[WIP] Experiment: AOT compilation flags

Akka.sln

@@ -279,6 +279,10 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Akka.TestKit.Xunit2.Tests",
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Akka.TestKit.Xunit.Tests", "src\contrib\testkits\Akka.TestKit.Xunit.Tests\Akka.TestKit.Xunit.Tests.csproj", "{F80F41E6-E5C7-4C92-B1CF-42539ECFBE68}"
 EndProject
+Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "AOT", "AOT", "{2E11BBFC-EA1F-4C20-8076-0D8542397264}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Akka.AOT.App", "src\aot\Akka.AOT.App\Akka.AOT.App.csproj", "{6732F90D-59C9-45BA-801A-24BE2A12EB62}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -1318,6 +1322,18 @@ Global
 		{F80F41E6-E5C7-4C92-B1CF-42539ECFBE68}.Release|x64.Build.0 = Release|Any CPU
 		{F80F41E6-E5C7-4C92-B1CF-42539ECFBE68}.Release|x86.ActiveCfg = Release|Any CPU
 		{F80F41E6-E5C7-4C92-B1CF-42539ECFBE68}.Release|x86.Build.0 = Release|Any CPU
+		{6732F90D-59C9-45BA-801A-24BE2A12EB62}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{6732F90D-59C9-45BA-801A-24BE2A12EB62}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{6732F90D-59C9-45BA-801A-24BE2A12EB62}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{6732F90D-59C9-45BA-801A-24BE2A12EB62}.Debug|x64.Build.0 = Debug|Any CPU
+		{6732F90D-59C9-45BA-801A-24BE2A12EB62}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{6732F90D-59C9-45BA-801A-24BE2A12EB62}.Debug|x86.Build.0 = Debug|Any CPU
+		{6732F90D-59C9-45BA-801A-24BE2A12EB62}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{6732F90D-59C9-45BA-801A-24BE2A12EB62}.Release|Any CPU.Build.0 = Release|Any CPU
+		{6732F90D-59C9-45BA-801A-24BE2A12EB62}.Release|x64.ActiveCfg = Release|Any CPU
+		{6732F90D-59C9-45BA-801A-24BE2A12EB62}.Release|x64.Build.0 = Release|Any CPU
+		{6732F90D-59C9-45BA-801A-24BE2A12EB62}.Release|x86.ActiveCfg = Release|Any CPU
+		{6732F90D-59C9-45BA-801A-24BE2A12EB62}.Release|x86.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -1441,6 +1457,7 @@ Global
 		{337A85B5-4A7C-4883-8634-46E7E52A765F} = {7735F35A-E7B7-44DE-B6FB-C770B53EB69C}
 		{95017C99-E960-44E5-83AD-BF21461DF06F} = {7625FD95-4B2C-4A5B-BDD5-94B1493FAC8E}
 		{F80F41E6-E5C7-4C92-B1CF-42539ECFBE68} = {7625FD95-4B2C-4A5B-BDD5-94B1493FAC8E}
+		{6732F90D-59C9-45BA-801A-24BE2A12EB62} = {2E11BBFC-EA1F-4C20-8076-0D8542397264}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {03AD8E21-7507-4E68-A4E9-F4A7E7273164}

build-system/azure.aot.template.yaml

@@ -0,0 +1,33 @@
+parameters:
+  name: ''
+  displayName: ''
+  vmImage: ''
+  run_if: true
+  timeoutInMinutes: 10
+
+jobs:
+  - job: ${{ parameters.name }}
+    condition: eq( ${{ parameters.run_if }}, true )
+    displayName: ${{ parameters.displayName }}
+    timeoutInMinutes: ${{ parameters.timeoutInMinutes }}
+    pool:
+      vmImage: ${{ parameters.vmImage }}
+    steps:
+       - task: UseDotNet@2
+        displayName: 'Use .NET'
+        inputs:
+          packageType: 'sdk'
+          useGlobalJson: true
+
+      # Option 1: Use inline script to handle paths properly
+      - task: PowerShell@2
+        inputs:
+          targetType: 'inline'
+          script: |
+            ./scripts/test-aot-compatibility.ps1 net8.0
+          pwsh: true
+
+      - script: 'echo 1>&2'
+        failOnStderr: true
+        displayName: 'If above is partially succeeded, then fail'
+        condition: eq(variables['Agent.JobStatus'], 'SucceededWithIssues')

build-system/pr-validation.yaml

@@ -112,3 +112,15 @@ jobs:
       command: "dotnet pack -c Release -o bin/nuget"
       outputDirectory: "bin/nuget"
       artifactName: "nuget_pack-$(Build.BuildId)"
+
+  - template: azure.aot.template.yaml
+    parameters:
+      name: "aot_linux"
+      displayName: "AOT Compilation (Linux)"
+      vmImage: "ubuntu-latest"
+
+  - template: azure.aot.template.yaml
+    parameters:
+      name: "aot_windows"
+      displayName: "AOT Compilation (Windows)"
+      vmImage: "windows-latest"

