[Bug]: v8 coverage lowers when more tests are executed

[TWiStErRob]

Version

29.7.0

Steps to reproduce

1. Clone https://github.com/TWiStErRob/repros/tree/main/jest/v8-flaky-coverage
2. npm install
3. npm test -- --runInBand wrapped.test.js -> tests pass, coverage 100%
4. npm test -- --runInBand -> tests pass, coverage missing lines

Expected behavior

Everything passes and coverage is better or equivalent to when only a single test is executed.

Actual behavior

File that is covered by a single test file to 100% loses coverage when an additional test is executed. The additional test calls the original function.

Additional context

Anything relevant changed in the repro will make it work correctly. So:

• v8 -> babel ✅
• changing the order of execution of tests (sorted.js < -> >) ✅
  We used a testSequencer to consistently reproduce the issue, otherwise it was flaky!
• changing the order via removing --runInBand ✅
  We also used this to consistently reproduce the issue, otherwise it was flaky!

Environment

System:
    OS: macOS 14.1.2
    CPU: (12) arm64 Apple M2 Pro or (10) arm64 Apple M1 Pro
  Binaries:
    Node: 20.10.0 - /opt/homebrew/opt/node@20/bin/node
    npm: 10.2.3 - /opt/homebrew/opt/node@20/bin/npm
  npmPackages:
    jest: ^29.7.0 => 29.7.0 

Also on github actions ubuntu-latest (so Ubuntu 22.04 and x64).

[kwmhp]

Hi
This seems to be the same problem as in my issue #14764
Have you tested this with Node 20.9.0?

[TWiStErRob]

Yep, confirmed 20.9.0 -> 20.10.0 causes it.

Raised nodejs/node#51251

[ritchieanesco]

+1 also getting code coverage failure after updating to 20.10.0.

[cenfun]

I found that comment following two lines in node_modules/collect-v8-coverage/index.js will fix it.

    //await this.postSession('Profiler.stopPreciseCoverage');

    //await this.postSession('Profiler.disable');

[ritchieanesco]

Verified that commenting out both lines fixes the issue.

[github-actions]

This issue is stale because it has been open 30 days with no activity. Remove stale label or comment or this will be closed in 30 days.

[TWiStErRob]

Still an issue.