fix(typescript-estree): pass extraFileExtensions to projectService

[alfredringstad]

PR Checklist

• Addresses an existing open issue: fixes Bug: parserOptions.projectService does not respect extraFileExtensions #8899
• That issue was marked as accepting prs
• Steps in Contributing were taken

Overview

Uses setHostConfiguration to pass extraFileExtensions to project service, when using EXPERIMENTAL_useProjectService. This fixes an issue where project service would not detect the appropriate tsconfig file when using non-default file extensions.

The tests are checking that the configFilePath is set in the compiler options. If it's not, it's an indication that the default inferred project is used. I duplicated the test cases used for the non-experimental projects option.

[typescript-eslint]

Thanks for the PR, @alfredringstad!

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The core maintainers work on this in their personal time, so please understand that it may not be possible for them to review your work immediately.

Thanks again!

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🟥 Failed Commands
nx run-many --target=test --parallel --exclude integration-tests --exclude website --exclude website-eslint
nx run-many --target=lint --parallel --exclude eslint-plugin
nx test eslint-plugin-internal --coverage=false

✅ Successfully ran 12 targets

• nx run integration-tests:test
• nx run repo-tools:postinstall-script
• nx run-many --target=typecheck --parallel
• nx test type-utils --coverage=false
• nx test typescript-eslint --coverage=false
• nx run types:build
• nx test repo-tools --coverage=false
• nx test ast-spec --coverage=false
• nx test scope-manager --coverage=false
• nx test parser --coverage=false
• nx run repo-tools:generate-configs
• nx run-many --target=build --parallel --exclude=website --exclude=website-eslint

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[JoshuaKGoldberg]

Source code changes look great to me! And checking that the config file path is found as a form of testing is very snazzy. Nicely done. 😄

Just requesting changes on docs and a few testing things that I'm open to being pushed back on - what do you think?

[alfredringstad]

Thanks for the feedback @JoshuaKGoldberg! I've implemented your suggestions. Seems like CI failure is due to issues in the main v8 branch, the typescript-estree tests seem to work fine.

[JoshuaKGoldberg]

[Praise] 💯

[JoshuaKGoldberg]

This is great, thanks!

Normally I'd wait for a bit to let someone else review but I would like to unblock folks who need the extra file extensions from using the project.