Fix race condition in statsd external_env initialization#352
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StephenWakely merged 1 commit intoDataDog:masterfrom Jan 30, 2026
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Add sync.RWMutex to protect the externalEnv package variable from concurrent access when multiple goroutines call statsd.New() simultaneously. Uses RWMutex (not sync.Once) to allow re-initialization if the DD_EXTERNAL_ENV environment variable changes between client creations in the same process. Fixes data race detected in parallel tests at external_env.go:19
vickenty
approved these changes
Jan 30, 2026
StephenWakely
approved these changes
Jan 30, 2026
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This was referenced Feb 2, 2026
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A number of tests in one of our repos initiate a statsd client and we're consistently hitting data race failures while running unit tests with the race detector enabled.
This PR fixes the data race in external_env.go where externalEnv is accessed without synchronization during concurrent client creation.
The fix uses sync.RWMutex to protect reads and writes, allowing re-initialization across different environments in the same process while preventing races.
There are no API changes and a minimal performance impact on hot path (RLock for reads).
I tested with go test -race across parallel test suites in our repo and things look good.