856 lines
29 KiB
Nim
856 lines
29 KiB
Nim
# beacon_chain
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# Copyright (c) 2018-2022 Status Research & Development GmbH
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# Licensed and distributed under either of
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# * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT).
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# * Apache v2 license (license terms in the root directory or at https://www.apache.org/licenses/LICENSE-2.0).
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# at your option. This file may not be copied, modified, or distributed except according to those terms.
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{.push raises: [Defect].}
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import
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# Standard library
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std/[sequtils, tables],
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# Status libraries
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stew/results, chronicles,
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# Internal
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../spec/[beaconstate, helpers],
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../spec/datatypes/[phase0, altair, bellatrix],
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# Fork choice
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./fork_choice_types, ./proto_array,
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../consensus_object_pools/[spec_cache, blockchain_dag]
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export results, fork_choice_types
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export proto_array.len
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# https://github.com/ethereum/consensus-specs/blob/v0.12.1/specs/phase0/fork-choice.md
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# This is a port of https://github.com/sigp/lighthouse/pull/804
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# which is a port of "Proto-Array": https://github.com/protolambda/lmd-ghost
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# See also:
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# - Protolambda port of Lighthouse: https://github.com/protolambda/eth2-py-hacks/blob/ae286567/proto_array.py
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# - Prysmatic writeup: https://hackmd.io/bABJiht3Q9SyV3Ga4FT9lQ#High-level-concept
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# - Gasper Whitepaper: https://arxiv.org/abs/2003.03052
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# Forward declarations
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# ----------------------------------------------------------------------
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func compute_deltas(
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deltas: var openArray[Delta],
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indices: Table[Eth2Digest, Index],
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indices_offset: Index,
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votes: var openArray[VoteTracker],
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old_balances: openArray[Gwei],
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new_balances: openArray[Gwei]
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): FcResult[void]
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# Fork choice routines
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# ----------------------------------------------------------------------
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logScope:
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topics = "fork_choice"
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func init*(T: type ForkChoiceBackend,
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justifiedCheckpoint: Checkpoint,
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finalizedCheckpoint: Checkpoint,
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useProposerBoosting: bool): T =
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T(
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proto_array: ProtoArray.init(
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justifiedCheckpoint,
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finalizedCheckpoint),
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proposer_boosting: useProposerBoosting
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)
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proc init*(T: type ForkChoice,
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epochRef: EpochRef,
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blck: BlockRef,
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proposerBoosting: bool): T =
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## Initialize a fork choice context for a finalized state - in the finalized
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## state, the justified and finalized checkpoints are the same, so only one
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## is used here
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debug "Initializing fork choice",
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epoch = epochRef.epoch, blck = shortLog(blck)
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let
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justified = BalanceCheckpoint(
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checkpoint: Checkpoint(root: blck.root, epoch: epochRef.epoch),
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balances: epochRef.effective_balances)
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finalized = Checkpoint(root: blck.root, epoch: epochRef.epoch)
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best_justified = Checkpoint(
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root: blck.root, epoch: epochRef.epoch)
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ForkChoice(
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backend: ForkChoiceBackend.init(
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best_justified, finalized, proposerBoosting),
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checkpoints: Checkpoints(
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justified: justified,
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finalized: finalized,
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best_justified: best_justified),
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)
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func extend[T](s: var seq[T], minLen: int) =
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## Extend a sequence so that it can contains at least `minLen` elements.
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## If it's already bigger, the sequence is unmodified.