scripts/test-aot-compatibility.ps1

@@ -0,0 +1,64 @@
+param([string]$targetNetFramework = "net8.0")
+
+$rootDirectory = Split-Path $PSScriptRoot -Parent
+$publishOutput = dotnet publish $rootDirectory/src/aot/Akka.AOT.App/Akka.AOT.App.csproj -nodeReuse:false /p:UseSharedCompilation=false /p:ExposeExperimentalFeatures=true
+
+$actualWarningCount = 0
+
+foreach ($line in $($publishOutput -split "`r`n"))
+{
+    if ($line -like "*analysis warning IL*")
+    {
+        Write-Host $line
+
+        $actualWarningCount += 1
+    }
+}
+
+# Determine the OS-specific folder
+$osPlatform = [System.Runtime.InteropServices.RuntimeInformation]::OSDescription
+if ($osPlatform -match "Windows") {
+    $osFolder = "win-x64"
+} else {
+    $osFolder = "linux-x64"
+    # Default to linux
+}
+
+$testAppPath = Join-Path -Path $rootDirectory/src/aot/Akka.AOT.App/bin/Release/$targetNetFramework -ChildPath $osFolder/publish
+
+if (-Not (Test-Path $testAppPath)) {
+    Write-Error "Test App path does not exist: $testAppPath"
+    Exit 1
+}
+
+Write-Host $testAppPath
+pushd $testAppPath
+
+Write-Host "Executing test App..."
+if ($osPlatform -match "Windows") {
+    ./Akka.AOT.App.exe
+} else {
+    # Default to linux
+    ./Akka.AOT.App    
+}
+
+Write-Host "Finished executing test App"
+
+if ($LastExitCode -ne 0)
+{
+  Write-Host "There was an error while executing AotCompatibility Test App. LastExitCode is:", $LastExitCode
+}
+
+popd
+
+Write-Host "Actual warning count is:", $actualWarningCount
+$expectedWarningCount = 0
+
+$testPassed = 0
+if ($actualWarningCount -ne $expectedWarningCount)
+{
+    $testPassed = 1
+    Write-Host "Actual warning count:", $actualWarningCount, "is not as expected. Expected warning count is:", $expectedWarningCount
+}
+
+Exit $testPassed

src/aot/Akka.AOT.App/Actors/AotReceiveActor.cs

@@ -0,0 +1,18 @@
+// -----------------------------------------------------------------------
+//  <copyright file="AotReceiveActor.cs" company="Akka.NET Project">
+//      Copyright (C) 2009-2025 Lightbend Inc. <http://www.lightbend.com>
+//      Copyright (C) 2013-2025 .NET Foundation <https://github.com/akkadotnet/akka.net>
+//  </copyright>
+// -----------------------------------------------------------------------
+
+using Akka.Actor;
+
+namespace Akka.AOT.App.Actors;
+
+public class AotReceiveActor : ReceiveActor
+{
+    public AotReceiveActor()
+    {
+        ReceiveAny(o => Sender.Tell(o));
+    }
+}

src/aot/Akka.AOT.App/Actors/AotUntypedActor.cs

@@ -0,0 +1,18 @@
+// -----------------------------------------------------------------------
+//  <copyright file="AotUntypedActor.cs" company="Akka.NET Project">
+//      Copyright (C) 2009-2025 Lightbend Inc. <http://www.lightbend.com>
+//      Copyright (C) 2013-2025 .NET Foundation <https://github.com/akkadotnet/akka.net>
+//  </copyright>
+// -----------------------------------------------------------------------
+
+using Akka.Actor;
+
+namespace Akka.AOT.App.Actors;
+
+public class AotUntypedActor : UntypedActor
+{
+    protected override void OnReceive(object message)
+    { 
+        Sender.Tell(message);
+    }
+}

src/aot/Akka.AOT.App/Akka.AOT.App.csproj

@@ -0,0 +1,22 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>$(NetTestVersion)</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+
+    <IsPackable>false</IsPackable>
+  </PropertyGroup>
+
+  <PropertyGroup Label="AotSettings">
+    <PublishAot>true</PublishAot>
+    <TrimmerSingleWarn>false</TrimmerSingleWarn>
+    <SelfContained>true</SelfContained>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\core\Akka\Akka.csproj"/>
+  </ItemGroup>
+
+</Project>

