Etan Kissling 2a2bcea70d
group justified and finalized Checkpoint (#3841)
The justified and finalized `Checkpoint` are frequently passed around
together. This introduces a new `FinalityCheckpoint` data structure that
combines them into one.

Due to the large usage of this structure in fork choice, also took this
opportunity to update fork choice tests to the latest v1.2.0-rc.1 spec.
Many additional tests enabled, some need more work, e.g. EL mock blocks.
Also implemented `discard_equivocations` which was skipped in #3661,
and improved code reuse across fork choice logic while at it.
2022-07-06 13:33:02 +03:00

679 lines
18 KiB
Nim

# beacon_chain
# Copyright (c) 2018-2022 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: [Defect].}
# import ../interpreter # included to be able to use "suite"
func setup_votes(): tuple[fork_choice: ForkChoiceBackend, ops: seq[Operation]] =
var balances = @[Gwei(1), Gwei(1)]
let GenesisRoot = fakeHash(0)
# Initialize the fork choice context
# We start with epoch 0 fully finalized to avoid epoch 0 special cases.
result.fork_choice = ForkChoiceBackend.init(
FinalityCheckpoints(
justified: Checkpoint(root: GenesisRoot, epoch: Epoch(1)),
finalized: Checkpoint(root: GenesisRoot, epoch: Epoch(1))))
# ----------------------------------
# Head should be genesis
result.ops.add Operation(
kind: FindHead,
checkpoints: FinalityCheckpoints(
justified: Checkpoint(root: GenesisRoot, epoch: Epoch(1)),
finalized: Checkpoint(root: GenesisRoot, epoch: Epoch(1))),
justified_state_balances: balances,
expected_head: GenesisRoot)
# Add block 2
#
# 0
# /
# 2
result.ops.add Operation(
kind: ProcessBlock,
root: fakeHash(2),
parent_root: GenesisRoot,
blk_checkpoints: FinalityCheckpoints(
justified: Checkpoint(root: GenesisRoot, epoch: Epoch(1)),
finalized: Checkpoint(root: GenesisRoot, epoch: Epoch(1))))
# Head should be 2
#
# 0
# /
# 2 <- head
result.ops.add Operation(
kind: FindHead,
checkpoints: FinalityCheckpoints(
justified: Checkpoint(root: GenesisRoot, epoch: Epoch(1)),
finalized: Checkpoint(root: GenesisRoot, epoch: Epoch(1))),
justified_state_balances: balances,
expected_head: fakeHash(2))
# Add block 1 as a fork
#
# 0
# / \
# 2 1
result.ops.add Operation(
kind: ProcessBlock,
root: fakeHash(1),
parent_root: GenesisRoot,
blk_checkpoints: FinalityCheckpoints(
justified: Checkpoint(root: GenesisRoot, epoch: Epoch(1)),
finalized: Checkpoint(root: GenesisRoot, epoch: Epoch(1))))
# Head is still 2 due to tiebreaker as fakeHash(2) (0xD8...) > fakeHash(1) (0x7C...)
#
# 0
# / \
# head-> 2 1
result.ops.add Operation(
kind: FindHead,
checkpoints: FinalityCheckpoints(
justified: Checkpoint(root: GenesisRoot, epoch: Epoch(1)),
finalized: Checkpoint(root: GenesisRoot, epoch: Epoch(1))),
justified_state_balances: balances,
expected_head: fakeHash(2))
# Add a vote to block 1
#
# 0
# / \
# 2 1 <- +vote
result.ops.add Operation(
kind: ProcessAttestation,
validator_index: ValidatorIndex(0),
block_root: fakeHash(1),
target_epoch: Epoch(2))
# Head is now 1 as 1 has an extra vote
#
# 0
# / \
# 2 1 <- head
result.ops.add Operation(
kind: FindHead,
checkpoints: FinalityCheckpoints(
justified: Checkpoint(root: GenesisRoot, epoch: Epoch(1)),
finalized: Checkpoint(root: GenesisRoot, epoch: Epoch(1))),
justified_state_balances: balances,
expected_head: fakeHash(1))
# Add a vote to block 2
#
# 0
# / \
# +vote-> 2 1
result.ops.add Operation(
kind: ProcessAttestation,
validator_index: ValidatorIndex(1),
block_root: fakeHash(2),
target_epoch: Epoch(2))