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## The extension is zero-initialized
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if s.len < minLen:
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s.setLen(minLen)
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func on_tick*(self: var Checkpoints, time: BeaconTime): FcResult[void] =
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if self.time > time:
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return err ForkChoiceError(kind: fcInconsistentTick)
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# Reset store.proposer_boost_root if this is a new slot
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if time.slotOrZero > self.time.slotOrZero:
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self.proposer_boost_root = default(Eth2Digest)
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self.time = time
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ok()
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proc on_tick(self: var Checkpoints, dag: ChainDAGRef, time: BeaconTime):
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FcResult[void] =
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let prev_time = self.time
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? self.on_tick(time)
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let newEpoch = prev_time.slotOrZero.epoch() != time.slotOrZero.epoch()
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if newEpoch and
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self.best_justified.epoch > self.justified.checkpoint.epoch:
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let blck = dag.getBlockRef(self.best_justified.root).valueOr:
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return err ForkChoiceError(
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kind: fcJustifiedNodeUnknown,
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blockRoot: self.best_justified.root)
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let ancestor = blck.atEpochStart(self.finalized.epoch)
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if ancestor.blck.root == self.finalized.root:
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let epochRef = dag.getEpochRef(blck, self.best_justified.epoch, false)
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if epochRef.isSome():
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self.justified = BalanceCheckpoint(
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checkpoint: Checkpoint(root: blck.root, epoch: epochRef[].epoch),
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balances: epochRef[].effective_balances)
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else:
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# Shouldn't happen for justified data unless fork choice is out of sync
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# with ChainDAG
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warn "No `EpochRef` for justified epoch, skipping update - report bug",
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justified = shortLog(self.justified.checkpoint),
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best = shortLog(self.best_justified.epoch),
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blck = shortLog(blck)
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ok()
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func process_attestation_queue(self: var ForkChoice) {.gcsafe.}
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proc update_time(self: var ForkChoice, dag: ChainDAGRef, time: BeaconTime):
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FcResult[void] =
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const step_size = seconds(SECONDS_PER_SLOT.int)
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if time > self.checkpoints.time:
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# Call on_tick at least once per slot.
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while time >= self.checkpoints.time + step_size:
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? on_tick(self.checkpoints, dag, self.checkpoints.time + step_size)
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if self.checkpoints.time < time:
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# Might create two ticks for the last slot.
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? on_tick(self.checkpoints, dag, time)
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self.process_attestation_queue() # Only run if time changed!
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ok()
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func process_attestation*(
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self: var ForkChoiceBackend,
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validator_index: ValidatorIndex,
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block_root: Eth2Digest,
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target_epoch: Epoch
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) =
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if block_root.isZero:
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return
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## Add an attestation to the fork choice context
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self.votes.extend(validator_index.int + 1)
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template vote: untyped = self.votes[validator_index]
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# alias
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if target_epoch > vote.next_epoch or vote == default(VoteTracker):
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# TODO: the "default" condition is probably unneeded
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vote.next_root = block_root
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vote.next_epoch = target_epoch
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{.noSideEffect.}:
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trace "Integrating vote in fork choice",
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validator_index = validator_index,
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new_vote = shortLog(vote)
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func process_attestation_queue(self: var ForkChoice) =
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self.queuedAttestations.keepItIf:
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if it.slot < self.checkpoints.time.slotOrZero:
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for validator_index in it.attesting_indices:
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self.backend.process_attestation(
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validator_index, it.block_root, it.slot.epoch())
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false
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else:
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true
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func contains*(self: ForkChoiceBackend, block_root: Eth2Digest): bool =
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## Returns `true` if a block is known to the fork choice
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## and `false` otherwise.
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##
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## In particular, before adding a block, its parent must be known to the fork choice
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self.proto_array.indices.contains(block_root)
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# https://github.com/ethereum/consensus-specs/blob/v0.12.1/specs/phase0/fork-choice.md#on_attestation
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proc on_attestation*(
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self: var ForkChoice,
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dag: ChainDAGRef,
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attestation_slot: Slot,
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beacon_block_root: Eth2Digest,
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attesting_indices: openArray[ValidatorIndex],
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wallTime: BeaconTime
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): FcResult[void] =
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? self.update_time(dag, wallTime)
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if beacon_block_root.isZero:
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return ok()
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if attestation_slot < self.checkpoints.time.slotOrZero:
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for validator_index in attesting_indices:
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# attestation_slot and target epoch must match, per attestation rules
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self.backend.process_attestation(
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validator_index, beacon_block_root, attestation_slot.epoch)
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else:
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# Spec:
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# Attestations can only affect the fork choice of subsequent slots.
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# Delay consideration in the fork choice until their slot is in the past.
