[Node 20] ESM Loaders no longer have `process.argv` access
Nobody has claimed this yet.
- Dominant language
- JavaScript
- Stars
- 122k
- Forks
- 37.3k
- Avg merge
- 4d 2h
- Merged PRs (30d)
- 283
Description
Version
20.x
Platform
Darwin MacBook-Pro-2.local 21.3.0 Darwin Kernel Version 21.3.0: Wed Jan 5 21:37:58 PST 2022; root:xnu-8019.80.24~20/RELEASE_ARM64_T6000 arm64
Subsystem
No response
What steps will reproduce the bug?
// foo.mjs
console.log('argv:', process.argv);
// bar.mjs
console.log('hello from bar', process.version);
Run:
$ node --loader ./foo.mjs bar.mjs --hello=world
Output:
$ node --loader ./foo.mjs bar.mjs --hello=world
# (node:37260) ExperimentalWarning: Custom ESM Loaders is an experimental feature. This feature could change at any time
# (Use `node --trace-warnings ...` to show where the warning was created)
# argv: [
# '/.../.volta/tools/image/node/18.12.1/bin/node',
# '/.../bar.mjs',
# '--hello=world'
# ]
# hello from bar v18.12.1
$ volta install node@20.2.0 # or any 20.x
$ node --loader ./foo.mjs bar.mjs --hello=world
# (node:37288) ExperimentalWarning: Custom ESM Loaders is an experimental feature and might change at any time
# (Use `node --trace-warnings ...` to show where the warning was created)
# argv: [ '/.../.volta/tools/image/node/20.2.0/bin/node' ]
# hello from bar v20.2.0
How often does it reproduce? Is there a required condition?
Every time.
What is the expected behavior? Why is that the expected behavior?
Have access to process.argv
What do you see instead?
Doesn't receive any arguments beyond node path
Additional information
This is a breaking change introduced by #44710 & it was not listed in the PR notes.
Additionally, this breaking change wasn't listed in the 20.x Changelog
As indicated by https://github.com/nodejs/node/pull/44710#issuecomment-1609957745, the knowledge of this impact is assumed based on the user understanding (& awareness) of loaders now being off main thread.
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 by reproducing the Node 18.x and 20.x commands shown in the issue with foo.mjs and bar.mjs. Read the linked #44710 discussion and the Custom ESM Loader Hooks section of doc/changelogs/CHANGELOG_V20.md to understand the intended behavior. Done means resolving the process.argv regression or documenting the confirmed breaking change in the appropriate release notes.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- javascript, node.js
- Domain
- backend
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Active
- Clarity
- Mostly clear
- Newbie friendliness
- 45/100