diff --git a/setup.py b/setup.py index 863761daa3..6ca46c6368 100644 --- a/setup.py +++ b/setup.py @@ -497,7 +497,7 @@ def imports(cls, preset_name: str): return super().imports(preset_name) + f''' from typing import Protocol from eth2spec.altair import {preset_name} as altair -from eth2spec.utils.ssz.ssz_typing import Bytes20, ByteList, ByteVector, uint256, Union +from eth2spec.utils.ssz.ssz_typing import Bytes8, Bytes20, ByteList, ByteVector, uint256, Union ''' @classmethod @@ -527,16 +527,12 @@ class NoopExecutionEngine(ExecutionEngine): def execute_payload(self: ExecutionEngine, execution_payload: ExecutionPayload) -> bool: return True - def notify_forkchoice_updated(self: ExecutionEngine, head_block_hash: Hash32, finalized_block_hash: Hash32) -> None: + def notify_forkchoice_updated(self: ExecutionEngine, + head_block_hash: Hash32, + finalized_block_hash: Hash32, + payload_attributes: Optional[PayloadAttributes]) -> None: pass - def prepare_payload(self: ExecutionEngine, - parent_hash: Hash32, - timestamp: uint64, - random: Bytes32, - feeRecipient: ExecutionAddress) -> PayloadId: - raise NotImplementedError("no default block production") - def get_payload(self: ExecutionEngine, payload_id: PayloadId) -> ExecutionPayload: raise NotImplementedError("no default block production") @@ -683,7 +679,7 @@ def combine_dicts(old_dict: Dict[str, T], new_dict: Dict[str, T]) -> Dict[str, T ignored_dependencies = [ 'bit', 'boolean', 'Vector', 'List', 'Container', 'BLSPubkey', 'BLSSignature', - 'Bytes1', 'Bytes4', 'Bytes20', 'Bytes32', 'Bytes48', 'Bytes96', 'Bitlist', 'Bitvector', + 'Bytes1', 'Bytes4', 'Bytes8', 'Bytes20', 'Bytes32', 'Bytes48', 'Bytes96', 'Bitlist', 'Bitvector', 'uint8', 'uint16', 'uint32', 'uint64', 'uint128', 'uint256', 'bytes', 'byte', 'ByteList', 'ByteVector', 'Dict', 'dict', 'field', 'ceillog2', 'floorlog2', 'Set', diff --git a/specs/merge/fork-choice.md b/specs/merge/fork-choice.md index ea4a5588a9..44e729104a 100644 --- a/specs/merge/fork-choice.md +++ b/specs/merge/fork-choice.md @@ -12,6 +12,7 @@ - [`ExecutionEngine`](#executionengine) - [`notify_forkchoice_updated`](#notify_forkchoice_updated) - [Helpers](#helpers) + - [`PayloadAttributes`](#payloadattributes) - [`PowBlock`](#powblock) - [`get_pow_block`](#get_pow_block) - [`is_valid_terminal_pow_block`](#is_valid_terminal_pow_block) @@ -43,8 +44,14 @@ This function performs two actions *atomically*: * Applies finality to the execution state: it irreversibly persists the chain of all execution payloads and corresponding state, up to and including `finalized_block_hash`. +Additionally, if `payload_attributes` is provided, this function sets in motion a payload build process on top of +`head_block_hash` with the result to be gathered by a followup call to `get_payload`. + ```python -def notify_forkchoice_updated(self: ExecutionEngine, head_block_hash: Hash32, finalized_block_hash: Hash32) -> None: +def notify_forkchoice_updated(self: ExecutionEngine, + head_block_hash: Hash32, + finalized_block_hash: Hash32, + payload_attributes: Optional[PayloadAttributes]) -> None: ... ``` @@ -52,6 +59,18 @@ def notify_forkchoice_updated(self: ExecutionEngine, head_block_hash: Hash32, fi ## Helpers +### `PayloadAttributes` + +Used to signal to initiate the payload build process via `notify_forkchoice_updated`. + +```python +@dataclass +class PayloadAttributes(object): + timestamp: uint64 + random: Bytes32 + fee_recipient: ExecutionAddress +``` + ### `PowBlock` ```python diff --git a/specs/merge/validator.md b/specs/merge/validator.md