fix: htmlFallbackMiddleware should check fullBundleMode memoryFiles

Author: underfin

packages/vite/src/node/preview.ts

@@ -246,7 +246,9 @@ export async function preview(
 
   // html fallback
   if (config.appType === 'spa' || config.appType === 'mpa') {
-    app.use(htmlFallbackMiddleware(distDir, config.appType === 'spa'))
+    app.use(
+      htmlFallbackMiddleware(distDir, config.appType === 'spa', false, {}),
+    )
   }
 
   // apply post server hooks from plugins

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

@@ -939,7 +939,14 @@ export async function _createServer(
 
   // html fallback
   if (config.appType === 'spa' || config.appType === 'mpa') {
-    middlewares.use(htmlFallbackMiddleware(root, config.appType === 'spa'))
+    middlewares.use(
+      htmlFallbackMiddleware(
+        root,
+        config.appType === 'spa',
+        !!config.experimental.fullBundleMode,
+        server.memoryFiles,
+      ),
+    )
   }
 
   // run post config hooks

packages/vite/src/node/server/middlewares/htmlFallback.ts

@@ -9,6 +9,8 @@ const debug = createDebugger('vite:html-fallback')
 export function htmlFallbackMiddleware(
   root: string,
   spaFallback: boolean,
+  fullBundleMode: boolean,
+  memoryFiles: Record<string, string | Uint8Array>,
 ): Connect.NextHandleFunction {
   // Keep the named function. The name is visible in debug logs via `DEBUG=connect:dispatcher ...`
   return function viteHtmlFallbackMiddleware(req, _res, next) {
@@ -31,6 +33,12 @@ export function htmlFallbackMiddleware(
     const url = cleanUrl(req.url!)
     const pathname = decodeURIComponent(url)
 
+    function checkFileExists(htmlPathName: string) {
+      return fullBundleMode
+        ? memoryFiles[htmlPathName]
+        : fs.existsSync(path.join(root, htmlPathName))
+    }
+
     // .html files are not handled by serveStaticMiddleware
     // so we need to check if the file exists
     if (pathname.endsWith('.html')) {
@@ -43,8 +51,7 @@ export function htmlFallbackMiddleware(
     }
     // trailing slash should check for fallback index.html
     else if (pathname.endsWith('/')) {
-      const filePath = path.join(root, pathname, 'index.html')
-      if (fs.existsSync(filePath)) {
+      if (checkFileExists(path.join(pathname, 'index.html'))) {
         const newUrl = url + 'index.html'
         debug?.(`Rewriting ${req.method} ${req.url} to ${newUrl}`)
         req.url = newUrl
@@ -53,8 +60,7 @@ export function htmlFallbackMiddleware(
     }
     // non-trailing slash should check for fallback .html
     else {
-      const filePath = path.join(root, pathname + '.html')
-      if (fs.existsSync(filePath)) {
+      if (checkFileExists(pathname + '.html')) {
         const newUrl = url + '.html'
         debug?.(`Rewriting ${req.method} ${req.url} to ${newUrl}`)
         req.url = newUrl