[BREAKING] Obsoleting ReflectingExecutor in favor of source gen

dotnet/samples/GettingStarted/Workflows/Concurrent/Concurrent/Program.cs

@@ -72,8 +72,8 @@ private static async Task Main()
 /// <summary>
 /// Executor that starts the concurrent processing by sending messages to the agents.
 /// </summary>
-internal sealed class ConcurrentStartExecutor() :
-    Executor<string>("ConcurrentStartExecutor")
+internal sealed partial class ConcurrentStartExecutor() :
+    Executor("ConcurrentStartExecutor")
 {
     /// <summary>
     /// Starts the concurrent processing by sending messages to the agents.
@@ -83,7 +83,8 @@ internal sealed class ConcurrentStartExecutor() :
     /// <param name="cancellationToken">The <see cref="CancellationToken"/> to monitor for cancellation requests.
     /// The default is <see cref="CancellationToken.None"/>.</param>
     /// <returns>A task representing the asynchronous operation</returns>
-    public override async ValueTask HandleAsync(string message, IWorkflowContext context, CancellationToken cancellationToken = default)
+    [MessageHandler]
+    public async ValueTask HandleAsync(string message, IWorkflowContext context, CancellationToken cancellationToken = default)
     {
         // Broadcast the message to all connected agents. Receiving agents will queue
         // the message but will not start processing until they receive a turn token.

dotnet/samples/GettingStarted/Workflows/Directory.Build.props

@@ -0,0 +1,13 @@
+<Project>
+
+  <Import Project="$([MSBuild]::GetPathOfFileAbove('Directory.Build.props', '$(MSBuildThisFileDirectory)../'))" />
+
+  <!-- Include Workflows source generator for samples using [MessageHandler] attribute -->
+  <ItemGroup>
+    <ProjectReference Include="$(RepoRoot)/dotnet/src/Microsoft.Agents.AI.Workflows.Generators/Microsoft.Agents.AI.Workflows.Generators.csproj"
+                      OutputItemType="Analyzer"
+                      ReferenceOutputAssembly="false"
+                      GlobalPropertiesToRemove="TargetFramework" />
+  </ItemGroup>
+
+</Project>

dotnet/src/Microsoft.Agents.AI.Workflows/Executor.cs

@@ -1,5 +1,7 @@
 // Copyright (c) Microsoft. All rights reserved.
 
+#pragma warning disable CS0618 // Type or member is obsolete - Internal use of obsolete types for backward compatibility
+
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;

dotnet/src/Microsoft.Agents.AI.Workflows/Reflection/IMessageHandler.cs

@@ -1,5 +1,6 @@
 // Copyright (c) Microsoft. All rights reserved.
 
+using System;
 using System.Threading;
 using System.Threading.Tasks;
 
@@ -9,6 +10,12 @@ namespace Microsoft.Agents.AI.Workflows.Reflection;
 /// A message handler interface for handling messages of type <typeparamref name="TMessage"/>.
 /// </summary>
 /// <typeparam name="TMessage"></typeparam>
+/// <remarks>
+/// This interface is obsolete. Use the <see cref="MessageHandlerAttribute"/> on methods in a partial class
+/// deriving from <see cref="Executor"/> instead.
+/// </remarks>
+[Obsolete("Use [MessageHandler] attribute on methods in a partial class deriving from Executor. " +
+          "This interface will be removed in a future version.")]
 public interface IMessageHandler<TMessage>
 {
     /// <summary>
@@ -28,6 +35,12 @@ public interface IMessageHandler<TMessage>
 /// </summary>
 /// <typeparam name="TMessage">The type of message to handle.</typeparam>
 /// <typeparam name="TResult">The type of result returned after handling the message.</typeparam>
+/// <remarks>
+/// This interface is obsolete. Use the <see cref="MessageHandlerAttribute"/> on methods in a partial class
+/// deriving from <see cref="Executor"/> instead.
+/// </remarks>
+[Obsolete("Use [MessageHandler] attribute on methods in a partial class deriving from Executor. " +
+          "This interface will be removed in a future version.")]
 public interface IMessageHandler<TMessage, TResult>
 {
     /// <summary>

dotnet/src/Microsoft.Agents.AI.Workflows/Reflection/MessageHandlerInfo.cs

@@ -1,5 +1,7 @@
 // Copyright (c) Microsoft. All rights reserved.
 
