Fix NotFoundSetOnFormSubmit_ResponseNotStarted_SSR test and enhanced navigation timing issue

src/Components/Web.JS/src/Boot.Web.ts

@@ -65,13 +65,14 @@ function boot(options?: Partial<WebStartOptions>) : Promise<void> {
     },
   };
 
-  attachComponentDescriptorHandler(rootComponentManager);
-  attachStreamingRenderingListener(options?.ssr, navigationEnhancementCallbacks);
-
+  // Initialize enhanced navigation as early as possible to prevent timing issues
   if (!options?.ssr?.disableDomPreservation) {
     attachProgressivelyEnhancedNavigationListener(navigationEnhancementCallbacks);
   }
 
+  attachComponentDescriptorHandler(rootComponentManager);
+  attachStreamingRenderingListener(options?.ssr, navigationEnhancementCallbacks);
+
   enableFocusOnNavigate(jsEventRegistry);
 
   // Wait until the initial page response completes before activating interactive components.

src/Components/Web.JS/src/Services/NavigationEnhancement.ts

@@ -35,9 +35,15 @@ different bundles that only contain minimal content.
 const acceptHeader = 'text/html; blazor-enhanced-nav=on';
 
 let currentEnhancedNavigationAbortController: AbortController | null;
-let navigationEnhancementCallbacks: NavigationEnhancementCallbacks;
+let navigationEnhancementCallbacks: Promise<NavigationEnhancementCallbacks>;
+let navigationEnhancementCallbacksResolver: (callbacks: NavigationEnhancementCallbacks) => void;
 let performingEnhancedPageLoad: boolean;
 
+// Initialize the promise that will be resolved when callbacks are set
+navigationEnhancementCallbacks = new Promise<NavigationEnhancementCallbacks>((resolve) => {
+  navigationEnhancementCallbacksResolver = resolve;
+});
+
 // This gets initialized to the current URL when we load.
 // After that, it gets updated every time we successfully complete a navigation.
 let currentContentUrl = location.href;
@@ -57,7 +63,7 @@ export function hasNeverStartedAnyEnhancedPageLoad() {
 }
 
 export function attachProgressivelyEnhancedNavigationListener(callbacks: NavigationEnhancementCallbacks) {
-  navigationEnhancementCallbacks = callbacks;
+  navigationEnhancementCallbacksResolver(callbacks);
   document.addEventListener('click', onDocumentClick);
   document.addEventListener('submit', onDocumentSubmit);
   window.addEventListener('popstate', onPopState);
@@ -201,8 +207,11 @@ export async function performEnhancedPageLoad(internalDestinationHref: string, i
   // Notify any interactive runtimes that an enhanced navigation is starting
   notifyEnhancedNavigationListeners(internalDestinationHref, interceptedLink);
 
+  // Wait for navigation enhancement callbacks to be initialized before proceeding
+  const callbacks = await navigationEnhancementCallbacks;
+
   // Notify handlers that enhanced navigation is starting
-  navigationEnhancementCallbacks.enhancedNavigationStarted();
+  callbacks.enhancedNavigationStarted();
 
   // Now request the new page via fetch, and a special header that tells the server we want it to inject
   // framing boundaries to distinguish the initial document and each subsequent streaming SSR update.
@@ -305,7 +314,7 @@ export async function performEnhancedPageLoad(internalDestinationHref: string, i
         // For HTML responses, regardless of the status code, display it
         const parsedHtml = new DOMParser().parseFromString(initialContent, 'text/html');
         synchronizeDomContent(document, parsedHtml);
-        navigationEnhancementCallbacks.documentUpdated();
+        callbacks.documentUpdated();
       } else if (responseContentType?.startsWith('text/') && initialContent) {
         // For any other text-based content, we'll just display it, because that's what
         // would happen if this was a non-enhanced request.
@@ -344,7 +353,7 @@ export async function performEnhancedPageLoad(internalDestinationHref: string, i
     }
 
     performingEnhancedPageLoad = false;
-    navigationEnhancementCallbacks.enhancedNavigationCompleted();
+    callbacks.enhancedNavigationCompleted();
 
     // For non-GET requests, the destination has to be the same URL you're already on, or result in a redirection
     // (post/redirect/get). You're not allowed to POST to a different URL without redirecting, because then back/forwards

src/Components/test/E2ETest/ServerRenderingTests/NoInteractivityTest.cs

@@ -205,7 +205,7 @@ private void AssertNotFoundRendered_ResponseStarted_Or_POST(bool hasReExecutionM
     public void NotFoundSetOnFormSubmit_ResponseNotStarted_SSR(bool hasReExecutionMiddleware, bool hasCustomNotFoundPageSet)
     {
         string reexecution = hasReExecutionMiddleware ? "/reexecution" : "";
-        string testUrl = $"{ServerPathBase}{reexecution}/post-not-found-ssr-streaming?useCustomNotFoundPage={hasCustomNotFoundPageSet}";
+        string testUrl = $"{ServerPathBase}{reexecution}/post-not-found-ssr?useCustomNotFoundPage={hasCustomNotFoundPageSet}";
         Navigate(testUrl);
         Browser.FindElement(By.Id("not-found-form")).FindElement(By.TagName("button")).Click();