Fix POST with re-execution.

Author: ilonatommy

src/Components/Endpoints/src/RazorComponentEndpointInvoker.cs

@@ -121,7 +121,7 @@ await _renderer.InitializeStandardComponentServicesAsync(
             try
             {
                 var isBadRequest = false;
-                quiesceTask = _renderer.DispatchSubmitEventAsync(result.HandlerName, out isBadRequest);
+                quiesceTask = _renderer.DispatchSubmitEventAsync(result.HandlerName, out isBadRequest, isReExecuted);
                 if (isBadRequest)
                 {
                     return;

src/Components/Endpoints/src/Rendering/EndpointHtmlRenderer.EventDispatch.cs

@@ -22,7 +22,7 @@ internal partial class EndpointHtmlRenderer
     private readonly Dictionary<(int ComponentId, int FrameIndex), string> _namedSubmitEventsByLocation = new();
     private readonly Dictionary<string, HashSet<(int ComponentId, int FrameIndex)>> _namedSubmitEventsByScopeQualifiedName = new(StringComparer.Ordinal);
 
-    internal Task DispatchSubmitEventAsync(string? handlerName, out bool isBadRequest)
+    internal Task DispatchSubmitEventAsync(string? handlerName, out bool isBadRequest, bool isReExecuted = false)
     {
         if (string.IsNullOrEmpty(handlerName))
         {
@@ -34,6 +34,14 @@ internal Task DispatchSubmitEventAsync(string? handlerName, out bool isBadReques
 
         if (!_namedSubmitEventsByScopeQualifiedName.TryGetValue(handlerName, out var locationsForName) || locationsForName.Count == 0)
         {
+            if (isReExecuted)
+            {
+                // If we are re-executing, we do not expect to find a new form on the page we re-execute to.
+                // This does not mean that the request is bad, we want the re-execution to succeed.
+                isBadRequest = false;
+                return Task.CompletedTask;
+            }
+
             // This may happen if you deploy an app update and someone still on the old page submits a form,
             // or if you're dynamically building the UI and the submitted form doesn't exist the next time
             // the page is rendered

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

@@ -149,7 +149,6 @@ private void AssertNotFoundContentNotRendered(bool responseHasStarted)
         }
     }
 
-
     private void AssertUrlNotChanged(string expectedUrl) =>
         Browser.True(() => Browser.Url.Contains(expectedUrl), $"Expected URL to contain '{expectedUrl}', but found '{Browser.Url}'");
 
@@ -274,7 +273,7 @@ public void NotFoundSetOnInitialization_ResponseStarted_CustomRouter_SSR(bool ha
 
         if (hasReExecutionMiddleware)
         {
-            AssertReExecutionPageRendered(); 
+            AssertReExecutionPageRendered();
         }
         else
         {
@@ -372,7 +371,6 @@ public void NotFoundSetOnFormSubmit_ResponseStarted_SSR(bool hasReExecutionMiddl
         Navigate(testUrl);
         Browser.FindElement(By.Id("not-found-form")).FindElement(By.TagName("button")).Click();
 
-
         bool notFoundContentForRenderingProvided = hasCustomNotFoundPageSet || hasReExecutionMiddleware;
         if (notFoundContentForRenderingProvided)
         {