Skip to content

fix: skip finalization advance for stale finalized sources #802

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Draft
latifkasuli wants to merge 1 commit into
base: main
Choose a base branch
from
Draft

fix: skip finalization advance for stale finalized sources #802

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
7 changes: 4 additions & 3 deletions src/lean_spec/forks/lstar/spec.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -556,13 +556,14 @@ def process_attestations(
# Finalization requires a continuous chain of trust from the
# previously finalized checkpoint up to the new justified point.
#
# If every slot in between is justifiable relative to the old
# finalized point, then the earlier source checkpoint becomes finalized.
# If the source is newer than the old finalized point and every
# slot in between is justifiable relative to that old finalized
# point, then the earlier source checkpoint becomes finalized.
#
# In short:
#
# If there is no break in the chain, advance finalization.
if not any(
if source.slot > finalized_slot and not any(
Slot(slot).is_justifiable_after(finalized_slot)
for slot in range(source.slot + Slot(1), target.slot)
):
Expand Down
125 changes: 125 additions & 0 deletions tests/consensus/lstar/state_transition/test_finalization.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -496,6 +496,131 @@ def test_finalization_prunes_stale_pending_votes_and_rebases_window(
)


def test_stale_finalized_source_justifies_without_rewinding_finalization(
state_transition_test: StateTransitionTestFiller,
) -> None:
"""
Test the post-state when a vote uses a source behind the finalized boundary.

Scenario
--------
1. Finalize block_4 through ordinary supermajority attestations
2. Process block_7 with a supermajority attesting from block_1 to block_6

Expected Behavior
-----------------
1. The post-state slot is 7
2. latest_justified_slot advances to 6
3. latest_finalized_slot remains 4
4. justified_slots marks slots 5 and 6 as justified
5. There are no pending justifications
"""
state_transition_test(
pre=generate_pre_state(),
blocks=[
BlockSpec(slot=Slot(1), label="block_1"),
BlockSpec(
slot=Slot(2),
parent_label="block_1",
label="block_2",
attestations=[
AggregatedAttestationSpec(
validator_ids=[
ValidatorIndex(0),
ValidatorIndex(1),
ValidatorIndex(2),
],
slot=Slot(2),
target_slot=Slot(1),
target_root_label="block_1",
),
],
),
BlockSpec(
slot=Slot(3),
parent_label="block_2",
label="block_3",
attestations=[
AggregatedAttestationSpec(
validator_ids=[
ValidatorIndex(0),
ValidatorIndex(1),
],
slot=Slot(3),
target_slot=Slot(2),
target_root_label="block_2",
),
],
),
BlockSpec(slot=Slot(4), parent_label="block_3", label="block_4"),
BlockSpec(
slot=Slot(5),
parent_label="block_4",
label="block_5",
attestations=[
AggregatedAttestationSpec(
validator_ids=[
ValidatorIndex(0),
ValidatorIndex(1),
ValidatorIndex(2),
],
slot=Slot(5),
target_slot=Slot(4),
target_root_label="block_4",
),
],
),
BlockSpec(
slot=Slot(6),
parent_label="block_5",
label="block_6",
attestations=[
AggregatedAttestationSpec(
validator_ids=[
ValidatorIndex(0),
ValidatorIndex(1),
ValidatorIndex(2),
],
slot=Slot(6),
target_slot=Slot(5),
target_root_label="block_5",
),
],
),
BlockSpec(
slot=Slot(7),
parent_label="block_6",
forced_attestations=[
AggregatedAttestationSpec(
validator_ids=[
ValidatorIndex(0),
ValidatorIndex(1),
ValidatorIndex(2),
],
slot=Slot(7),
source_slot=Slot(1),
source_root_label="block_1",
target_slot=Slot(6),
target_root_label="block_6",
),
],
),
],
post=StateExpectation(
slot=Slot(7),
latest_justified_slot=Slot(6),
latest_justified_root_label="block_6",
latest_finalized_slot=Slot(4),
latest_finalized_root_label="block_4",
justified_slots=JustifiedSlots(data=[]).model_copy(
update={"data": [Boolean(True), Boolean(True)]}
),
justifications_roots=JustificationRoots(data=[]),
justifications_validators=JustificationValidators(data=[]),
),
)


def test_non_adjacent_justification_finalizes_across_non_justifiable_gap(
state_transition_test: StateTransitionTestFiller,
) -> None:
Expand Down