[Bug]: Preset modules defining path to jest-preset.js via exports are not working on Windows

[Filipoliko]

Version

29.7.0

Steps to reproduce

1. Start your favorite Windows machine, this bug is only reproducible there :)
2. Clone https://github.com/Filipoliko/jest-preset-windows
3. Run npm ci
4. Run npm test
5. You should see the error

Expected behavior

No error, Jest should recognise that package.json file of my-jest-preset defines exports for ./jest-preset.

Actual behavior

Jest fails to start the test run due to missing jest-preset.js file, but only on Windows machines.

Jest v29.7.0 error message:

> [email protected] test
> jest
● Validation Error:
  Preset my-jest-preset not found.
  Configuration Documentation:
  https://jestjs.io/docs/configuration
Error: Process completed with exit code 1.

Jest v30.0.0-alpha.7 error message:

> [email protected] test
> jest
● Validation Error:
  Preset my-jest-preset not found relative to rootDir D:\a\jest-preset-windows\jest-preset-windows.
  Configuration Documentation:
  https://jestjs.io/docs/configuration
Error: Process completed with exit code 1.

Additional context

See pipeline results https://github.com/Filipoliko/jest-preset-windows/actions/runs/13372503574 (v29), https://github.com/Filipoliko/jest-preset-windows/actions/runs/13372781509 (v30) - it shows that the same jest configuration works for Linux and MacOS, but fails for Windows.

The path to jest-preset.js file is defined via exports definition in package.json - see https://github.com/Filipoliko/jest-preset-windows/blob/main/packages/my-jest-preset/package.json#L6

Environment

System:
    OS: Windows 10 10.0.20348
    CPU: (4) x64 AMD EPYC 7763 64-Core Processor                
  Binaries:
    Node: 22.13.1 - C:\hostedtoolcache\windows\node\22.13.1\x64\node.EXE
    Yarn: 1.22.22 - C:\npm\prefix\yarn.CMD
    npm: 10.9.2 - C:\hostedtoolcache\windows\node\22.13.1\x64\npm.CMD
  npmPackages:
    jest: 30.0.0-alpha.7 => 30.0.0-alpha.7