+#pragma warning disable CS0618 // Type or member is obsolete - Internal use of obsolete types for backward compatibility
+
 using System;
 using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;

dotnet/src/Microsoft.Agents.AI.Workflows/Reflection/ReflectingExecutor.cs

@@ -1,5 +1,6 @@
 // Copyright (c) Microsoft. All rights reserved.
 
+using System;
 using System.Diagnostics.CodeAnalysis;
 
 namespace Microsoft.Agents.AI.Workflows.Reflection;
@@ -10,6 +11,12 @@ namespace Microsoft.Agents.AI.Workflows.Reflection;
 /// <typeparam name="TExecutor">The actual type of the <see cref="ReflectingExecutor{TExecutor}"/>.
 /// This is used to reflectively discover handlers for messages without violating ILTrim requirements.
 /// </typeparam>
+/// <remarks>
+/// This type is obsolete. Use the <see cref="MessageHandlerAttribute"/> on methods in a partial class
+/// deriving from <see cref="Executor"/> instead.
+/// </remarks>
+[Obsolete("Use [MessageHandler] attribute on methods in a partial class deriving from Executor. " +
+          "This type will be removed in a future version.")]
 public class ReflectingExecutor<
     [DynamicallyAccessedMembers(
         ReflectionDemands.RuntimeInterfaceDiscoveryAndInvocation)

dotnet/src/Microsoft.Agents.AI.Workflows/Reflection/RouteBuilderExtensions.cs

@@ -1,5 +1,7 @@
 // Copyright (c) Microsoft. All rights reserved.
 
+#pragma warning disable CS0618 // Type or member is obsolete - Internal use of obsolete types for backward compatibility
+
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;

dotnet/src/Microsoft.Agents.AI.Workflows/StatefulExecutor.cs

@@ -1,5 +1,7 @@
 // Copyright (c) Microsoft. All rights reserved.
 
+#pragma warning disable CS0618 // Type or member is obsolete - Internal use of obsolete types for backward compatibility
+
 using System;
 using System.Threading;
 using System.Threading.Tasks;

dotnet/tests/Microsoft.Agents.AI.Workflows.UnitTests/ReflectionSmokeTest.cs

@@ -1,5 +1,7 @@
 // Copyright (c) Microsoft. All rights reserved.
 
+#pragma warning disable CS0618 // Type or member is obsolete - Testing legacy reflection-based pattern
+
 using System;
 using System.Threading;
 using System.Threading.Tasks;

dotnet/tests/Microsoft.Agents.AI.Workflows.UnitTests/Sample/01_Simple_Workflow_Sequential.cs

@@ -1,5 +1,7 @@
 // Copyright (c) Microsoft. All rights reserved.
 
+#pragma warning disable CS0618 // Type or member is obsolete - Testing legacy reflection-based pattern
+
 using System;
 using System.IO;
 using System.Linq;

dotnet/tests/Microsoft.Agents.AI.Workflows.UnitTests/Sample/02_Simple_Workflow_Condition.cs

@@ -1,5 +1,7 @@
 // Copyright (c) Microsoft. All rights reserved.
 
+#pragma warning disable CS0618 // Type or member is obsolete - Testing legacy reflection-based pattern
+
 using System;
 using System.IO;
 using System.Linq;

dotnet/tests/Microsoft.Agents.AI.Workflows.UnitTests/Sample/03_Simple_Workflow_Loop.cs

@@ -1,5 +1,7 @@
 // Copyright (c) Microsoft. All rights reserved.
 
+#pragma warning disable CS0618 // Type or member is obsolete - Testing legacy reflection-based pattern
+
 using System;
 using System.IO;
 using System.Threading;