[Bug]: uncaught async error crashes jest --watch

[benjaminjkraft]

Version

29.5.0

Steps to reproduce

1. Write a test which throws an error after completing.
2. Run jest --watch <test file>.
3. After the error is thrown, Jest crashes rather than reporting it with the usual "error after test finished".

Repro repo here, run npx jest --watchAll and wait 1s.

Expected behavior

I expected Jest to report the failure, but continue in watch-mode.

Actual behavior

Jest crashes and doesn't continue to watch.

Additional context

Seems to only happen when running just one test file, so I'm guessing it has to do with tests that run in-band instead of in a worker?

Environment

System:
  OS: macOS 13.2.1
  CPU: (10) x64 Apple M1 Max
Binaries:
  Node: 16.17.1 - /nix/store/fyaisfdhkviz6sb628qxlmy5wcasqfhq-nodejs-16.17.1/bin/node
  npm: 8.12.1 - ~/.local/bin/npm
npmPackages:
  jest: ^29.5.0 => 29.5.0

[AppSphere]

I am facing a similar issue where the Jest Crashes with an error
Error: Error: spawnSync /bin/sh ENOBUFS
On Local it just works fine. This happens in Github Actions during PR run.

[mrazauskas]

@benjaminjkraft This is expected behaviour. You should look through the Testing Asynchronous Code guide.

The test case in your reproduction throws when the test run is already finished. Jest should crash, because something fatal happened. That test simply should not pass. You should await the promises, mock timers, catch errors inside a test. If something throws outside of any test, this is considered fatal.

[benjaminjkraft]

I understand that I'm supposed to await promises. I nonetheless find this frustrating because it means watch mode is useless if I am debugging why the test is not correctly awaiting its promises! And I find it a bit confusing because if I run multiple tests (and thus, I'm guessing, multiple workers) in watch-mode the test will actually pass (with a warning about open handles). I guess what you are saying means the fact that it doesn't crash in that case is a bug?

[mrazauskas]

Ah.. Looks like I misunderstood the problem, open handles is different case.

I copied you the test case from your repo into larger code base. Jest crashes with --watch, but show the "has failed to exit gracefully" error with --watchAll. You are right, this is because of workers being involved with --watchAll and more test running at once.

This can be solved by tweaking shouldRunInBand() logic in the below lines:

https://github.com/facebook/jest/blob/470d72ee74e50291bf8593954f24eb75b5621351/packages/jest-core/src/testSchedulerHelper.ts#L45-L47

Thanks for more details. I think the behaviour should be more predictable.

[github-actions]

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