Style variables missing in Next.js

[sumanbh]

Something is off with the logic of nextjsMode - it does not include all the generated styles if the styles are coming from a library/package:

Workaround: if we remove the clear call, then we do get all the styles (as far as I can tell).

[SukkaW]

The .clear() was used to de-duplicated stylex rules, since stylex-webpack is able to collect stylex rules from both chunk information and the loader.

It is weird that the styles coming from library/modules are not included in the stylex chunk:

stylex-webpack/src/index.ts

Lines 110 to 116 in 67b9c12

	compiler.options.optimization.splitChunks.cacheGroups[STYLEX_CHUNK_NAME] = {
	name: STYLEX_CHUNK_NAME,
	test: VIRTUAL_CSS_PATTERN,
	type: 'css/mini-extract',
	chunks: 'all',
	enforce: true
	};

[sumanbh]

Could it be related to RSC? Not an exact replication but we can see a similar issue here - https://github.com/sumanbh/next-stylex-webpack - navigating from home / to /test by clicking "Go to test" results in no styles from the test page.

Also, shouldn't stylex-webpack collect styles from all pages? I've found this next.js specific logic results in different file sizes (and missing style variables) for the generated css file based on the route user's in.

[SukkaW]

Could it be related to RSC? Not an exact replication but we can see a similar issue here - https://github.com/sumanbh/next-stylex-webpack - navigating from home / to /test by clicking "Go to test" results in no styles from the test page.

I can't re-produce this using npm run build && npm run start. So this only happens with HMR.

Also, shouldn't stylex-webpack collect styles from all pages? I've found this next.js specific logic results in different file sizes (and missing style variables) for the generated css file based on the route user's in.

In fact, the nextjsMode was trying to collect styles from all pages because Next.js by default compiles RSC and client bundle separately.

[SukkaW]

Update

Actually, after navigation to /test, the new CSS Rules have been collected and the new CSS has been generated:

However, for some reason compilation.updateAsset didn't trigger the HMR update of the new module. And this is something out of my reach.