fix: populate originalFileNames when resolving CSS asset paths

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

@@ -473,7 +473,10 @@ export function cssPostPlugin(config: ResolvedConfig): Plugin {
       ? rollupOptionsOutput[0]
       : rollupOptionsOutput
   )?.assetFileNames
-  const getCssAssetDirname = (cssAssetName: string) => {
+  const getCssAssetDirname = (
+    cssAssetName: string,
+    originalFileName?: string,
+  ) => {
     const cssAssetNameDir = path.dirname(cssAssetName)
     if (!assetFileNames) {
       return path.join(config.build.assetsDir, cssAssetNameDir)
@@ -484,7 +487,7 @@ export function cssPostPlugin(config: ResolvedConfig): Plugin {
         assetFileNames({
           type: 'asset',
           names: [cssAssetName],
-          originalFileNames: [],
+          originalFileNames: originalFileName ? [originalFileName] : [],
           source: '/* vite internal call, ignore */',
         }),
       )
@@ -693,13 +696,14 @@ export function cssPostPlugin(config: ResolvedConfig): Plugin {
             const resolveAssetUrlsInCss = (
               chunkCSS: string,
               cssAssetName: string,
+              originalFileName?: string,
             ) => {
               const encodedPublicUrls = encodePublicUrlsInCSS(config)
 
               const relative = config.base === './' || config.base === ''
               const cssAssetDirname =
                 encodedPublicUrls || relative
-                  ? slash(getCssAssetDirname(cssAssetName))
+                  ? slash(getCssAssetDirname(cssAssetName, originalFileName))
                   : undefined
 
               const toRelative = (filename: string) => {
@@ -786,7 +790,11 @@ export function cssPostPlugin(config: ResolvedConfig): Plugin {
 
                 let cssContent = styles.get(id)!
 
-                cssContent = resolveAssetUrlsInCss(cssContent, cssAssetName)
+                cssContent = resolveAssetUrlsInCss(
+                  cssContent,
+                  cssAssetName,
+                  originalFileName,
+                )
 
                 urlEmitTasks.push({
                   cssAssetName,
@@ -880,7 +888,11 @@ export function cssPostPlugin(config: ResolvedConfig): Plugin {
                     ) ?? false,
                   )
 
-                  chunkCSS = resolveAssetUrlsInCss(chunkCSS, cssAssetName)
+                  chunkCSS = resolveAssetUrlsInCss(
+                    chunkCSS,
+                    cssAssetName,
+                    originalFileName,
+                  )
 
                   // wait for previous tasks as well
                   chunkCSS = await codeSplitEmitQueue.run(async () => {
@@ -957,7 +969,11 @@ export function cssPostPlugin(config: ResolvedConfig): Plugin {
                 }
               } else {
                 // resolve public URL from CSS paths, we need to use absolute paths
-                chunkCSS = resolveAssetUrlsInCss(chunkCSS, getCssBundleName())
+                chunkCSS = resolveAssetUrlsInCss(
+                  chunkCSS,
+                  getCssBundleName(),
+                  defaultCssBundleName,
+                )
                 // finalizeCss is called for the aggregated chunk in generateBundle
 
                 chunkCSSMap.set(chunk.fileName, chunkCSS)
@@ -1046,9 +1062,9 @@ export function cssPostPlugin(config: ResolvedConfig): Plugin {
             name: getCssBundleName(),
             type: 'asset',
             source: extractedCss,
-            // this file is an implicit entry point, use `style.css` as the original file name
+            // this file is an implicit entry point, use defaultCssBundleName as the original file name
             // this name is also used as a key in the manifest
-            originalFileName: 'style.css',
+            originalFileName: defaultCssBundleName,
           })
         }
       }