Re-run test in v23 is slower than v22 on Windows

💥 Regression Report

Re-run test in version 23 is significantly slower than version 22 on Windows

Last working version

Worked up to version: 22.4.4

Stopped working in version: 23.0.0

To Reproduce

repo: testjest22 repo: testjest23

These two repos only contains a test file jest.test.js and install different jest version.

test('foo', () => {
  expect('foo').toBe('foo')
})

run yarn test --watchAll --env=node

then, press Enter to trigger a test run In v22, it takes about 0.05s, but over 2s in v23

When editing test file to trigger re-run, v22 can finish in 0.5s but v23 usually takes close to 3s

Run npx envinfo --preset jest

  System:
    OS: Windows 10
    CPU: x64 Intel(R) Core(TM) i5-5250U CPU @ 1.60GHz
  Binaries:
    Yarn: 1.7.0 - C:\Program Files (x86)\Yarn\bin\yarn.CMD
    npm: 5.6.0 - C:\Program Files\nodejs\npm.CMD

Update: It is an issue only on Windows, test it on Linux, just a little bit slower but acceptable.

[paradite]

Similar experience when trying to upgrade jest on OS X. To test the performance, we run jest --watch then a option Using 22.4.4, this takes 20 seconds Using 23.0.0, this takes 58 seconds So the slowdown happens with the version 23 major release. In both cases, we make sure snapshots are updated and all changes are committed (git status is clean). Will try to create a minimal reproducible repo if I have time.

[deleteme]

@SimenB The slowdown happens on OS X too.