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self.queuedAttestations.add(QueuedAttestation(
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slot: attestation_slot,
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attesting_indices: @attesting_indices,
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block_root: beacon_block_root))
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ok()
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# https://github.com/ethereum/consensus-specs/blob/v1.1.10/specs/phase0/fork-choice.md#should_update_justified_checkpoint
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func should_update_justified_checkpoint(
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self: var Checkpoints,
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dag: ChainDAGRef,
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epochRef: EpochRef): FcResult[bool] =
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# To address the bouncing attack, only update conflicting justified
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# checkpoints in the fork choice if in the early slots of the epoch.
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# Otherwise, delay incorporation of new justified checkpoint until next epoch
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# boundary.
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#
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# See https://ethresear.ch/t/prevention-of-bouncing-attack-on-ffg/6114 for
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# more detailed analysis and discussion.
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if self.time.slotOrZero.since_epoch_start() < SAFE_SLOTS_TO_UPDATE_JUSTIFIED:
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return ok(true)
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let
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justified_slot = self.justified.checkpoint.epoch.start_slot()
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new_justified_checkpoint = epochRef.current_justified_checkpoint
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justified_blck = dag.getBlockRef(new_justified_checkpoint.root).valueOr:
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return err ForkChoiceError(
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kind: fcJustifiedNodeUnknown,
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blockRoot: new_justified_checkpoint.root)
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let justified_ancestor = justified_blck.atSlot(justified_slot)
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if justified_ancestor.blck.root != self.justified.checkpoint.root:
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return ok(false)
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ok(true)
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proc process_state(self: var Checkpoints,
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dag: ChainDAGRef,
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epochRef: EpochRef,
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blck: BlockRef): FcResult[void] =
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let
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state_justified_epoch = epochRef.current_justified_checkpoint.epoch
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state_finalized_epoch = epochRef.finalized_checkpoint.epoch
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trace "Processing epoch",
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epoch = epochRef.epoch,
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state_justified_epoch = state_justified_epoch,
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current_justified = self.justified.checkpoint.epoch,
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state_finalized_epoch = state_finalized_epoch,
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current_finalized = self.finalized.epoch
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if state_justified_epoch > self.justified.checkpoint.epoch:
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if state_justified_epoch > self.best_justified.epoch:
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self.best_justified = epochRef.current_justified_checkpoint
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if ? should_update_justified_checkpoint(self, dag, epochRef):
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let
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justifiedBlck = blck.atEpochStart(state_justified_epoch)
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justifiedEpochRef = dag.getEpochRef(
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justifiedBlck.blck, state_justified_epoch, false)
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if justifiedEpochRef.isOk():
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self.justified =
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BalanceCheckpoint(
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checkpoint: Checkpoint(
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root: justifiedBlck.blck.root,
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epoch: state_justified_epoch
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),
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balances: justifiedEpochRef[].effective_balances)
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else:
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# Shouldn't happen, unless fork choice is out of sync with ChainDAG
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warn "Skipping justified checkpoint update, no EpochRef - report bug",
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epoch = epochRef.epoch,
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justifiedBlck = shortLog(justifiedBlck),
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state_justified = shortLog(epochRef.current_justified_checkpoint),
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state_finalized = shortLog(epochRef.finalized_checkpoint)
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if state_finalized_epoch > self.finalized.epoch:
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self.finalized = epochRef.finalized_checkpoint
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if self.justified.checkpoint.epoch != state_justified_epoch or
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self.justified.checkpoint.root != epochRef.current_justified_checkpoint.root:
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if (state_justified_epoch > self.justified.checkpoint.epoch) or
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((? dag.getBlockRef(self.justified.checkpoint.root).orErr(
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ForkChoiceError(
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kind: fcJustifiedNodeUnknown,
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blockRoot: self.justified.checkpoint.root))).atEpochStart(
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self.finalized.epoch).blck.root != self.finalized.root):
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let
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justifiedBlck = blck.atEpochStart(state_justified_epoch)
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justifiedEpochRef = dag.getEpochRef(
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justifiedBlck.blck, state_justified_epoch, false)
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if justifiedEpochRef.isOk():
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self.justified =
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BalanceCheckpoint(
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checkpoint: Checkpoint(
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root: justifiedBlck.blck.root,
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epoch: justifiedEpochRef[].epoch
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),
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balances: justifiedEpochRef[].effective_balances)
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else:
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warn "Skipping justified checkpoint update, no EpochRef - report bug",
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epoch = epochRef.epoch,
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justifiedBlck = shortLog(justifiedBlck),
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state_justified = shortLog(epochRef.current_justified_checkpoint),
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state_finalized = shortLog(epochRef.finalized_checkpoint)
