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# beacon_chain
# Copyright (c) 2018-2024 Status Research & Development GmbH
# Licensed and distributed under either of
# * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT).
# * Apache v2 license (license terms in the root directory or at https://www.apache.org/licenses/LICENSE-2.0).
# at your option. This file may not be copied, modified, or distributed except according to those terms.
{.push raises: [].}
import
# Standard library
std/[sequtils, tables],
# Status libraries
results, chronicles,
# Internal
../spec/[beaconstate, helpers, state_transition_block],
../spec/datatypes/[phase0, altair, bellatrix],
# Fork choice
./fork_choice_types, ./proto_array,
../consensus_object_pools/[spec_cache, blockchain_dag]
export results, fork_choice_types
export proto_array.len
# https://github.com/ethereum/consensus-specs/blob/v1.3.0/specs/phase0/fork-choice.md
# This is a port of https://github.com/sigp/lighthouse/pull/804
# which is a port of "Proto-Array": https://github.com/protolambda/lmd-ghost
# See also:
# - Protolambda port of Lighthouse: https://github.com/protolambda/eth2-py-hacks/blob/ae286567/proto_array.py
# - Prysmatic writeup: https://hackmd.io/bABJiht3Q9SyV3Ga4FT9lQ#High-level-concept
# - Gasper Whitepaper: https://arxiv.org/abs/2003.03052
# Forward declarations
# ----------------------------------------------------------------------
type Index = fork_choice_types.Index
func compute_deltas(
deltas: var openArray[Delta],
indices: Table[Eth2Digest, Index],
indices_offset: Index,
votes: var openArray[VoteTracker],
old_balances: openArray[Gwei],
new_balances: openArray[Gwei]
): FcResult[void]
# Fork choice routines
# ----------------------------------------------------------------------
logScope: topics = "fork_choice"
func init*(
T: type ForkChoiceBackend, checkpoints: FinalityCheckpoints): T =
T(proto_array: ProtoArray.init(checkpoints))
proc init*(
T: type ForkChoice, epochRef: EpochRef, blck: BlockRef): T =
## Initialize a fork choice context for a finalized state - in the finalized
## state, the justified and finalized checkpoints are the same, so only one
## is used here
debug "Initializing fork choice",
epoch = epochRef.epoch, blck = shortLog(blck)
let checkpoint = Checkpoint(root: blck.root, epoch: epochRef.epoch)
ForkChoice(
backend: ForkChoiceBackend.init(
FinalityCheckpoints(
justified: checkpoint,
finalized: checkpoint)),
checkpoints: Checkpoints(
justified: BalanceCheckpoint(
checkpoint: checkpoint,
total_active_balance: epochRef.total_active_balance,
balances: epochRef.effective_balances),
finalized: checkpoint,
best_justified: checkpoint))
