,
            ..
        } = create_genesis_config_with_leader(
            1_000_000_000_000_000,
            &Pubkey::new_unique(),
            bootstrap_validator_stake_lamports(),
        );
        let mut bank = Bank::new(&genesis_config);

        fn mock_ix_processor(
            _pubkey: &Pubkey,
            _data: &[u8],
            invoke_context: &mut dyn InvokeContext,
        ) -> std::result::Result<(), InstructionError> {
            let compute_budget = invoke_context.get_bpf_compute_budget();
            assert_eq!(
                *compute_budget,
                BpfComputeBudget {
                    max_units: 1,
                    ..BpfComputeBudget::default()
                }
            );
            Ok(())
        }
        let program_id = solana_sdk::pubkey::new_rand();
        bank.add_builtin("mock_program", program_id, mock_ix_processor);

        let message = Message::new(
            &[
                compute_budget::request_units(1),
                Instruction::new_with_bincode(program_id, &0, vec![]),
            ],
            Some(&mint_keypair.pubkey()),
        );
        let tx = Transaction::new(&[&mint_keypair], message, bank.last_blockhash());
        bank.process_transaction(&tx).unwrap();
    }
}