console.log doens't work when there is an infinite loop after it.

[searene]

Describe the bug

I noticed that console.log doesn't print anything when there's an infinite loop after it. Here is the test:

import { describe, it, expect} from 'vitest';

describe('add', () => {
  it ('1 + 1', () => {
    console.log("abc");
    while (true) {

    }
    expect(1 + 1).toBe(2);
  })
})

Here is the output after running yarn run vitest in the terminal

yarn run v1.22.18
$ /Users/joey/WebstormProjects/vitest-ext-basic-example/node_modules/.bin/vitest

 DEV  v0.12.10 /Users/joey/WebstormProjects/vitest-ext-basic-example

 · add.test.ts (1)

As you can see, abc isn't pointed out.

It should print something because sometimes we write infinite loop by accident, and we want to know where the error is. console.log gives a way to inspect the reason.

Reproduction

https://stackblitz.com/edit/vitest-dev-vitest-mrqmmn?file=test%2Fbasic.test.ts

System Info

System:
    OS: macOS 12.4
    CPU: (8) x64 Intel(R) Core(TM) i7-4770HQ CPU @ 2.20GHz
    Memory: 563.12 MB / 16.00 GB
    Shell: 5.8.1 - /bin/zsh
  Binaries:
    Node: 18.2.0 - ~/.nvm/versions/node/v18.2.0/bin/node
    Yarn: 1.22.18 - /usr/local/bin/yarn
    npm: 8.9.0 - ~/.nvm/versions/node/v18.2.0/bin/npm
  Browsers:
    Chrome: 101.0.4951.64
    Safari: 15.5
  npmPackages:
    vite: ^2.9.9 => 2.9.9 
    vitest: ^0.12.6 => 0.12.10

Used Package Manager

yarn

Validations

• [X] Follow our Code of Conduct
• [X] Read the Contributing Guidelines.
• [X] Read the docs.
• [X] Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• [X] Check that this is a concrete bug. For Q&A open a GitHub Discussion or join our Discord Chat Server.
• [X] The provided reproduction is a minimal reproducible example of the bug.

[sheremet-va]

Yes, this is because logging is delegated to the main process on the last tick of the event loop, but infinite loop prevents us from reaching it.

[ilovedesert001]

Yes, this is because logging is delegated to the main process on the last tick of the event loop, but infinite loop prevents us from reaching it.

is there any way to disable this process when debugging ?

[sheremet-va]

is there any way to disable this process when debugging ?

No

[emersonthis]

Even if the logging output isn't available, it seems like the infinite looping should be constrained by the timeout value. So the expected behavior would be that the loop runs for as long as the timeout value allows and then fails. Does this make sense? Would this be something easier to implement?

[sheremet-va]

is there any way to disable this process when debugging ?

We can probably add an option to not intercept console.log here:

https://github.com/vitest-dev/vitest/blob/393bf60cde7df1aaeff73486eea58edb1663dd6a/packages/vitest/src/runtime/setup.node.ts#L51

[hi-ogawa]

is there any way to disable this process when debugging ?

I think you can patch globalThis.console back to direct stdout writing like this:

https://stackblitz.com/edit/vitest-dev-vitest-aff1ys?file=repro.test.ts

import { it, beforeAll } from 'vitest';

beforeAll(async () => {
  const { Console } = await import("node:console");
  globalThis.console = new Console(process.stdout, process.stderr);
});

it ('repro', () => {
  console.log("@@ before-loop");
  let i = 0;
  while (true) {
    console.log("@@ inside-loop", i++);
  }
})

One caveat is that --pool=threads seems to have a problem with flushing output in obvious infinite-loop like above, so it can print only "before-loop" part of logs. I tested with --pool=forks and it can print "inside-loop" logs.

(On stackblitz, the terminal gets stuck sometimes, so I also tested locally on my PC and the behavior regarding --pool seems to be same).