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1 Commits

Author SHA1 Message Date
robobun
d3ff6a5e35 Fix process.stdin not receiving data after pause/resume (#23362)
## Summary

Fixed a race condition where calling `pause()` followed by `resume()` on
`process.stdin` would prevent data from being received, causing the
process to exit immediately instead of listening for input.

## Root Cause

The issue was in the pause/resume event handling logic in
`ProcessObjectInternals.ts`:

1. When `pause()` is called, the "pause" event handler schedules a
`disown()` call for the next tick
2. When `resume()` is called immediately after, it calls `own()` to
acquire a stream reader
3. On the next tick, the scheduled `disown()` from step 1 executes and
incorrectly releases the reader that was just acquired in step 2

This race condition left the stream without a reader, so no data could
be received.

## Solution

Added a `pendingDisown` flag that:
- Gets set to `true` when scheduling a disown operation
- Gets cleared to `false` when `own()` is called (during resume)
- Prevents the scheduled disown from executing if it has been cancelled
by a subsequent `own()` call

## Test Plan

- [x] Added regression tests in
`test/regression/issue/stdin-pause-resume.test.ts`
- [x] Verified fix with original reproduction case
- [x] Existing stdin/tty tests still pass
(`tty-readstream-ref-unref.test.ts`,
`tty-reopen-after-stdin-eof.test.ts`)

## Reproduction

Before this fix, the following code would exit immediately:
```ts
process.stdin.on("data", chunk => {
  process.stdout.write(chunk);
});
process.stdin.pause();
process.stdin.resume();
```

After the fix, it correctly waits for and processes input.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude <noreply@anthropic.com>
2025-10-07 22:04:40 -07:00