Removed readonly option from both attributes since we can read from the field itself. Now supports nullable fields and sealed classes.

Author: ShawnLaMountain

src/ThunderDesign.Net-PCL.SourceGenerators/UnifiedPropertyGenerator.cs

@@ -168,8 +168,8 @@ private static void GenerateUnifiedPropertyClass(
                 voidTypeSymbol);
 
             // Generate properties
-            GenerateBindableProperties(source, bindableFields, classSymbol);
-            GenerateRegularProperties(source, propertyFields, classSymbol);
+            GenerateBindableProperties(source, bindableFields, classSymbol, compilation);
+            GenerateRegularProperties(source, propertyFields, classSymbol, compilation);
 
             source.AppendLine("}");
             if (!string.IsNullOrEmpty(classSymbol.ContainingNamespace?.ToDisplayString()))
@@ -256,6 +256,7 @@ private static void GenerateClassHeader(
             if (!string.IsNullOrEmpty(ns))
                 source.AppendLine($"namespace {ns} {{");
 
+            source.AppendLine("#nullable enable");
             source.AppendLine("using ThunderDesign.Net.Threading.Extentions;");
             source.AppendLine("using ThunderDesign.Net.Threading.Objects;");
 
@@ -302,18 +303,22 @@ private static void GenerateInfrastructureMembers(
                 new ITypeSymbol[] { stringTypeSymbol },
                 voidTypeSymbol))
             {
-                source.AppendLine(@"
-    public virtual void OnPropertyChanged([System.Runtime.CompilerServices.CallerMemberName] string propertyName = """")
-    {
+                // Only use 'virtual' if the class is not sealed
+                string virtualModifier = classSymbol.IsSealed ? "" : "virtual ";
+                
+                source.AppendLine($@"
+    public {virtualModifier}void OnPropertyChanged([System.Runtime.CompilerServices.CallerMemberName] string propertyName = """")
+    {{
         this.NotifyPropertyChanged(PropertyChanged, propertyName);
-    }");
+    }}");
             }
         }
 
         private static void GenerateBindableProperties(
             StringBuilder source, 
             List<BindableFieldInfo> bindableFields, 
-            INamedTypeSymbol classSymbol)
+            INamedTypeSymbol classSymbol,
+            Compilation compilation)
         {
             foreach (var info in bindableFields)
             {
@@ -327,17 +332,22 @@ private static void GenerateBindableProperties(
 
                 var fieldSymbol = info.FieldSymbol;
                 var fieldName = fieldSymbol.Name;
-                var typeName = fieldSymbol.Type.ToDisplayString();
+                
+                // Use NullableFlowState-aware display string to properly handle nullable types
+                var typeName = GetNullableAwareTypeName(fieldSymbol.Type, compilation);
 
                 var args = info.AttributeData.ConstructorArguments;
-                var readOnly = args.Length > 0 && (bool)args[0].Value!;
-                var threadSafe = args.Length > 1 && (bool)args[1].Value!;
-                var notify = args.Length > 2 && (bool)args[2].Value!;
+                
+                // Check if field is readonly (takes precedence over attribute parameter)
+                var readOnly = fieldSymbol.IsReadOnly;
+                
+                var threadSafe = args.Length > 0 && (bool)args[0].Value!;
+                var notify = args.Length > 1 && (bool)args[1].Value!;
 
                 string[] alsoNotify = GetAlsoNotifyProperties(args);
 
-                var getterEnum = args.Length > 4 ? args[4].Value : null;
-                var setterEnum = args.Length > 5 ? args[5].Value : null;
+                var getterEnum = args.Length > 3 ? args[3].Value : null;
+                var setterEnum = args.Length > 4 ? args[4].Value : null;
 
                 // Convert the numeric enum value to its string representation
                 string getterValue = getterEnum != null ? GetAccessibilityName((int)getterEnum) : "Public";
@@ -381,10 +391,10 @@ private static void GenerateBindableProperties(
 
         private static string[] GetAlsoNotifyProperties(ImmutableArray<TypedConstant> args)
         {
-            if (args.Length <= 3)
+            if (args.Length <= 2)
                 return Array.Empty<string>();
 
