pkg/lightning: fix TestRegionJobBaseWorker waitgroup race

[D3Hunter]

What problem does this PR solve?

Issue Number: close #66702

Problem Summary:

TestRegionJobBaseWorker/if_the_region_has_no_leader,_rescan_the_region is flaky in nextgen CI. In test helper prepareAndExecute, jobInCh <- job happened before jobWg.Add(1), so worker-side Done could race ahead and trigger sync: negative WaitGroup counter.

What changed and how does it work?

• Reordered test helper accounting to call jobWg.Add(1) before jobInCh <- job.
• This guarantees waitgroup accounting is established before workers can decrement it.

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No need to test

  • I checked and no code files have been changed.

Side effects

• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Breaking backward compatibility

Documentation

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Changes MySQL compatibility

Release note

Please refer to Release Notes Language Style Guide to write a quality release note.

None

Summary by CodeRabbit

• Tests
  • Improved job worker test to tighten synchronization around enqueue timing, reducing flakiness for timing-sensitive scenarios and ensuring more reliable verification of job enqueueing and processing behavior.

[ti-chi-bot]

Skipping CI for Draft Pull Request.
If you want CI signal for your change, please convert it to an actual PR.
You can still manually trigger a test run with /test all

[coderabbitai]

📝 Walkthrough

Walkthrough

Moved the WaitGroup increment to occur before enqueuing the job and added an optional after-send callback to the test helper to control timing, preventing a race that could cause a negative WaitGroup counter in the job worker tests.

Changes

Cohort / File(s)	Summary
Job Worker Test pkg/lightning/backend/local/job_worker_test.go	Moved jobWg.Add(1) to execute before jobInCh <- job; added an afterSendFn callback parameter to prepareAndExecute to allow deferred actions after sending; updated imports and test usage accordingly to avoid WaitGroup race that could lead to negative counter.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Poem

I am a rabbit in the CI night,
I nudge the counter to set it right,
Send then wait, no panic in sight,
Tests now hop steady, calm, and light. 🐇✨

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and specifically identifies the main fix: reordering WaitGroup operations to eliminate a race condition in the TestRegionJobBaseWorker test.
Linked Issues check	✅ Passed	The PR directly addresses the root cause identified in #66702 by reordering jobWg.Add(1) before jobInCh <- job, preventing the negative WaitGroup counter panic described in the issue.
Out of Scope Changes check	✅ Passed	All changes are scoped to fixing the identified race condition in TestRegionJobBaseWorker; no unrelated modifications are present in the test file changes.
Description check	✅ Passed	The pull request description follows the required template with complete sections: issue number, problem summary, what changed, test checklist, and release notes.

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[tiprow]

Hi @D3Hunter. Thanks for your PR.

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@pkg/lightning/backend/local/job_worker_test.go`:
- Around line 164-171: The test uses time.Sleep in the t.Run case to wait for
worker startup; replace that with a channel handshake to make startup
deterministic: create a chan struct{} in the test, pass a preRunFn to
prepareAndExecute that closes/signals the channel when the worker is ready, and
before enqueuing/waiting on the job block until that channel is signaled; update
references to prepareAndExecute and the preRunFn callback (and the test case
name "track waitgroup before enqueue to avoid negative counter") so the
worker-first scheduling is explicit and no sleep is used.

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro

Run ID: 67f83917-17ad-4d23-808b-c01597fdfea1

📥 Commits

Reviewing files that changed from the base of the PR and between c909831 and 6549f6f.

📒 Files selected for processing (1)

• pkg/lightning/backend/local/job_worker_test.go

[pantheon-ai]

Review Complete

Findings: 0 issues
Posted: 0
Duplicates/Skipped: 0

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 78.2657%. Comparing base (c909831) to head (f4b1b1e).
⚠️ Report is 2 commits behind head on master.

Additional details and impacted files

@@               Coverage Diff                @@
##             master     #66703        +/-   ##
================================================
+ Coverage   77.6902%   78.2657%   +0.5755%     
================================================
  Files          2008       1938        -70     
  Lines        549382     536987     -12395     
================================================
- Hits         426816     420277      -6539     
+ Misses       120901     116275      -4626     
+ Partials       1665        435      -1230     

Flag	Coverage Δ
integration	44.0730% <ø> (-4.1172%)	⬇️
unit	76.6859% <ø> (+0.3404%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Components	Coverage Δ
dumpling	56.7974% <ø> (ø)
parser	∅ <ø> (∅)
br	48.8279% <ø> (-12.0552%)	⬇️

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[D3Hunter]

/retest

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[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: GMHDBJD, joechenrh

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2026-03-05 07:14:49.436589407 +0000 UTC m=+428734.014668591: ☑️ agreed by GMHDBJD.
• 2026-03-05 08:40:05.602090826 +0000 UTC m=+433850.180170020: ☑️ agreed by joechenrh.

[pantheon-ai]

✅ Code looks good. No issues found.

[D3Hunter]

/retest

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@D3Hunter: PRs from untrusted users cannot be marked as trusted with /ok-to-test in this repo meaning untrusted PR authors can never trigger tests themselves. Collaborators can still trigger tests on the PR using /test.

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[D3Hunter]

/retest

[tiprow]

@D3Hunter: PRs from untrusted users cannot be marked as trusted with /ok-to-test in this repo meaning untrusted PR authors can never trigger tests themselves. Collaborators can still trigger tests on the PR using /test.

Details

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