core/bazel: fix race#135
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There's a race in `streamOutput` and `streamAndParseTargets` where the stderr buffer was being read / written concurrently. When the context gets cancelled and bails, it's trying to read the buffer while it's still being written to by the other goroutine. The streaming goroutine should block until the other goroutine exits, so that it doesn't attempt to read the byte buffer concurrently. Fixes #134.
yushan8
approved these changes
Jun 30, 2026
sbalabanov
requested changes
Jun 30, 2026
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this blocks on copying goroutine, in which case it does not make any sense to have a goroutine at all but rather block on a main thread.
what we need to have instead is a cancellable Copy, or at least a cancellable io.Reader.
This wrapper is better than nothing on pure blocking reads: https://github.com/uber/tango/pull/108/changes#diff-279a703791b2ff1b50139ea545c8aca00928b154a414330229e4891ec895aaf2
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the main thread is already blocked before we call errgroup.Wait() because we're calling cmd.Wait().
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Fix a race during Bazel query cancellation by replacing concurrent pipe readers with file-backed stdout/stderr capture.
This avoids buffer races and inherited-pipe hangs while preserving live stderr, context cancellation, SIGTERM/SIGKILL escalation, and context-aware parsing.
Added regression coverage for cancellation and descendant processes holding output descriptors.