Support for trimming and AOT

src/NServiceBus.Core.Tests/MessageMutators/MutateInstanceMessage/MutateIncomingMessageBehaviorTests.cs

@@ -165,6 +165,25 @@ public async Task When_mutator_uses_the_object_setter_should_use_the_object_over
         }
     }
 
+    [Test]
+    public async Task When_typed_replacement_is_followed_by_object_setter_should_use_the_object_overload()
+    {
+        var behavior = new MutateIncomingMessageBehavior([]);
+
+        var context = new InterceptUpdateMessageIncomingLogicalMessageContext();
+
+        context.Services.AddTransient<IMutateIncomingMessages>(sp => new MutatorWhichDeclaresAMessageType());
+        context.Services.AddTransient<IMutateIncomingMessages>(sp => new MutatorWhichMutatesTheBody());
+
+        await behavior.Invoke(context, ctx => Task.CompletedTask);
+
+        using (Assert.EnterMultipleScope())
+        {
+            Assert.That(context.UpdateMessageWithTypeCalled, Is.False);
+            Assert.That(context.UpdateMessageObjCalled, Is.True);
+        }
+    }
+
     class InterceptUpdateMessageIncomingLogicalMessageContext : TestableIncomingLogicalMessageContext
     {
         public bool UpdateMessageCalled { get; private set; }

src/NServiceBus.Core.Tests/MessageMutators/MutateInstanceMessage/MutateOutgoingMessageBehaviorTests.cs

@@ -161,6 +161,25 @@ public async Task When_mutator_uses_the_object_setter_should_use_the_object_over
         }
     }
 
+    [Test]
+    public async Task When_typed_replacement_is_followed_by_object_setter_should_use_the_object_overload()
+    {
+        var behavior = new MutateOutgoingMessageBehavior([]);
+
+        var context = new InterceptUpdateMessageOutgoingLogicalMessageContext();
+
+        context.Services.AddTransient<IMutateOutgoingMessages>(sp => new MutatorWhichDeclaresAMessageType());
+        context.Services.AddTransient<IMutateOutgoingMessages>(sp => new MutatorWhichMutatesTheBody());
+
+        await behavior.Invoke(context, ctx => Task.CompletedTask);
+
+        using (Assert.EnterMultipleScope())
+        {
+            Assert.That(context.UpdateMessageWithTypeCalled, Is.False);
+            Assert.That(context.UpdateMessageObjCalled, Is.True);
+        }
+    }
+
     class InterceptUpdateMessageOutgoingLogicalMessageContext : TestableOutgoingLogicalMessageContext
     {
         public bool UpdateMessageCalled { get; private set; }

src/NServiceBus.Core.Tests/TrimmedEndpointTests.cs

@@ -35,8 +35,8 @@ public async Task Scanner_disabled_endpoint_publishes_trimmed_and_processes_a_me
 
             // The AddMessageType and AddHandler calls in the sample are intercepted by source generators. If they
             // were not intercepted, the RequiresUnreferencedCode fallback would surface as IL2026 trim warnings at
-            // the sample's own call sites. Trim warnings inside NServiceBus.Core itself are tracked separately by
-            // the TrimmabilityWarnings approval test.
+            // the sample's own call sites. Trim warnings inside NServiceBus.Core itself fail the Core build via
+            // EnableTrimAnalyzer.
             var sampleTrimWarnings = publishResult.Output.Split(Environment.NewLine)
                 .Where(line => line.Contains("Program.cs") && line.Contains("IL2026"))
                 .ToArray();

src/NServiceBus.Core/EndpointCreator.cs

@@ -193,13 +193,14 @@ void Configure()
 
