Worker exits with code 0 (and not 7) when throwing inside uncaughtException #37996

This is the underlying bug that kept my workaround of #37988 from working.

• Version: v15.12.0
• Platform: Linux alex-desktop 5.8.0-48-generic npm install is unbelievably slow, fails in certain environments #54~20.04.1-Ubuntu SMP Sat Mar 20 13:40:25 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux

What steps will reproduce the bug?

index.js

const path = require('path');
const { Worker } = require('worker_threads');
const worker = new Worker(path.join(__dirname, 'worker.js'));

worker
  .on('online', () => {
    console.log('online');
  })
  .on('error', (err) => {
    console.log('error: %s', err);
  })
  .on('exit', (code) => {
    console.log('exit: %s', code);
    process.exit();
  });

worker.js

process.on('uncaughtException', function () {
  throw new Error('uncaughtException');
});

throw new Error('oopsie');

node index.js

online
error: Error: uncaughtException
    at process.<anonymous> (/home/alex/src/issues/worker-exit-code/worker.js:2:9)
    at process.emit (events.js:315:20)
    at internal/process/execution.js:163:25
    at process.workerOnGlobalUncaughtException [as _fatalException] (internal/main/worker_thread.js:194:15)

exit: 0    <================

node worker.js
echo $?
7           <================

How often does it reproduce? Is there a required condition?

10/10 would reproduce again

What is the expected behavior?

Exit code 7 for the worker

Exit code >0 for the worker. Exit codes of workers don't seem to be aligned with the main process, I'm fine with anything other than 0.

What do you see instead?

Exit code 0, which is why my error handling didn't catch it