FM-252: Adopt next configuration at the end of the checkpoint period

Makefile

@@ -1,18 +1,18 @@
 .PHONY: all build test lint license check-fmt check-clippy actor-bundle
 
-BUILTIN_ACTORS_TAG:=v11.0.0
-BUILTIN_ACTORS_DIR:=../builtin-actors
-BUILTIN_ACTORS_CODE:=$(shell find $(BUILTIN_ACTORS_DIR) -type f -name "*.rs" | grep -v target)
-BUILTIN_ACTORS_BUNDLE:=$(shell pwd)/$(BUILTIN_ACTORS_DIR)/output/bundle.car
-
-IPC_ACTORS_TAG:=origin/dev
-IPC_ACTORS_DIR:=$(shell pwd)/../ipc-solidity-actors
-IPC_ACTORS_CODE:=$(shell find $(IPC_ACTORS_DIR) -type f -name "*.sol")
-IPC_ACTORS_BUILD:=fendermint/vm/ipc_actors/build.rs
-IPC_ACTORS_OUT:=$(IPC_ACTORS_DIR)/out
-IPC_ACTORS_ABI:=$(IPC_ACTORS_OUT)/.compile.abi
-
-FENDERMINT_CODE:=$(shell find . -type f \( -name "*.rs" -o -name "Cargo.toml" \) | grep -v target)
+BUILTIN_ACTORS_TAG    ?= v11.0.0
+BUILTIN_ACTORS_DIR    := ../builtin-actors
+BUILTIN_ACTORS_CODE   := $(shell find $(BUILTIN_ACTORS_DIR) -type f -name "*.rs" | grep -v target)
+BUILTIN_ACTORS_BUNDLE := $(shell pwd)/$(BUILTIN_ACTORS_DIR)/output/bundle.car
+
+IPC_ACTORS_TAG        ?= origin/dev
+IPC_ACTORS_DIR        := $(shell pwd)/../ipc-solidity-actors
+IPC_ACTORS_CODE       := $(shell find $(IPC_ACTORS_DIR) -type f -name "*.sol")
+IPC_ACTORS_BUILD      := fendermint/vm/ipc_actors/build.rs
+IPC_ACTORS_OUT        := $(IPC_ACTORS_DIR)/out
+IPC_ACTORS_ABI        := $(IPC_ACTORS_OUT)/.compile.abi
+
+FENDERMINT_CODE       := $(shell find . -type f \( -name "*.rs" -o -name "Cargo.toml" \) | grep -v target)
 
 # Override PROFILE env var to choose between `local | ci`
 PROFILE?=local

fendermint/vm/actor_interface/Cargo.toml

@@ -12,6 +12,7 @@ license.workspace = true
 anyhow = { workspace = true }
 ethers = { workspace = true }
 lazy_static = { workspace = true }
+libsecp256k1 = { workspace = true }
 paste = { workspace = true }
 serde = { workspace = true }
 serde_tuple = { workspace = true }

fendermint/vm/actor_interface/src/ipc.rs

@@ -73,8 +73,11 @@ pub mod gateway {
     use ethers::contract::{EthAbiCodec, EthAbiType};
     use ethers::core::types::{H160, U256};
     use fendermint_vm_genesis::ipc::GatewayParams;
-    use fvm_shared::address::Payload;
+    use fendermint_vm_genesis::ValidatorKey;
+    use fendermint_vm_ipc_actors::gateway_manager_facet::Membership;
+    use fvm_shared::address::{Payload, Protocol};
     use fvm_shared::econ::TokenAmount;
+    use libsecp256k1::PublicKey;
 
     use crate::eam::{self, EthAddress};
 
@@ -126,6 +129,50 @@ pub mod gateway {
         }
     }
 
+    /// Tendermint compatible validator set.
+    pub struct ValidatorSet {
+        pub configuration_number: u64,
+        /// Validators with their voting power.
+        pub validators: Vec<(ValidatorKey, u64)>,
+    }
+
+    impl TryFrom<Membership> for ValidatorSet {
+        type Error = anyhow::Error;
+
+        fn try_from(value: Membership) -> Result<Self, Self::Error> {
+            let mut validators = Vec::new();
+            let max_weight = U256::from(u64::MAX);
+
+            for v in value.validators {
+                if v.addr.addr_type != Protocol::Secp256k1 as u8 {
+                    // We can't use delegated addresses for validation.
+                    // However, when we saved the membership, there is a `worker_addr` field
+                    // that should have contained a public key type address. If not, ignore.
+                    continue;
+                }
+
+                // Tendermint limits the weights to u64, so anything above that is wasted.
+                let w = if v.weight > max_weight {
+                    u64::MAX
+                } else {
+                    v.weight.as_u64()
+                };
+
+                let pk: PublicKey =
+                    todo!("oops, we can't restore a public key from an f1 type Address :O");
+
+                let vk = ValidatorKey(pk);
+
+                validators.push((vk, w));
+            }
+
+            Ok(Self {
+                configuration_number: value.configuration_number,
+                validators,
+            })
+        }
+    }
+
     fn tokens_to_u256(value: TokenAmount) -> U256 {
         // XXX: Ignoring any error resulting from larger fee than what fits into U256. This is in genesis after all.
         U256::from_big_endian(&value.atto().to_bytes_be().1)

