Node.js 15.9 regression with Jest ESM

[ai]

After upgrading Node.js 15.8 → 15.9 Jest stopped supporting ESM.

• Version: 15.9
• Platform: Linux foxbat 5.10.15-200.fc33.x86_64 #1 SMP Wed Feb 10 17:46:55 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux

What steps will reproduce the bug?

echo '{ "private": true, "type": "module" }' > package.json
yarn add nanoevents
echo "import { createNanoEvents } from 'nanoevents'" > index.js
echo "import './index.js'; it.todo('test')" > index.test.js
yarn add jest@next

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

Always

What is the expected behavior?

volta install node@15.8
node --experimental-vm-modules node_modules/.bin/jest

(node:60479) ExperimentalWarning: VM Modules is an experimental feature. This feature could change at any time
(Use `node --trace-warnings ...` to show where the warning was created)
 PASS  ./index.test.js
  ✎ todo test

Test Suites: 1 passed, 1 total
Tests:       1 todo, 1 total
Snapshots:   0 total
Time:        0.173 s
Ran all test suites.

What do you see instead?

volta install node@15.9
node --experimental-vm-modules node_modules/.bin/jest

(node:60418) ExperimentalWarning: VM Modules is an experimental feature. This feature could change at any time
(Use `node --trace-warnings ...` to show where the warning was created)
 FAIL  ./index.test.js
  ● Test suite failed to run

    linking error, dependency promises must be resolved on instantiate

Additional information

[targos]

/cc @devsnek

Could it be that #37300 did have an effect on the public API after all?

[SimenB]

I assume this is a bug in Jest's implementation which is surfaced by some added check. I'm happy to fix that if I could get some pointers to what might be wrong to cause such a warning

[Trott]

Could it be that #37300 did have an effect on the public API after all?

I did a git bisect on this issue and it is indeed that commit where the problem was introduced.

521c08d

[Trott]

Somewhat related: Maybe let's see if we can land nodejs/citgm#728 to close nodejs/citgm#684?

[SimenB]

Jest's tests are not failing on 15.9, so it wouldn't have caught this particular error.

But yes, should definitely try to land it in CITGM regardless 👍

[ai]

15.11 still has an issue

[SimenB]

I still think it's more likely to be a bug in Jest's implementation than anything, but I'm not sure where. I've had next to no time for OSS in the last few months unfortunately, so haven't found the time to dig into this

[akauppi]

Getting similar errors: linking error, not in local cache. akauppi/firebase-jest-testing#5

Likely the same reason. On node 15.10.0 (macOS + Homebrew).

Nice to see people are on this. Let me know if further (testing) assistance is appreciated.

[devsnek]

i've never used jest before. how do i make it print a proper stack trace instead of just the error message?

[ai]

@devsnek Node.js errors about ESM linking have no stack trace right now.

Jest prints stack trace if an error has it.

[devsnek]

@ai ...yes they do

[ai]

Sorry. My fault, I just found that I saw only ESM errors in Jest :(

[devsnek]

Found the issue. Pretty cool race condition. Also reproduces without 521c08d.

Minimal repro:

const { SourceTextModule, SyntheticModule } = require('vm');

const tm = new SourceTextModule('import "a"');

tm
  .link(async () => {
    const tm2 = new SourceTextModule('import "b"');
    tm2.link(async () => {
      const sm = new SyntheticModule([], () => {});
      await sm.link(() => {});
      await sm.evaluate();
      return sm;
    }).then(() => tm2.evaluate());
    return tm2;
  })
  .then(() => tm.evaluate())
  .then(() => {
    console.log('dun');
  })
  .catch((e) => {
    console.error(e);
  });

Working on a fix....

@SimenB a good short-term fix is to only call link at the top level import, and let it automatically call the linker cb on the dependencies (and same with evaluate, you don't need to call it on each module)