Merge e88a2f3 into b97eab3

Author: maneesht

.changeset/brown-trains-melt.md

@@ -0,0 +1,5 @@
+---
+"@firebase/auth": patch
+---
+
+Fix issue where using signInWithRedirect in Firebase Studio required a route rewrite for the auth handler widget.

packages/auth/src/core/util/handler.ts

@@ -129,7 +129,15 @@ export async function _getRedirectUrl(
 
 function getHandlerBase({ config }: AuthInternal): string {
   if (!config.emulator) {
-    return `https://${config.authDomain}/${WIDGET_PATH}`;
+    const path = `https://${config.authDomain}/${WIDGET_PATH}`;
+    if (
+      typeof process !== 'undefined' &&
+      process.env.FIREBASE_USE_HANDLER_EXT
+    ) {
+      // Static servers require extensions to infer Content-Type
+      return `${path}.html`;
+    }
+    return path;
   }
 
   return _emulatorUrl(config, EMULATOR_WIDGET_PATH);