vitest hangs with stubbed process

[tkalmar]

Describe the bug

Vitest hangs ( npx vitest run) if a test stubs the global process.
After updating vitest from 0.34 to 1.4.0
The culprit is the stubbed process, if removed everything works as expected.

Reproduction

vi.stubGlobal('process', { server: false, client: true });

describe('reproducer', () => {
  it('should not hang', () => {
    expect(undefined).toBeUndefined();
  });
});

System Info

System:
    OS: Linux 5.15 Ubuntu 22.04.4 LTS 22.04.4 LTS (Jammy Jellyfish)
    CPU: (16) x64 11th Gen Intel(R) Core(TM) i7-11850H @ 2.50GHz
    Memory: 106.68 GB / 125.50 GB
    Container: Yes
    Shell: 5.1.16 - /bin/bash
  Binaries:
    Node: 18.18.2 - ~/.nvm/versions/node/v18.18.2/bin/node
    npm: 9.8.1 - ~/.nvm/versions/node/v18.18.2/bin/npm
  Browsers:
    Chromium: 122.0.6261.128
  npmPackages:
    @vitest/coverage-istanbul: 0.30.1 => 0.30.1 
    vitest: 1.3.1 => 1.3.1

Used Package Manager

npm

Validations

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• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
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• The provided reproduction is a minimal reproducible example of the bug.

[hi-ogawa]

I don't know how far we can allow manipulating globals, but for this specific case of process, the minimal reproduction seems to be process.memoryUsage:
https://stackblitz.com/edit/vitest-dev-vitest-khv9rc?file=test%2Fbasic.test.ts

process.memoryUsage = undefined;

I'm guessing that memoryUsage is used by tinypools and it's throwing inside this try/catch, so no result is coming back:

https://github.com/tinylibs/tinypool/blob/6ca7bb480a9d0c54dac04eaab5e6523d300f1791/src/entry/worker.ts#L126-L135

For your case, I understand it turns out to be a regression, but maybe you could also do:

vi.stubGlobal('process', { ...process, server: false, client: true });

Or stubGlobal is mostly equivalently just process.server = false etc... so you could simply mutate the global by yourselves.

[AriPerkkio]

We could store reference of memoryUsage in Tinypool before Vitest's entrypoint is imported. We do similarly in birpc for couple of public APIs: https://github.com/antfu/birpc/blob/72510536cedb301953e0550d884667804d7268d0/src/index.ts#L145-L147

[AriPerkkio]

tinylibs/tinypool#83 fixes this issue. However there are still some process APIs that need to be saved on Vitest's side if pool: 'forks' is used.