fendermint/vm/interpreter/src/fvm/exec.rs

@@ -1,8 +1,11 @@
 // Copyright 2022-2023 Protocol Labs
 // SPDX-License-Identifier: Apache-2.0, MIT
 
+use anyhow::Context;
 use async_trait::async_trait;
 use std::collections::HashMap;
+use tendermint_rpc::endpoint::validators;
+use tendermint_rpc::Paging;
 
 use fendermint_vm_actor_interface::{cron, system};
 use fvm::executor::ApplyRet;
@@ -12,7 +15,10 @@ use tendermint_rpc::Client;
 
 use crate::ExecInterpreter;
 
-use super::{state::FvmExecState, FvmMessage, FvmMessageInterpreter};
+use super::{
+    state::{ipc::Configuration, FvmExecState},
+    FvmMessage, FvmMessageInterpreter,
+};
 
 /// The return value extended with some things from the message that
 /// might not be available to the caller, because of the message lookups
@@ -119,27 +125,35 @@ where
         Ok((state, ret))
     }
 
-    async fn end(&self, state: Self::State) -> anyhow::Result<(Self::State, Self::EndOutput)> {
-        // TODO #252: Epoch transitions for checkpointing.
-        // TODO #254: Construct checkpoint.
-        // TODO #255: Broadcast signature, if validating.
-
-        #[cfg(test)]
-        {
-            use anyhow::Context;
-            use tendermint_rpc::endpoint::validators;
-            use tendermint_rpc::Paging;
-
+    async fn end(&self, mut state: Self::State) -> anyhow::Result<(Self::State, Self::EndOutput)> {
+        // Epoch transitions for checkpointing.
+        if self.gateway.enabled(&mut state)? && !self.gateway.is_root(&mut state)? {
             let height: tendermint::block::Height = state
                 .block_height()
                 .try_into()
                 .context("block height is not u64")?;
 
-            let validators: validators::Response =
-                self._client.validators(height, Paging::All).await?;
+            let checkpoint_period = self.gateway.bottom_up_check_period(&mut state)?;
+
+            if height.value() % checkpoint_period == 0 {
+                // TODO #254: Put the next configuration number for the parent to expect in the checkpoint.
+                let _next_config_number =
+                    match self.gateway.activate_next_configuration(&mut state)? {
+                        Configuration::Unchanged(cnr) => cnr,
+                        Configuration::Activated(membership) => {
+                            let current_validators: validators::Response =
+                                self._client.validators(height, Paging::All).await?;
+
+                            let _current_validators = current_validators.validators;
+
+                            // TODO #252: Work out the difference between the current and the next validators.
+                            membership.configuration_number
+                        }
+                    };
 
-            // This is the power table.
-            let _validators = validators.validators;
+                // TODO #254: Construct checkpoint.
+                // TODO #255: Broadcast signature, if validating.
+            }
         }
 
         Ok((state, ()))

fendermint/vm/interpreter/src/fvm/mod.rs

@@ -21,6 +21,8 @@ pub use genesis::FvmGenesisOutput;
 use libsecp256k1::{PublicKey, SecretKey};
 pub use query::FvmQueryRet;
 
+use self::state::ipc::GatewayCaller;
+
 pub type FvmMessage = fvm_shared::message::Message;
 
 /// Interpreter working on already verified unsigned messages.
@@ -40,6 +42,8 @@ pub struct FvmMessageInterpreter<DB, C> {
     /// Indicate whether transactions should be fully executed during the checks performed
     /// when they are added to the mempool, or just the most basic ones are performed.
     exec_in_check: bool,
+    /// Helper to call the IPC Gateway contract.
+    gateway: GatewayCaller,
     _phantom_db: PhantomData<DB>,
 }
 