# Head is back to 2 due to tiebreaker as fakeHash(2) (0xD8...) > fakeHash(1) (0x7C...)
#
# 0
# / \
# head-> 2 1
result.ops.add Operation(
kind: FindHead,
checkpoints: FinalityCheckpoints(
justified: Checkpoint(root: GenesisRoot, epoch: Epoch(1)),
finalized: Checkpoint(root: GenesisRoot, epoch: Epoch(1))),
justified_state_balances: balances,
expected_head: fakeHash(2))
# Add block 3 as on chain 1
#
# 0
# / \
# 2 1
# |
# 3
result.ops.add Operation(
kind: ProcessBlock,
root: fakeHash(3),
parent_root: fakeHash(1),
blk_checkpoints: FinalityCheckpoints(
justified: Checkpoint(root: GenesisRoot, epoch: Epoch(1)),
finalized: Checkpoint(root: GenesisRoot, epoch: Epoch(1))))
# Head is still 2
#
# 0
# / \
# head-> 2 1
result.ops.add Operation(
kind: FindHead,
checkpoints: FinalityCheckpoints(
justified: Checkpoint(root: GenesisRoot, epoch: Epoch(1)),
finalized: Checkpoint(root: GenesisRoot, epoch: Epoch(1))),
justified_state_balances: balances,
expected_head: fakeHash(2)
)
# Move validator #0 vote from 1 to 3
#
# 0
# / \
# 2 1 <- -vote
# |
# 3 <- +vote
result.ops.add Operation(
kind: ProcessAttestation,
validator_index: ValidatorIndex(0),
block_root: fakeHash(3),
target_epoch: Epoch(3))
# Head is still 2
#
# 0
# / \
# head-> 2 1
result.ops.add Operation(
kind: FindHead,
checkpoints: FinalityCheckpoints(
justified: Checkpoint(root: GenesisRoot, epoch: Epoch(1)),
finalized: Checkpoint(root: GenesisRoot, epoch: Epoch(1))),
justified_state_balances: balances,
expected_head: fakeHash(2))
# Move validator #1 vote from 2 to 1 (this is an equivocation, but fork choice doesn't
# care)
#
# 0
# / \
# -vote-> 2 1 <- +vote
# |
# 3
result.ops.add Operation(
kind: ProcessAttestation,
validator_index: ValidatorIndex(1),
block_root: fakeHash(1),
target_epoch: Epoch(3))
# Head is now 3
#
# 0
# / \
# 2 1
# |
# 3 <- head
result.ops.add Operation(
kind: FindHead,
checkpoints: FinalityCheckpoints(
justified: Checkpoint(root: GenesisRoot, epoch: Epoch(1)),
finalized: Checkpoint(root: GenesisRoot, epoch: Epoch(1))),
justified_state_balances: balances,
expected_head: fakeHash(3))
# Add block 4 on chain 1-3
#
# 0
# / \
# 2 1
# |
# 3
# |
# 4
result.ops.add Operation(
kind: ProcessBlock,
root: fakeHash(4),
parent_root: fakeHash(3),
blk_checkpoints: FinalityCheckpoints(
justified: Checkpoint(root: GenesisRoot, epoch: Epoch(1)),
finalized: Checkpoint(root: GenesisRoot, epoch: Epoch(1))))
# Head is now 4
#
# 0
# / \
# 2 1
# |
# 3
# |
# 4 <- head
result.ops.add Operation(
kind: FindHead,
checkpoints: FinalityCheckpoints(
justified: Checkpoint(root: GenesisRoot, epoch: Epoch(1)),
finalized: Checkpoint(root: GenesisRoot, epoch: Epoch(1))),
justified_state_balances: balances,
expected_head: fakeHash(4))
# Add block 5, which has a justified epoch of 2.
#
# 0
# / \
# 2 1
# |
# 3
# |
# 4
# /
# 5 <- justified epoch = 2
result.ops.add Operation(
kind: ProcessBlock,
root: fakeHash(5),
parent_root: fakeHash(4),
blk_checkpoints: FinalityCheckpoints(
justified: Checkpoint(root: fakeHash(5), epoch: Epoch(2)),
finalized: Checkpoint(root: fakeHash(5), epoch: Epoch(2))))
# Ensure that 5 is filtered out and the head stays at 4.
#
# 0
# / \
# 2 1
# |
# 3
# |
# 4 <- head
# /
# 5
result.ops.add Operation(
kind: FindHead,
checkpoints: FinalityCheckpoints(
justified: Checkpoint(root: GenesisRoot, epoch: Epoch(1)),
finalized: Checkpoint(root: GenesisRoot, epoch: Epoch(1))),
justified_state_balances: balances,
expected_head: fakeHash(4))
# Add block 6, which has a justified epoch of 0.
#
# 0
# / \
# 2 1
# |
# 3
# |
# 4
# / \
# 5 6 <- justified epoch = 0
result.ops.add Operation(
kind: ProcessBlock,
root: fakeHash(6),
parent_root: fakeHash(4),
blk_checkpoints: FinalityCheckpoints(
justified: Checkpoint(root: GenesisRoot, epoch: Epoch(1)),
finalized: Checkpoint(root: GenesisRoot, epoch: Epoch(1))))
