Fix asyncWriter data race and send-on-closed-channel panic#345
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The closed flag was read in Write (logging goroutine) and written in Close (shutdown) with no synchronization: a data race, plus a send-on-closed-channel panic (Write passes the closed check, Close closes aw.out, Write then sends). An atomic.Bool fixes the race but not the panic — the check and the send are separate ops on separate objects. Add a sync.Mutex guarding the closed-check and the channel send in Write, and the close in Close, so a Write can never send on an already-closed channel. Reproduced under -race first (data race + panic), green after the mutex. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## main #345 +/- ##
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+ Coverage 66.44% 66.46% +0.02%
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Files 51 51
Lines 8177 8183 +6
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+ Hits 5433 5439 +6
Misses 2369 2369
Partials 375 375 ☔ View full report in Codecov by Harness. 🚀 New features to boost your workflow:
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Summary
The
closedflag was read inWrite(logging goroutine) and written inClose(shutdown) with no synchronization — a data race, plus a
send on closed channelpanic (TOCTOU:Writepasses theclosedcheck,Closeclosesaw.out,Writethen sends).An
atomic.Boolfixes the race but not the panic (check and send areseparate ops on separate objects). Added a
sync.Mutexguarding theclosed-check + channel send inWriteand the close inClose.Test plan
TestAsyncWriter_ConcurrentWriteClosewritten first; under-raceitfailed with both a data-race report and the panic (confirming atomic-alone
is insufficient), then green after the mutex
make test-all+go test -race ./cmd/...greenNo README trigger files touched.
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