Add IReactiveObject source generator and tests

README.md

@@ -51,6 +51,7 @@ ReactiveUI Source Generators automatically generate ReactiveUI objects to stream
 - `[ViewModelControlHost("YourNameSpace.CustomControl")]`
 - `[BindableDerivedList]` Generates a derived list from a ReadOnlyObservableCollection backing field
 - `[ReactiveCollection]` Generates property changed notifications on add, remove, new actions on a ObservableCollection backing field
+- `[IReactiveObject]` Generates IReactiveObject implementation for classes not able to inherit from ReactiveObject
 
 #### IViewFor Registration generator
 
@@ -684,6 +685,19 @@ public partial class MyReactiveClass : ReactiveObject
 }
 ```
 
+### ReactiveObject implementation for classes not able to inherit from ReactiveObject
+```csharp
+using ReactiveUI;
+using ReactiveUI.SourceGenerators;
+
+[IReactiveObject]
+public partial class MyReactiveClass
+{
+    [Reactive]
+    private string _myProperty;
+}
+```
+
 ### TODO:
 - Add ObservableAsProperty to generate from a IObservable method with parameters.
 

src/ReactiveUI.SourceGenerator.Tests/REACTIVEOBJ/ReactiveObjectGeneratorTests.FromReactiveObject#ReactiveUI.SourceGenerators.IReactiveObjectAttribute.g.verified.cs

@@ -0,0 +1,19 @@
+//HintName: ReactiveUI.SourceGenerators.IReactiveObjectAttribute.g.cs
+// Copyright (c) 2025 .NET Foundation and Contributors. All rights reserved.
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for full license information.
+
+// <auto-generated/>
+#pragma warning disable
+#nullable enable
+namespace ReactiveUI.SourceGenerators;
+
+/// <summary>
+/// IReactiveObject Attribute.
+/// </summary>
+/// <seealso cref="System.Attribute" />
+[global::System.AttributeUsage(global::System.AttributeTargets.Class, AllowMultiple = false, Inherited = false)]
+internal sealed class IReactiveObjectAttribute : global::System.Attribute;
+#nullable restore
+#pragma warning restore

src/ReactiveUI.SourceGenerator.Tests/REACTIVEOBJ/ReactiveObjectGeneratorTests.FromReactiveObject#TestNs.TestVM.IReactiveObject.g.verified.cs

@@ -0,0 +1,68 @@
+//HintName: TestNs.TestVM.IReactiveObject.g.cs
+// <auto-generated/>
+#pragma warning disable
+#nullable enable
+using System;
+using System.Diagnostics.CodeAnalysis;
+using System.ComponentModel;
+using ReactiveUI;
+
+namespace TestNs
+{
+    /// <summary>
+    /// Partial class for the TestVM which contains ReactiveUI IReactiveObject initialization.
+    /// </summary>
+    public partial class TestVM : IReactiveObject
+    {
+        private bool _propertyChangingEventsSubscribed;
+        private bool _propertyChangedEventsSubscribed;
+
+        /// <inheritdoc/>
+        public event PropertyChangingEventHandler? PropertyChanging
+        {
+            add
+            {
+                if (!_propertyChangingEventsSubscribed)
+                {
+                    this.SubscribePropertyChangingEvents();
+                    _propertyChangingEventsSubscribed = true;
+                }
+
+                PropertyChangingHandler += value;
+            }
+            remove => PropertyChangingHandler -= value;
+        }
+
+        /// <inheritdoc/>
+        public event PropertyChangedEventHandler? PropertyChanged
+        {
+            add
+            {
+                if (!_propertyChangedEventsSubscribed)
+                {
+                    this.SubscribePropertyChangedEvents();
+                    _propertyChangedEventsSubscribed = true;
+                }
+
+                PropertyChangedHandler += value;
+            }
+            remove => PropertyChangedHandler -= value;
+        }
+
+        [SuppressMessage("Roslynator", "RCS1159:Use EventHandler<T>", Justification = "Long term design.")]
+        private event PropertyChangingEventHandler? PropertyChangingHandler;
+
+        [SuppressMessage("Roslynator", "RCS1159:Use EventHandler<T>", Justification = "Long term design.")]
