Fix hardcoded path to codegen cli for monorepos

[byCedric]

Summary

Fixes #35429

This fix is fairly straightforward. Instead of hardcoding two separate paths for this repo or a simple user's project, we ask Node to resolve react-native-codegen.

Because react-native-codegen is moved into the /packages/* folder, it's part of a workspace in this repository. That means that this fix works not only for monorepos in general but also resolves the right path within the react native repository.

You can test this out yourself when running this command in either the root, or any other workspace in this repository:

node --print "require('path').dirname(require.resolve('react-native-codegen/package.json'))"

I've tested this on Node 16 and 18, and seems to work nicely. Note that you have to specify react-native-codegen/package.json. That's because the react-native-codegen package itself is technically invalid; it's missing an entry point within the package (no main). When running node --print "require.resolve('react-native-codegen')" Node can't resolve the main entry point, and will fail during this process.

Changelog

[iOS] [Fixed] - Fix incorrect codegen CLI paths in monorepo projects

Test Plan

See PR #35429

[cipolleschi]

Hi @byCedric, thank you so much for the contribution. Could you log into https://app.circleci.com, please?
This will renew the GitHub token that CircleCI knows and it will start the CI pipelines. Thank you so much. 🙏

[facebook-github-bot]

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

[byCedric]

Hi @byCedric, thank you so much for the contribution. Could you log into https://app.circleci.com, please? This will renew the GitHub token that CircleCI knows and it will start the CI pipelines. Thank you so much. 🙏

No problem @cipolleschi :) I just authenticated, but it might be related to me creating this PR from a fork? It also seems that I can't manually trigger a restart from CircleCI.

Either way, there is one thing that might be good to add to this fix. Technically, for isolated modules, this fix is not 100% correct. In isolation mode, the current directory where node --print is being executed matters. Because react-native-codegen is a child/dependency of react-native, it should be resolved from the react-native dir, not the project's ios folder. (see additional comment here)

But this is sufficient for the current package managers :)

[cipolleschi]

/rebase

[analysis-bot]

Platform	Engine	Arch	Size (bytes)	Diff
android	hermes	arm64-v8a	7,102,569	+0
android	hermes	armeabi-v7a	6,470,637	+0
android	hermes	x86	7,520,037	+0
android	hermes	x86_64	7,378,724	+0
android	jsc	arm64-v8a	8,967,444	+0
android	jsc	armeabi-v7a	7,698,293	+0
android	jsc	x86	9,029,584	+0
android	jsc	x86_64	9,507,429	+0

Base commit: e11cfe9
Branch: main

[analysis-bot]

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

Base commit: 9517320
Branch: main

[pull-bot]

PR build artifact for 189b5cb is ready.
To use, download tarball from "Artifacts" tab in this CircleCI job then run yarn add <path to tarball> in your React Native project.

[pull-bot]

PR build artifact for 189b5cb is ready.
To use, download tarball from "Artifacts" tab in this CircleCI job then run yarn add <path to tarball> in your React Native project.

[kelset]

That's because the react-native-codegen package itself is technically invalid; it's missing an entry point within the package (no main). When running node --print "require.resolve('react-native-codegen')" Node can't resolve the main entry point, and will fail during this process.

can't this be addressed in this PR? I am not aware of any reasons why the package.json of codegen can't have the main field set

[byCedric]

That's because the react-native-codegen package itself is technically invalid; it's missing an entry point within the package (no main). When running node --print "require.resolve('react-native-codegen')" Node can't resolve the main entry point, and will fail during this process.

can't this be addressed in this PR? I am not aware of any reasons why the package.json of codegen can't have the main field set

I think it's a side-effect worth mentioning but not necessarily required to fix. We'd probably always want to resolve the <pkg>/package.json, because that's the only file that is guaranteed to be resolved in the "root of the package".

If you have an entry point like "main": "dist/index.js", node resolves require.resolve('<pkg>') to something like .../node_modules/<pkg>/dist/index.js, which isn't the package installation directory. You can see this in the Expo template files.

But maybe just adding a main stub, or even exports to the files that are relevant, might make it a bit nicer in general :)

[facebook-github-bot]

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

[peterpme]

Thank you @byCedric for the PR and thanks to everyone else for reviewing it :) Happy Thanksgiving!

[react-native-bot]

This pull request was successfully merged by @byCedric in 4a4ccee.

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