Reject writes after StandardInputWriter finishes with a clear error#311
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iCharlesHu merged 1 commit intoJun 12, 2026
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Retaining the StandardInputWriter beyond the run body closure no longer hangs, but using the writer after that point failed with a cryptic 'Bad file descriptor', and nothing flagged the misuse. Track whether the writer has finished and throw a descriptive SubprocessError on a subsequent write, instead of writing to a closed and possibly recycled file descriptor. finish() is now explicitly idempotent. Document the writer's lifetime contract on StandardInputWriter and Execution.standardInputWriter: it is valid only within the body closure, run calls finish() automatically when the body returns, and awaiting the child's full output without finishing first can deadlock.
jakepetroules
approved these changes
Jun 11, 2026
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Retaining the
StandardInputWriterbeyond the run body closure no longer hangs, but using the writer after that point failed with a cryptic 'Bad file descriptor', and nothing flagged the misuse. Track whether the writer has finished and throw a descriptiveSubprocessErroron a subsequent write, instead of writing to a closed and possibly recycled file descriptor.finish()is now explicitly idempotent.Document the writer's lifetime contract on
StandardInputWriterandExecution.standardInputWriter: it is valid only within the body closure, run calls finish() automatically when the body returns, and awaiting the child's full output without finishing first can deadlock.Resolves: #186