Remove unused CSS output files when inlined

[bluwy]

Changes

fix #8567

Fixes 2 issues:

1. Fix Vite preloading CSS references by updating importedCss.
2. CSS files inlined to any pages should not be deleted.

I'm actually unsure if there's a bug in no2, where in the css-dangling-references fixture, the CSS is not inlined/duplicated to both the pages.

Testing

The existing tests (especially css-dangling-references) should pass

Docs

n/a. bug fix.

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[ematipico]

It's better to avoid delete

bundle[id] = undefined

This page contains some information about why: https://biomejs.dev/linter/rules/no-delete

I predict that doing so will trigger the TS compiler, though

[bluwy]

The convention when dealing with rollup bundles is to delete it rather than setting it to undefined. Otherwise it kinda means that "the chunk exists but it's undefined".

[artursopelnik]

+1

[lilnasy]

This is great!
I was unsure about the timing of our "post" plugin against vite's preload plugin, but I can now see that it is "post" as well.

Tested against threlte docs as well, which is where the issue was discovered. Works perfectly!

[lilnasy]

2. CSS files inlined to any pages should not be deleted.

That doesn't sound right.

I'm actually unsure if there's a bug in no2, where in the css-dangling-references fixture, the CSS is not inlined/duplicated to both the pages.

You're right, the fixture does not work how I imagined. The html is not rendered either. I think what we might be noticing is that import.meta.glob() is not compatible with rendering on the server.

[bluwy]

2. CSS files inlined to any pages should not be deleted.

That doesn't sound right.

Sorry I messed up my wording a bit 😅 I mean CSS files not inlined to any pages should not be deleted. That was why I added the sheetAddedToPage guard.