transaction: resolve orphaned locks whose primary was never written

[eduralph]

check_txn_status matched only ExtractedErrors, but its plan delivers per-key errors as MultipleKeyErrors, so the Rollback_if_not_exist escalation in get_txn_status_from_lock was unreachable and an orphaned secondary lock poisoned its key permanently. Accept both wrappers.

Refs #531

Signed-off-by: Eduard Ralph eduard@ralphovi.net

Summary by CodeRabbit

• Bug Fixes
  • Improved transaction status handling when multiple per-key errors are returned.
  • txn_not_found is now consistently reported as “transaction not found” instead of a generic error.
  • Ensures orphaned locks (primary never written) properly trigger rollback escalation and lock cleanup.
• Tests
  • Added coverage for the missing-primary/orphaned-lock scenario, including verification that lock resolution is invoked once.

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📝 Walkthrough

Walkthrough

check_txn_status now handles Error::MultipleKeyErrors when converting txn_not_found key failures. Tests cover an orphaned lock whose primary transaction was never written and verify rollback escalation removes the lock.

Changes

Transaction status error handling

Layer / File(s)	Summary
Expand transaction status error handling src/transaction/lock.rs	check_txn_status processes Error::MultipleKeyErrors like Error::ExtractedErrors, converting a matching KeyError into Error::TxnNotFound.
Validate orphaned-lock rollback escalation src/transaction/lock.rs	An async test captures status requests and verifies rollback_if_not_exist escalation, lock removal, and one ResolveLock invocation.

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

Possibly related issues

• Orphaned secondary lock is never resolved: reads fail with TxnNotFound forever (regression in #519) #543: Covers the MultipleKeyErrors handling and orphaned-lock rollback escalation addressed by this PR.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly matches the main change: resolving orphaned transaction locks when the primary was never written.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[eduralph]

@ekexium to raise awareness

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[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: ekexium

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• OWNERS [ekexium]

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2026-07-20 02:41:27.429603463 +0000 UTC m=+1199873.465698519: ☑️ agreed by ekexium.

[eduralph]

@pingyu - we're 1 LGTM away from getting this merged