Add support for generic constraints to Actor source generator

src/Dapr.Actors.Generators/ActorClientGenerator.cs

@@ -164,6 +164,62 @@ private static void GenerateActorClientCode(SourceProductionContext context, Act
             var actorClientClassTypeParameters = descriptor.InterfaceType.TypeParameters
                 .Select(x => SyntaxFactory.TypeParameter(x.ToString()));
 
+            // Create constraint clauses for type parameters
+            var constraintClauses = new List<TypeParameterConstraintClauseSyntax>();
+
+            // For each type parameter, create constraint clauses based on the interface's constraints
+            foreach (var typeParam in descriptor.InterfaceType.TypeParameters)
+            {
+                if (typeParam.HasReferenceTypeConstraint ||
+                    typeParam.HasValueTypeConstraint ||
+                    typeParam.HasUnmanagedTypeConstraint ||
+                    typeParam.HasNotNullConstraint ||
+                    typeParam.ConstraintTypes.Length > 0)
+                {
+                    var constraints = new List<TypeParameterConstraintSyntax>();
+
+                    // Add class/struct constraints
+                    if (typeParam.HasReferenceTypeConstraint)
+                    {
+                        constraints.Add(SyntaxFactory.ClassOrStructConstraint(SyntaxKind.ClassConstraint));
+                    }
+                    else if (typeParam.HasValueTypeConstraint)
+                    {
+                        constraints.Add(SyntaxFactory.ClassOrStructConstraint(SyntaxKind.StructConstraint));
+                    }
+
+                    // Add unmanaged constraint
+                    if (typeParam.HasUnmanagedTypeConstraint)
+                    {
+                        constraints.Add(SyntaxFactory.TypeConstraint(SyntaxFactory.IdentifierName("unmanaged")));
+                    }
+
+                    // Add type constraints (e.g., where T : IInterface)
+                    foreach (var constraintType in typeParam.ConstraintTypes)
+                    {
+                        constraints.Add(SyntaxFactory.TypeConstraint(
+                            SyntaxFactory.ParseTypeName(constraintType.ToString())));
+                    }
+
+                    // Add notnull constraint
+                    if (typeParam.HasNotNullConstraint)
+                    {
+                        constraints.Add(SyntaxFactory.TypeConstraint(SyntaxFactory.IdentifierName("notnull")));
+                    }
+
+                    // Add new() constraint - must be last
+                    if (typeParam.HasConstructorConstraint)
+                    {
+                        constraints.Add(SyntaxFactory.ConstructorConstraint());
+                    }
+
+                    constraintClauses.Add(
+                        SyntaxFactory.TypeParameterConstraintClause(
+                            SyntaxFactory.IdentifierName(typeParam.Name),
+                            SyntaxFactory.SeparatedList(constraints)));
+                }
+            }
+
             var actorClientClassDeclaration = (actorClientClassTypeParameters.Count() == 0)
                 ? SyntaxFactory.ClassDeclaration(descriptor.ClientTypeName)
                     .WithModifiers(SyntaxFactory.TokenList(actorClientClassModifiers))
@@ -174,6 +230,7 @@ private static void GenerateActorClientCode(SourceProductionContext context, Act
                 : SyntaxFactory.ClassDeclaration(descriptor.ClientTypeName)
                     .WithModifiers(SyntaxFactory.TokenList(actorClientClassModifiers))
                     .WithTypeParameterList(SyntaxFactory.TypeParameterList(SyntaxFactory.SeparatedList(actorClientClassTypeParameters)))
+                    .WithConstraintClauses(SyntaxFactory.List(constraintClauses)) // Add constraint clauses to the class
                     .WithMembers(SyntaxFactory.List(actorMembers))
                     .WithBaseList(SyntaxFactory.BaseList(
                         SyntaxFactory.Token(SyntaxKind.ColonToken),

