Add Partial Property support for Reactive property (#172)

* Add Partial Property support for Reactive property

* Update Tests

* Update ReactiveCommand from base

* Resolve merge conflict

* Add Test and Documentation

* Update Is Packable to false

---------

Co-authored-by: Glenn <5834289+glennawatson@users.noreply.github.com>

Author: ChrisPulman

README.md

@@ -11,7 +11,7 @@ This documentation covers using ReactiveUI Source Generators to simplify and enh
 
 ReactiveUI Source Generators automatically generate ReactiveUI objects to streamline your code. These Source Generators are designed to work with ReactiveUI V19.5.31+ and support the following features:
 
-- `[Reactive]`
+- `[Reactive]` With field and access modifiers, partial property support (C# 13 Visual Studio Version 17.12.0)
 - `[ObservableAsProperty]`
 - `[ObservableAsProperty(PropertyName = "ReadOnlyPropertyName")]`
 - `[ReactiveCommand]`
@@ -131,6 +131,23 @@ public partial class MyReactiveClass : ReactiveObject
 }
 ```
 
+### Usage Reactive property from partial property
+
+Partial properties are supported in C# 13 and Visual Studio 17.12.0 and later.
+Both the getter and setter must be empty, and the `[Reactive]` attribute must be placed on the property.
+Override and Virtual properties are supported.
+Set Access Modifier is also supported on partial properties.
+
+```csharp
+using ReactiveUI.SourceGenerators;
+
+public partial class MyReactiveClass : ReactiveObject
+{
+    [Reactive]
+    public partial string MyProperty { get; set; }
+}
+```
+
 ## Usage ObservableAsPropertyHelper `[ObservableAsProperty]`
 
 ObservableAsPropertyHelper is used to create a read-only property from an IObservable. The generated code will create a backing field and a property that returns the value of the backing field. The backing field is initialized with the value of the IObservable when the class is instantiated.

src/Directory.Packages.props

@@ -35,7 +35,7 @@
     <PackageVersion Include="xunit.runner.console" Version="2.9.3" />
     <PackageVersion Include="xunit.runner.visualstudio" Version="3.0.1" />
     <PackageVersion Include="Xunit.StaFact" Version="1.2.69" />
-    <PackageVersion Include="FluentAssertions" Version="8.0.0" />
+    <PackageVersion Include="FluentAssertions" Version="8.0.1" />
     <PackageVersion Include="Microsoft.Reactive.Testing" Version="6.0.1" />
     <PackageVersion Include="PublicApiGenerator" Version="11.3.0" />
     <PackageVersion Include="coverlet.msbuild" Version="6.0.3" />
@@ -45,4 +45,4 @@
     <PackageVersion Include="Basic.Reference.Assemblies.Net80" Version="1.8.0" />
     <PackageVersion Include="Basic.Reference.Assemblies.Net80Windows" Version="1.8.0" />
   </ItemGroup>
-</Project>
+</Project>

src/ReactiveUI.SourceGenerator.Tests/REACTIVE/ReactiveGeneratorTests.FromReactivePartialProperties#ReactiveUI.SourceGenerators.AccessModifier.g.verified.cs

@@ -0,0 +1,37 @@
+//HintName: ReactiveUI.SourceGenerators.AccessModifier.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>
+/// AccessModifier.
+/// </summary>
+internal enum AccessModifier
+{
+    Public,
+    Protected,
+    Internal,
+    Private,
+    InternalProtected,
+    PrivateProtected,
+    Init,
+}
+
+/// <summary>
+/// InheritanceModifier.
+/// </summary>
+internal enum InheritanceModifier
+{
+    None,
+    Virtual,
+    Override,
+    New,
+}
+#nullable restore
+#pragma warning restore

src/ReactiveUI.SourceGenerator.Tests/REACTIVE/ReactiveGeneratorTests.FromReactivePartialProperties#ReactiveUI.SourceGenerators.ReactiveAttribute.g.verified.cs

@@ -0,0 +1,40 @@
+//HintName: ReactiveUI.SourceGenerators.ReactiveAttribute.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.
+
+using System;
+
+// <auto-generated/>
+#pragma warning disable
+#nullable enable