# Move both votes to 5.
#
# 0
# / \
# 2 1
# |
# 3
# |
# 4
# / \
# +2 vote-> 5 6
result.ops.add Operation(
kind: ProcessAttestation,
validator_index: ValidatorIndex(0),
block_root: fakeHash(5),
target_epoch: Epoch(4))
result.ops.add Operation(
kind: ProcessAttestation,
validator_index: ValidatorIndex(1),
block_root: fakeHash(5),
target_epoch: Epoch(4))
# Add blocks 7, 8 and 9. Adding these blocks helps test the `best_descendant`
# functionality.
#
# 0
# / \
# 2 1
# |
# 3
# |
# 4
# / \
# 5 6
# |
# 7
# |
# 8
# /
# 9
result.ops.add Operation(
kind: ProcessBlock,
root: fakeHash(7),
parent_root: fakeHash(5),
blk_checkpoints: FinalityCheckpoints(
justified: Checkpoint(root: fakeHash(5), epoch: Epoch(2)),
finalized: Checkpoint(root: GenesisRoot, epoch: Epoch(1))))
result.ops.add Operation(
kind: ProcessBlock,
root: fakeHash(8),
parent_root: fakeHash(7),
blk_checkpoints: FinalityCheckpoints(
justified: Checkpoint(root: fakeHash(5), epoch: Epoch(2)),
finalized: Checkpoint(root: GenesisRoot, epoch: Epoch(1))))
# Finalizes 5
result.ops.add Operation(
kind: ProcessBlock,
root: fakeHash(9),
parent_root: fakeHash(8),
blk_checkpoints: FinalityCheckpoints(
justified: Checkpoint(root: fakeHash(5), epoch: Epoch(2)),
finalized: Checkpoint(root: fakeHash(5), epoch: Epoch(2))))
# Ensure that 6 is the head, even though 5 has all the votes. This is testing to ensure
# that 5 is filtered out due to a differing justified epoch.
#
# 0
# / \
# 2 1
# |
# 3
# |
# 4
# / \
# 5 6 <- head
# |
# 7
# |
# 8
# /
# 9
result.ops.add Operation(
kind: FindHead,
checkpoints: FinalityCheckpoints(
justified: Checkpoint(root: GenesisRoot, epoch: Epoch(1)),
finalized: Checkpoint(root: GenesisRoot, epoch: Epoch(1))),
justified_state_balances: balances,
expected_head: fakeHash(6))
# Change fork-choice justified epoch to 1, and the start block to 5 and ensure that 9 is
# the head.
#
# << Change justified epoch to 1 >>
#
# 0
# / \
# 2 1
# |
# 3
# |
# 4
# / \
# 5 6
# |
# 7
# |
# 8
# /
# head-> 9
result.ops.add Operation(
kind: FindHead,
checkpoints: FinalityCheckpoints(
justified: Checkpoint(root: fakeHash(5), epoch: Epoch(2)),
finalized: Checkpoint(root: fakeHash(5), epoch: Epoch(2))),
justified_state_balances: balances,
expected_head: fakeHash(9))
# Update votes to block 9
# 0
# / \
# 2 1
# |
# 3
# |
# 4
# / \
# 5 6
# |
# 7
# |
# 8
# /
# 9 <- +2 votes
result.ops.add Operation(
kind: ProcessAttestation,
validator_index: ValidatorIndex(0),
block_root: fakeHash(9),
target_epoch: Epoch(5))
result.ops.add Operation(
kind: ProcessAttestation,
validator_index: ValidatorIndex(1),
block_root: fakeHash(9),
target_epoch: Epoch(5))
# Head should still be 9
result.ops.add Operation(
kind: FindHead,
checkpoints: FinalityCheckpoints(
justified: Checkpoint(root: fakeHash(5), epoch: Epoch(2)),
finalized: Checkpoint(root: fakeHash(5), epoch: Epoch(2))),
justified_state_balances: balances,
expected_head: fakeHash(9))
# Add block 10 (also finalizes 5)
# 0
# / \
# 2 1
# |
# 3
# |
# 4
# / \
# 5 6
# |
# 7
# |
# 8
# / \
# 9 10
result.ops.add Operation(
kind: ProcessBlock,
root: fakeHash(10),
parent_root: fakeHash(8),
blk_checkpoints: FinalityCheckpoints(
justified: Checkpoint(root: fakeHash(5), epoch: Epoch(2)),
finalized: Checkpoint(root: fakeHash(5), epoch: Epoch(2))))
# Head should still be 9
result.ops.add Operation(
kind: FindHead,
checkpoints: FinalityCheckpoints(
justified: Checkpoint(root: fakeHash(5), epoch: Epoch(2)),
finalized: Checkpoint(root: fakeHash(5), epoch: Epoch(2))),
justified_state_balances: balances,
expected_head: fakeHash(9))
# Introduce 2 new validators
balances = @[Gwei(1), Gwei(1), Gwei(1), Gwei(1)]
# Have them vote for block 10
# 0
# / \
# 2 1
# |
# 3
# |
# 4
# / \
# 5 6
# |
# 7
# |
# 8
# / \
# 9 10 <- +2 votes
result.ops.add Operation(
kind: ProcessAttestation,
validator_index: ValidatorIndex(2),
block_root: fakeHash(10),
target_epoch: Epoch(5))
result.ops.add Operation(
kind: ProcessAttestation,
validator_index: ValidatorIndex(3),
block_root: fakeHash(10),
target_epoch: Epoch(5))