     void ConfigureMessageTypes(IEnumerable<Type> messageTypesHandled)
     {
-        var allowDynamicTypeLoading = settings.IsDynamicTypeLoadingEnabled();
+        var configuredDynamicTypeLoading = settings.IsDynamicTypeLoadingEnabled();
         var strictMode = settings.Get<AssemblyScanningComponent.Configuration>().StrictRegisteredOnlyMode;
         var messageMetadataRegistry = settings.GetOrCreate<MessageMetadataRegistry>();
         // Strict mode is the stronger non-overridable policy: it must be in effect before Initialize so
         // pre-initialization registrations are enforced against it, and it disables dynamic type loading.
+        var allowDynamicTypeLoading = configuredDynamicTypeLoading && !strictMode;
         messageMetadataRegistry.StrictRegisteredOnlyMode = strictMode;
-        messageMetadataRegistry.Initialize(conventions.IsMessageType, allowDynamicTypeLoading && !strictMode);
+        messageMetadataRegistry.Initialize(conventions.IsMessageType, allowDynamicTypeLoading);
 
         messageMetadataRegistry.RegisterMessageTypes(hostingConfiguration.AvailableTypes);
         messageMetadataRegistry.RegisterMessageTypesBypassingChecks(messageTypesHandled);

src/NServiceBus.Core/MessageMutators/MutateInstanceMessage/MutateIncomingMessageContext.cs

@@ -40,6 +40,8 @@ public object Message
         {
             ArgumentNullException.ThrowIfNull(value);
             MessageInstanceChanged = true;
+            // The setter declares no message type, so drop any type declared by an earlier replacement.
+            ReplacementMessageType = null;
             message = value;
         }
     }

src/NServiceBus.Core/MessageMutators/MutateInstanceMessage/MutateOutgoingMessageContext.cs

@@ -42,6 +42,8 @@ public object OutgoingMessage
         {
             ArgumentNullException.ThrowIfNull(value);
             MessageInstanceChanged = true;
+            // The setter declares no message type, so drop any type declared by an earlier replacement.
+            ReplacementMessageType = null;
             outgoingMessage = value;
         }
     }

src/NServiceBus.Core/NServiceBus.Core.csproj

@@ -6,6 +6,7 @@
     <SignAssembly>true</SignAssembly>
     <AssemblyOriginatorKeyFile>..\NServiceBus.snk</AssemblyOriginatorKeyFile>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
+    <IsTrimmable>true</IsTrimmable>
   </PropertyGroup>
 
   <ItemGroup>

src/NServiceBus.Core/Routing/AssemblyRouteSource.cs

@@ -19,10 +19,12 @@ public AssemblyRouteSource(Assembly messageAssembly, UnicastRoute route)
         this.route = route;
     }
 
-    [RequiresUnreferencedCode(TrimmingMessage)]
+    [UnconditionalSuppressMessage("Trimming", "IL2026", Justification = "Scanning the configured assembly is intentional; this source can only be constructed through APIs annotated with RequiresUnreferencedCode.")]
+    static Type[] ScanAssemblyTypes(Assembly assembly) => assembly.GetTypes();
+
     public IEnumerable<RouteTableEntry> GenerateRoutes(Conventions conventions)
     {
-        var routes = messageAssembly.GetTypes()
+        var routes = ScanAssemblyTypes(messageAssembly)
             .Where(t => conventions.IsMessageType(t))
             .Select(t => new RouteTableEntry(t, route))
             .ToArray();

src/NServiceBus.Core/Routing/MessageDrivenSubscriptions/AssemblyPublisherSource.cs

@@ -19,10 +19,12 @@ public AssemblyPublisherSource(Assembly messageAssembly, PublisherAddress addres
         this.address = address;
     }
 
-    [RequiresUnreferencedCode(TrimmingMessage)]
+    [UnconditionalSuppressMessage("Trimming", "IL2026", Justification = "Scanning the configured assembly is intentional; this source can only be constructed through APIs annotated with RequiresUnreferencedCode.")]
+    static Type[] ScanAssemblyTypes(Assembly assembly) => assembly.GetTypes();
+
     public IEnumerable<PublisherTableEntry> GenerateWithBestPracticeEnforcement(Conventions conventions)
     {
-        var entries = messageAssembly.GetTypes()
+        var entries = ScanAssemblyTypes(messageAssembly)
             .Where(conventions.IsEventType)
             .Select(t => new PublisherTableEntry(t, address))
             .ToArray();
@@ -35,10 +37,9 @@ public IEnumerable<PublisherTableEntry> GenerateWithBestPracticeEnforcement(Conv
         return entries;
     }
 
