wip: use builtin css handling

Author: sapphi-red

packages/vite/src/node/build.ts

@@ -644,7 +644,19 @@ async function buildEnvironment(
     // TODO: remove this and enable rolldown's CSS support later
     moduleTypes: {
       ...options.rollupOptions.moduleTypes,
-      '.css': 'js',
+      // https://github.com/rolldown/rolldown/blob/4020de442a8ab0f7973794ead3b8aa04e316d558/crates/rolldown/src/module_loader/module_task.rs#L120
+      // @ts-expect-error css
+      '.sass': 'css',
+      // @ts-expect-error css
+      '.scss': 'css',
+      // @ts-expect-error css
+      '.sss': 'css',
+      // @ts-expect-error css
+      '.styl': 'css',
+      // @ts-expect-error css
+      '.stylus': 'css',
+      // @ts-expect-error css
+      '.less': 'css',
     },
   }
 

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

@@ -794,11 +794,6 @@ async function prepareRolldownOptimizerRun(
         extensions: ['.js', '.css'],
         conditionNames: ['browser'],
       },
-      // TODO: remove this and enable rolldown's CSS support later
-      moduleTypes: {
-        '.css': 'js',
-        ...rollupOptions.moduleTypes,
-      },
     })
     if (canceled) {
       await bundle.close()
@@ -1078,11 +1073,6 @@ export async function extractExportsData(
       ...remainingRollupOptions,
       plugins,
       input: [filePath],
-      // TODO: remove this and enable rolldown's CSS support later
-      moduleTypes: {
-        '.css': 'js',
-        ...remainingRollupOptions.moduleTypes,
-      },
     })
     const result = await build.generate({
       ...rollupOptions.output,

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

@@ -611,8 +611,7 @@ export function cssPostPlugin(config: ResolvedConfig): RolldownPlugin {
           code = `export default ${JSON.stringify(content)}`
         } else {
           // empty module when it's not a CSS module nor `?inline`
-          // NOTE: add `export {}` otherwise rolldown treats the module as CJS (https://github.com/rolldown/rolldown/issues/2394)
-          code = 'export {}'
+          code = css
         }
 
         return {

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

@@ -235,7 +235,8 @@ export function buildImportAnalysisPlugin(config: ResolvedConfig): [Plugin] {
       }
     },
 
-    async transform(source, importer) {
+    async transform(source, importer, opts) {
+      if (opts?.moduleType === 'css') return
       if (isInNodeModules(importer) && !dynamicImportPrefixRE.test(source)) {
         return
       }

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

@@ -85,11 +85,6 @@ async function bundleWorkerEntry(
     onwarn(warning, warn) {
       onRollupWarning(warning, warn, workerEnvironment)
     },
-    // TODO: remove this and enable rolldown's CSS support later
-    moduleTypes: {
-      '.css': 'js',
-      ...rollupOptions.moduleTypes,
-    },
     // preserveEntrySignatures: false,
   })
   let chunk: OutputChunk