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ok()
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func process_block*(self: var ForkChoiceBackend,
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block_root: Eth2Digest,
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parent_root: Eth2Digest,
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justified_checkpoint: Checkpoint,
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finalized_checkpoint: Checkpoint): FcResult[void] =
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self.proto_array.onBlock(
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block_root, parent_root, justified_checkpoint, finalized_checkpoint)
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proc process_block*(self: var ForkChoice,
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dag: ChainDAGRef,
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epochRef: EpochRef,
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blckRef: BlockRef,
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blck: ForkyTrustedBeaconBlock,
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wallTime: BeaconTime): FcResult[void] =
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? update_time(self, dag, wallTime)
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? process_state(self.checkpoints, dag, epochRef, blckRef)
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let committees_per_slot = get_committee_count_per_slot(epochRef)
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for attestation in blck.body.attestations:
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let _ = dag.getBlockRef(attestation.data.target.root).valueOr:
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continue
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let committee_index = block:
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let v = CommitteeIndex.init(attestation.data.index, committees_per_slot)
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if v.isErr():
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warn "Unexpected committee index in block attestation",
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blck = shortLog(blck),
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data = shortLog(attestation.data)
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continue
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v.get()
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if attestation.data.beacon_block_root in self.backend:
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for validator in get_attesting_indices(
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epochRef, attestation.data.slot, committee_index,
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attestation.aggregation_bits):
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self.backend.process_attestation(
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validator,
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attestation.data.beacon_block_root,
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attestation.data.target.epoch)
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# Add proposer score boost if the block is timely
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let
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time_into_slot =
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self.checkpoints.time - self.checkpoints.time.slotOrZero.start_beacon_time
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is_before_attesting_interval = time_into_slot < attestationSlotOffset
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if self.checkpoints.time.slotOrZero == blck.slot and
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is_before_attesting_interval:
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self.checkpoints.proposer_boost_root = blckRef.root
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? process_block(
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self.backend, blckRef.root, blck.parent_root,
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epochRef.current_justified_checkpoint,
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epochRef.finalized_checkpoint
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)
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trace "Integrating block in fork choice",
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block_root = shortLog(blckRef)
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ok()
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func find_head*(
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self: var ForkChoiceBackend,
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justifiedCheckpoint: Checkpoint,
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finalizedCheckpoint: Checkpoint,
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justified_state_balances: seq[Gwei],
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proposer_boost_root: Eth2Digest
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): FcResult[Eth2Digest] =
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## Returns the new blockchain head
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# Compute deltas with previous call
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# we might want to reuse the `deltas` buffer across calls
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var deltas = newSeq[Delta](self.proto_array.indices.len)
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? deltas.compute_deltas(
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indices = self.proto_array.indices,
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indices_offset = self.proto_array.nodes.offset,
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votes = self.votes,
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old_balances = self.balances,
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new_balances = justified_state_balances
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)
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# Apply score changes
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? self.proto_array.applyScoreChanges(
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deltas, justifiedCheckpoint, finalizedCheckpoint,
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justified_state_balances, proposer_boost_root, self.proposer_boosting
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)
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self.balances = justified_state_balances
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# Find the best block
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var new_head{.noinit.}: Eth2Digest
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? self.proto_array.findHead(new_head, justifiedCheckpoint.root)
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{.noSideEffect.}:
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trace "Fork choice requested",
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justifiedCheckpoint = shortLog(justifiedCheckpoint),
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finalizedCheckpoint = shortLog(finalizedCheckpoint),
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fork_choice_head = shortLog(new_head)
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return ok(new_head)
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# https://github.com/ethereum/consensus-specs/blob/v0.12.1/specs/phase0/fork-choice.md#get_head
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proc get_head*(self: var ForkChoice,
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dag: ChainDAGRef,
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wallTime: BeaconTime): FcResult[Eth2Digest] =
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? self.update_time(dag, wallTime)
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self.backend.find_head(
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self.checkpoints.justified.checkpoint,
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self.checkpoints.finalized,
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self.checkpoints.justified.balances,
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self.checkpoints.proposer_boost_root
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)
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func prune*(
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self: var ForkChoiceBackend, finalized_root: Eth2Digest
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): FcResult[void] =
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## Prune blocks preceding the finalized root as they are now unneeded.
