fix: Eslint on Danger not matching project config

[gabrieldonadel]

Summary

I've been noticing this for a while now, every time that someone changes a file inside rn-tester Danger comments a bunch of warnings regarding inline styles, e.g. #34567 (comment), even though that is disabled inside .eslintrc https://github.com/facebook/react-native/blob/8edf4e9e3adcc85743e3c86a25ab3748b276a3da/packages/rn-tester/.eslintrc#L3

After some investigation, I realized that the problem was that the Eslint Node.js API used by @seadub/danger-plugin-eslint was not able to locate any .eslintrc files due to the location of the directory where danger is invoked. By using process.chdir we can ensure that eslint will run from the root folder and that it will be able to find all .eslintrc files

Changelog

[Internal] [Fixed] - fix eslint config when running Danger

Test Plan

run yarn danger pr https://github.com/facebook/react-native/pull/34976

After

Before

[analysis-bot]

Platform	Engine	Arch	Size (bytes)	Diff
android	hermes	arm64-v8a	7,777,435	+4
android	hermes	armeabi-v7a	7,178,432	+10
android	hermes	x86	8,090,431	+6
android	hermes	x86_64	8,062,115	-5
android	jsc	arm64-v8a	9,636,875	-6
android	jsc	armeabi-v7a	8,401,168	+0
android	jsc	x86	9,586,058	+0
android	jsc	x86_64	10,179,228	+2

Base commit: a575472
Branch: main

[analysis-bot]

Platform	Engine	Arch	Size (bytes)	Diff
ios	-	universal	n/a	--

Base commit: a575472
Branch: main

[yungsters]

Would it also work if you instead set options.cwd?

Documentation: https://eslint.org/docs/latest/developer-guide/nodejs-api

Suggested change

	// Ensures that eslint is run from root folder and that it can find .eslintrc
	process.chdir('../../');
	eslint.default();
	eslint.default({
	// Ensures that eslint is run from root folder and that it can find .eslintrc
	cwd: '../../',
	});

[gabrieldonadel]

Not really, that was my first approach too @yungsters but unfortunately @sgtcoolguy/danger-plugin-eslint only allows us to change the baseConfig.

https://github.com/sgtcoolguy/danger-plugin-eslint/blob/master/src/index.ts#L24

[yungsters]

Oh no… thanks for sharing. And yes, as @cipolleschi shared, thanks for fixing! I suspect this was one of the issues that blocked me from making progress on #34401. 🥰

[cipolleschi]

Woah, Great finding @gabrieldonadel! I think this happened when we moved danger in a node package within the packages folder.

[facebook-github-bot]

@yungsters has imported this pull request. If you are a Meta employee, you can view this diff on Phabricator.

[react-native-bot]

This pull request was successfully merged by @gabrieldonadel in 55b09da.

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