feat(jest-message-util): add support for error causes

[brodo]

Summary

Adds support for error causes.

This fixes #12999

Example output:

● Test suite failed to run
    
        Test exception
    
          at Object.<anonymous> (packages/jest-message-util/src/__tests__/messages.test.ts:419:5)
    
        Cause:
         Cause Error
    
              at Object.<anonymous> (packages/jest-message-util/src/__tests__/messages.test.ts:419:41)

      at Object.log (packages/jest-message-util/src/__tests__/messages.test.ts:428:11)

I'm sure this can be made prettier, but as a minimal implementation I think it is good enough.

Test plan

I've added a single unit test that checks if the cause is contained in the generated message. Otherwise I just looked at the output manually.

[brodo]

@mrazauskas Thanks for the quick review. I did all the changes and added the snapshot file. I also added a link to the Node changelog to where this feature was introduced. (It was indeed 16.9.0).

[SimenB]

sweet, thanks!

[brodo]

I implemented all the changes @SimenB requested.

BTW: I don't know if keeping this all in one commit is the best way to do it. I assumed it's the best, so it's only one commit when it's merged but I don't know if it's a good idea for the review process. Would it be better to have several commits for the review process and then squash them before they are merged?

[SimenB]

We squash on merge anyways, so multiple commits are easier for review. The diff in this PR is quite small though, so no big issue 🙂

[GerkinDev]

Hey, thank you very much for this ! GG

[dubzzz]

I might be wrong but it seems that jest-circus already pre-processes the error, leading to this code not to be executed for something like:

function g() {
  throw new Error("boom");
}
function f() {
  try {
    g();
  } catch (err) {
    throw new Error("plouf", { cause: err });
  }
}
it("works", () => {
  f();
});

Do I miss something to properly use cause?

EDIT: I re-read the code, it's written "ExecError is an error thrown outside of the test suite (not inside an it or before/after each hooks). If it's thrown, none of the tests in the file are executed.", so not impacting it or test is expected. And it works well when f() runs outside of the it.

[SimenB]

we should work with causes inside functions as well. Wanna send a PR? 😀

[dubzzz]

Wanna send a PR?

Currently trying to check how to do. As errors are extracted from a string in jest-message-util (see formatResultsErrors which uses result.failureMessages, a string version). 😂

Seems that we rebuild an error out of this text version via separateMessageFromStack.

[SimenB]

IIRC it's https://github.com/facebook/jest/blob/6d2632adae0f0fa1fe116d3b475fd9783d0de1b5/packages/jest-circus/src/utils.ts#L438-L439

[dubzzz]

By the way, I do have a working version of it locally I switched from result.failureMessage to result.failureDetails, but I'll need to replug checkForCommonEnvironmentErrors

[dubzzz]

By the way, switching to the raw Error object instead of its string versions should drop errors I got reported many times in fast-check that might be related to separateMessageFromStack not able to re-extract the stack and message from some complex and nested ones.

[dubzzz]

@SimenB Here my drafty work dubzzz@887c2b6. I'll rework on it as many things sucks in it. Details being unknown, cause too, I'll need to put something cleaner and safer probably fall-backing onto the original stringified version of the error.

[dubzzz]

PR opened to add the support for it and test, see #13935

[github-actions]

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