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self.proto_array.prune(finalized_root)
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func prune*(self: var ForkChoice): FcResult[void] =
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self.backend.prune(self.checkpoints.finalized.root)
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func compute_deltas(
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deltas: var openArray[Delta],
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indices: Table[Eth2Digest, Index],
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indices_offset: Index,
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votes: var openArray[VoteTracker],
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old_balances: openArray[Gwei],
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new_balances: openArray[Gwei]
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): FcResult[void] =
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## Update `deltas`
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## between old and new balances
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## between votes
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##
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## `deltas.len` must match `indices.len` (lenght match)
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##
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## Error:
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## - If a value in indices is greater than `indices.len`
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## - If a `Eth2Digest` in `votes` does not exist in `indices`
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## except for the `default(Eth2Digest)` (i.e. zero hash)
|
|
|
|
for val_index, vote in votes.mpairs():
|
|
# No need to create a score change if the validator has never voted
|
|
# or if votes are for the zero hash (alias to the genesis block)
|
|
if vote.current_root.isZero and vote.next_root.isZero:
|
|
continue
|
|
|
|
# If the validator was not included in `old_balances` (i.e. did not exist)
|
|
# its balance is zero
|
|
let old_balance = if val_index < old_balances.len: old_balances[val_index]
|
|
else: 0
|
|
|
|
# If the validator is not known in the `new_balances` then use balance of zero
|
|
#
|
|
# It is possible that there is a vote for an unknown validator if we change our
|
|
# justified state to a new state with a higher epoch on a different fork
|
|
# because that fork may have on-boarded less validators than the previous fork.
|
|
#
|
|
# Note that attesters are not different as they are activated only under finality
|
|
let new_balance = if val_index < new_balances.len: new_balances[val_index]
|
|
else: 0
|
|
|
|
if vote.current_root != vote.next_root or old_balance != new_balance:
|
|
# Ignore the current or next vote if it is not known in `indices`.
|
|
# We assume that it is outside of our tree (i.e., pre-finalization) and therefore not interesting.
|
|
if vote.current_root in indices:
|
|
let index = indices.unsafeGet(vote.current_root) - indices_offset
|
|
if index >= deltas.len:
|
|
return err ForkChoiceError(
|
|
kind: fcInvalidNodeDelta,
|
|
index: index)
|
|
deltas[index] -= Delta old_balance
|
|
# Note that delta can be negative
|
|
# TODO: is int64 big enough?
|
|
|
|
if vote.next_root in indices:
|
|
let index = indices.unsafeGet(vote.next_root) - indices_offset
|
|
if index >= deltas.len:
|
|
return err ForkChoiceError(
|
|
kind: fcInvalidNodeDelta,
|
|
index: index)
