🐛 GitHub reporter output is invalid when colors are enabled

[brianhelba]

What happened?

Following the change in #9120, running biome ci now enables the github reporter when the environment contains GITHUB_ACTION=true. However, by default, biome ci still uses color output, which currently breaks the intended functionality.

Specifically, Biome's color output causes lines of github reporter output (written to stdout) to be wrapped with the characters 0x1b 0x5b 0x30 0x6d (or ESC[0m), which is the ANSI escape sequence to "reset all modes (styles and colors)". These extra characters breaks GitHub's ability to process such lines as workflow commands, which defeats the purpose of the github reporter.

Note, if the command is run as biome ci --reporter=default --reporter=github color output is disabled (due to #3281) and the output is correctly detected by GitHub. However, biome ci ought to "just work" too.

---

I think there are 2 potential fixes:

1. Make biome ci (when GITHUB_ACTION=true) actually work the same as --reporter=default --reporter=github, which would effectively also set --colors=off, per fix(cli): disable colors when using the github reporter #3281.
2. Ensure that the stdout output of the github has "clean" lines with no ANSI control characters. I suspect that control characters could still technically be output by the github reporter (if colors needed to be reset), but they'd have to be on totally separate lines from the actual "workflow commands". Additionally, maybe part of fix(cli): disable colors when using the github reporter #3281 could actually be reverted, so that when --reporter=default --reporter=github is explicitly enabled, the default reporter could still produce color output.

I think 2 would be the most user-friendly behavior. However, 1 seems easier and would only deprive users of colors when running inside GitHub Actions.

Code of Conduct

• I agree to follow Biome's Code of Conduct

[brianhelba]

Ping @ematipico , related to your recent work. Thank you!

[khushal-winner]

I’d like to work on this. If no one is actively working on it, I can start investigating

[dyc3]

@brianhelba just for reference, do you have a link to a run's logs so we can see the issue?

[brianhelba]

@dyc3 Sure, here's 2 runs with Biome 2.4.4 that intentionally have errors:

• biome ci
  • "Annotations" at the top of the page does not show Biome errors
  • the raw log contains an ::error ... line, since it's not captured by GitHub Actions
  • this ::error line is wrapped by escape characters
• biome ci --colors=off
  • "Annotations" at the top of the page correctly shows the Biome error "File content differs from formatting output"
  • no ::error appears in the raw log, since it's captured by GitHub Actions

[dyc3]

I think the solution might be as simple as making sure there's a newline after the reset characters, so that the ::error... is at the literal start of the line.

[brianhelba]

@dyc3 That makes sense, given what I've observed about GitHub workflow commands.

As mentioned in my issue, perhaps #3281 could partially be reverted too. Color on the non-github lines shouldn't be a problem after your proposed changed.