+namespace ReactiveUI.SourceGenerators;
+
+/// <summary>
+/// ReactiveAttribute.
+/// </summary>
+/// <seealso cref="Attribute" />
+[AttributeUsage(AttributeTargets.Field | AttributeTargets.Property, AllowMultiple = false, Inherited = false)]
+internal sealed class ReactiveAttribute : Attribute
+{
+    /// <summary>
+    /// Gets the AccessModifier of the set property.
+    /// </summary>
+    /// <value>
+    /// The AccessModifier of the set property.
+    /// </value>
+    public AccessModifier SetModifier { get; init; }
+
+    /// <summary>
+    /// Gets the InheritanceModifier of the property.
+    /// </sumary>
+    public InheritanceModifier Inheritance { get; init; }
+
+    /// <summary>
+    /// Use Required attribute to indicate that the property is required.
+    /// </summary>
+    public bool UseRequired { get; init; }
+}
+#nullable restore
+#pragma warning restore

src/ReactiveUI.SourceGenerator.Tests/REACTIVE/ReactiveGeneratorTests.FromReactiveProperiesWithAttributes#ReactiveUI.SourceGenerators.ReactiveAttribute.g.verified.cs

@@ -15,7 +15,7 @@ namespace ReactiveUI.SourceGenerators;
 /// ReactiveAttribute.
 /// </summary>
 /// <seealso cref="Attribute" />
-[AttributeUsage(AttributeTargets.Field, AllowMultiple = false, Inherited = false)]
+[AttributeUsage(AttributeTargets.Field | AttributeTargets.Property, AllowMultiple = false, Inherited = false)]
 internal sealed class ReactiveAttribute : Attribute
 {
     /// <summary>

src/ReactiveUI.SourceGenerator.Tests/REACTIVE/ReactiveGeneratorTests.FromReactiveProperiesWithAttributes#TestNs.TestVM.Properties.g.verified.cs

@@ -12,6 +12,7 @@ namespace TestNs
     /// </summary>
     public partial class TestVM
     {
+        
         /// <inheritdoc cref="_test3"/>
         [global::System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
         [global::System.Runtime.Serialization.DataMemberAttribute()]

src/ReactiveUI.SourceGenerator.Tests/REACTIVE/ReactiveGeneratorTests.FromReactiveProperties#ReactiveUI.SourceGenerators.ReactiveAttribute.g.verified.cs

@@ -15,7 +15,7 @@ namespace ReactiveUI.SourceGenerators;
 /// ReactiveAttribute.
 /// </summary>
 /// <seealso cref="Attribute" />
-[AttributeUsage(AttributeTargets.Field, AllowMultiple = false, Inherited = false)]
+[AttributeUsage(AttributeTargets.Field | AttributeTargets.Property, AllowMultiple = false, Inherited = false)]
 internal sealed class ReactiveAttribute : Attribute
 {
     /// <summary>

src/ReactiveUI.SourceGenerator.Tests/REACTIVE/ReactiveGeneratorTests.FromReactiveProperties#TestNs.TestVM.Properties.g.verified.cs

@@ -12,6 +12,7 @@ namespace TestNs
     /// </summary>
     public partial class TestVM
     {
+        
         /// <inheritdoc cref="_test1"/>
         [global::System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
         public int Test1

src/ReactiveUI.SourceGenerator.Tests/REACTIVE/ReactiveGeneratorTests.FromReactivePropertiesWithAccess#ReactiveUI.SourceGenerators.ReactiveAttribute.g.verified.cs

@@ -15,7 +15,7 @@ namespace ReactiveUI.SourceGenerators;
 /// ReactiveAttribute.
 /// </summary>
 /// <seealso cref="Attribute" />
-[AttributeUsage(AttributeTargets.Field, AllowMultiple = false, Inherited = false)]
+[AttributeUsage(AttributeTargets.Field | AttributeTargets.Property, AllowMultiple = false, Inherited = false)]
 internal sealed class ReactiveAttribute : Attribute
 {
     /// <summary>

src/ReactiveUI.SourceGenerator.Tests/REACTIVE/ReactiveGeneratorTests.FromReactivePropertiesWithAccess#TestNs.TestVM.Properties.g.verified.cs

@@ -12,6 +12,7 @@ namespace TestNs
     /// </summary>
     public partial class TestVM
     {
+        
         /// <inheritdoc cref="_test2"/>
         [global::System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
         public int Test2