More effective stopping of the renderer.

Author: ilonatommy

src/Components/Components/src/PublicAPI.Unshipped.txt

@@ -12,3 +12,4 @@ Microsoft.AspNetCore.Components.SupplyParameterFromPersistentComponentStateAttri
 Microsoft.Extensions.DependencyInjection.SupplyParameterFromPersistentComponentStateProviderServiceCollectionExtensions
 static Microsoft.AspNetCore.Components.Infrastructure.RegisterPersistentComponentStateServiceCollectionExtensions.AddPersistentServiceRegistration<TService>(Microsoft.Extensions.DependencyInjection.IServiceCollection! services, Microsoft.AspNetCore.Components.IComponentRenderMode! componentRenderMode) -> Microsoft.Extensions.DependencyInjection.IServiceCollection!
 static Microsoft.Extensions.DependencyInjection.SupplyParameterFromPersistentComponentStateProviderServiceCollectionExtensions.AddSupplyValueFromPersistentComponentStateProvider(this Microsoft.Extensions.DependencyInjection.IServiceCollection! services) -> Microsoft.Extensions.DependencyInjection.IServiceCollection!
+virtual Microsoft.AspNetCore.Components.RenderTree.Renderer.SignalRendererToFinishRendering() -> void

src/Components/Components/src/RenderTree/Renderer.cs

@@ -44,6 +44,7 @@ public abstract partial class Renderer : IDisposable, IAsyncDisposable
     private bool _rendererIsDisposed;
 
     private bool _hotReloadInitialized;
+    private bool _rendererIsStopped;
 
     /// <summary>
     /// Allows the caller to handle exceptions from the SynchronizationContext when one is available.
@@ -658,6 +659,12 @@ internal void AddToRenderQueue(int componentId, RenderFragment renderFragment)
     {
         Dispatcher.AssertAccess();
 
+        if (_rendererIsStopped)
+        {
+            // Once we're stopped, we'll disregard further attempts to queue anything
+            return;
+        }
+
         var componentState = GetOptionalComponentState(componentId);
         if (componentState == null)
         {
@@ -724,14 +731,22 @@ private ComponentState GetRequiredRootComponentState(int componentId)
         return componentState;
     }
 
+    /// <summary>
+    /// Stop adding render requests to the render queue.
+    /// </summary>
+    protected virtual void SignalRendererToFinishRendering()
+    {
+        _rendererIsStopped = true;
+    }
+
     /// <summary>
     /// Processes pending renders requests from components if there are any.
     /// </summary>
     protected virtual void ProcessPendingRender()
     {
-        if (_rendererIsDisposed)
+        if (_rendererIsDisposed || _rendererIsStopped)
         {
-            // Once we're disposed, we'll disregard further attempts to render anything
+            // Once we're disposed or stopped, we'll disregard further attempts to render anything
             return;
         }
 

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

@@ -176,21 +176,10 @@ protected override void AddPendingTask(ComponentState? componentState, Task task
         base.AddPendingTask(componentState, task);
     }
 
-    private void SignalRendererToFinishRendering()
+    protected override void SignalRendererToFinishRendering()
     {
         _rendererIsStopped = true;
-    }
-
-    protected override void ProcessPendingRender()
-    {
-        if (_rendererIsStopped)
-        {
-            // When the application triggers a NotFound event, we continue rendering the current batch.
-            // However, after completing this batch, we do not want to process any further UI updates,
-            // as we are going to return a 404 status and discard the UI updates generated so far.
-            return;
-        }
-        base.ProcessPendingRender();
+        base.SignalRendererToFinishRendering();
     }
 
     // For tests only