Clear some caches from MVC on hot reload event (#33386)

* Trigger action descriptor provider on hot reload.
* Clear other caches that are keyed off of Type
* Clean up MvcSandbox

Author: pranavkm

src/Components/Web.JS/dist/Release/blazor.server.js

@@ -5,27 +5,19 @@
 using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Linq;
-using System.Threading;
 using Microsoft.AspNetCore.Mvc.Core;
 using Microsoft.Extensions.Internal;
 
 namespace Microsoft.AspNetCore.Mvc.Controllers
 {
-    internal class DefaultControllerPropertyActivator : IControllerPropertyActivator
+    internal sealed class DefaultControllerPropertyActivator : IControllerPropertyActivator
     {
         private static readonly Func<Type, PropertyActivator<ControllerContext>[]> _getPropertiesToActivate =
             GetPropertiesToActivate;
-        private object _initializeLock = new object();
-        private bool _initialized;
-        private ConcurrentDictionary<Type, PropertyActivator<ControllerContext>[]>? _activateActions;
+        private readonly ConcurrentDictionary<Type, PropertyActivator<ControllerContext>[]> _activateActions = new();
 
         public void Activate(ControllerContext context, object controller)
         {
-            LazyInitializer.EnsureInitialized(
-                ref _activateActions,
-                ref _initialized,
-                ref _initializeLock);
-
             var controllerType = controller.GetType();
             var propertiesToActivate = _activateActions!.GetOrAdd(
                 controllerType,
@@ -38,6 +30,8 @@ public void Activate(ControllerContext context, object controller)
             }
         }
 
+        public void ClearCache() => _activateActions.Clear();
+
         public Action<ControllerContext, object> GetActivatorDelegate(ControllerActionDescriptor actionDescriptor)
         {
             if (actionDescriptor == null)

src/Mvc/Mvc.Core/src/Controllers/DefaultControllerPropertyActivator.cs

@@ -12,13 +12,15 @@
 using Microsoft.AspNetCore.Mvc.ApplicationParts;
 using Microsoft.AspNetCore.Mvc.Controllers;
 using Microsoft.AspNetCore.Mvc.Filters;
+using Microsoft.AspNetCore.Mvc.HotReload;
 using Microsoft.AspNetCore.Mvc.Infrastructure;
 using Microsoft.AspNetCore.Mvc.ModelBinding;
 using Microsoft.AspNetCore.Mvc.ModelBinding.Metadata;
 using Microsoft.AspNetCore.Mvc.ModelBinding.Validation;
 using Microsoft.AspNetCore.Mvc.Routing;
 using Microsoft.AspNetCore.Routing;
 using Microsoft.Extensions.DependencyInjection.Extensions;
+using Microsoft.Extensions.Hosting;
 using Microsoft.Extensions.Options;
 
 namespace Microsoft.Extensions.DependencyInjection
@@ -51,13 +53,20 @@ public static IMvcCoreBuilder AddMvcCore(this IServiceCollection services)
                 throw new ArgumentNullException(nameof(services));
             }
 
-            var partManager = GetApplicationPartManager(services);
+            var environment = GetServiceFromCollection<IWebHostEnvironment>(services);
+            var partManager = GetApplicationPartManager(services, environment);
             services.TryAddSingleton(partManager);
 
             ConfigureDefaultFeatureProviders(partManager);
             ConfigureDefaultServices(services);
             AddMvcCoreServices(services);
 
+            if (environment?.IsDevelopment() ?? false)
+            {
+                services.TryAddEnumerable(
+                    ServiceDescriptor.Singleton<IActionDescriptorChangeProvider, HotReloadService>());
+            }
+
             var builder = new MvcCoreBuilder(services, partManager);
 
             return builder;
@@ -71,14 +80,13 @@ private static void ConfigureDefaultFeatureProviders(ApplicationPartManager mana
             }
         }
 
-        private static ApplicationPartManager GetApplicationPartManager(IServiceCollection services)
+        private static ApplicationPartManager GetApplicationPartManager(IServiceCollection services, IWebHostEnvironment? environment)
         {
             var manager = GetServiceFromCollection<ApplicationPartManager>(services);
             if (manager == null)
             {
                 manager = new ApplicationPartManager();
 
-                var environment = GetServiceFromCollection<IWebHostEnvironment>(services);
                 var entryAssemblyName = environment?.ApplicationName;
                 if (string.IsNullOrEmpty(entryAssemblyName))
                 {

src/Mvc/Mvc.Core/src/DependencyInjection/MvcCoreServiceCollectionExtensions.cs

@@ -0,0 +1,64 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Reflection.Metadata;
+using System.Threading;
+using Microsoft.AspNetCore.Mvc.Controllers;
+using Microsoft.AspNetCore.Mvc.Infrastructure;
+using Microsoft.AspNetCore.Mvc.ModelBinding;
+using Microsoft.AspNetCore.Mvc.ModelBinding.Metadata;
+using Microsoft.Extensions.Primitives;
+
+[assembly: MetadataUpdateHandler(typeof(Microsoft.AspNetCore.Mvc.HotReload.HotReloadService))]
+
+namespace Microsoft.AspNetCore.Mvc.HotReload
+{
+    internal sealed class HotReloadService : IActionDescriptorChangeProvider, IDisposable
+    {
+        private readonly DefaultModelMetadataProvider? _modelMetadataProvider;
+        private readonly DefaultControllerPropertyActivator? _controllerPropertyActivator;
+        private CancellationTokenSource _tokenSource = new();
+
+        public HotReloadService(
+            IModelMetadataProvider modelMetadataProvider,
+            IControllerPropertyActivator controllerPropertyActivator)
+        {
+            ClearCacheEvent += NotifyClearCache;
+            if (modelMetadataProvider.GetType() == typeof(DefaultModelMetadataProvider))
+            {
+                _modelMetadataProvider = (DefaultModelMetadataProvider)modelMetadataProvider;
+            }
+
+            if (controllerPropertyActivator is DefaultControllerPropertyActivator defaultControllerPropertyActivator)
+            {
+                _controllerPropertyActivator = defaultControllerPropertyActivator;
+            }
+        }
+
+        public static event Action? ClearCacheEvent;
+
+        public static void ClearCache(Type[]? _)
+        {
+            ClearCacheEvent?.Invoke();
+        }
+
+        IChangeToken IActionDescriptorChangeProvider.GetChangeToken() => new CancellationChangeToken(_tokenSource.Token);
+
+        private void NotifyClearCache()
+        {
+            // Trigger the ActionDescriptorChangeProvider
+            var current = Interlocked.Exchange(ref _tokenSource, new CancellationTokenSource());
+            current.Cancel();
+
+            // Clear individual caches
+            _modelMetadataProvider?.ClearCache();
+            _controllerPropertyActivator?.ClearCache();
+        }
+
+        public void Dispose()
+        {
+            ClearCacheEvent -= NotifyClearCache;
+        }
+    }
+}

src/Mvc/Mvc.Core/src/HotReload/HotReloadService.cs

@@ -19,7 +19,7 @@ namespace Microsoft.AspNetCore.Mvc.ModelBinding.Metadata
     /// </summary>
     public class DefaultModelMetadataProvider : ModelMetadataProvider
     {
-        private readonly ModelMetadataCache _modelMetadataCache = new ModelMetadataCache();
+        private readonly ConcurrentDictionary<ModelMetadataIdentity, ModelMetadataCacheEntry> _modelMetadataCache = new();
         private readonly Func<ModelMetadataIdentity, ModelMetadataCacheEntry> _cacheEntryFactory;
         private readonly ModelMetadataCacheEntry _metadataCacheEntryForObjectType;
 
@@ -71,6 +71,8 @@ private DefaultModelMetadataProvider(
         /// <value>Same as <see cref="MvcOptions.ModelBindingMessageProvider"/> in all production scenarios.</value>
         protected DefaultModelBindingMessageProvider ModelBindingMessageProvider { get; }
 
+        internal void ClearCache() => _modelMetadataCache.Clear();
+
         /// <inheritdoc />
         public override IEnumerable<ModelMetadata> GetMetadataForProperties(Type modelType)
         {
@@ -442,10 +444,6 @@ protected virtual DefaultMetadataDetails CreateParameterDetails(ModelMetadataIde
                 ModelAttributes.GetAttributesForParameter(key.ParameterInfo!, key.ModelType));
         }
 
-        private class ModelMetadataCache : ConcurrentDictionary<ModelMetadataIdentity, ModelMetadataCacheEntry>
-        {
-        }
-
         private readonly struct ModelMetadataCacheEntry
         {
             public ModelMetadataCacheEntry(ModelMetadata metadata, DefaultMetadataDetails details)

src/Mvc/Mvc.Core/src/ModelBinding/Metadata/DefaultModelMetadataProvider.cs

@@ -152,7 +152,7 @@ public void AddMvcCore_UsesOriginalHostingEnvironment()
         {
             // Arrange
             var services = new ServiceCollection();
-            var environment = new Mock<IWebHostEnvironment>(MockBehavior.Strict);
+            var environment = new Mock<IWebHostEnvironment>();
             environment.SetupGet(e => e.ApplicationName).Returns((string)null).Verifiable();
             services.AddSingleton<IWebHostEnvironment>(environment.Object);
 
@@ -173,10 +173,10 @@ public void AddMvcCore_UsesLastHostingEnvironment()
         {
             // Arrange
             var services = new ServiceCollection();
-            var environment = new Mock<IWebHostEnvironment>(MockBehavior.Strict);
+            var environment = new Mock<IWebHostEnvironment>();
             services.AddSingleton<IWebHostEnvironment>(environment.Object);
 
-            environment = new Mock<IWebHostEnvironment>(MockBehavior.Strict);
+            environment = new Mock<IWebHostEnvironment>();
             environment.SetupGet(e => e.ApplicationName).Returns((string)null).Verifiable();
             services.AddSingleton<IWebHostEnvironment>(environment.Object);
 
@@ -196,7 +196,7 @@ public void AddMvcCore_GetsPartsForApplication()
         {
             // Arrange
             var services = new ServiceCollection();
-            var environment = new Mock<IWebHostEnvironment>(MockBehavior.Strict);
+            var environment = new Mock<IWebHostEnvironment>();
             var assemblyName = typeof(MvcCoreServiceCollectionExtensionsTest).Assembly.GetName();
             var applicationName = assemblyName.FullName;
             environment.SetupGet(e => e.ApplicationName).Returns(applicationName).Verifiable();