+        private event PropertyChangedEventHandler? PropertyChangedHandler;
+
+        /// <inheritdoc/>
+        void IReactiveObject.RaisePropertyChanging(PropertyChangingEventArgs args) =>
+            PropertyChangingHandler?.Invoke(this, args);
+
+        /// <inheritdoc/>
+        void IReactiveObject.RaisePropertyChanged(PropertyChangedEventArgs args) =>
+            PropertyChangedHandler?.Invoke(this, args);
+    }
+}
+#nullable restore
+#pragma warning restore

src/ReactiveUI.SourceGenerator.Tests/ReactiveUI.SourceGenerators.Tests.csproj

@@ -40,6 +40,7 @@
     <Folder Include="OAPH\" />
     <Folder Include="REACTIVECMD\" />
     <Folder Include="REACTIVE\" />
+    <Folder Include="REACTIVEOBJ\" />
     <Folder Include="REACTIVECOLL\" />
   </ItemGroup>
 

src/ReactiveUI.SourceGenerator.Tests/TestHelper.cs

@@ -87,6 +87,7 @@ public string VerifiedFilePath()
             nameof(ViewModelControlHostGenerator) => "CONTROLHOST",
             nameof(BindableDerivedListGenerator) => "DERIVEDLIST",
             nameof(ReactiveCollectionGenerator) => "REACTIVECOLL",
+            nameof(ReactiveObjectGenerator) => "REACTIVEOBJ",
             _ => name,
         };
     }

src/ReactiveUI.SourceGenerator.Tests/UnitTests/ReactiveObjectGeneratorTests.cs

@@ -0,0 +1,41 @@
+// Copyright (c) 2025 ReactiveUI and contributors. All rights reserved.
+// Licensed to the ReactiveUI and contributors under one or more agreements.
+// The ReactiveUI and contributors licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for full license information.
+
+using ReactiveUI.SourceGenerators;
+
+namespace ReactiveUI.SourceGenerator.Tests;
+
+/// <summary>
+/// Unit tests for the Reactive generator.
+/// </summary>
+[TestFixture]
+public class ReactiveObjectGeneratorTests : TestBase<ReactiveObjectGenerator>
+{
+    /// <summary>
+    /// Froms the reactive object.
+    /// </summary>
+    /// <returns>A task to monitor the async.</returns>
+    [Test]
+    public Task FromReactiveObject()
+    {
+        // Arrange: Setup the source code that matches the generator input expectations.
+        const string sourceCode = """
+                using System;
+                using ReactiveUI.SourceGenerators;
+                using System.Reactive.Linq;
+                namespace TestNs;
+
+                [IReactiveObject]
+                public partial class TestVM
+                {
+                    [Reactive]
+                    private int _test1 = 10;
+                }
+            """;
+
+        // Act: Initialize the helper and run the generator. Assert: Verify the generated code.
+        return TestHelper.TestPass(sourceCode);
+    }
+}

src/ReactiveUI.SourceGenerators.Execute/Person.cs

@@ -4,7 +4,6 @@
 // See the LICENSE file in the project root for full license information.
 
 using System.Diagnostics.CodeAnalysis;
-using ReactiveUI;
 using ReactiveUI.SourceGenerators;
 
 namespace SGReactiveUI.SourceGenerators.Test;
@@ -14,7 +13,8 @@ namespace SGReactiveUI.SourceGenerators.Test;
 /// </summary>
 /// <seealso cref="ReactiveUI.ReactiveObject" />
 [ExcludeFromCodeCoverage]
-public partial class Person : ReactiveObject
+[IReactiveObject]
+public partial class Person
 {
     /// <summary>
     /// Gets or sets a value indicating whether this <see cref="Person"/> is deleted.
@@ -23,5 +23,5 @@ public partial class Person : ReactiveObject
     ///   <c>true</c> if deleted; otherwise, <c>false</c>.
     /// </value>
     [Reactive]
-    public bool Deleted { get; set; }
+    public partial bool Deleted { get; set; }
 }

src/ReactiveUI.SourceGenerators.Roslyn/AttributeDefinitions.cs

@@ -77,6 +77,8 @@ internal enum SplatRegistrationType
         #pragma warning restore
         """;
 
+    public const string ReactiveObjectAttributeType = "ReactiveUI.SourceGenerators.IReactiveObjectAttribute";
+
     public static string ReactiveObjectAttribute => $$"""
 // Copyright (c) {{DateTime.Now.Year}} .NET Foundation and Contributors. All rights reserved.
 // Licensed to the .NET Foundation under one or more agreements.
@@ -89,12 +91,12 @@ internal enum SplatRegistrationType
 namespace ReactiveUI.SourceGenerators;
 
 /// <summary>
-/// ReactiveObjectAttribute.
+/// IReactiveObject Attribute.
 /// </summary>
 /// <seealso cref="System.Attribute" />
 [global::System.CodeDom.Compiler.GeneratedCode("ReactiveUI.SourceGenerators.ReactiveObjectGenerator", "{{ReactiveGenerator.GeneratorVersion}}")]
 [global::System.AttributeUsage(global::System.AttributeTargets.Class, AllowMultiple = false, Inherited = false)]
-internal sealed class ReactiveObjectAttribute : global::System.Attribute;
+internal sealed class IReactiveObjectAttribute : global::System.Attribute;
 #nullable restore
 #pragma warning restore
 """;

src/ReactiveUI.SourceGenerators.Roslyn/BindableDerivedList/BindableDerivedListGenerator.cs

@@ -3,8 +3,6 @@
 // The ReactiveUI and contributors licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for full license information.
