Clear caches from more places on a hot reload event

src/Components/Components/src/ComponentFactory.cs

@@ -11,7 +11,7 @@
 
 namespace Microsoft.AspNetCore.Components
 {
-    internal class ComponentFactory
+    internal sealed class ComponentFactory
     {
         private static readonly BindingFlags _injectablePropertyBindingFlags
             = BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic;
@@ -25,6 +25,8 @@ public ComponentFactory(IComponentActivator componentActivator)
             _componentActivator = componentActivator ?? throw new ArgumentNullException(nameof(componentActivator));
         }
 
+        public void ClearCache() => _cachedInitializers.Clear();
+
         public IComponent InstantiateComponent(IServiceProvider serviceProvider, [DynamicallyAccessedMembers(Component)] Type componentType)
         {
             var component = _componentActivator.CreateInstance(componentType);

src/Components/Components/src/Microsoft.AspNetCore.Components.WarningSuppressions.xml

@@ -17,7 +17,7 @@
       <argument>ILLink</argument>
       <argument>IL2026</argument>
       <property name="Scope">member</property>
-      <property name="Target">M:Microsoft.AspNetCore.Components.RouteTableFactory.&lt;GetRouteableComponents&gt;g__GetRouteableComponents|3_0(System.Collections.Generic.List{System.Type},System.Reflection.Assembly)</property>
+      <property name="Target">M:Microsoft.AspNetCore.Components.RouteTableFactory.&lt;GetRouteableComponents&gt;g__GetRouteableComponents|4_0(System.Collections.Generic.List{System.Type},System.Reflection.Assembly)</property>
     </attribute>
     <attribute fullname="System.Diagnostics.CodeAnalysis.UnconditionalSuppressMessageAttribute">
       <argument>ILLink</argument>

src/Components/Components/src/Reflection/ComponentProperties.cs

@@ -20,6 +20,8 @@ internal static class ComponentProperties
         private readonly static ConcurrentDictionary<Type, WritersForType> _cachedWritersByType
             = new ConcurrentDictionary<Type, WritersForType>();
 
+        public static void ClearCache() => _cachedWritersByType.Clear();
+
         public static void SetProperties(in ParameterView parameters, object target)
         {
             if (target == null)

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

@@ -10,6 +10,7 @@
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Components.HotReload;
+using Microsoft.AspNetCore.Components.Reflection;
 using Microsoft.AspNetCore.Components.Rendering;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Logging;
@@ -126,6 +127,10 @@ private static IComponentActivator GetComponentActivatorOrDefault(IServiceProvid
 
         private async void RenderRootComponentsOnHotReload()
         {
+            // Before re-rendering the root component, also clear any well-known caches in the framework
+            _componentFactory.ClearCache();
+            ComponentProperties.ClearCache();
+
             await Dispatcher.InvokeAsync(() =>
             {
                 if (_rootComponents is null)

src/Components/Components/src/Routing/RouteTableFactory.cs

@@ -30,6 +30,8 @@ public static RouteTable Create(RouteKey routeKey)
             return routeTable;
         }
 
+        public static void ClearCaches() => Cache.Clear();
+
         private static List<Type> GetRouteableComponents(RouteKey routeKey)
         {
             var routeableComponents = new List<Type>();

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

@@ -9,6 +9,7 @@
 using System.Runtime.ExceptionServices;
 using System.Threading;
 using System.Threading.Tasks;
+using Microsoft.AspNetCore.Components.HotReload;
 using Microsoft.Extensions.Logging;
 
 namespace Microsoft.AspNetCore.Components.Routing
@@ -33,7 +34,7 @@ static readonly IReadOnlyDictionary<string, object> _emptyParametersDictionary
 
         private Task _previousOnNavigateTask = Task.CompletedTask;
 
-        private RouteKey _currentRouteKey;
+        private RouteKey _routeTableLastBuiltForRouteKey;
 
         private bool _onNavigateCalled = false;
 
@@ -91,6 +92,11 @@ public void Attach(RenderHandle renderHandle)
             _baseUri = NavigationManager.BaseUri;
             _locationAbsolute = NavigationManager.Uri;
             NavigationManager.LocationChanged += OnLocationChanged;
+
+            if  (HotReloadFeature.IsSupported)
+            {
+                HotReloadManager.OnDeltaApplied += ClearRouteCaches;
+            }
         }
 
         /// <inheritdoc />
@@ -131,6 +137,10 @@ public async Task SetParametersAsync(ParameterView parameters)
         public void Dispose()
         {
             NavigationManager.LocationChanged -= OnLocationChanged;
+            if (HotReloadFeature.IsSupported)
+            {
+                HotReloadManager.OnDeltaApplied -= ClearRouteCaches;
+            }
         }
 
         private static string StringUntilAny(string str, char[] chars)
@@ -145,13 +155,19 @@ private void RefreshRouteTable()
         {
             var routeKey = new RouteKey(AppAssembly, AdditionalAssemblies);
 
-            if (!routeKey.Equals(_currentRouteKey))
+            if (!routeKey.Equals(_routeTableLastBuiltForRouteKey))
             {
-                _currentRouteKey = routeKey;
+                _routeTableLastBuiltForRouteKey = routeKey;
                 Routes = RouteTableFactory.Create(routeKey);
             }
         }
 