src/aot/Akka.AOT.App/Program.cs

@@ -0,0 +1,27 @@
+using Akka.Actor;
+using Akka.AOT.App.Actors;
+
+namespace Akka.AOT.App;
+
+class Program
+{
+    static async Task Main(string[] args)
+    {
+        var system = ActorSystem.Create("MySystem");
+
+        // create AotUntypedActor
+        var untypedActorProps = Props.Create(() => new AotUntypedActor());
+        var untypedActor = system.ActorOf(untypedActorProps, "untyped-actor");
+
+        // create AotReceiveActor
+        var receiveActorProps = Props.Create(() => new AotReceiveActor());
+        var receiveActor = system.ActorOf(receiveActorProps, "receive-actor");
+
+        // send a message to both actors
+        Console.WriteLine(await untypedActor.Ask("Hello, untyped actor!"));
+        Console.WriteLine(await receiveActor.Ask("Hello, receive actor!"));
+
+        // terminate the actor system
+        await system.Terminate();
+    }
+}

src/core/Akka.TestKit/TestKitBase_ActorOf.cs

@@ -6,7 +6,6 @@
 //-----------------------------------------------------------------------
 
 using System;
-using System.Linq.Expressions;
 using Akka.Actor;
 using Akka.Actor.Dsl;
 
@@ -71,7 +70,7 @@ public IActorRef ActorOf(Props props, string name)
         /// <typeparam name="TActor">The type of the actor.</typeparam>
         /// <param name="factory">An expression that calls the constructor of <typeparamref name="TActor"/></param>
         /// <returns>TBD</returns>
-        public IActorRef ActorOf<TActor>(Expression<Func<TActor>> factory) where TActor : ActorBase
+        public IActorRef ActorOf<TActor>(Func<TActor> factory) where TActor : ActorBase
         {
             return Sys.ActorOf(Props.Create(factory), null);
         }
@@ -87,7 +86,7 @@ public IActorRef ActorOf<TActor>(Expression<Func<TActor>> factory) where TActor
         /// <param name="factory">An expression that calls the constructor of <typeparamref name="TActor"/></param>
         /// <param name="name">The name of the actor.</param>
         /// <returns>TBD</returns>
-        public IActorRef ActorOf<TActor>(Expression<Func<TActor>> factory, string name) where TActor : ActorBase
+        public IActorRef ActorOf<TActor>(Func<TActor> factory, string name) where TActor : ActorBase
         {
             return Sys.ActorOf(Props.Create(factory), name);
         }
@@ -201,7 +200,7 @@ public TestActorRef<TActor> ActorOfAsTestActorRef<TActor>(Props props, string na
         /// <param name="supervisor">The supervisor</param>
         /// <param name="name">Optional: The name.</param>
         /// <returns>TBD</returns>
-        public TestActorRef<TActor> ActorOfAsTestActorRef<TActor>(Expression<Func<TActor>> factory, IActorRef supervisor, string name = null) where TActor : ActorBase
+        public TestActorRef<TActor> ActorOfAsTestActorRef<TActor>(Func<TActor> factory, IActorRef supervisor, string name = null) where TActor : ActorBase
         {
             return new TestActorRef<TActor>(Sys, Props.Create(factory), supervisor, name);
         }
@@ -218,7 +217,7 @@ public TestActorRef<TActor> ActorOfAsTestActorRef<TActor>(Expression<Func<TActor
         /// <param name="factory">An expression that calls the constructor of <typeparamref name="TActor"/></param>
         /// <param name="name">Optional: The name.</param>
         /// <returns>TBD</returns>
-        public TestActorRef<TActor> ActorOfAsTestActorRef<TActor>(Expression<Func<TActor>> factory, string name = null) where TActor : ActorBase
+        public TestActorRef<TActor> ActorOfAsTestActorRef<TActor>(Func<TActor> factory, string name = null) where TActor : ActorBase
         {
             return new TestActorRef<TActor>(Sys, Props.Create(factory), NoSupervisor, name);
         }
@@ -333,7 +332,7 @@ public TestFSMRef<TFsmActor, TState, TData> ActorOfAsTestFSMRef<TFsmActor, TStat
         /// <param name="name">Optional: The name.</param>
         /// <param name="withLogging">Optional: If set to <c>true</c> logs state changes of the FSM as Debug messages. Default is <c>false</c>.</param>
         /// <returns>TBD</returns>
-        public TestFSMRef<TFsmActor, TState, TData> ActorOfAsTestFSMRef<TFsmActor, TState, TData>(Expression<Func<TFsmActor>> factory, IActorRef supervisor, string name = null, bool withLogging = false)
+        public TestFSMRef<TFsmActor, TState, TData> ActorOfAsTestFSMRef<TFsmActor, TState, TData>(Func<TFsmActor> factory, IActorRef supervisor, string name = null, bool withLogging = false)
             where TFsmActor : FSM<TState, TData>
         {
             return new TestFSMRef<TFsmActor, TState, TData>(Sys, Props.Create(factory), supervisor, name, withLogging);
@@ -351,7 +350,7 @@ public TestFSMRef<TFsmActor, TState, TData> ActorOfAsTestFSMRef<TFsmActor, TStat
         /// <param name="name">Optional: The name.</param>
         /// <param name="withLogging">Optional: If set to <c>true</c> logs state changes of the FSM as Debug messages. Default is <c>false</c>.</param>
         /// <returns>TBD</returns>
-        public TestFSMRef<TFsmActor, TState, TData> ActorOfAsTestFSMRef<TFsmActor, TState, TData>(Expression<Func<TFsmActor>> factory, string name = null, bool withLogging = false)
+        public TestFSMRef<TFsmActor, TState, TData> ActorOfAsTestFSMRef<TFsmActor, TState, TData>(Func<TFsmActor> factory, string name = null, bool withLogging = false)
             where TFsmActor : FSM<TState, TData>
         {
             return new TestFSMRef<TFsmActor, TState, TData>(Sys, Props.Create(factory), NoSupervisor, name, withLogging);

