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fix: data races in progress bar counters and stat maps - #881
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- progressbar: IncrementCompletedObjects and IncrementTotalObjects used atomic.AddInt64 to write the counters but read them back with plain loads in fmt.Sprintf. Concurrent workers raced on the read. Use the value returned by AddInt64 and atomic.LoadInt64 for the other counter. - log/stat: Statistics() iterated the internal maps without holding their mutexes, racing with Collect() from worker goroutines and risking a "concurrent map iteration and map write" fatal error. Hold both locks for the duration of the read. - log: Close() closed the shared output channel unconditionally, so a second call panicked with "close of closed channel". Guard it with a sync.Once on the Logger so it is safe to call multiple times. Adds a test for each: `go test -race` fails all three without the fix and passes with it. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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Context
Three data races / re-entrancy bugs, each reproducible under
go test -race.Root cause and fix
progressbar:IncrementCompletedObjects()/IncrementTotalObjects()updated one counter atomically but read both with plain field access infmt.Sprintf. Now uses theatomic.AddInt64return value plusatomic.LoadInt64for the other counter.log/stat:Statistics()iterated the stat maps without holding their locks while workers were still callingCollect(). Now lockstotalCountthensuccCount(the only place both are held;add()holds one at a time, so no inverse ordering exists).log:Close()closedoutputChunconditionally, so a second call panicked with "close of closed channel". Guarded with async.Onceon theLogger.Tests
TestCommandProgress_ConcurrentIncrement,TestStatisticsConcurrentCollect,TestCloseMultipleTimes(plusTestStatisticsCollect/TestStatisticsDisabledfor the changed function). With the fixes reverted,-racereportsWARNING: DATA RACEatprogressbar.go:69andstat.go:46/102, and the log test panics.Linux, Go 1.24,
go test -count=1 -race ./...: all packagesok.gofmt,go vet,staticcheck,unparam,semgrep: clean.🤖 Generated with Claude Code