Use shorter error message for file resolution issues.

[EvanBacon]

Summary

• Part of the resolution error is very verbose and somewhat hard to make sense of.
• This PR condenses the matchable segments to reduce duplicate contents.
  • Add optional (/index)? segment to prevent needing a second line.
  • Modify header none of these files exist: to account for the single line no file matched the pattern. I find this line more helpful as it implies the issue may be due to the pattern and not to the lack of file existence. Generally when users are reporting this issue to Expo CLI, it's because they need to modify srcExts.
  • Reduce duplicate references in extensions (.native|.native.js|.js|.native.json|.json) -> (.native)?.(native|js|json). This clearly has an issue where .native.native would technically match the listed pattern––open to suggestions on how to format this differently. However, .native seems like it shouldn't be present regardless. Worth noting that I hadn't noticed the extraneous .native before because the length of the error message.
• reference to discord proposal.

Test plan

• Unit tests cover this well.

[facebook-github-bot]

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

[motiz88]

This looks great! Re: .native.native, that seems weird - is it just an artifact of the current tests or does it show up in real-world usage too?

[motiz88]

Oh, found the .native bug:

metro/packages/metro-resolver/src/resolve.js

Lines 463 to 464 in c39b51b

	if (context.preferNativePlatform) {
	const filePath = resolveSourceFileForExt(context, `.native${sourceExt}`);

We need to check that sourceExt isn't empty.

[facebook-github-bot]

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

[motiz88]

I think the case I was concerned about was something like ['.fb.js', 'js', 'json'] - where the fb part should not be factored out, i.e. .(fb)?.(js|json) would be wrong.

[facebook-github-bot]

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

[facebook-github-bot]

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

[rshest]

@EvanBacon Note that this still can't be merged, unfortunately, due to both merge conflicts with the mainline, and also some outstanding follow up still required (as requested by Moti).

[EvanBacon]

@rshest will follow up when I have more time. Wasn't accounting for the facebook-specific logic when I opened the PR.