|
|
deltas[index] += Delta new_balance
|
|
# Note that delta can be negative
|
|
# TODO: is int64 big enough?
|
|
|
|
vote.current_root = vote.next_root
|
|
return ok()
|
|
|
|
# Sanity checks
|
|
# ----------------------------------------------------------------------
|
|
# Sanity checks on internal private procedures
|
|
|
|
when isMainModule:
|
|
import stew/endians2
|
|
|
|
func fakeHash(index: SomeInteger): Eth2Digest =
|
|
## Create fake hashes
|
|
## Those are just the value serialized in big-endian
|
|
## We add 16x16 to avoid having a zero hash are those are special cased
|
|
## We store them in the first 8 bytes
|
|
## as those are the one used in hash tables Table[Eth2Digest, T]
|
|
result.data[0 ..< 8] = (16*16+index).uint64.toBytesBE()
|
|
|
|
proc tZeroHash() =
|
|
echo " fork_choice compute_deltas - test zero votes"
|
|
|
|
const validator_count = 16
|
|
var deltas = newSeqUninitialized[Delta](validator_count)
|
|
|
|
var indices: Table[Eth2Digest, Index]
|
|
var votes: seq[VoteTracker]
|
|
var old_balances: seq[Gwei]
|
|
var new_balances: seq[Gwei]
|
|
|
|
for i in 0 ..< validator_count:
|
|
indices.add fakeHash(i), i
|
|
votes.add default(VoteTracker)
|
|
old_balances.add 0
|
|
new_balances.add 0
|
|
|
|
let err = deltas.compute_deltas(
|
|
indices, indices_offset = 0, votes, old_balances, new_balances
|
|
)
|
|
|
|
doAssert err.isOk, "compute_deltas finished with error: " & $err
|
|
|
|
doAssert deltas == newSeq[Delta](validator_count), "deltas should be zeros"
|
|
|
|
for vote in votes:
|
|
doAssert vote.current_root == vote.next_root, "The vote should have been updated"
|
|
|
|
|
|
proc tAll_voted_the_same() =
|
|
echo " fork_choice compute_deltas - test all same votes"
|
|
|
|
const
|
|
Balance = Gwei(42)
|
|
validator_count = 16
|
|
var deltas = newSeqUninitialized[Delta](validator_count)
|
|
|
|
var indices: Table[Eth2Digest, Index]
|
|
var votes: seq[VoteTracker]
|
|
var old_balances: seq[Gwei]
|
|
var new_balances: seq[Gwei]
|
|
|
|
for i in 0 ..< validator_count:
|
|
indices.add fakeHash(i), i
|
|
votes.add VoteTracker(
|
|
current_root: default(Eth2Digest),
|
|
next_root: fakeHash(0), # Get a non-zero hash
|
|
next_epoch: Epoch(0)
|
|
)
|
|
old_balances.add Balance
|
|
new_balances.add Balance
|
|
|
|
let err = deltas.compute_deltas(
|
|
indices, indices_offset = 0, votes, old_balances, new_balances
|
|
)
|
|
|
|
doAssert err.isOk, "compute_deltas finished with error: " & $err
|
|
|
|
for i, delta in deltas.pairs:
|
|
if i == 0:
|
|
doAssert delta == Delta(Balance * validator_count), "The 0th root should have a delta"
|
|
else:
|
|
doAssert delta == 0, "The non-0 indexes should have a zero delta"
|
|
|
|
for vote in votes:
|
|
doAssert vote.current_root == vote.next_root, "The vote should have been updated"
|
|
|
|
|
|
proc tDifferent_votes() =
|
|
echo " fork_choice compute_deltas - test all different votes"
|
|
|
|
const
|
|
Balance = Gwei(42)
|
|
validator_count = 16
|
|
var deltas = newSeqUninitialized[Delta](validator_count)
|
|
|
|
var indices: Table[Eth2Digest, Index]
|
|
var votes: seq[VoteTracker]
|
|
var old_balances: seq[Gwei]
|
|
var new_balances: seq[Gwei]
|
|
|
|
for i in 0 ..< validator_count:
|
|
indices.add fakeHash(i), i
|
|
votes.add VoteTracker(
|
|
current_root: default(Eth2Digest),
|
|
next_root: fakeHash(i), # Each vote for a different root
|
|
next_epoch: Epoch(0)
|
|
)
|
|
old_balances.add Balance
|
|
new_balances.add Balance
|
|
|
|
