[Windows] process.stdin.unref doesn't work

• Version: v10.10.0
• Platform: Windows x64

parent.js

require('child_process').spawn('node', ['child.js'], {
  stdio: 'inherit',
});

child.js

const doNothing = () => {};
process.stdin.on('data', doNothing);

require('child_process').spawn('node', ['-v']).on('exit', () => {
  process.stdin.unref();
  console.log('After printing this, the process should exit');
});

Run with node parent.js

Results

Linux: The process terminates by itself
Mac: The process terminates by itself
Windows: The process keeps running until Enter is pressed

This strange behavior seems to break some npm modules.

Other details

Adding process.stdin.removeListener('data', doNothing)
or process.stdin.removeAllListeners('data')
before unref doesn't make any difference.

When enter is pressed, it doesn't trigger data callback, just terminates the process.

---

Edit

Simplified code:

// parent.js
process.stdin.on('data', () => {});
setTimeout(() => {
  process.stdin.unref();
  console.log('After printing this, the process should exit');
});

Here we don't have a child process. Run with node parent.js

Results on windows

50% of times - the process exits
50% of times - the process keeps running

[lovinglyy]

The simplified code is always working fine for me, the first one I can reproduce that it's needed to press enter on Windows. Node v10.10.0 also.

[bzoz]

Can reproduce with v10, does not reproduce with v8.

[bzoz]

This is caused by #21528

/cc @addaleax

[addaleax]

That most likely means that the streams implementation for Windows does not clean up fully when uv_close() is used without an extra uv_read_stop() that precedes it.

We can revert #21528 without any issues, but the real issue is almost certainly a libuv one.

[bzoz]

Ok, its a libuv bug. I have a fix, I will open a PR with a fix soon.

[bzoz]

Fix in libuv/libuv#2005

[cjihrig]

Reopening until the next libuv update.