Incident Dossier

The Lock That Left Too Soon

Two transactions serialize on the same key. The first commits, returns success, and yet a second transaction started immediately afterward reads the pre-commit value because the lock was already gone.

Initial failing signallock is dropped before commit appliesExpected behavior: holdsLock(a) === true during commit · actual behavior: holdsLock(a) === false during commit

Progress

1Reproduce the bugRun checks

2Edit the fixOpen

3Pass checksOpen

4Submit fixOpen

Reproduction Steps

Run npm test.
Trace commit: notice the lock entry is deleted before the pending writes are applied.
Hold the lock through the entire commit, including the post-commit observation point.
Release the lock only after the data is visible.

Focus Mode

Start

src/transaction.js

Likely area

src/transaction.js

Challenge Coach

Hints reveal broad direction first, then narrow toward the suspect path without showing hidden tests or exact solution code.

TopicReliability

DifficultyEasy

Est. time14 min

Workspacepreparing

Explorer

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Evidence Map

Failing signal loaded from challenge API
Workspace files loaded from workspace API
Results rendered only after API run/submit

Autosaved

workspace

Outputread-onlyready$ prepare workspace

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