func extend[T](s: var seq[T], minLen: int) =
## Extend a sequence so that it can contains at least `minLen` elements.
## If it's already bigger, the sequence is unmodified.
## The extension is zero-initialized
if s.len < minLen:
s.setLen(minLen)
proc update_justified(
self: var Checkpoints, dag: ChainDAGRef, blck: BlockRef, epoch: Epoch) =
let
epochRef = dag.getEpochRef(blck, epoch, false).valueOr:
# Shouldn't happen for justified data unless out of sync with ChainDAG
warn "Skipping justified checkpoint update, no EpochRef - report bug",
blck, epoch, error
return
justified = Checkpoint(root: blck.root, epoch: epochRef.epoch)
trace "Updating justified",
store = self.justified.checkpoint, state = justified
self.justified = BalanceCheckpoint(
checkpoint: Checkpoint(root: blck.root, epoch: epochRef.epoch),
total_active_balance: epochRef.total_active_balance,
balances: epochRef.effective_balances)
proc update_justified(
self: var Checkpoints, dag: ChainDAGRef,
justified: Checkpoint): FcResult[void] =
let blck = dag.getBlockRef(justified.root).valueOr:
return err ForkChoiceError(
kind: fcJustifiedNodeUnknown,
blockRoot: justified.root)
self.update_justified(dag, blck, justified.epoch)
ok()
# https://github.com/ethereum/consensus-specs/blob/v1.5.0-alpha.9/specs/phase0/fork-choice.md#update_checkpoints
proc update_checkpoints(
self: var Checkpoints, dag: ChainDAGRef,
checkpoints: FinalityCheckpoints): FcResult[void] =
## Update checkpoints in store if necessary
# Update justified checkpoint
if checkpoints.justified.epoch > self.justified.checkpoint.epoch:
? self.update_justified(dag, checkpoints.justified)
# Update finalized checkpoint
if checkpoints.finalized.epoch > self.finalized.epoch:
trace "Updating finalized",
store = self.finalized, state = checkpoints.finalized
self.finalized = checkpoints.finalized
ok()
# https://github.com/ethereum/consensus-specs/blob/v1.4.0-beta.1/specs/phase0/fork-choice.md#on_tick_per_slot
proc on_tick(
self: var ForkChoice, dag: ChainDAGRef, time: BeaconTime): FcResult[void] =
## Must be called at least once per slot.
let previous_time = self.checkpoints.time
# Update store time
if time < previous_time:
return err ForkChoiceError(kind: fcInconsistentTick)
self.checkpoints.time = time
let
current_slot = time.slotOrZero
previous_slot = previous_time.slotOrZero
# If this is a new slot, reset store.proposer_boost_root
if current_slot > previous_slot:
self.checkpoints.proposer_boost_root = ZERO_HASH
# If a new epoch, pull-up justification and finalization from previous epoch
if current_slot > previous_slot and current_slot.is_epoch:
for realized in self.backend.proto_array.realizePendingCheckpoints():
? self.checkpoints.update_checkpoints(dag, realized)
ok()
func process_attestation(
self: var ForkChoiceBackend,
validator_index: ValidatorIndex,
block_root: Eth2Digest,
target_epoch: Epoch
) =
## Add an attestation to the fork choice context
self.votes.extend(validator_index.int + 1)
template vote: untyped = self.votes[validator_index]
if target_epoch > vote.next_epoch or vote.next_root.isZero:
vote.next_root = block_root
vote.next_epoch = target_epoch
trace "Integrating vote in fork choice",
validator_index = validator_index,
new_vote = shortLog(vote)
proc process_attestation_queue(self: var ForkChoice, slot: Slot) =
# Spec:
# Attestations can only affect the fork choice of subsequent slots.
# Delay consideration in the fork choice until their slot is in the past.
let startTick = Moment.now()
self.queuedAttestations.keepItIf:
if it.slot < slot:
for validator_index in it.attesting_indices:
self.backend.process_attestation(
validator_index, it.block_root, it.slot.epoch())
false
else:
true
let endTick = Moment.now()
debug "Processed attestation queue", processDur = endTick - startTick
func contains*(self: ForkChoiceBackend, block_root: Eth2Digest): bool =
## Returns `true` if a block is known to the fork choice
## and `false` otherwise.
##
## In particular, before adding a block, its parent must be known to the fork choice
self.proto_array.indices.contains(block_root)
proc update_time*(self: var ForkChoice, dag: ChainDAGRef, time: BeaconTime):
FcResult[void] =
# `time` is the wall time, meaning it changes on every call typically
const step_size = seconds(SECONDS_PER_SLOT.int)
if time > self.checkpoints.time:
let
preSlot = self.checkpoints.time.slotOrZero()
postSlot = time.slotOrZero()
# Call on_tick at least once per slot.
while time >= self.checkpoints.time + step_size:
? self.on_tick(dag, self.checkpoints.time + step_size)
if time > self.checkpoints.time:
