worker: `messageerror` listeners remain during `exit`
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Description
Version
v24.14.1
The typo is also present in the v26.8.1 source and
in the current main branch.
Platform
Microsoft Windows NT 10.0.26200.0 x64
Subsystem
worker_threads
What steps will reproduce the bug?
Run the following without any third-party dependencies:
const { Worker } = require('node:worker_threads');
const worker = new Worker('', { eval: true });
const listener = () => {};
worker.on('message', listener);
worker.on('messageerror', listener);
worker.on('exit', () => {
console.log({
message: worker.listenerCount('message'),
messageerror: worker.listenerCount('messageerror'),
});
});
How often does it reproduce? Is there a required condition?
It reproduces every time on v24.14.1 and on the current main branch at
7177c14789a7376866dfe6c04f5cd4da489cfbe6. It occurs both when a worker exits
normally and when it is stopped with worker.terminate().
What is the expected behavior? Why is that the expected behavior?
Both messaging listener counts should be zero while the exit listener is
running:
{ message: 0, messageerror: 0 }
The worker exit cleanup explicitly removes the message listeners before
emitting exit and appears intended to do the same for messageerror.
What do you see instead?
The message listener is removed, but the messageerror listener is still
present:
{ message: 0, messageerror: 1 }
Additional information
The targeted cleanup currently calls
removeAllListeners('messageerrors'), but the event name is messageerror:
The typo was introduced in commit 5968c5423530aeaa10c02eae3e8423c6514cdd1a:
https://github.com/nodejs/node/commit/5968c5423530aeaa10c02eae3e8423c6514cdd1a
There is a later generic removeAllListeners() call after the exit event is
emitted, so this report does not claim a persistent listener leak. The observed
problem is that the targeted pre-exit cleanup does not remove messageerror
listeners as intended.
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start in lib/internal/worker.js around the exit cleanup at lines 395-396 and compare the event name used for message listeners with the messageerror event name. Re-run the reproduction from the issue and confirm that both listener counts are zero while the exit listener runs.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- javascript
- Domain
- backend
- Issue type
- Bug
- Difficulty
- 1/5
- Estimated time
- Under an hour
- Activity status
- Active
- Clarity
- Clearly specified
- Newbie friendliness
- 90/100