Fix overridden member metadata in source generation

Honor inherited serialization metadata on overridden members so source-generated contexts match reflection for property names, ignore settings, ordering, and related member attributes.

Add regression tests for overridden properties in both reflection and source-generated paths.

Follow-up to #120

Author: xoofx

src/Tomlyn.SourceGeneration/TomlSerializerContextGenerator.cs

@@ -4309,18 +4309,46 @@ private static bool TryGetDictionaryValueType(ITypeSymbol type, out ITypeSymbol
     }
 
     private static bool HasAttribute(ISymbol symbol, string attributeMetadataName)
+        => TryGetAttribute(symbol, attributeMetadataName, out _);
+
+    private static bool TryGetAttribute(ISymbol symbol, string attributeMetadataName, out AttributeData attribute)
     {
-        foreach (var attr in symbol.GetAttributes())
+        foreach (var current in EnumerateSelfAndBaseSymbols(symbol))
         {
-            if (attr.AttributeClass?.ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat) == "global::" + attributeMetadataName)
+            foreach (var attr in current.GetAttributes())
             {
-                return true;
+                if (attr.AttributeClass?.ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat) == "global::" + attributeMetadataName)
+                {
+                    attribute = attr;
+                    return true;
+                }
             }
         }
 
+        attribute = null!;
         return false;
     }
 
+    private static IEnumerable<ISymbol> EnumerateSelfAndBaseSymbols(ISymbol symbol)
+    {
+        for (var current = symbol; current is not null; current = GetBaseSymbol(current))
+        {
+            yield return current;
+        }
+    }
+
+    private static ISymbol? GetBaseSymbol(ISymbol symbol)
+    {
+        return symbol switch
+        {
+            IPropertySymbol property => property.OverriddenProperty,
+            IMethodSymbol method => method.OverriddenMethod,
+            IEventSymbol @event => @event.OverriddenEvent,
+            INamedTypeSymbol named => named.BaseType,
+            _ => null,
+        };
+    }
+
     private static bool ImplementsInterface(ITypeSymbol type, string interfaceMetadataName)
     {
         if (type is not INamedTypeSymbol named)
@@ -4341,22 +4369,18 @@ private static bool ImplementsInterface(ITypeSymbol type, string interfaceMetada
 
     private static string GetSerializedName(ISymbol member, string memberName, string? namingPolicyExpression)
     {
-        foreach (var attr in member.GetAttributes())
+        if (TryGetAttribute(member, "Tomlyn.Serialization.TomlPropertyNameAttribute", out var tomlAttr) &&
+            tomlAttr.ConstructorArguments.Length == 1 &&
+            tomlAttr.ConstructorArguments[0].Value is string tomlName)
         {
-            var attrName = attr.AttributeClass?.ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat);
-            if (attrName == "global::Tomlyn.Serialization.TomlPropertyNameAttribute" &&
-                attr.ConstructorArguments.Length == 1 &&
-                attr.ConstructorArguments[0].Value is string tomlName)
-            {
-                return tomlName;
-            }
+            return tomlName;
+        }
 
-            if (attrName == "global::System.Text.Json.Serialization.JsonPropertyNameAttribute" &&
-                attr.ConstructorArguments.Length == 1 &&
-                attr.ConstructorArguments[0].Value is string jsonName)
-            {
-                return jsonName;
-            }
+        if (TryGetAttribute(member, "System.Text.Json.Serialization.JsonPropertyNameAttribute", out var jsonAttr) &&
+            jsonAttr.ConstructorArguments.Length == 1 &&
+            jsonAttr.ConstructorArguments[0].Value is string jsonName)
+        {
+            return jsonName;
         }
 
         if (namingPolicyExpression is not null && TryConvertKnownName(memberName, namingPolicyExpression, out var converted))
@@ -4369,13 +4393,8 @@ private static string GetSerializedName(ISymbol member, string memberName, strin
 
     private static ObjectCreationHandlingKind GetObjectCreationHandling(ISymbol symbol)
     {
-        foreach (var attr in symbol.GetAttributes())
+        if (TryGetAttribute(symbol, JsonObjectCreationHandlingAttributeMetadataName, out var attr))
         {
-            if (attr.AttributeClass?.ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat) != "global::" + JsonObjectCreationHandlingAttributeMetadataName)
-            {
-                continue;
-            }
-
             if (attr.ConstructorArguments.Length == 1 && attr.ConstructorArguments[0].Value is int constructorValue)
             {
                 return constructorValue switch
@@ -4405,27 +4424,21 @@ private static ObjectCreationHandlingKind GetObjectCreationHandling(ISymbol symb
 
     private static int GetOrder(ISymbol member)
     {
-        int? tomlOrder = null;
-        int? jsonOrder = null;
+        if (TryGetAttribute(member, "Tomlyn.Serialization.TomlPropertyOrderAttribute", out var tomlAttr) &&
+            tomlAttr.ConstructorArguments.Length == 1 &&
+            tomlAttr.ConstructorArguments[0].Value is int tomlOrder)
+        {
+            return tomlOrder;
+        }
 