# Check that the head is now 10.
#
# 0
# / \
# 2 1
# |
# 3
# |
# 4
# / \
# 5 6
# |
# 7
# |
# 8
# / \
# 9 10 <- head
result.ops.add Operation(
kind: FindHead,
checkpoints: FinalityCheckpoints(
justified: Checkpoint(root: fakeHash(5), epoch: Epoch(2)),
finalized: Checkpoint(root: fakeHash(5), epoch: Epoch(2))),
justified_state_balances: balances,
expected_head: fakeHash(10))
# Set the last 2 validators balances to 0
balances = @[Gwei(1), Gwei(1), Gwei(0), Gwei(0)]
# head should be 9 again
# .
# |
# 8
# / \
# head -> 9 10
result.ops.add Operation(
kind: FindHead,
checkpoints: FinalityCheckpoints(
justified: Checkpoint(root: fakeHash(5), epoch: Epoch(2)),
finalized: Checkpoint(root: fakeHash(5), epoch: Epoch(2))),
justified_state_balances: balances,
expected_head: fakeHash(9))
# Set the last 2 validators balances back to 1
balances = @[Gwei(1), Gwei(1), Gwei(1), Gwei(1)]
# head should be 10 again
# .
# |
# 8
# / \
# 9 10 <- head
result.ops.add Operation(
kind: FindHead,
checkpoints: FinalityCheckpoints(
justified: Checkpoint(root: fakeHash(5), epoch: Epoch(2)),
finalized: Checkpoint(root: fakeHash(5), epoch: Epoch(2))),
justified_state_balances: balances,
expected_head: fakeHash(10))
# Remove the validators
balances = @[Gwei(1), Gwei(1)]
# head should be 9 again
# .
# |
# 8
# / \
# head -> 9 10
result.ops.add Operation(
kind: FindHead,
checkpoints: FinalityCheckpoints(
justified: Checkpoint(root: fakeHash(5), epoch: Epoch(2)),
finalized: Checkpoint(root: fakeHash(5), epoch: Epoch(2))),
justified_state_balances: balances,
expected_head: fakeHash(9))
# Ensure that pruning does prune.
#
#
# 0
# / \
# 2 1
# |
# 3
# |
# 4
# -------pruned here ------
# 5 6
# |
# 7
# |
# 8
# / \
# 9 10
# Note: 5 and 6 become orphans
# - 5 is the new root
# - 6 is a discarded chain
result.ops.add Operation(
kind: Prune,
finalized_root: fakeHash(5),
expected_len: 6)
# Prune shouldn't have changed the head
result.ops.add Operation(
kind: FindHead,
checkpoints: FinalityCheckpoints(
justified: Checkpoint(root: fakeHash(5), epoch: Epoch(2)),
finalized: Checkpoint(root: fakeHash(5), epoch: Epoch(2))),
justified_state_balances: balances,
expected_head: fakeHash(9))
# Add block 11
#
# 5 6
# |
# 7
# |
# 8
# / \
# 9 10
# |
# 11
result.ops.add Operation(
kind: ProcessBlock,
root: fakeHash(11),
parent_root: fakeHash(9),
blk_checkpoints: FinalityCheckpoints(
justified: Checkpoint(root: fakeHash(5), epoch: Epoch(2)),
finalized: Checkpoint(root: fakeHash(5), epoch: Epoch(2))))
# Head is now 11
result.ops.add Operation(
kind: FindHead,
checkpoints: FinalityCheckpoints(
justified: Checkpoint(root: fakeHash(5), epoch: Epoch(2)),
finalized: Checkpoint(root: fakeHash(5), epoch: Epoch(2))),
justified_state_balances: balances,
expected_head: fakeHash(11))
proc test_votes() =
test "fork_choice - testing with votes":
# for i in 0 ..< 12:
# echo " block (", i, ") hash: ", fakeHash(i)
# echo " ------------------------------------------------------"
var (ctx, ops) = setup_votes()
ctx.run(ops)
test_votes()