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fix: a potential deadlock in chain follower fork handling #6235

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Merged
hanabi1224 merged 3 commits into from
Nov 6, 2025
Merged

fix: a potential deadlock in chain follower fork handling #6235

hanabi1224 merged 3 commits into from
Nov 6, 2025

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@hanabi1224 hanabi1224 commented Nov 6, 2025 •
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Summary of changes

During fork handling, is_ready_for_validation could return true for a tipset whose grandparent is validated but parent is not, which potentially causes a deadlock.

This will likely fix #6042 (comment)

Changes introduced in this pull request:

Reference issue to close (if applicable)

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Change checklist

  • I have performed a self-review of my own code,
  • I have made corresponding changes to the documentation. All new code adheres to the team's documentation standards,
  • I have added tests that prove my fix is effective or that my feature works (if possible),
  • I have made sure the CHANGELOG is up-to-date. All user-facing changes should be reflected in this document.

Summary by CodeRabbit

  • Refactor

    • Internal helper renamed; behavior and user-facing logic unchanged.

  • Documentation

    • Changelog updated to include the fix; duplicate entry placement corrected.

  • Chores

    • No user-visible changes or new functionality in this release.

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coderabbitai bot commented Nov 6, 2025 •
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Walkthrough

Renamed an internal helper in SyncStateMachine from is_validated to is_parent_validated in src/chain_sync/chain_follower.rs; logic unchanged and all internal call sites updated. Also added a changelog entry for PR 6235 in CHANGELOG.md.

Changes

Cohort / File(s) Change Summary
SyncStateMachine method rename
src/chain_sync/chain_follower.rs		 Renamed internal helper is_validated → is_parent_validated; preserved logic (checks stateless_mode or parent_state presence); updated all internal callers.
Changelog updates
CHANGELOG.md		 Added PR 6235 entry ("Fixed a potential deadlock in chain follower when handling fork(s)") in unreleased and Forest v0.30.2 "Garuda" sections (duplicate entries).

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~3 minutes

  • Single, localized rename with consistent caller updates.
  • Minor documentation/changelog edits.

Files/areas to spot-check:

  • src/chain_sync/chain_follower.rs — ensure no external/public API break and tests/uses updated.
  • CHANGELOG.md — verify duplicate entries are intentional.

Suggested reviewers

  • elmattic
  • LesnyRumcajs

Pre-merge checks and finishing touches

❌ Failed checks (1 warning, 1 inconclusive)
Check name Status Explanation Resolution
Docstring Coverage ⚠️ Warning Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. You can run @coderabbitai generate docstrings to improve docstring coverage.
Linked Issues check ❓ Inconclusive The PR addresses a deadlock in fork handling by renaming is_validated to is_parent_validated, which aligns with fixing the root cause of desynchronization in issue #6042 but does not comprehensively address all stated objectives (future-dated blocks, state-root versions, F3 handling). Clarify whether this incremental deadlock fix is a complete solution to issue #6042 or a partial fix that requires additional changes to address all identified root causes.
✅ Passed checks (3 passed)
Check name Status Explanation
Description Check ✅ Passed Check skipped - CodeRabbit’s high-level summary is enabled.
Title check ✅ Passed The title clearly summarizes the main change: fixing a potential deadlock in chain follower fork handling, which directly relates to the root cause identified in the PR description.
Out of Scope Changes check ✅ Passed All changes are focused on the deadlock issue: renaming the internal helper method and updating the CHANGELOG accordingly, with no unrelated modifications detected.
✨ Finishing touches
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  • Post copyable unit tests in a comment
  • Commit unit tests in branch hm/potential-deadlock-in-fork-handling
📜 Recent review details

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Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 0e39f2f and 10b0ae1.

📒 Files selected for processing (1)
  • CHANGELOG.md (1 hunks)
✅ Files skipped from review due to trivial changes (1)
  • CHANGELOG.md
⏰ Context from checks skipped due to timeout of 90000ms. You can increase the timeout in your CodeRabbit configuration to a maximum of 15 minutes (900000ms). (8)
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@hanabi1224 hanabi1224 force-pushed the hm/potential-deadlock-in-fork-handling branch from da6fde3 to 0e39f2f Compare November 6, 2025 12:38
@hanabi1224 hanabi1224 marked this pull request as ready for review November 6, 2025 12:43
@hanabi1224 hanabi1224 requested a review from a team as a code owner November 6, 2025 12:43
@hanabi1224 hanabi1224 requested review from LesnyRumcajs and sudo-shashank and removed request for a team November 6, 2025 12:43
LesnyRumcajs
LesnyRumcajs previously approved these changes Nov 6, 2025
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changelog?

@hanabi1224
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hanabi1224 commented Nov 6, 2025

changelog?

@LesnyRumcajs updated

@hanabi1224 hanabi1224 enabled auto-merge November 6, 2025 12:55
@hanabi1224 hanabi1224 added this pull request to the merge queue Nov 6, 2025
Merged via the queue into main with commit e31b3cb Nov 6, 2025
51 checks passed
@hanabi1224 hanabi1224 deleted the hm/potential-deadlock-in-fork-handling branch November 6, 2025 13:43
@hanabi1224 hanabi1224 mentioned this pull request Nov 6, 2025
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@coderabbitai coderabbitai bot mentioned this pull request Dec 1, 2025
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@LesnyRumcajs LesnyRumcajs LesnyRumcajs approved these changes

@akaladarshi akaladarshi akaladarshi approved these changes

@sudo-shashank sudo-shashank Awaiting requested review from sudo-shashank sudo-shashank is a code owner automatically assigned from ChainSafe/forest

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Synchronization backwards cannot be restored

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@hanabi1224 @LesnyRumcajs @akaladarshi