Repository navigation
the child process created by child_process.fork can't receive message correctly when using ES module #39140
Description
- Version: v16.4.0、v14.17.1
- Platform: Windows 10 x64
- Subsystem: child_process
What steps will reproduce the bug?
when using ES module and child_process to fork child process, even 'spawn' event has happend，child process failed receive message from parent process.
Complete Testcase
package.json:
{
"type": "module"
}master.js
import { join } from 'path'
import { fork } from 'child_process'
import { fileURLToPath } from 'url'
const __dirname = join(
fileURLToPath(import.meta.url),
'../'
)
const worker = fork(
join(__dirname, './worker.js')
);
worker.on('spawn', () => {
console.log('start success');
worker.send('hello', () => console.log('send success'));
});worker.js
console.log('child process has started, processID:', process.pid);
process.on('message', (msg) => {
console.log('child process get msg:', msg);
});console ouput:
start success
send success
child process has started, processID: 6224
if i delay 1s send message to child process, it works:
worker.on('spawn', () => {
console.log('start success');
setTimeout(() => {
worker.send('hello', () => console.log('send success'));
}, 1000);
});console output:
start success
child process has started, processID: 18156
send success
child process get msg: hello
What is the expected behavior?
the expected behavior just like this:
start success
send success
child process has started, processID: 16428
child process get msg: hello
when i rename worker.js to worker.cjs, got expected result.
Possible cause
I suspect this may have something to do with ESM asynchronous execution.
Activity
Linkgoron commentedon Jun 28, 2021
I think that this is a duplicate of #37782
tl;dr, yes this is an issue with how loading is now async, and the message is emitted too early before having an option to register
huseyinacacak-janea commentedon Nov 14, 2024
Hi @xiefenga, I wanted to look into this issue but wasn't able to reproduce it (I tried Node.js v18.20.4, v20.18.0, v22.10.0, and v23.1.0).
Do you think this issue can be closed now?
xiefenga commentedon Nov 14, 2024
maybe it has been fixed in new version
xiefenga commentedon Nov 14, 2024
but i can't judge whethor can close this issue or not
xiefenga commentedon Nov 14, 2024
i tried in v20.15.0, it worked as expected, i think this issue can be closed