Cover held ordering locks in cfworkers

[seongmin36]

Closes #879.

WorkersMessageQueue.processMessage() returns shouldProcess: false when an ordering key lock is already held, which is what tells a queue handler to retry the message instead of running it out of order. src/mod.test.ts covered the lock being taken and released, but never the already-held case.

test/mq.test.ts already covers that branch, but it stubs get() to return a lock unconditionally, so the lock key itself is never exercised. This test takes the lock with a real processMessage() call and then sends a second message for the same ordering key without releasing it, which is the state a queue handler is in while the first message is still in flight. That also proves the key processMessage() writes is the one it later reads back.

Checks

• mise run check-each cfworkers — passes.
• vitest run — 44 tests pass across 3 files.
• Confirmed the test is not vacuous: replacing the lock check in processMessage() with if (false) makes it fail with expected true to be false, and it passes again once reverted.

Rebased onto main after #1016 touched the same file; both tests coexist.

No changelog fragment, since this is test-only work; the commit carries Changelog: none.

AI disclosure

Per AI_POLICY.md: I wrote the test myself. Claude Code (claude-opus-5) helped diagnose why my first attempt asserted against the lock-acquire path instead of the lock-exists path, and ran the checks listed above. The commit carries the Assisted-by: Claude Code:claude-opus-5 trailer.

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[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: ASSERTIVE

Plan: Pro Plus

Run ID: 38149dc9-80aa-4798-b714-08b2174516ce

📥 Commits

Reviewing files that changed from the base of the PR and between 81416ae and 26b91a7.

📒 Files selected for processing (1)

• packages/cfworkers/src/mod.test.ts

Included review availability: Your plan provides up to 4 included reviews per hour; 3 remain after this review.

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📝 Walkthrough

Walkthrough

Added test coverage for WorkersMessageQueue.processMessage() when a second message uses an existing ordering lock. The test verifies shouldProcess: false and confirms that no message or release callback is returned.

Changes

Queue ordering lock behavior

Layer / File(s)	Summary
Duplicate ordering key test packages/cfworkers/src/mod.test.ts	The test verifies that the first message is processed and the second message with the same ordering key is rejected without a payload or release callback.

Estimated code review effort: 2 (Simple) | ~10 minutes

Merge Risk: ⚪ Minimal · up to 26b91

This test-only change adds coverage for held ordering-key locks without changing production behavior. No actionable merge-blocking risk remains after normal checks and review.

Suggested reviewers: 2chanhaeng

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly identifies the main change: adding coverage for held ordering locks in cfworkers.
Description check	✅ Passed	The description explains the test change, expected behavior, linked issue, validation results, and test-only scope.
Linked Issues check	✅ Passed	The PR satisfies issue #879 by testing that a second message with the same ordering key returns shouldProcess: false while the lock remains held.
Out of Scope Changes check	✅ Passed	The changes are limited to the requested test in packages/cfworkers/src/mod.test.ts. No unrelated code or public API changes are present.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 1…

Full details: Docstring Coverage

Explanation

No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 1 files.

✨ Finishing Touches

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• Create PR with unit tests

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ All tests successful. No failed tests found.

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[dahlia]

Thanks!