# Might create two ticks for the last slot.
? self.on_tick(dag, time)
if preSlot != postSlot:
self.process_attestation_queue(postSlot)
ok()
# https://github.com/ethereum/consensus-specs/blob/v1.4.0-beta.5/specs/phase0/fork-choice.md#on_attestation
proc on_attestation*(
self: var ForkChoice,
dag: ChainDAGRef,
attestation_slot: Slot,
beacon_block_root: Eth2Digest,
attesting_indices: openArray[ValidatorIndex],
wallTime: BeaconTime
): FcResult[void] =
? self.update_time(dag, max(wallTime, attestation_slot.start_beacon_time))
if attestation_slot < self.checkpoints.time.slotOrZero:
for validator_index in attesting_indices:
# attestation_slot and target epoch must match, per attestation rules
self.backend.process_attestation(
validator_index, beacon_block_root, attestation_slot.epoch)
else:
# Spec:
# Attestations can only affect the fork choice of subsequent slots.
# Delay consideration in the fork choice until their slot is in the past.
self.queuedAttestations.add(QueuedAttestation(
slot: attestation_slot,
attesting_indices: @attesting_indices,
block_root: beacon_block_root))
ok()
# https://github.com/ethereum/consensus-specs/blob/v1.4.0-beta.1/specs/phase0/fork-choice.md#on_attester_slashing
func process_equivocation*(
self: var ForkChoice,
validator_index: ValidatorIndex
) =
self.backend.votes.extend(validator_index.int + 1)
# Disallow future votes
template vote: untyped = self.backend.votes[validator_index]
if vote.next_epoch != FAR_FUTURE_EPOCH or not vote.next_root.isZero:
vote.next_epoch = FAR_FUTURE_EPOCH
vote.next_root.reset()
trace "Integrating equivocation in fork choice",
validator_index
# https://github.com/ethereum/consensus-specs/blob/v1.3.0/specs/phase0/fork-choice.md#on_block
func process_block*(self: var ForkChoiceBackend,
bid: BlockId,
parent_root: Eth2Digest,
checkpoints: FinalityCheckpoints,
unrealized = none(FinalityCheckpoints)): FcResult[void] =
self.proto_array.onBlock(bid, parent_root, checkpoints, unrealized)
proc process_block*(self: var ForkChoice,
dag: ChainDAGRef,
epochRef: EpochRef,
blckRef: BlockRef,
unrealized: FinalityCheckpoints,
blck: ForkyTrustedBeaconBlock,
wallTime: BeaconTime): FcResult[void] =
? update_time(self, dag, max(wallTime, blckRef.slot.start_beacon_time))
for attester_slashing in blck.body.attester_slashings:
for idx in getValidatorIndices(attester_slashing):
let i = ValidatorIndex.init(idx).valueOr:
continue
self.process_equivocation(i)
for attestation in blck.body.attestations:
if attestation.data.beacon_block_root in self.backend:
for validator_index in dag.get_attesting_indices(attestation, true):
self.backend.process_attestation(
validator_index,
attestation.data.beacon_block_root,
attestation.data.target.epoch)
trace "Integrating block in fork choice",
block_root = shortLog(blckRef)
# Add proposer score boost if the block is timely
let slot = self.checkpoints.time.slotOrZero
if slot == blck.slot and
self.checkpoints.time < slot.attestation_deadline and
self.checkpoints.proposer_boost_root == ZERO_HASH:
self.checkpoints.proposer_boost_root = blckRef.root
# Update checkpoints in store if necessary
? update_checkpoints(self.checkpoints, dag, epochRef.checkpoints)
# If block is from a prior epoch, pull up the post-state to next epoch to
# realize new finality info
let unrealized_is_better =
unrealized.justified.epoch > epochRef.checkpoints.justified.epoch or
unrealized.finalized.epoch > epochRef.checkpoints.finalized.epoch
if unrealized_is_better:
if epochRef.epoch < slot.epoch:
trace "Pulling up chain tip",
blck = shortLog(blckRef), checkpoints = epochRef.checkpoints, unrealized
? update_checkpoints(self.checkpoints, dag, unrealized)
? process_block(
self.backend, blckRef.bid, blck.parent_root, unrealized)
else:
? process_block(
self.backend, blckRef.bid, blck.parent_root,
epochRef.checkpoints, some unrealized) # Realized in `on_tick`
else:
? process_block(
self.backend, blckRef.bid, blck.parent_root, epochRef.checkpoints)