let err = deltas.compute_deltas(
|
|
indices, indices_offset = 0, votes, old_balances, new_balances
|
|
)
|
|
|
|
doAssert err.isOk, "compute_deltas finished with error: " & $err
|
|
|
|
for i, delta in deltas.pairs:
|
|
doAssert delta == Delta(Balance), "Each root should have a delta"
|
|
|
|
for vote in votes:
|
|
doAssert vote.current_root == vote.next_root, "The vote should have been updated"
|
|
|
|
|
|
proc tMoving_votes() =
|
|
echo " fork_choice compute_deltas - test moving votes"
|
|
|
|
const
|
|
Balance = Gwei(42)
|
|
validator_count = 16
|
|
TotalDeltas = Delta(Balance * validator_count)
|
|
var deltas = newSeqUninitialized[Delta](validator_count)
|
|
|
|
var indices: Table[Eth2Digest, Index]
|
|
var votes: seq[VoteTracker]
|
|
var old_balances: seq[Gwei]
|
|
var new_balances: seq[Gwei]
|
|
|
|
for i in 0 ..< validator_count:
|
|
indices.add fakeHash(i), i
|
|
votes.add VoteTracker(
|
|
# Move vote from root 0 to root 1
|
|
current_root: fakeHash(0),
|
|
next_root: fakeHash(1),
|
|
next_epoch: Epoch(0)
|
|
)
|
|
old_balances.add Balance
|
|
new_balances.add Balance
|
|
|
|
let err = deltas.compute_deltas(
|
|
indices, indices_offset = 0, votes, old_balances, new_balances
|
|
)
|
|
|
|
doAssert err.isOk, "compute_deltas finished with error: " & $err
|
|
|
|
for i, delta in deltas.pairs:
|
|
if i == 0:
|
|
doAssert delta == -TotalDeltas, "0th root should have a negative delta"
|
|
elif i == 1:
|
|
doAssert delta == TotalDeltas, "1st root should have a positive delta"
|
|
else:
|
|
doAssert delta == 0, "The non-0 and non-1 indexes should have a zero delta"
|
|
|
|
for vote in votes:
|
|
doAssert vote.current_root == vote.next_root, "The vote should have been updated"
|
|
|
|
|
|
proc tMove_out_of_tree() =
|
|
echo " fork_choice compute_deltas - test votes for unknown subtree"
|
|
|
|
const Balance = Gwei(42)
|
|
|
|
var indices: Table[Eth2Digest, Index]
|
|
var votes: seq[VoteTracker]
|
|
|
|
# Add a block
|
|
indices.add fakeHash(1), 0
|
|
|
|
# 2 validators
|
|
var deltas = newSeqUninitialized[Delta](2)
|
|
let old_balances = @[Balance, Balance]
|
|
let new_balances = @[Balance, Balance]
|
|
|
|
# One validator moves their vote from the block to the zero hash
|
|
votes.add VoteTracker(
|
|
current_root: fakeHash(1),
|
|
next_root: default(Eth2Digest),
|
|
next_epoch: Epoch(0)
|
|
)
|
|
|
|
# One validator moves their vote from the block to something outside of the tree
|
|
votes.add VoteTracker(
|
|
current_root: fakeHash(1),
|
|
next_root: fakeHash(1337),
|
|
next_epoch: Epoch(0)
|
|
)
|
|
|
|
let err = deltas.compute_deltas(
|
|
indices, indices_offset = 0, votes, old_balances, new_balances
|
|
)
|
|
|
|
doAssert err.isOk, "compute_deltas finished with error: " & $err
|
|
|
|
doAssert deltas[0] == -Delta(Balance)*2, "The 0th block should have lost both balances."
|
|
|
|
for vote in votes:
|
|
doAssert vote.current_root == vote.next_root, "The vote should have been updated"
|
|
|
|
|
|
proc tChanging_balances() =
|
|
echo " fork_choice compute_deltas - test changing balances"
|
|
|
|
const
|
|
OldBalance = Gwei(42)
|
|
NewBalance = OldBalance * 2
|
|
validator_count = 16
|
|
TotalOldDeltas = Delta(OldBalance * validator_count)
|
|
TotalNewDeltas = Delta(NewBalance * validator_count)
|
|
var deltas = newSeqUninitialized[Delta](validator_count)
|
|
|
|
var indices: Table[Eth2Digest, Index]
|
|
var votes: seq[VoteTracker]
|
|
var old_balances: seq[Gwei]
|
|
var new_balances: seq[Gwei]
|
|
|
|
