Customization hooks / ESM loaders reports importing JSON warning on commonjs modules

[hyrious]

Version

v22.1.0

Platform

Darwin MAGIT00999.local 23.5.0 Darwin Kernel Version 23.5.0: Wed May 1 20:09:52 PDT 2024; root:xnu-10063.121.3~5/RELEASE_X86_64 x86_64

Subsystem

No response

What steps will reproduce the bug?

Prepare the 3 files:

// register.mjs
import { register } from 'module'
import { readFile } from 'fs/promises'

export async function load(url, context, nextLoad) {
  const result = await nextLoad(url, context)
  if (result.format === 'commonjs') {
    // https://nodejs.org/api/module.html#:~:text=result.source%20%3F%3F%3D%20await%20readFile(new%20URL(result.responseURL%20%3F%3F%20url))%3B
    result.source ??= await readFile(new URL(result.responseURL ?? url))
  }
  return result
}

register('./register.mjs?' + Date.now(), import.meta.url)

// test.js
require('./package.json')

// package.json
{}

Then execute:

> node --import ./register.mjs test.js
(node:5296) ExperimentalWarning: Importing JSON modules is an experimental feature and might change at any time
(Use `node --trace-warnings ...` to show where the warning was created)

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

It happens only with:

result.source ??= await readFile(new URL(result.responseURL ?? url));

If it does not handle commonjs files like this, it won't happen.

What is the expected behavior? Why is that the expected behavior?

require(json_file) in commonjs modules should not emit this warning.

What do you see instead?

It emits warning

(node:5296) ExperimentalWarning: Importing JSON modules is an experimental feature and might change at any time

Additional information

No response

[benjamingr]

@nodejs/loaders @joyeecheung

[joyeecheung]

Likely a regression from #47999

[github-actions]

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.

[joyeecheung]

This no longer reproduce on main. On the other hand, module.register has been deprecated anyway.