ok()
func find_head(
self: var ForkChoiceBackend,
current_epoch: Epoch,
checkpoints: FinalityCheckpoints,
justified_total_active_balance: Gwei,
justified_state_balances: seq[Gwei],
proposer_boost_root: Eth2Digest
): FcResult[Eth2Digest] =
## Returns the new blockchain head
# Compute deltas with previous call
# we might want to reuse the `deltas` buffer across calls
var deltas = newSeq[Delta](self.proto_array.indices.len)
? deltas.compute_deltas(
indices = self.proto_array.indices,
indices_offset = self.proto_array.nodes.offset,
votes = self.votes,
old_balances = self.balances,
new_balances = justified_state_balances)
# Apply score changes
? self.proto_array.applyScoreChanges(
deltas, current_epoch, checkpoints,
justified_total_active_balance, proposer_boost_root)
self.balances = justified_state_balances
# Find the best block
var new_head{.noinit.}: Eth2Digest
? self.proto_array.findHead(new_head, checkpoints.justified.root)
trace "Fork choice requested",
checkpoints, fork_choice_head = shortLog(new_head)
return ok(new_head)
# https://github.com/ethereum/consensus-specs/blob/v1.4.0-beta.1/specs/phase0/fork-choice.md#get_head
proc get_head*(self: var ForkChoice,
dag: ChainDAGRef,
wallTime: BeaconTime): FcResult[Eth2Digest] =
? self.update_time(dag, wallTime)
self.backend.find_head(
self.checkpoints.time.slotOrZero.epoch,
FinalityCheckpoints(
justified: self.checkpoints.justified.checkpoint,
finalized: self.checkpoints.finalized),
self.checkpoints.justified.total_active_balance,
self.checkpoints.justified.balances,
self.checkpoints.proposer_boost_root)
# https://github.com/ethereum/consensus-specs/blob/v1.5.0-alpha.9/fork_choice/safe-block.md#get_safe_beacon_block_root
func get_safe_beacon_block_root*(self: ForkChoice): Eth2Digest =
# Use most recent justified block as a stopgap
self.checkpoints.justified.checkpoint.root
func prune*(
self: var ForkChoiceBackend, checkpoints: FinalityCheckpoints
): FcResult[void] =
## Prune blocks preceding the finalized root as they are now unneeded.
self.proto_array.prune(checkpoints)
func prune*(self: var ForkChoice): FcResult[void] =
self.backend.prune(
FinalityCheckpoints(
justified: self.checkpoints.justified.checkpoint,
finalized: self.checkpoints.finalized))
func mark_root_invalid*(self: var ForkChoice, root: Eth2Digest) =
try:
let nodePhysicalIdx =
self.backend.proto_array.indices[root] -
self.backend.proto_array.nodes.offset
if nodePhysicalIdx < self.backend.proto_array.nodes.buf.len:
self.backend.proto_array.nodes.buf[nodePhysicalIdx].invalid = true
self.backend.proto_array.propagateInvalidity(nodePhysicalIdx)
# Best-effort; attempts to mark unknown roots invalid harmlessly ignored
except KeyError:
discard
func compute_deltas(
deltas: var openArray[Delta],
indices: Table[Eth2Digest, Index],
indices_offset: Index,
votes: var openArray[VoteTracker],
old_balances: openArray[Gwei],
new_balances: openArray[Gwei]
): FcResult[void] =
## Update `deltas`
## between old and new balances
## between votes
##
## `deltas.len` must match `indices.len` (length match)
##
## Error:
## - If a value in indices is greater than `indices.len`
## - If a `Eth2Digest` in `votes` does not exist in `indices`
## 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.Gwei
# 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.Gwei
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_epoch != FAR_FUTURE_EPOCH or not vote.next_root.isZero:
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.Gwei
new_balances.add 0.Gwei
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:
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:
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:
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:
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
# 2 validator at the start, 1 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()
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