Error when: node v20, --test --loader, await import

[iambumblehead]

Version

v20.0.0

Platform

Darwin Bumbles-MBP.home 21.6.0 Darwin Kernel Version 21.6.0: Thu Mar 9 20:08:59 PST 2023; root:xnu-8020.240.18.700.8~1/RELEASE_X86_64 x86_64

What steps will reproduce the bug?

• clone this repo or download this package
• run npm test from the cloned or unpacked package
• see the error

Essentially, using --loader and await import('./path/to/module.js') from inside any imported module causes the test to fail for no reason related to the test or any of the files used.

A copy of the error seen in the test process is attached here

testnode$ npm test    

> test
> node --experimental-loader=./anyloader.js --test

ℹ (node:55506) ExperimentalWarning: Custom ESM Loaders is an experimental feature and might change at any time
ℹ (Use `node --trace-warnings ...` to show where the warning was created)
✖ should not show promise resolution error (3.975453ms)
  Error: Promise resolution is still pending but the event loop has already resolved
      at process.emit (node:events:523:35)

ℹ tests 1
ℹ suites 0
ℹ pass 0
ℹ fail 0
ℹ cancelled 1
ℹ skipped 0
ℹ todo 0
ℹ duration_ms 8.432653
ℹ THIS CONSOLE LOG IS PREINTED
ℹ tests 1
ℹ suites 0
ℹ pass 0
ℹ fail 0
ℹ cancelled 1
ℹ skipped 0
ℹ todo 0
ℹ duration_ms 150.112342

✖ failing tests:

✖ should not show promise resolution error (3.975453ms)
  Error: Promise resolution is still pending but the event loop has already resolved
      at process.emit (node:events:523:35)

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

The issue is reproduced every time on this machine, using the package attached above

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

The test in the attached package should pass without any error, following the behaviour of previous versions of node from v12 onward.

What do you see instead?

Error: Promise resolution is still pending but the event loop has already resolved

In the example failing test, the test process reaches the passing condition but the test fails regardless

[panva]

I've experienced the same problem in one my projects which uses ava test runner. Great job with a no-dependency reproduction.

Not sure if test_runner Issues and PRs related to the test runner subsystem. or loaders Issues and PRs related to ES module loaders . Better ping both.

cc @nodejs/loaders, @nodejs/test_runner

[aduh95]

I suspect this is a duplicate of #47566.

[GeoffreyBooth]

Can you please test now against latest main or nightly?

[aladdin-add]

@GeoffreyBooth I have tried the nightly, and it's still failing: https://github.com/iambumblehead/esmock/actions/runs/4804121738/jobs/8549299803?pr=199

[aduh95]

It seems to be the same thing as nodejs/help#3902 (comment)

[MoLow]

I have performed some testing, and it seems like the real issue is the combination of --test --loader, and --require.
on my machine this only reproduces inside vscode where NODE_OPTIONS is set to --require the bootloader file from https://github.com/microsoft/vscode-js-debug/blob/main/src/targets/node/bootloader.ts

@iambumblehead can you please compare your repro when running through vscode and through an external cli interface?

[MoLow]

see this repro for example:
27e08d4

[iambumblehead]

@MoLow politely, neither --require nor vscode were used to repro the issue reported here

[MoLow]

@nodejs/loaders I have checked the repro provided by @iambumblehead, and the root cause is process.on('beforeExit' is called multiple times (node:test uses beforeExit to cancel all ongoing tests),

see this repro

// file.js
process.on('beforeExit', () => {
  console.log('beforeExit')
})
import('./anyfile.js')
console.log('THIS CONSOLE LOG IS PREINTED')

./node  file.js                                                                                              ✔
THIS CONSOLE LOG IS PREINTED
beforeExit

./node --experimental-loader="data:text/javascript,export default true"  file.js                             ✔
(node:62415) 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)
THIS CONSOLE LOG IS PREINTED
beforeExit
beforeExit
beforeExit

[koshic]

Shorter example (20.1.0, macOS):

test.mjs

import { test } from "node:test";

import "fs"; // any other module

test("test", async (t) => {
  await import("data:text/javascript,");
});

node --experimental-loader 'data:text/javascript,' test.mjs

[MoLow]

I have verified - this has been fixed via #47964