Crashed worker never resolves promises

[Julusian]

I have a simple case where if a child terminates, that is never reported back to the application in a way that can be handled.

test-child.ts

import { expose } from 'threads/worker'

expose({
	async doit(): Promise<void> {
		console.log('thread: hello!')
		process.exit(1)
	},
})

run.ts

import { spawn, Thread, Worker } from 'threads'

void (async () => {
	const thread1 = await spawn(new Worker('./test-child'))

	setInterval(() => {
		console.log('master: tick')
	}, 1000)

	Thread.events(thread1).subscribe((event) => console.log('Thread event:', event))

	try {
		console.log('master: before')

		await thread1.doit()
	} catch (e) {
		console.log('master: it errored', e)
	}

	console.log('master: we are done')
	await Thread.terminate(thread1)
})()

Note: the code is written in typescript, but it is being compiled to js before executing, so this shouldnt be something ts-node specific.

The output of this ends up being:

  threads:master:spawn Initializing new thread +0ms
  threads:master:messages Message from worker before finishing initialization: { type: 'init', exposed: { type: 'module', methods: [ 'doit' ] } } +0ms
master: before
  threads:master:messages Sending command to run function to worker: { type: 'run', uid: 1, method: 'doit', args: [] } +0ms
thread: hello!
master: tick
master: tick

If I remove the setInterval, then it instead immediately terminates, so the worker_thread is definitely terminating.

I would expect a line master: it errored to be logged as the call failed, and probably a Thread event: too so that the dead worker can be restarted

[andywer]

Hey @Julusian!

On what platform are you: Browser, node.js, electron? It is almost impossible to have a solution for this issue that reliably works across all of these platforms, but maybe it's good enough for now if we can fix it for your specific use case.

[Julusian]

This is nodejs 14

[andywer]

Let's check if subscribing to workers' exit event does the job…