-            var arg = args[3];
+            var arg = args[2];
             if (arg.Kind == TypedConstantKind.Array && arg.Values != null)
             {
                 return arg.Values
@@ -474,7 +484,8 @@ private static void GenerateReadWriteBindableProperty(
         private static void GenerateRegularProperties(
             StringBuilder source, 
             List<PropertyFieldInfo> propertyFields, 
-            INamedTypeSymbol classSymbol)
+            INamedTypeSymbol classSymbol,
+            Compilation compilation)
         {
             foreach (var info in propertyFields)
             {
@@ -488,13 +499,18 @@ private static void GenerateRegularProperties(
 
                 var fieldSymbol = info.FieldSymbol;
                 var fieldName = fieldSymbol.Name;
-                var typeName = fieldSymbol.Type.ToDisplayString();
+                
+                // Use NullableFlowState-aware display string to properly handle nullable types
+                var typeName = GetNullableAwareTypeName(fieldSymbol.Type, compilation);
 
                 var args = info.AttributeData.ConstructorArguments;
-                var readOnly = args.Length > 0 && (bool)args[0].Value!;
-                var threadSafe = args.Length > 1 && (bool)args[1].Value!;
-                var getterEnum = args.Length > 2 ? args[2].Value : null;
-                var setterEnum = args.Length > 3 ? args[3].Value : null;
+                
+                // Check if field is readonly (takes precedence over attribute parameter)
+                var readOnly = fieldSymbol.IsReadOnly;
+                
+                var threadSafe = args.Length > 0 && (bool)args[0].Value!;
+                var getterEnum = args.Length > 1 ? args[1].Value : null;
+                var setterEnum = args.Length > 2 ? args[2].Value : null;
 
                 // Convert the numeric enum value to its string representation
                 string getterValue = getterEnum != null ? GetAccessibilityName((int)getterEnum) : "Public";
@@ -581,6 +597,21 @@ private static void GenerateReadWriteProperty(
     }}");
         }
 
+        private static string GetNullableAwareTypeName(ITypeSymbol typeSymbol, Compilation compilation)
+        {
+            // Create a SymbolDisplayFormat that includes nullable annotations
+            var format = new SymbolDisplayFormat(
+                globalNamespaceStyle: SymbolDisplayGlobalNamespaceStyle.Omitted,
+                typeQualificationStyle: SymbolDisplayTypeQualificationStyle.NameAndContainingTypesAndNamespaces,
+                genericsOptions: SymbolDisplayGenericsOptions.IncludeTypeParameters,
+                miscellaneousOptions: SymbolDisplayMiscellaneousOptions.EscapeKeywordIdentifiers |
+                                     SymbolDisplayMiscellaneousOptions.UseSpecialTypes |
+                                     SymbolDisplayMiscellaneousOptions.IncludeNullableReferenceTypeModifier
+            );
+
+            return typeSymbol.ToDisplayString(format);
+        }
+
         private static bool ImplementsInterface(INamedTypeSymbol type, string interfaceName)
         {
             return type.AllInterfaces.Any(i => i.ToDisplayString() == interfaceName);

src/ThunderDesign.Net-PCL.Threading.Shared/Attributes/BindablePropertyAttribute.cs

@@ -9,22 +9,19 @@ namespace ThunderDesign.Net.Threading.Attributes
     [AttributeUsage(AttributeTargets.Field, Inherited = false, AllowMultiple = false)]
     public sealed class BindablePropertyAttribute : Attribute
     {
-        public bool ReadOnly { get; }
         public bool ThreadSafe { get; }
         public bool Notify { get; }
         public string[] AlsoNotify { get; }
         public AccessorAccessibility Getter { get; }
         public AccessorAccessibility Setter { get; }
 
         public BindablePropertyAttribute(
-            bool readOnly = false,
             bool threadSafe = true,
             bool notify = true,
             string[] alsoNotify = null,
             AccessorAccessibility getter = AccessorAccessibility.Public,
             AccessorAccessibility setter = AccessorAccessibility.Public)
         {
-            ReadOnly = readOnly;
             ThreadSafe = threadSafe;
             Notify = notify;
             AlsoNotify = alsoNotify ?? Array.Empty<string>();

src/ThunderDesign.Net-PCL.Threading.Shared/Attributes/PropertyAttribute.cs

@@ -7,18 +7,15 @@ namespace ThunderDesign.Net.Threading.Attributes
     [AttributeUsage(AttributeTargets.Field, AllowMultiple = false, Inherited = false)]
     public sealed class PropertyAttribute : Attribute
     {
-        public bool ReadOnly { get; }
         public bool ThreadSafe { get; }
         public AccessorAccessibility Getter { get; }
         public AccessorAccessibility Setter { get; }
 
         public PropertyAttribute(
-            bool readOnly = false, 
             bool threadSafe = true,
             AccessorAccessibility getter = AccessorAccessibility.Public,
             AccessorAccessibility setter = AccessorAccessibility.Public)
         {
-            ReadOnly = readOnly;
             ThreadSafe = threadSafe;
             Getter = getter;
             Setter = setter;