 
-using System;
-using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Linq;
 using System.Text;

src/ReactiveUI.SourceGenerators.Roslyn/Core/Extensions/FieldSyntaxExtensions.cs

@@ -5,6 +5,7 @@
 
 using System.Globalization;
 using Microsoft.CodeAnalysis;
+using ReactiveUI.SourceGenerators.Helpers;
 
 namespace ReactiveUI.SourceGenerators.Extensions;
 
@@ -124,7 +125,7 @@ internal static bool IsTargetTypeValid(this IFieldSymbol fieldSymbol)
     {
         var isObservableObject = fieldSymbol.ContainingType.InheritsFromFullyQualifiedMetadataName("ReactiveUI.ReactiveObject");
         var isIObservableObject = fieldSymbol.ContainingType.ImplementsFullyQualifiedMetadataName("ReactiveUI.IReactiveObject");
-        var hasObservableObjectAttribute = fieldSymbol.ContainingType.HasOrInheritsAttributeWithFullyQualifiedMetadataName("ReactiveUI.SourceGenerators.ReactiveObjectAttribute");
+        var hasObservableObjectAttribute = fieldSymbol.ContainingType.HasOrInheritsAttributeWithFullyQualifiedMetadataName(AttributeDefinitions.ReactiveObjectAttributeType);
 
         return isIObservableObject || isObservableObject || hasObservableObjectAttribute;
     }
@@ -138,7 +139,7 @@ internal static bool IsTargetTypeValid(this IPropertySymbol propertySymbol)
     {
         var isObservableObject = propertySymbol.ContainingType.InheritsFromFullyQualifiedMetadataName("ReactiveUI.ReactiveObject");
         var isIObservableObject = propertySymbol.ContainingType.ImplementsFullyQualifiedMetadataName("ReactiveUI.IReactiveObject");
-        var hasObservableObjectAttribute = propertySymbol.ContainingType.HasOrInheritsAttributeWithFullyQualifiedMetadataName("ReactiveUI.SourceGenerators.ReactiveObjectAttribute");
+        var hasObservableObjectAttribute = propertySymbol.ContainingType.HasOrInheritsAttributeWithFullyQualifiedMetadataName(AttributeDefinitions.ReactiveObjectAttributeType);
 
         return isIObservableObject || isObservableObject || hasObservableObjectAttribute;
     }
@@ -152,7 +153,7 @@ internal static bool IsTargetTypeValid(this IMethodSymbol methodSymbol)
     {
         var isObservableObject = methodSymbol.ContainingType.InheritsFromFullyQualifiedMetadataName("ReactiveUI.ReactiveObject");
         var isIObservableObject = methodSymbol.ContainingType.ImplementsFullyQualifiedMetadataName("ReactiveUI.IReactiveObject");
-        var hasObservableObjectAttribute = methodSymbol.ContainingType.HasOrInheritsAttributeWithFullyQualifiedMetadataName("ReactiveUI.SourceGenerators.ReactiveObjectAttribute");
+        var hasObservableObjectAttribute = methodSymbol.ContainingType.HasOrInheritsAttributeWithFullyQualifiedMetadataName(AttributeDefinitions.ReactiveObjectAttributeType);
 
         return isIObservableObject || isObservableObject || hasObservableObjectAttribute;
     }

src/ReactiveUI.SourceGenerators.Roslyn/IViewFor/IViewForGenerator.Execute.cs

@@ -26,8 +26,6 @@ public partial class IViewForGenerator
     internal static readonly string GeneratorName = typeof(IViewForGenerator).FullName!;
     internal static readonly string GeneratorVersion = typeof(IViewForGenerator).Assembly.GetName().Version.ToString();
 
-    private static readonly string[] excludeFromCodeCoverage = ["[global::System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]"];
-
     private static IViewForInfo? GetClassInfo(in GenericGeneratorAttributeSyntaxContext context, CancellationToken token)
     {
         if (!(context.TargetNode is ClassDeclarationSyntax declaredClass && declaredClass.Modifiers.Any(SyntaxKind.PartialKeyword)))
@@ -126,7 +124,7 @@ public partial class IViewForGenerator
     private static string GenerateSource(string containingTypeName, string containingNamespace, string containingClassVisibility, string containingType, IViewForInfo iviewForInfo)
     {
         // Prepare any forwarded property attributes
-        var forwardedAttributesString = string.Join("\n        ", excludeFromCodeCoverage);
+        var forwardedAttributesString = string.Join("\n        ", AttributeDefinitions.ExcludeFromCodeCoverage);
 
         switch (iviewForInfo.BaseType)
         {

src/ReactiveUI.SourceGenerators.Roslyn/ReactiveObject/Models/ReactiveObjectInfo.cs

@@ -0,0 +1,13 @@
+// Copyright (c) 2025 ReactiveUI and contributors. All rights reserved.
+// Licensed to the ReactiveUI and contributors under one or more agreements.
+// The ReactiveUI and contributors licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for full license information.
+
+namespace ReactiveUI.SourceGenerators.Models;
+
+/// <summary>
+/// A model with gathered info on a given command method.
+/// </summary>
+internal sealed record ReactiveObjectInfo(
+    TargetInfo TargetInfo,
+    string ViewModelTypeName);