fix: remove extra path shorten when resolving from a dir

[fi3ework]

Description

fix #13320

When resolving nested packages, path.dirname inadvertently shortens the initial resolving path. Although pnpm tolerates this due to its topological structure, Yarn3 does not. To fix this, the proposed PR prevents path.dirname from being invoked when the importer is already a directory.

Additional context

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What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

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[patak-dev]

Should we guard against importer being a directory? Is it valid to pass to resolve a dir as importer? I would imagine we would need checks in other places too if that is valid. I wonder if we should fix the resolve call referenced here: #13320 (comment), adding a generic /index.js to the basedir used as importer. mmmm... looks like we can't because of this existence check. I'm fine applying this as a temporal patch (adding a comment about why is needed), but I think we may be treating a symptom here.

[bluwy]

I think it's better to fix the importer path too, something like how CSS does currently should be good enough:

vite/packages/vite/src/node/plugins/css.ts

Line 937 in 5c3fa05

path.join(basedir, '*'),

so it's handled properly in the resolver.

[fi3ework]

Agree it's better to prevent resolving from dir if possible. IIUC, maybe we could join package.json with basedir here

vite/packages/vite/src/node/optimizer/index.ts

Line 895 in bd86375

return await resolve(nestedPath, basedir, undefined, ssr)

to fix this issue as we are pretty sure basedir is the directory of package.json of dep to optimize?

[patak-dev]

Interesting, resolving as /package.json is a clever trick. I wonder if it may not confuse us more though compared to using the more explicit path.join(basedir, '*') that we know also works. @bluwy what do you think? We could try any of them during the 4.4 beta.

[bluwy]

I think using /package.json sounds good too, since we know that exists 👍

[patak-dev]

/ecosystem-ci run

[vite-ecosystem-ci]

📝 Ran ecosystem CI: Open

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astro	✅ success
histoire	✅ success
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previewjs	✅ success
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