support overridable property

Author: neominky

src/ReactiveUI.SourceGenerators/AttributeDefinitions.cs

@@ -133,6 +133,7 @@ internal sealed class ReactiveAttribute : Attribute
     /// The AccessModifier of the set property.
     /// </value>
     public AccessModifier SetModifier { get; init; }
+    public bool Overridable { get; init; } = false;
 }
 #nullable restore
 #pragma warning restore

src/ReactiveUI.SourceGenerators/ObservableAsProperty/ObservableAsPropertyGenerator{FromField}.Execute.cs

@@ -55,6 +55,10 @@ public sealed partial class ObservableAsPropertyGenerator
         // Get the can PropertyName member, if any
         attributeData.TryGetNamedArgument("ReadOnly", out bool? isReadonly);
 
+        // Get Overridable value from the attribute
+        attributeData.TryGetNamedArgument("Overridable", out bool? overridableArgument);
+        var overridable = overridableArgument == false ? "virtual" : string.Empty;
+
         token.ThrowIfCancellationRequested();
 
         // Get the property type and name
@@ -198,7 +202,8 @@ public sealed partial class ObservableAsPropertyGenerator
             isReferenceTypeOrUnconstraindTypeParameter,
             includeMemberNotNullOnSetAccessor,
             forwardedPropertyAttributes,
-            isReadonly == false ? string.Empty : "readonly"),
+            isReadonly == false ? string.Empty : "readonly",
+            overridable),
             builder.ToImmutable());
     }
 

src/ReactiveUI.SourceGenerators/Reactive/Models/PropertyInfo.cs

@@ -24,4 +24,5 @@ internal sealed record PropertyInfo(
     bool IsReferenceTypeOrUnconstrainedTypeParameter,
     bool IncludeMemberNotNullOnSetAccessor,
     EquatableArray<string> ForwardedAttributes,
-    string AccessModifier);
+    string AccessModifier,
+    string Overridable);

src/ReactiveUI.SourceGenerators/Reactive/ReactiveGenerator.Execute.cs

@@ -75,6 +75,10 @@ public sealed partial class ReactiveGenerator
             _ => "public",
         };
 
+        // Get Overridable value from the attribute
+        attributeData.TryGetNamedArgument("Overridable", out bool? overridableArgument);
+        var overridable = overridableArgument == true ? "virtual" : string.Empty;
+
         token.ThrowIfCancellationRequested();
 
         // Get the property type and name
@@ -214,7 +218,8 @@ public sealed partial class ReactiveGenerator
             isReferenceTypeOrUnconstraindTypeParameter,
             includeMemberNotNullOnSetAccessor,
             forwardedAttributesString,
-            accessModifier),
+            accessModifier,
+            overridable),
             builder.ToImmutable());
     }
 
@@ -282,7 +287,7 @@ private static string GetPropertySyntax(PropertyInfo propertyInfo)
 $$"""
         /// <inheritdoc cref="{{propertyInfo.FieldName}}"/>
         {{propertyAttributes}}
-        {{propertyInfo.TargetVisibility}} {{propertyInfo.TypeNameWithNullabilityAnnotations}} {{propertyInfo.PropertyName}}
+        {{propertyInfo.TargetVisibility}} {{propertyInfo.Overridable}} {{propertyInfo.TypeNameWithNullabilityAnnotations}} {{propertyInfo.PropertyName}}
         { 
             get => {{propertyInfo.FieldName}};
             [global::System.Diagnostics.CodeAnalysis.MemberNotNull("{{propertyInfo.FieldName}}")]
@@ -295,7 +300,7 @@ private static string GetPropertySyntax(PropertyInfo propertyInfo)
 $$"""
         /// <inheritdoc cref="{{propertyInfo.FieldName}}"/>
         {{propertyAttributes}}
-        {{propertyInfo.TargetVisibility}} {{propertyInfo.TypeNameWithNullabilityAnnotations}} {{propertyInfo.PropertyName}} { get => {{propertyInfo.FieldName}}; {{setModifier}}set => this.RaiseAndSetIfChanged(ref {{propertyInfo.FieldName}}, value); }
+        {{propertyInfo.TargetVisibility}} {{propertyInfo.Overridable}} {{propertyInfo.TypeNameWithNullabilityAnnotations}} {{propertyInfo.PropertyName}} { get => {{propertyInfo.FieldName}}; {{setModifier}}set => this.RaiseAndSetIfChanged(ref {{propertyInfo.FieldName}}, value); }
 """;
     }