Blazor 404 code re-execution is compatible with OnNavigateAsync

src/Components/Components/src/Routing/Router.cs

@@ -220,17 +220,20 @@ private void ClearRouteCaches()
 
     internal virtual void Refresh(bool isNavigationIntercepted)
     {
+        // endpointRouterData is populated only in navigations that passed through SSR, including re-executions
+        var endpointRouteData = RoutingStateProvider?.RouteData;
+
         // If an `OnNavigateAsync` task is currently in progress, then wait
         // for it to complete before rendering. Note: because _previousOnNavigateTask
         // is initialized to a CompletedTask on initialization, this will still
         // allow first-render to complete successfully.
-        if (_previousOnNavigateTask.Status != TaskStatus.RanToCompletion)
+        if (_previousOnNavigateTask.Status != TaskStatus.RanToCompletion && endpointRouteData is null)
         {
             if (Navigating != null)
             {
                 _renderHandle.Render(Navigating);
+                return;
             }
-            return;
         }
 
         var relativePath = NavigationManager.ToBaseRelativePath(_locationAbsolute.AsSpan());
@@ -239,7 +242,7 @@ internal virtual void Refresh(bool isNavigationIntercepted)
         ComponentsActivityHandle activityHandle;
 
         // In order to avoid routing twice we check for RouteData
-        if (RoutingStateProvider?.RouteData is { } endpointRouteData)
+        if (endpointRouteData is not null)
         {
             activityHandle = RecordDiagnostics(endpointRouteData.PageType.FullName, endpointRouteData.Template);
 

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

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System.Net.Http;
+using System;
 using Components.TestServer.RazorComponents;
 using Microsoft.AspNetCore.Components.E2ETest;
 using Microsoft.AspNetCore.Components.E2ETest.Infrastructure;
@@ -125,6 +126,25 @@ public void BrowserNavigationToNotExistingPath_ReExecutesTo404(bool streaming)
         AssertReExecutionPageRendered();
     }
 
+    [Fact]
+    public void BrowserNavigationToNotExistingPath_WithOnNavigateAsync_ReExecutesTo404()
+    {
+        AppContext.SetSwitch("Microsoft.AspNetCore.Components.Endpoints.NavigationManager.DisableThrowNavigationException", isEnabled: true);
+
+        // using query for controlling router parameters does not work in re-execution scenario, we have to rely on other communication channel
+        const string useOnNavigateAsyncSwitch = "Components.TestServer.RazorComponents.UseOnNavigateAsync";
+        AppContext.SetSwitch(useOnNavigateAsyncSwitch, true);
+        try
+        {
+            Navigate($"{ServerPathBase}/reexecution/not-existing-page");
+            AssertReExecutionPageRendered();
+        }
+        finally
+        {
+            AppContext.SetSwitch(useOnNavigateAsyncSwitch, false);
+        }
+    }
+
     private void AssertReExecutionPageRendered() =>
         Browser.Equal("Welcome On Page Re-executed After Not Found Event", () => Browser.Exists(By.Id("test-info")).Text);
 

src/Components/test/testassets/Components.TestServer/RazorComponents/App.razor

@@ -3,6 +3,10 @@
 @using Components.WasmMinimal.Pages.NotFound
 @using TestContentPackage.NotFound
 @using Components.TestServer.RazorComponents
+@using Microsoft.AspNetCore.Components
+@using Microsoft.AspNetCore.Components.Routing
+@using Microsoft.AspNetCore.Components.Web
+@using System.Threading.Tasks
 
 @code {
     [Parameter]
@@ -17,8 +21,14 @@
     [SupplyParameterFromQuery(Name = "appSetsEventArgsPath")]
     public bool AppSetsEventArgsPath { get; set; }
 
+    [Parameter]
+    [SupplyParameterFromQuery(Name = "useOnNavigateAsync")]
+    public string? UseOnNavigateAsync { get; set; }
+
     private Type? NotFoundPageType { get; set; }
     private NavigationManager _navigationManager = default!;
+    private bool ShouldDelayOnNavigateAsync
+        => bool.TryParse(UseOnNavigateAsync, out var result) && result;
 
     [Inject]
     private NavigationManager NavigationManager
@@ -70,6 +80,21 @@
             _navigationManager.OnNotFound -= OnNotFoundEvent;
         }
     }
+
+    private Task HandleOnNavigateAsync(NavigationContext args)
+    {
+        if (!ShouldDelayOnNavigateAsync)
+        {
+            return Task.CompletedTask;
+        }
+
+        return PerformOnNavigateAsyncWork();
+    }
+
+    private async Task PerformOnNavigateAsyncWork()
+    {
+        await Task.Yield();
+    }
 }
 
 <!DOCTYPE html>
@@ -93,7 +118,7 @@
     {
         @if (NotFoundPageType is not null)
         {
-            <Router AppAssembly="@typeof(App).Assembly" AdditionalAssemblies="new[] { typeof(TestContentPackage.NotFound.NotFoundPage).Assembly }" NotFoundPage="NotFoundPageType">
+            <Router AppAssembly="@typeof(App).Assembly" AdditionalAssemblies="new[] { typeof(TestContentPackage.NotFound.NotFoundPage).Assembly }" NotFoundPage="NotFoundPageType" OnNavigateAsync="HandleOnNavigateAsync">
                 <Found Context="routeData">
                     <RouteView RouteData="@routeData" />
                     <FocusOnNavigate RouteData="@routeData" Selector="[data-focus-on-navigate]" />
@@ -102,7 +127,7 @@
         }
         else
         {
-            <Router AppAssembly="@typeof(App).Assembly" AdditionalAssemblies="new[] { typeof(TestContentPackage.NotFound.NotFoundPage).Assembly }">
+            <Router AppAssembly="@typeof(App).Assembly" AdditionalAssemblies="new[] { typeof(TestContentPackage.NotFound.NotFoundPage).Assembly }" OnNavigateAsync="HandleOnNavigateAsync">
                 <Found Context="routeData">
                     <RouteView RouteData="@routeData" />
                     <FocusOnNavigate RouteData="@routeData" Selector="[data-focus-on-navigate]" />