test/Dapr.Actors.Generators.Test/ActorClientGeneratorTests.cs

@@ -877,4 +877,120 @@ public interface ITestActor
 
         await test.RunAsync();
     }
+
+    [Fact]
+    public async Task TestGenericWithConstraints()
+    {
+        var originalSource = @"
+using Dapr.Actors.Generators;
+using System.Threading.Tasks;
+
+namespace Test
+{
+    public interface ITrait 
+    {
+        string GetName();
+    }
+
+    [GenerateActorClient]
+    public interface ITestActor<in TTrait> where TTrait : ITrait
+    {
+        Task<bool> SetTrait(TTrait trait);
+        Task<ITrait> GetTrait(string name);
+    }
+}";
+
+        var generatedSource = @"// <auto-generated/>
+#nullable enable
+namespace Test
+{
+    public sealed class TestActorClient<TTrait> : Test.ITestActor<TTrait> where TTrait : Test.ITrait
+    {
+        private readonly Dapr.Actors.Client.ActorProxy actorProxy;
+        public TestActorClient(Dapr.Actors.Client.ActorProxy actorProxy)
+        {
+            if (actorProxy is null)
+            {
+                throw new System.ArgumentNullException(nameof(actorProxy));
+            }
+
+            this.actorProxy = actorProxy;
+        }
+
+        public System.Threading.Tasks.Task<Test.ITrait> GetTrait(string name)
+        {
+            return this.actorProxy.InvokeMethodAsync<string, Test.ITrait>(""GetTrait"", name);
+        }
+
+        public System.Threading.Tasks.Task<bool> SetTrait(TTrait trait)
+        {
+            return this.actorProxy.InvokeMethodAsync<TTrait, bool>(""SetTrait"", trait);
+        }
+    }
+}";
+
+        await CreateTest(originalSource, "Test.TestActorClient.g.cs", generatedSource).RunAsync();
+    }
+
+    [Fact]
+    public async Task TestGenericWithMultipleTypeParametersAndConstraints()
+    {
+        var originalSource = @"
+using Dapr.Actors.Generators;
+using System.Threading.Tasks;
+
+namespace Test
+{
+    public interface ITrait 
+    {
+        string GetName();
+    }
+
+    public interface IValidator<T>
+    {
+        bool Validate(T item);
+    }
+
+    [GenerateActorClient]
+    public interface ITestActor<TTrait, TValidator> 
+        where TTrait : ITrait, new() 
+        where TValidator : class, IValidator<TTrait>
+    {
+        Task<bool> SetTrait(TTrait trait);
+        Task<TTrait> GetValidatedTrait(string name);
+    }
+}";
+
+        var generatedSource = @"// <auto-generated/>
+#nullable enable
+namespace Test
+{
+    public sealed class TestActorClient<TTrait, TValidator> : Test.ITestActor<TTrait, TValidator> where TTrait : Test.ITrait, new()
+        where TValidator : class, Test.IValidator<TTrait>
+    {
+        private readonly Dapr.Actors.Client.ActorProxy actorProxy;
+        public TestActorClient(Dapr.Actors.Client.ActorProxy actorProxy)
+        {
+            if (actorProxy is null)
+            {
+                throw new System.ArgumentNullException(nameof(actorProxy));
+            }
+
+            this.actorProxy = actorProxy;
+        }
+
+        public System.Threading.Tasks.Task<TTrait> GetValidatedTrait(string name)
+        {
+            return this.actorProxy.InvokeMethodAsync<string, TTrait>(""GetValidatedTrait"", name);
+        }
+
+        public System.Threading.Tasks.Task<bool> SetTrait(TTrait trait)
+        {
+            return this.actorProxy.InvokeMethodAsync<TTrait, bool>(""SetTrait"", trait);
+        }
+    }
+}";
+
+        await CreateTest(originalSource, "Test.TestActorClient.g.cs", generatedSource).RunAsync();
+    }
 }