-    [RequiresUnreferencedCode(TrimmingMessage)]
     public IEnumerable<PublisherTableEntry> GenerateWithoutBestPracticeEnforcement(Conventions conventions)
     {
-        var entries = messageAssembly.GetTypes()
+        var entries = ScanAssemblyTypes(messageAssembly)
             .Where(type => conventions.IsMessageType(type) && !conventions.IsCommandType(type))
             .Select(t => new PublisherTableEntry(t, address))
             .ToArray();

src/NServiceBus.Core/Routing/MessageDrivenSubscriptions/NamespacePublisherSource.cs

@@ -13,17 +13,20 @@ class NamespacePublisherSource : IPublisherSource
     readonly string messageNamespace;
     readonly PublisherAddress address;
 
+    [RequiresUnreferencedCode(AssemblyPublisherSource.TrimmingMessage)]
     public NamespacePublisherSource(Assembly messageAssembly, string messageNamespace, PublisherAddress address)
     {
         this.messageAssembly = messageAssembly;
         this.address = address;
         this.messageNamespace = messageNamespace;
     }
 
-    [UnconditionalSuppressMessage("Trimming", "IL2026", Justification = "The public namespace publisher API is annotated with RequiresUnreferencedCode because this source intentionally scans the configured assembly.")]
+    [UnconditionalSuppressMessage("Trimming", "IL2026", Justification = "Scanning the configured assembly is intentional; this source can only be constructed through APIs annotated with RequiresUnreferencedCode.")]
+    static Type[] ScanAssemblyTypes(Assembly assembly) => assembly.GetTypes();
+
     public IEnumerable<PublisherTableEntry> GenerateWithBestPracticeEnforcement(Conventions conventions)
     {
-        var entries = messageAssembly.GetTypes()
+        var entries = ScanAssemblyTypes(messageAssembly)
             .Where(t => conventions.IsEventType(t) && string.Equals(t.Namespace, messageNamespace, StringComparison.OrdinalIgnoreCase))
             .Select(t => new PublisherTableEntry(t, address))
             .ToArray();
@@ -36,10 +39,9 @@ public IEnumerable<PublisherTableEntry> GenerateWithBestPracticeEnforcement(Conv
         return entries;
     }
 
-    [UnconditionalSuppressMessage("Trimming", "IL2026", Justification = "The public namespace publisher API is annotated with RequiresUnreferencedCode because this source intentionally scans the configured assembly.")]
     public IEnumerable<PublisherTableEntry> GenerateWithoutBestPracticeEnforcement(Conventions conventions)
     {
-        var entries = messageAssembly.GetTypes()
+        var entries = ScanAssemblyTypes(messageAssembly)
             .Where(t => conventions.IsMessageType(t) && !conventions.IsCommandType(t) && string.Equals(t.Namespace, messageNamespace, StringComparison.OrdinalIgnoreCase))
             .Select(t => new PublisherTableEntry(t, address))
             .ToArray();

src/NServiceBus.Core/Routing/NamespaceRouteSource.cs

@@ -21,10 +21,12 @@ public NamespaceRouteSource(Assembly messageAssembly, string messageNamespace, U
         this.messageNamespace = messageNamespace;
     }
 
-    [RequiresUnreferencedCode(AssemblyRouteSource.TrimmingMessage)]
+    [UnconditionalSuppressMessage("Trimming", "IL2026", Justification = "Scanning the configured assembly is intentional; this source can only be constructed through APIs annotated with RequiresUnreferencedCode.")]
+    static Type[] ScanAssemblyTypes(Assembly assembly) => assembly.GetTypes();
+
     public IEnumerable<RouteTableEntry> GenerateRoutes(Conventions conventions)
     {
-        var routes = messageAssembly.GetTypes()
+        var routes = ScanAssemblyTypes(messageAssembly)
             .Where(t => conventions.IsMessageType(t) && string.Equals(t.Namespace, messageNamespace, StringComparison.OrdinalIgnoreCase))
             .Select(t => new RouteTableEntry(t, route))
             .ToArray();