fix(core): Disable buildin lightingcss when inject style

[witsaint]

Summary

For production builds, it is recommended to use the default behavior of Rsbuild, which extracts CSS into separate bundles to allow browsers to load CSS and JS assets in parallel.

Related Links

[Bug]: rsbuild injectStyles

Checklist

• Tests updated (or not required).
• Documentation updated (or not required).

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[chenjiahan]

Can you explain why do we need to disable builtin lightingcss when using injectStyles?

[witsaint]

Can you explain why do we need to disable builtin lightingcss when using injectStyles?

1: As described in our documentation, when we open injectStyles,If you need to enable this option in production mode, please note that the inlined CSS code will not go through Rsbuild's default CSS minimizer.

2:
a： When I debugger Rsbuild，I found that there were five loaders before stylePostLoader

b：The latest loader is builtin lightingcss

The same is shown in rspack.config.web.mjs

c：I found that after using postcss with cssnano, source works fine，But by buildin lightingcss,Found a lot of \n

d: When I remove buildin lightingcss in loader, css compression is fine when injectStyles is turned on

[chenjiahan]

Get. I believe this fix is not the optimal solution as it prevents PostCSS and LightningCSS from working together.

We can solve this problem by simply adding a minify option to Rspack's lightningcss-loader and enanbling minify when output.injectStyles is used.

[chenjiahan]

Sorry, we should not change the order of lightningcss-loader and postcss-loader, this is an unexpected change.

Take Tailwind CSS as an example. Tailwind CSS it is a PostCSS plugin, it will generate some CSS code, then Lightning CSS will add vendor prefixes to those CSS properties. If we change the loader order, this will be broken.

[chenjiahan]

If we need to adjust the default loader behavior, it is best to first discuss the impact of doing so.