index 2de4ef6b1a..1e90b6b387 100644 --- a/specs/merge/validator.md +++ b/specs/merge/validator.md @@ -11,9 +11,12 @@ - [Introduction](#introduction) - [Prerequisites](#prerequisites) - [Custom types](#custom-types) +- [Helpers](#helpers) + - [`get_pow_block_at_terminal_total_difficulty`](#get_pow_block_at_terminal_total_difficulty) + - [`get_terminal_pow_block`](#get_terminal_pow_block) + - [`get_payload_id`](#get_payload_id) - [Protocols](#protocols) - [`ExecutionEngine`](#executionengine) - - [`prepare_payload`](#prepare_payload) - [`get_payload`](#get_payload) - [Beacon chain responsibilities](#beacon-chain-responsibilities) - [Block proposal](#block-proposal) @@ -39,38 +42,73 @@ Please see related Beacon Chain doc before continuing and use them as a referenc | Name | SSZ equivalent | Description | | - | - | - | -| `PayloadId` | `uint64` | Identifier of a payload building process | +| `PayloadId` | `Bytes8` | Identifier of a payload building process | -## Protocols +## Helpers -### `ExecutionEngine` +### `get_pow_block_at_terminal_total_difficulty` + +```python +def get_pow_block_at_terminal_total_difficulty(pow_chain: Sequence[PowBlock]) -> Optional[PowBlock]: + # `pow_chain` abstractly represents all blocks in the PoW chain + for block in pow_chain: + parent = get_pow_block(block.parent_hash) + block_reached_ttd = block.total_difficulty >= TERMINAL_TOTAL_DIFFICULTY + parent_reached_ttd = parent.total_difficulty >= TERMINAL_TOTAL_DIFFICULTY + if block_reached_ttd and not parent_reached_ttd: + return block + + return None +``` -*Note*: `prepare_payload` and `get_payload` functions are added to the `ExecutionEngine` protocol for use as a validator. +### `get_terminal_pow_block` -The body of each of these functions is implementation dependent. -The Engine API may be used to implement them with an external execution engine. +```python +def get_terminal_pow_block(pow_chain: Sequence[PowBlock]) -> Optional[PowBlock]: + if TERMINAL_BLOCK_HASH != Hash32(): + # Terminal block hash override takes precedence over terminal total difficulty + pow_block_overrides = [block for block in pow_chain if block.block_hash == TERMINAL_BLOCK_HASH] + if not any(pow_block_overrides): + return None + return pow_block_overrides[0] -#### `prepare_payload` + return get_pow_block_at_terminal_total_difficulty(pow_chain) +``` -Given the set of execution payload attributes, `prepare_payload` initiates a process of building an execution payload -on top of the execution chain tip identified by `parent_hash`. +### `get_payload_id` + +Given the `head_block_hash` and the `payload_attributes` that were used to +initiate the build process via `notify_forkchoice_updated`, `get_payload_id()` +returns the `payload_id` used to retrieve the payload via `get_payload`. ```python -def prepare_payload(self: ExecutionEngine, - parent_hash: Hash32, - timestamp: uint64, - random: Bytes32, - fee_recipient: ExecutionAddress) -> PayloadId: - """ - Return ``payload_id`` that is used to obtain the execution payload in a subsequent ``get_payload`` call. - """ - ... +def get_payload_id(parent_hash: Hash32, payload_attributes: PayloadAttributes) -> PayloadId: + return PayloadId( + hash( + parent_hash + + uint_to_bytes(payload_attributes.timestamp) + + payload_attributes.random + + payload_attributes.fee_recipient + )[0:8] + ) ``` +*Note*: This function does *not* use simple serialize `hash_tree_root` as to +avoid requiring simple serialize hashing capabilities in the Execution Layer. + +## Protocols + +### `ExecutionEngine` + +*Note*: `get_payload` function is added to the `ExecutionEngine` protocol for use as a validator. + +The body of this function is implementation dependent. +The Engine API may be used to implement it with an external execution engine. + #### `get_payload` Given the `payload_id`, `get_payload` returns the most recent version of the execution payload that -has been built since the corresponding call to `prepare_payload` method. +has been built since the corresponding call to `notify_forkchoice_updated` method. ```python def get_payload(self: ExecutionEngine, payload_id: PayloadId) -> ExecutionPayload: @@ -92,38 +130,17 @@ All validator responsibilities remain unchanged other than those noted below. Na To obtain an execution payload, a block proposer building a block on top of a `state` must take the following actions: -1. Set `payload_id = prepare_execution_payload(state, pow_chain, fee_recipient, execution_engine)`, where: +1. Set `payload_id = prepare_execution_payload(state, pow_chain, finalized_block_hash, fee_recipient, execution_engine)`, where: * `state` is the state object after applying `process_slots(state, slot)` transition to the resulting state of the parent block processing * `pow_chain` is a list that abstractly represents all blocks in the PoW chain + * `finalized_block_hash` is the hash of the latest finalized execution payload (`Hash32()` if none yet finalized) * `fee_recipient` is the value suggested to be used for the `coinbase` field of the execution payload ```python -def get_pow_block_at_terminal_total_difficulty(pow_chain: Sequence[PowBlock]) -> Optional[PowBlock]: - # `pow_chain` abstractly represents all blocks in the PoW chain - for block in pow_chain: - parent = get_pow_block(block.parent_hash) - block_reached_ttd = block.total_difficulty >= TERMINAL_TOTAL_DIFFICULTY - parent_reached_ttd = parent.total_difficulty >= TERMINAL_TOTAL_DIFFICULTY - if block_reached_ttd and not parent_reached_ttd: - return block - - return None - - -def get_terminal_pow_block(pow_chain: Sequence[PowBlock]) -> Optional[PowBlock]: - if TERMINAL_BLOCK_HASH != Hash32(): - # Terminal block hash override takes precedence over terminal total difficulty - pow_block_overrides = [block for block in pow_chain if block.block_hash == TERMINAL_BLOCK_HASH] - if not any(pow_block_overrides): - return None - return pow_block_overrides[0] - - return get_pow_block_at_terminal_total_difficulty(pow_chain) - - def prepare_execution_payload(state: BeaconState, pow_chain: Sequence[PowBlock], + finalized_block_hash: Hash32, fee_recipient: ExecutionAddress, execution_engine: ExecutionEngine) -> Optional[PayloadId]: if not is_merge_complete(state): @@ -137,9 +154,14 @@ def prepare_execution_payload(state: BeaconState, # Post-merge, normal payload parent_hash = state.latest_execution_payload_header.block_hash - timestamp = compute_timestamp_at_slot(state, state.slot) - random = get_randao_mix(state, get_current_epoch(state)) - return execution_engine.prepare_payload(parent_hash, timestamp, random, fee_recipient) + # Set the forkchoice head and initiate the payload build process + payload_attributes = PayloadAttributes( + timestamp=compute_timestamp_at_slot(state, state.slot), + random=get_randao_mix(state, get_current_epoch(state)), + fee_recipient=fee_recipient, + ) + execution_engine.notify_forkchoice_updated(parent_hash, finalized_block_hash, payload_attributes) + return get_payload_id(parent_hash, payload_attributes) ``` 2. Set `block.body.execution_payload = get_execution_payload(payload_id, execution_engine)`, where: