Add --projectRoot option

[rasimx]

Checklist

• npm test, tests passing
• npm run test:snap (to update the snapshot)

[AriPerkkio]

Should this be passed to test-exclude as cwd as well?

c8/lib/report.js

Lines 39 to 45 in 7f1069d

	this.exclude = new Exclude({
	exclude: exclude,
	include: include,
	extension: extension,
	relativePath: !allowExternal,
	excludeNodeModules: excludeNodeModules
	})

[rasimx]

Should this be passed to test-exclude as cwd as well?

c8/lib/report.js

Lines 39 to 45 in 7f1069d

	this.exclude = new Exclude({
	exclude: exclude,
	include: include,
	extension: extension,
	relativePath: !allowExternal,
	excludeNodeModules: excludeNodeModules
	})

I do not think so. This option affects only the paths in the lcov file.

[AriPerkkio]

I wonder if this option overlaps with the undocumented resolve option. Have you tried using it as the projectRoot in istanbul-reporter options?

projectRoot: this.resolve || process.cwd(),

With the current changes it feels like you'd need to keep projectRoot and resolve in sync manually.

c8/lib/parse-args.js

Lines 136 to 139 in 7f1069d

	.option('resolve', {
	default: '',
	describe: 'resolve paths to alternate base directory'
	})

c8/lib/report.js

Line 97 in 7f1069d

const path = resolve(this.resolve, v8ScriptCov.url)

[rasimx]

To be honest, I don't understand why the 'resolve' option is needed. Whatever I specify there, it does not affect the final files.

[rasimx]

I tried using this, but it didn't help me.

[rasimx]

projectRoot only affects paths in lcov files. We are currently using a fork in a working project and it works fine.

[AriPerkkio]

I did some testing with the this.resolve option now, and it indeed seems to have no effect at all. The v8ScriptCov.url paths are absolute, not relative. No idea what that API is supposed to do.

[AriPerkkio]

I do not think so. This option affects only the paths in the lcov file.

I still think this same option should be used in test-exclude as cwd. This is what nyc does, and this project seems to mimic its API quite well. Let's wait for project maintainers to make the final call though.

nyc has cwd option, which is used as projectRoot for istanbul-lib-report and as cwd for test-exclude:

You can change the project root directory with the --cwd option.

• https://github.com/istanbuljs/nyc/blob/v15.1.0/index.js#L69
• https://github.com/istanbuljs/nyc/blob/v15.1.0/index.js#L465

This feature is also something that is needed in vitest in order to change project root: vitest-dev/vitest#1902.

[bcoe]

Hello @rasimx could you provide a description in your PR of the problem you're trying to solve?

I believe the resolve functionality rewrites the output from v8 to resolve under an alternate path, allowing you to remove leading directories, etc. Whereas passing projectRoot to the Reporter is only used by a couple reporters (clover and cobertura, see search).

[AriPerkkio]

@rasimx looks like an alternative way to pass this option was implemented in #423.

It's included in c8@7.13.0.

[bcoe]

@rasimx looks like an alternative way to pass this option was implemented in #423.

I would prefer that we expose this reporterOptions configuration so that it can be configured in package configuration, or with --reporter-options.projectRoot -- reasoning being that the options available for the reporter sometimes have names that are a bit confusing because they sound like top level configuration for c8 itself (this is why I was initially confused by this PR).

@rasimx closing this for now, since I did't hear back from you with my last update. But, I'd be happy to land this work in the future if you're willing to update based on this suggestion.