Cannot be used in Worker threads (Node 10.x)

[RomainMuller]

The module cannot be loaded within a Worker thread, as process.chdir is not available (undefined) in there. The following line causes a TypeError: Object prototype may only be an Object or null: undefined:

node-graceful-fs/polyfills.js

Line 22 in feedd03

if (Object.setPrototypeOf) Object.setPrototypeOf(process.chdir, chdir)

I reckon the solution would be to have graceful-fs also not provide chdir in this scenario.

[vijayshukla30]

When you going to release this fix getting error not able to even start the application.

[coreyfarrell]

What version of node.js does this effect? In my tests typeof process.chdir === 'function' from a worker thread.

[RomainMuller]

At least in node 10, as per https://nodejs.org/docs/latest-v10.x/api/process.html#process_process_chdir_directory:

This feature is not available in Worker threads.

Although the same note still stands on the latest release, although it appears to be defined there:

/// worker-demo.js

const { Worker, isMainThread, parentPort } = require('worker_threads');

if (isMainThread) {
  const worker = new Worker(__filename);
  worker.on('message', ({ chdir }) => console.error(`(${process.version}) process.chdir is a ${chdir}`))
} else {
  parentPort.postMessage({ chdir: typeof process.chdir });
}

$ /usr/local/opt/node@10/bin/node --experimental-worker worker-demo.js
(v10.23.2) process.chdir is a undefined

$ /usr/local/opt/node@12/bin/node --experimental-worker worker-demo.js
(v12.20.1) process.chdir is a function

[mf-corey]

Thanks for the quick fix on this issue. I encountered it as well, it was preventing my Electron app from starting in node 10.20.1. The fix merged in this PR is the correct strategy, but I had luck launching my app with this small stop-gap that swallows the error... Use at your own risk.

var originalSetPrototypeOf = Object.setPrototypeOf;
Object.setPrototypeOf = function(a, b) {
  try {
    return originalSetPrototypeOf.apply(null, arguments);
  } catch (_error) {
    return console.error(_error);
  }
};