src/core/Akka/Actor/ActorCell.cs

@@ -223,6 +223,8 @@ public virtual ActorTaskScheduler TaskScheduler
         /// </summary>
         /// <param name="sendSupervise">TBD</param>
         /// <param name="mailboxType">TBD</param>
+        [UnconditionalSuppressMessage("AssemblyFiles", "IL2072",
+            Justification = "All MailboxType implementations in Akka.NET have IProducesMessageQueue<T> interfaces preserved, and all actor types have IRequiresMessageQueue<T> interfaces preserved")]
         public void Init(bool sendSupervise, MailboxType mailboxType)
         {
             /*

src/core/Akka/Actor/Deployer.cs

@@ -134,6 +134,22 @@ private RouterConfig CreateRouterConfig(string routerTypeAlias, Config deploymen
             if (deployment.IsNullOrEmpty())
                 throw ConfigurationException.NullOrEmptyConfig<RouterConfig>();
 
+            #if AOT_ENABLED
+            // In AOT mode, use factory functions from TypeHints
+            if (!Internal.TypeHints.DefaultRouterFactories.TryGetValue(routerTypeAlias, out var factory))
+            {
+                var message = $"Router type '{routerTypeAlias}' is not supported in AOT mode. " +
+                    "Only built-in routers (round-robin, random, smallest-mailbox, broadcast, scatter-gather, " +
+                    "consistent-hashing, tail-chopping) are available.";
+
+                if (routerTypeAlias is "cluster-metrics-adaptive-group" or "cluster-metrics-adaptive-pool")
+                    message += " Cluster metrics routers require Akka.Cluster.Metrics which is not AOT-compatible yet.";
+
+                throw new ConfigurationException(message);
+            }
+
+            return factory(deployment);
+            #else
             var path = string.Format("akka.actor.router.type-mapping.{0}", routerTypeAlias);
             var routerTypeName = _settings.Config.GetString(path, null);
 
@@ -170,6 +186,7 @@ private RouterConfig CreateRouterConfig(string routerTypeAlias, Config deploymen
             var routerConfig = (RouterConfig)Activator.CreateInstance(routerType, deployment);
 
             return routerConfig;
+            #endif
         }
     }
 }

src/core/Akka/Actor/Extensions.cs

@@ -6,6 +6,7 @@
 //-----------------------------------------------------------------------
 
 using System;
+using System.Diagnostics.CodeAnalysis;
 
 namespace Akka.Actor
 {
@@ -107,7 +108,7 @@ public static T WithExtension<T>(this ActorSystem system) where T : class, IExte
         /// <param name="system">The actor system from which to retrieve the extension or to register with if it does not exist.</param>
         /// <param name="extensionId">The type of the extension to register if it does not exist in the given actor system.</param>
         /// <returns>The extension retrieved from the given actor system.</returns>
-        public static T WithExtension<T>(this ActorSystem system, Type extensionId) where T : class, IExtension
+        public static T WithExtension<T>(this ActorSystem system, [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicParameterlessConstructor)] Type extensionId) where T : class, IExtension
         {
             if (system.HasExtension<T>())
                 return system.GetExtension<T>();
@@ -126,7 +127,7 @@ public static T WithExtension<T>(this ActorSystem system, Type extensionId) wher
         /// <typeparam name="TI">The type associated with the extension to retrieve if it does not exist within the system.</typeparam>
         /// <param name="system">The actor system from which to retrieve the extension or to register with if it does not exist.</param>
         /// <returns>The extension retrieved from the given actor system.</returns>
-        public static T WithExtension<T,TI>(this ActorSystem system) where T : class, IExtension
+        public static T WithExtension<T, [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicParameterlessConstructor)] TI>(this ActorSystem system) where T : class, IExtension
                                                                      where TI: IExtensionId
         {
             if (system.HasExtension<T>())