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worker_threads not respecting --require in process.execArgv or process.env.NODE_OPTIONS #37410
Closed as not planned
Description
- Versions:
- v12.20.2
- v14.15.5
- v15.8.0
- Platforms:
- CentOS 7 (
Linux 3.10.0-1127.8.2.el7.x86_64 #1 SMP Tue May 12 16:57:42 UTC 2020 x86_64 GNU/Linux) - Windows 10 (
Microsoft Windows NT 10.0.19041.0 x64)
- CentOS 7 (
- Subsystem: worker_threads
What steps will reproduce the bug?
Mutate either process.env.NODE_OPTIONS or process.execArgv to include a --require flag before spawning a worker thread.
Test script
const { Worker, isMainThread, SHARE_ENV } = require('worker_threads')
const { once } = require('events')
if (module.parent && module.parent.id === 'internal/preload') {
// Preload
delete require.cache[__filename]
console.log('preloaded')
} else if (isMainThread && !process.send) {
// Main
const tests = [
async () => {
console.log('worker process.execArgv')
const orig = process.execArgv
process.execArgv = ['--require', __filename, ...process.execArgv]
const worker = new Worker(__filename)
await once(worker, 'exit')
process.execArgv = orig
},
async () => {
console.log('worker process.env.NO')
const orig = process.env.NODE_OPTIONS
process.env.NODE_OPTIONS = `--require ${__filename} ${process.env.NODE_OPTIONS}`
const worker = new Worker(__filename)
await once(worker, 'exit')
process.env.NODE_OPTIONS = orig
},
async () => {
console.log('worker SHARE_ENV')
const orig = process.env.NODE_OPTIONS
process.env.NODE_OPTIONS = `--require ${__filename} ${process.env.NODE_OPTIONS}`
const worker = new Worker(__filename, { env: SHARE_ENV })
await once(worker, 'exit')
process.env.NODE_OPTIONS = orig
},
]
;(async () => {
for (const f of tests) {
await f()
console.log()
}
})()
}What is the expected behavior?
The --require flag is respected in each case:
worker process.execArgv
preloaded
worker process.env.NO
preloaded
worker SHARE_ENV
preloaded
What do you see instead?
The --require flag is not respected:
worker process.execArgv
worker process.env.NO
worker SHARE_ENV
Additional information
tl;dr: Seems like the default value of env and execArgv options of the Worker constructor is the initial value of process.env and process.execArgv instead of the current value. This behavior is in contrast to child_process.fork.
Full test script
This is the full test script with all the tests I have done (detailed below).
Test script
const { Worker, isMainThread, SHARE_ENV, parentPort } = require('worker_threads')
const { fork } = require('child_process')
const { once } = require('events')
if (module.parent && module.parent.id === 'internal/preload') {
// Preload
delete require.cache[__filename]
console.log('preloaded')
} else if (isMainThread && !process.send) {
// Main
const tests = [
async () => {
console.log('worker control')
const worker = new Worker(__filename)
await once(worker, 'exit')
},
async () => {
console.log('worker process.execArgv')
const orig = process.execArgv
process.execArgv = ['--require', __filename, ...process.execArgv]
const worker = new Worker(__filename)
await once(worker, 'exit')
process.execArgv = orig
},
async () => {
console.log('worker execArgv option')
const worker = new Worker(__filename, { execArgv: ['--require', __filename, ...process.execArgv] })
await once(worker, 'exit')
},
async () => {
console.log('worker process.env.NO')
const orig = process.env.NODE_OPTIONS
process.env.NODE_OPTIONS = `--require ${__filename} ${process.env.NODE_OPTIONS}`
const worker = new Worker(__filename)
await once(worker, 'exit')
process.env.NODE_OPTIONS = orig
},
async () => {
console.log('worker SHARE_ENV')
const orig = process.env.NODE_OPTIONS
process.env.NODE_OPTIONS = `--require ${__filename} ${process.env.NODE_OPTIONS}`
const worker = new Worker(__filename, { env: SHARE_ENV })
await once(worker, 'exit')
process.env.NODE_OPTIONS = orig
},
async () => {
console.log('worker env option')
const worker = new Worker(__filename, { env: { NODE_OPTIONS: `--require ${__filename} ${process.env.NODE_OPTIONS}` } })
await once(worker, 'exit')
},
async () => {
console.log('fork control')
const cp = fork(__filename)
await once(cp, 'exit')
},
async () => {
console.log('fork process.execArgv')
const orig = process.execArgv
process.execArgv = ['--require', __filename, ...process.execArgv]
const cp = fork(__filename)
await once(cp, 'exit')
process.execArgv = orig
},
async () => {