for i in 0 ..< validator_count:
|
|
indices.add fakeHash(i), i
|
|
votes.add VoteTracker(
|
|
# Move vote from root 0 to root 1
|
|
current_root: fakeHash(0),
|
|
next_root: fakeHash(1),
|
|
next_epoch: Epoch(0)
|
|
)
|
|
old_balances.add OldBalance
|
|
new_balances.add NewBalance
|
|
|
|
let err = deltas.compute_deltas(
|
|
indices, indices_offset = 0, votes, old_balances, new_balances
|
|
)
|
|
|
|
doAssert err.isOk, "compute_deltas finished with error: " & $err
|
|
|
|
for i, delta in deltas.pairs:
|
|
if i == 0:
|
|
doAssert delta == -TotalOldDeltas, "0th root should have a negative delta"
|
|
elif i == 1:
|
|
doAssert delta == TotalNewDeltas, "1st root should have a positive delta"
|
|
else:
|
|
doAssert delta == 0, "The non-0 and non-1 indexes should have a zero delta"
|
|
|
|
for vote in votes:
|
|
doAssert vote.current_root == vote.next_root, "The vote should have been updated"
|
|
|
|
|
|
proc tValidator_appears() =
|
|
echo " fork_choice compute_deltas - test validator appears"
|
|
|
|
const Balance = Gwei(42)
|
|
|
|
var indices: Table[Eth2Digest, Index]
|
|
var votes: seq[VoteTracker]
|
|
|
|
# Add 2 blocks
|
|
indices.add fakeHash(1), 0
|
|
indices.add fakeHash(2), 1
|
|
|
|
# 1 validator at the start, 2 at the end
|
|
var deltas = newSeqUninitialized[Delta](2)
|
|
let old_balances = @[Balance]
|
|
let new_balances = @[Balance, Balance]
|
|
|
|
# Both moves vote from Block 1 to 2
|
|
for _ in 0 ..< 2:
|
|
votes.add VoteTracker(
|
|
current_root: fakeHash(1),
|
|
next_root: fakeHash(2),
|
|
next_epoch: Epoch(0)
|
|
)
|
|
|
|
|
|
let err = deltas.compute_deltas(
|
|
indices, indices_offset = 0, votes, old_balances, new_balances
|
|
)
|
|
|
|
doAssert err.isOk, "compute_deltas finished with error: " & $err
|
|
|
|
doAssert deltas[0] == -Delta(Balance), "Block 1 should have lost only 1 balance"
|
|
doAssert deltas[1] == Delta(Balance)*2, "Block 2 should have gained 2 balances"
|
|
|
|
for vote in votes:
|
|
doAssert vote.current_root == vote.next_root, "The vote should have been updated"
|
|
|
|
|
|
proc tValidator_disappears() =
|
|
echo " fork_choice compute_deltas - test validator disappears"
|
|
|
|
const Balance = Gwei(42)
|
|
|
|
var indices: Table[Eth2Digest, Index]
|
|
var votes: seq[VoteTracker]
|
|
|
|
# Add 2 blocks
|
|
indices.add fakeHash(1), 0
|
|
indices.add fakeHash(2), 1
|
|
|
|
# 1 validator at the start, 2 at the end
|
|
var deltas = newSeqUninitialized[Delta](2)
|
|
let old_balances = @[Balance, Balance]
|
|
let new_balances = @[Balance]
|
|
|
|
# Both moves vote from Block 1 to 2
|
|
for _ in 0 ..< 2:
|
|
votes.add VoteTracker(
|
|
current_root: fakeHash(1),
|
|
next_root: fakeHash(2),
|
|
next_epoch: Epoch(0)
|
|
)
|
|
|
|
|
|
let err = deltas.compute_deltas(
|
|
indices, indices_offset = 0, votes, old_balances, new_balances
|
|
)
|
|
|
|
doAssert err.isOk, "compute_deltas finished with error: " & $err
|
|
|
|
doAssert deltas[0] == -Delta(Balance)*2, "Block 1 should have lost 2 balances"
|
|
doAssert deltas[1] == Delta(Balance), "Block 2 should have gained 1 balance"
|
|
|
|
for vote in votes:
|
|
doAssert vote.current_root == vote.next_root, "The vote should have been updated"
|
|
|
|
|
|
# ----------------------------------------------------------------------
|
|
|
|
echo "fork_choice internal tests for compute_deltas"
|
|
tZeroHash()
|
|
tAll_voted_the_same()
|
|
tDifferent_votes()
|
|
tMoving_votes()
|
|
tChanging_balances()
|
|
tValidator_appears()
|
|
tValidator_disappears()
|