Describe the bug

After updating Vitest from 4.0.18 to 4.1.0, importOriginal from vi.mock is empty when using resetModules and isolate: false.

I run my tests with maxWorkers: 1, isolate: false, and vi.resetModules(); in a beforeEach. When using importOriginal from vi.mock in setupTests.js, the first test suite runs successfully. However, the second test throws this error:

No "connect" export is defined on the "react-redux" mock. Did you forget to return it from "vi.mock"?
If you need to partially mock a module, you can use "importOriginal" helper inside:

When logging original, the first test suite logs all exports from react-redux, but the second suite logs this instead:

[Object: null prototype] [Module] {} 

Reproduction

// vitest.config.js

export default defineConfig({
  test: {
    setupFiles: ['./setupTests.js'],
    maxWorkers: 1,
    isolate: false,
  },
})

// setupTests.js

vi.mock('react-redux', async (importOriginal) => {
  const original = await importOriginal();

  return {
    ...original,
    useSelector: (callback) => callback(),
    useDispatch: () => (callback) => callback(),
  };
});

beforeEach(() => {
  vi.resetModules();
});

Here is a StackBlitz example, with Lodash instead of react-redux:
https://stackblitz.com/edit/vitest-dev-vitest-z5dhbqpm?file=package.json&view=editor

System Info

- Vite 7
- Vitest 4.1.0

Used Package Manager

npm

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• The provided reproduction is a minimal reproducible example of the bug.