console.log('fork execArgv option')
const cp = fork(__filename, { execArgv: ['--require', __filename, ...process.execArgv] })
await once(cp, 'exit')
},
async () => {
console.log('fork process.env.NO')
const orig = process.env.NODE_OPTIONS
process.env.NODE_OPTIONS = `--require ${__filename} ${process.env.NODE_OPTIONS}`
const cp = fork(__filename)
await once(cp, 'exit')
process.env.NODE_OPTIONS = orig
},
async () => {
console.log('fork env option')
const cp = fork(__filename, { env: { NODE_OPTIONS: `--require ${__filename} ${process.env.NODE_OPTIONS}` } })
await once(cp, 'exit')
},
]
;(async () => {
for (const f of tests) {
await f()
console.log()
}
})()
}Expected output
worker control
worker process.execArgv
preloaded
worker execArgv option
preloaded
worker process.env.NO
preloaded
worker SHARE_ENV
preloaded
worker env option
preloaded
fork control
fork process.execArgv
preloaded
fork execArgv option
preloaded
fork process.env.NO
preloaded
fork env option
preloaded
Actual output
worker control
worker process.execArgv
worker execArgv option
preloaded
worker process.env.NO
worker SHARE_ENV
worker env option
preloaded
fork control
fork process.execArgv
preloaded
fork execArgv option
preloaded
fork process.env.NO
preloaded
fork env option
preloaded
Running node with --require affects worker threads
Modify the test script to use the following test case
async () => {
console.log('worker control')
const worker = new Worker(__filename)
await once(worker, 'exit')
}Then run the script with node --require ./main.js main.js outputs:
preloaded
worker control
preloaded
which shows the --require flag is respected in both the main thread and the worker thread
--require in Worker options is respected
When explicitly passing execArgv or env.NODE_OPTIONS to the Worker constructor options, the --require flag is respected:
async () => {
console.log('worker execArgv option')
const worker = new Worker(__filename, { execArgv: ['--require', __filename, ...process.execArgv] })
await once(worker, 'exit')
},
async () => {
console.log('worker env option')
const worker = new Worker(__filename, { env: { NODE_OPTIONS: `--require ${__filename} ${process.env.NODE_OPTIONS}` } })
await once(worker, 'exit')
},The above logs:
worker execArgv option
preloaded
worker env option
preloaded
child_process.fork respects --require in process.execArgv or process.env.NODE_OPTIONS
const { fork } = require('child_process')
async () => {
console.log('fork process.execArgv')
const orig = process.execArgv
process.execArgv = ['--require', __filename, ...process.execArgv]
const cp = fork(__filename)
await once(cp, 'exit')
process.execArgv = orig
},
async () => {
console.log('fork process.env.NO')
const orig = process.env.NODE_OPTIONS
process.env.NODE_OPTIONS = `--require ${__filename} ${process.env.NODE_OPTIONS}`
const cp = fork(__filename)
await once(cp, 'exit')
process.env.NODE_OPTIONS = orig
},The above logs:
fork process.execArgv
preloaded
fork process.env.NO
preloaded
Activity
aduh95 commentedon Feb 17, 2021
Related? #36531
clemyan commentedon Feb 17, 2021
Not really. As far as I understand the comment thread, #36531 occurs because
--requirepassed to the node process is respected by workers (which is intended and expected). This issue is about how--requireis not respected (by default) by workers if not passed to the node process.In order words:
--requireflag is ...new Workercp.forknode -r ...)process.execArgvorprocess.envWorker/fork#36531 is about the top-left "Respected" cell. This issue is about the "Not respected" cell.
aduh95 commentedon Feb 17, 2021
//cc @nodejs/workers
clemyan commentedon Feb 18, 2021
A little more investigation.
The discrepancy between
Workervscp.forkis probably because the default values ofexecArgvandenvare resolved in JS forcp.fork(here and here) while they are resolved in C++ forWorker(here and here).github-actions commentedon Jun 27, 2026
This issue has been marked as stale due to 210 days of inactivity.
It will be automatically closed in 30 days if no further activity occurs. If this is still relevant, please leave a comment or update it to keep it open.
github-actions commentedon Jul 28, 2026
This issue has been automatically closed after 30 days of inactivity following its stale status (no activity for a total of 120 days).
If this is still relevant, feel free to reopen it or leave a comment with additional details so we can continue the discussion.