Ubuntu: stdout and stderr data is not emitted on child processes (with piped stdio) #42438
Closed as not planned
Description
Version
v18.0.0-nightly20220311d8c4e375f2
Platform
Linux parallels-Parallels-Virtual-Platform 5.13.0-37-generic #42~20.04.1-Ubuntu SMP Tue Mar 15 15:44:28 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux
Subsystem
No response
What steps will reproduce the bug?
Run node main.js having following two files in same folder:
child.js
console.log("Some text");
const interval = setInterval(() => {
console.log("Other text")
}, 100)
setTimeout(() => clearInterval(interval), 1000);main.js
const childProcess = require('child_process');
const child = childProcess.spawn('node', ['child.js'], { stdio: 'pipe'});
if (child.stdout) {
console.log("Attach std listeners")
child.stdout.on('data', data => console.log("Child stdout:", String(data)));
child.stderr.on('data', data => console.log("Child stderr:", String(data)));
}
child.on('close', (...args) => { console.log("Child closed", args); });How often does it reproduce? Is there a required condition?
Always
What is the expected behavior?
Expected output (e.g. observable on macOS) is:
Attach std listeners
Child stdout: Some text
Child stdout: Other text
Child stdout: Other text
Child stdout: Other text
Child stdout: Other text
Child stdout: Other text
Child stdout: Other text
Child stdout: Other text
Child stdout: Other text
Child stdout: Other text
Child closed [ 0, null ]
What do you see instead?
Attach std listeners
CLOSED [ 0, null ]
Additional information
When stdio is set to inherit then the child output is exposed as expected.
I observe it on every Node.js version I've tried (v14, v16, v17, and latest build)