@@ -61,6 +65,7 @@ impl<DB, C> FvmMessageInterpreter<DB, C> {
             gas_overestimation_rate,
             gas_search_step,
             exec_in_check,
+            gateway: GatewayCaller::default(),
             _phantom_db: PhantomData,
         }
     }

fendermint/vm/interpreter/src/fvm/state/exec.rs

@@ -8,7 +8,7 @@ use fvm::{
     call_manager::DefaultCallManager,
     engine::MultiEngine,
     executor::{ApplyFailure, ApplyKind, ApplyRet, DefaultExecutor, Executor},
-    machine::{DefaultMachine, Machine, NetworkConfig},
+    machine::{DefaultMachine, Machine, Manifest, NetworkConfig},
     state_tree::StateTree,
     DefaultKernel,
 };
@@ -138,6 +138,11 @@ where
         self.executor.state_tree_mut()
     }
 
+    /// Built-in actor manifest to inspect code CIDs.
+    pub fn builtin_actors(&self) -> &Manifest {
+        self.executor.builtin_actors()
+    }
+
     /// Collect all the event emitters' delegated addresses, for those who have any.
     fn emitter_delegated_addresses(&self, apply_ret: &ApplyRet) -> anyhow::Result<ActorAddressMap> {
         let emitter_ids = apply_ret

fendermint/vm/interpreter/src/fvm/state/fevm.rs

@@ -41,6 +41,7 @@ pub type MockContractCall<T> = ethers::prelude::ContractCall<MockProvider, T>;
 ///
 /// let _period: u64 = caller.call(&mut state, |c| c.bottom_up_check_period()).unwrap();
 /// ```
+#[derive(Clone)]
 pub struct ContractCaller<C> {
     addr: Address,
     contract: C,

fendermint/vm/interpreter/src/fvm/state/ipc.rs

@@ -5,28 +5,79 @@ use super::{
     fevm::{ContractCaller, MockProvider},
     FvmExecState,
 };
-use fendermint_vm_actor_interface::{eam::EthAddress, ipc};
+use fendermint_vm_actor_interface::{eam::EthAddress, ipc::GATEWAY_ACTOR_ID};
 use fendermint_vm_ipc_actors::gateway_getter_facet::GatewayGetterFacet;
+use fendermint_vm_ipc_actors::gateway_manager_facet::{GatewayManagerFacet, Membership};
 use fvm_ipld_blockstore::Blockstore;
 
+/// Result of attempting to activate the next configuration.
+pub enum Configuration {
+    /// No change - return the current configuration number.
+    Unchanged(u64),
+    /// Activated the next configuration.
+    Activated(Membership),
+}
+
+#[derive(Clone)]
 pub struct GatewayCaller {
     getter: ContractCaller<GatewayGetterFacet<MockProvider>>,
+    manager: ContractCaller<GatewayManagerFacet<MockProvider>>,
 }
 
 impl GatewayCaller {
     pub fn new() -> Self {
-        let addr = EthAddress::from_id(ipc::GATEWAY_ACTOR_ID);
+        let addr = EthAddress::from_id(GATEWAY_ACTOR_ID);
         Self {
             getter: ContractCaller::new(addr, GatewayGetterFacet::new),
+            manager: ContractCaller::new(addr, GatewayManagerFacet::new),
+        }
+    }
+
+    /// Check that IPC is configured in this deployment.
+    pub fn enabled<DB: Blockstore>(&self, state: &mut FvmExecState<DB>) -> anyhow::Result<bool> {
+        match state.state_tree_mut().get_actor(GATEWAY_ACTOR_ID)? {
+            None => Ok(false),
+            Some(a) => Ok(!state.builtin_actors().is_placeholder_actor(&a.code)),
         }
     }
 
+    /// Return true if the current subnet is the root subnet.
+    pub fn is_root<DB: Blockstore>(&self, state: &mut FvmExecState<DB>) -> anyhow::Result<bool> {
+        let subnet_id = self.getter.call(state, |c| c.get_network_name())?;
+        Ok(subnet_id.route.is_empty())
+    }
+
+    /// Fetch the period at which this subnet should checkpoint itself to the parent.
     pub fn bottom_up_check_period<DB: Blockstore>(
         &self,
         state: &mut FvmExecState<DB>,
     ) -> anyhow::Result<u64> {
         self.getter.call(state, |c| c.bottom_up_check_period())
     }
+
+    /// Activate the next available configuration at the end of the checkpoint period
+    /// and return the new validator set. If there was no change, return nothing.
+    pub fn activate_next_configuration<DB: Blockstore>(
+        &self,
+        state: &mut FvmExecState<DB>,
+    ) -> anyhow::Result<Configuration> {
+        let current_cnr = self
+            .getter
+            .call(state, |c| c.get_current_configuration_number())?;
+
+        // In theory we could just call the transition, but currently it emits an event even if there is no change.
+        let next_cnr = self
+            .getter
+            .call(state, |c| c.get_last_configuration_number())?;
+
+        if current_cnr == next_cnr {
+            return Ok(Configuration::Unchanged(current_cnr));
+        }
+
+        let membership = self.manager.call(state, |c| c.update_membership())?;
+
+        Ok(Configuration::Activated(membership))
+    }
 }
 