+        private void ClearRouteCaches()
+        {
+            RouteTableFactory.ClearCaches();
+            _routeTableLastBuiltForRouteKey = default;
+        }
+
         internal virtual void Refresh(bool isNavigationIntercepted)
         {
             // If an `OnNavigateAsync` task is currently in progress, then wait

src/Components/Forms/src/EditContextDataAnnotationsExtensions.cs

@@ -7,7 +7,11 @@
 using System.ComponentModel.DataAnnotations;
 using System.Diagnostics.CodeAnalysis;
 using System.Reflection;
+using System.Reflection.Metadata;
 using System.Runtime.InteropServices;
+using Microsoft.AspNetCore.Components.HotReload;
+
+[assembly: MetadataUpdateHandler(typeof(Microsoft.AspNetCore.Components.Forms.EditContextDataAnnotationsExtensions))]
 
 namespace Microsoft.AspNetCore.Components.Forms
 {
@@ -37,6 +41,13 @@ public static IDisposable EnableDataAnnotationsValidation(this EditContext editC
             return new DataAnnotationsEventSubscriptions(editContext);
         }
 
+        private static event Action? OnClearCache;
+
+        private static void ClearCache(Type[]? _)
+        {
+            OnClearCache?.Invoke();
+        }
+
         private sealed class DataAnnotationsEventSubscriptions : IDisposable
         {
             private static readonly ConcurrentDictionary<(Type ModelType, string FieldName), PropertyInfo?> _propertyInfoCache = new();
@@ -51,6 +62,11 @@ public DataAnnotationsEventSubscriptions(EditContext editContext)
 
                 _editContext.OnFieldChanged += OnFieldChanged;
                 _editContext.OnValidationRequested += OnValidationRequested;
+
+                if (HotReloadFeature.IsSupported)
+                {
+                    OnClearCache += ClearCache;
+                }
             }
 
             private void OnFieldChanged(object? sender, FieldChangedEventArgs eventArgs)
@@ -115,6 +131,11 @@ public void Dispose()
                 _editContext.OnFieldChanged -= OnFieldChanged;
                 _editContext.OnValidationRequested -= OnValidationRequested;
                 _editContext.NotifyValidationStateChanged();
+
+                if (HotReloadFeature.IsSupported)
+                {
+                    OnClearCache -= ClearCache;
+                }
             }
 
             private static bool TryGetValidatableProperty(in FieldIdentifier fieldIdentifier, [NotNullWhen(true)] out PropertyInfo? propertyInfo)
@@ -132,6 +153,11 @@ private static bool TryGetValidatableProperty(in FieldIdentifier fieldIdentifier
 
                 return propertyInfo != null;
             }
+
+            internal void ClearCache()
+            {
+                _propertyInfoCache.Clear();
+            }
         }
     }
 }

src/Components/Forms/src/Microsoft.AspNetCore.Components.Forms.csproj

@@ -9,8 +9,19 @@
     <Trimmable>true</Trimmable>
   </PropertyGroup>
 
+  <ItemGroup>
+    <None Remove="Properties\ILLink.Substitutions.xml" />
+  </ItemGroup>
+
   <ItemGroup>
     <Reference Include="Microsoft.AspNetCore.Components" />
+    <Compile Include="$(ComponentsSharedSourceRoot)src\HotReloadFeature.cs" LinkBase="HotReload" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <EmbeddedResource Include="Properties\ILLink.Substitutions.xml">
+      <LogicalName>ILLink.Substitutions.xml</LogicalName>
+    </EmbeddedResource>
   </ItemGroup>
 
 </Project>

src/Components/Forms/src/Properties/ILLink.Substitutions.xml

@@ -0,0 +1,7 @@
+<linker>
+  <assembly fullname="Microsoft.AspNetCore.Components.Forms">
+    <type fullname="Microsoft.AspNetCore.Components.HotReload.HotReloadFeature" feature="System.Diagnostics.Debugger.IsSupported" featurevalue="false">
+      <method signature="System.Boolean get_IsSupported()" body="stub" value="false"  />
+    </type>
+  </assembly>
+</linker>

src/JSInterop/Microsoft.JSInterop/src/Infrastructure/DotNetDispatcher.cs

@@ -6,11 +6,14 @@
 using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
 using System.Reflection;
+using System.Reflection.Metadata;
 using System.Runtime.ExceptionServices;
 using System.Text;
 using System.Text.Json;
 using System.Threading.Tasks;
 
+[assembly: MetadataUpdateHandler(typeof(Microsoft.JSInterop.Infrastructure.DotNetDispatcher))]
+
 namespace Microsoft.JSInterop.Infrastructure
 {
     /// <summary>
@@ -426,6 +429,12 @@ private static Assembly GetRequiredLoadedAssembly(AssemblyKey assemblyKey)
                 ?? throw new ArgumentException($"There is no loaded assembly with the name '{assemblyKey.AssemblyName}'.");
         }
 
+        private static void ClearCache(Type[]? _)
+        {
+            _cachedMethodsByAssembly.Clear();
+            _cachedMethodsByType.Clear();
+        }
+
         private readonly struct AssemblyKey : IEquatable<AssemblyKey>
         {
             public AssemblyKey(Assembly assembly)