[Bug] debug shows warning message: added empty files for all: undefined for 'all" config

[stevez]

Describe the bug playwright config sample: all: { dir: ['./src'], filter: { '*/.tsx': true } },

Running 2 tests using 2 workers

✓ 1 [Desktop Chrome] › counter.spec.ts:3:1 › should count by click (2.0s) ✓ 2 [Desktop Chrome] › app.spec.ts:3:1 › should navigate to the about page (2.1s) [MCR] added coverage data: istanbul (9ms) [MCR] added coverage data: istanbul (15ms) globalTeardown ... [MCR] added coverage data: istanbul (3ms)

2 passed (4.1s) [MR] generating report data ... [MCR] added empty files for all: undefined [MCR] added coverage data: istanbul (1ms)

To Reproduce

• Version: 2.5.2
• Node Version: 20
• Have you tried the latest version (including node), and does the issue still exist?
• Steps to reproduce the actual behavior:
  1. checkout my forked example repo with the changes: https://github.com/stevez/nextjs-with-playwright-istanbul/commit/a677203c22befc6cc9784c688509b66186dd4bd7
  2. run npm test
  3. show debug message: [MCR] added empty files for all: undefined

Expected behavior A clear and concise description of what you expected to happen.

Errors or Screenshots Any captured error messages, or add screenshots to help explain your problem.

Make a minimal reproduction

• Provide the minimal, reproducible code and options of the bug.

- Or provide a GitHub repository with a minimal (but complete) example and simple/clear steps on how to reproduce the bug. 
https://github.com/stevez/nextjs-with-playwright-istanbul

The simpler you can make it, the more likely we are to successfully verify and fix the bug.

**Additional context**
Add any other context about the problem here.

[cenfun]

The all option is for V8 coverage only, not for istanbul. We don’t have enough time to support all the features of Istanbul, since you can use Istanbul itself via nyc rather than mcr. Istanbul is in mcr just provide the format of reports. mcr will focus on v8 coverage reports in the future.

mcr: https://github.com/cenfun/monocart-coverage-reports/ nyc: https://github.com/istanbuljs/nyc

In fact, you can ignore the warning meesage, It is not important. fixing is here: https://github.com/cenfun/monocart-coverage-reports/commit/8fdef048757b51eb8561c1b4a4443c9ab2449d40