 impl Default for GatewayCaller {

fendermint/vm/ipc_actors/src/gateway_diamond.rs

@@ -272,7 +272,7 @@ pub mod gateway_diamond {
         __abi,
     );
     #[rustfmt::skip]
-    const __DEPLOYED_BYTECODE: &[u8] = b"`\x80`@R6\x15`\x87W`\0\x805`\x01`\x01`\xE0\x1B\x03\x19\x16\x80\x82R\x7F\x80n\x0C\xBB\x9F\xCE)k\xBC3jH\xF4+\xF1\xDB\xC6\x97\"\xD1\x8D\x90\xD6\xFEp[u\x82\xC2\xBBK\xD2` R`@\x82 T`\x01`\x01`\xA0\x1B\x03\x16\x90\x81\x15`oWP\x81\x80\x916\x82\x807\x816\x91Z\xF4=\x82\x80>\x15`kW=\x90\xF3[=\x90\xFD[`$\x90`@Q\x90c\n\x82\xDDs`\xE3\x1B\x82R`\x04\x82\x01R\xFD[`\0\x805`\x01`\x01`\xE0\x1B\x03\x19\x16\x80\x82R\x7F\x80n\x0C\xBB\x9F\xCE)k\xBC3jH\xF4+\xF1\xDB\xC6\x97\"\xD1\x8D\x90\xD6\xFEp[u\x82\xC2\xBBK\xD2` R`@\x82 T`\x01`\x01`\xA0\x1B\x03\x16\x90\x81\x15`\xE9WP\x81\x80\x916\x82\x807\x816\x91Z\xF4=\x82\x80>\x15`kW=\x90\xF3[c\n\x82\xDDs`\xE3\x1B`\x80R`\x84R`$`\x80\xFD\xFE\xA2dipfsX\"\x12 7#\x08y\xE7\x8Bv\xA8\xF5^\xD5\xAB\x1D\xBB=\xE2\x81z\xE0H.;\x99\x1D\x066\x93\xF3m\r\xE5#dsolcC\0\x08\x13\x003";
+    const __DEPLOYED_BYTECODE: &[u8] = b"`\x80`@R6\x15`\x87W`\0\x805`\x01`\x01`\xE0\x1B\x03\x19\x16\x80\x82R\x7F\x80n\x0C\xBB\x9F\xCE)k\xBC3jH\xF4+\xF1\xDB\xC6\x97\"\xD1\x8D\x90\xD6\xFEp[u\x82\xC2\xBBK\xD2` R`@\x82 T`\x01`\x01`\xA0\x1B\x03\x16\x90\x81\x15`oWP\x81\x80\x916\x82\x807\x816\x91Z\xF4=\x82\x80>\x15`kW=\x90\xF3[=\x90\xFD[`$\x90`@Q\x90c\n\x82\xDDs`\xE3\x1B\x82R`\x04\x82\x01R\xFD[`\0\x805`\x01`\x01`\xE0\x1B\x03\x19\x16\x80\x82R\x7F\x80n\x0C\xBB\x9F\xCE)k\xBC3jH\xF4+\xF1\xDB\xC6\x97\"\xD1\x8D\x90\xD6\xFEp[u\x82\xC2\xBBK\xD2` R`@\x82 T`\x01`\x01`\xA0\x1B\x03\x16\x90\x81\x15`\xE9WP\x81\x80\x916\x82\x807\x816\x91Z\xF4=\x82\x80>\x15`kW=\x90\xF3[c\n\x82\xDDs`\xE3\x1B`\x80R`\x84R`$`\x80\xFD\xFE\xA2dipfsX\"\x12 \xDDD\xCB-\x05\x94H\xB6\x19g\xFD?\xCB\x9C\xD5\xE3\x08Z\xE1\xB9\xDB\xF8Q22V\x97\xDC\xF1\x17\xBEidsolcC\0\x08\x13\x003";
     /// The deployed bytecode of the contract.
     pub static GATEWAYDIAMOND_DEPLOYED_BYTECODE: ::ethers::core::types::Bytes = ::ethers::core::types::Bytes::from_static(
         __DEPLOYED_BYTECODE,