-        foreach (var attr in member.GetAttributes())
+        if (TryGetAttribute(member, "System.Text.Json.Serialization.JsonPropertyOrderAttribute", out var jsonAttr) &&
+            jsonAttr.ConstructorArguments.Length == 1 &&
+            jsonAttr.ConstructorArguments[0].Value is int jsonOrder)
         {
-            var attrName = attr.AttributeClass?.ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat);
-            if (attrName == "global::Tomlyn.Serialization.TomlPropertyOrderAttribute" &&
-                attr.ConstructorArguments.Length == 1 &&
-                attr.ConstructorArguments[0].Value is int toml)
-            {
-                tomlOrder = toml;
-            }
-            else if (attrName == "global::System.Text.Json.Serialization.JsonPropertyOrderAttribute" &&
-                     attr.ConstructorArguments.Length == 1 &&
-                     attr.ConstructorArguments[0].Value is int json)
-            {
-                jsonOrder = json;
-            }
+            return jsonOrder;
         }
 
-        return tomlOrder ?? jsonOrder ?? 0;
+        return 0;
     }
 
     private static bool TryConvertKnownName(string name, string namingPolicyExpression, out string converted)
@@ -4452,36 +4465,21 @@ private static bool TryConvertKnownName(string name, string namingPolicyExpressi
 
     private static IgnoreBehavior GetIgnoreBehavior(ISymbol symbol)
     {
-        TomlIgnoreAttributeModel? toml = null;
-        JsonIgnoreAttributeModel? json = null;
-
-        foreach (var attr in symbol.GetAttributes())
-        {
-            var attrName = attr.AttributeClass?.ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat);
-            if (attrName == "global::Tomlyn.Serialization.TomlIgnoreAttribute")
-            {
-                toml = TomlIgnoreAttributeModel.From(attr);
-            }
-            else if (attrName == "global::System.Text.Json.Serialization.JsonIgnoreAttribute")
-            {
-                json = JsonIgnoreAttributeModel.From(attr);
-            }
-        }
-
-        if (toml is not null)
+        if (TryGetAttribute(symbol, "Tomlyn.Serialization.TomlIgnoreAttribute", out var tomlAttr))
         {
+            var toml = TomlIgnoreAttributeModel.From(tomlAttr);
             // Interpret [TomlIgnore] with default Condition as "ignore always".
-            return toml.Value.Condition switch
+            return toml.Condition switch
             {
                 1 => new IgnoreBehavior(ignoreAlways: false, writeIgnore: WriteIgnoreKind.WhenWritingNull),
                 2 => new IgnoreBehavior(ignoreAlways: false, writeIgnore: WriteIgnoreKind.WhenWritingDefault),
                 _ => new IgnoreBehavior(ignoreAlways: true, writeIgnore: WriteIgnoreKind.None),
             };
         }
 
-        if (json is not null)
+        if (TryGetAttribute(symbol, "System.Text.Json.Serialization.JsonIgnoreAttribute", out var jsonAttr))
         {
-            var condition = json.Value.Condition ?? JsonIgnoreCondition.Always;
+            var condition = JsonIgnoreAttributeModel.From(jsonAttr).Condition ?? JsonIgnoreCondition.Always;
             return condition switch
             {
                 JsonIgnoreCondition.Never => new IgnoreBehavior(ignoreAlways: false, writeIgnore: WriteIgnoreKind.None),

src/Tomlyn.Tests/NewApiReflectionPocoTests.cs

@@ -75,6 +75,20 @@ private sealed class JsonNamedDerivedOptions : JsonNamedBaseOptions
         public string? Derived { get; init; }
     }
 
+    private abstract class JsonNamedOverriddenBaseOptions
+    {
+        [JsonPropertyName("baseValue")]
+        public virtual string? Base { get; init; }
+    }
+
+    private sealed class JsonNamedOverriddenDerivedOptions : JsonNamedOverriddenBaseOptions
+    {
+        [JsonPropertyName("derivedValue")]
+        public string? Derived { get; init; }
+
+        public override string? Base { get; init; }
+    }
+
     private sealed class PrivateSetterModel
     {
         [JsonInclude]
@@ -216,6 +230,25 @@ public void SerializeDeserialize_InheritedProperties_RespectJsonPropertyName()
         Assert.That(roundtrip.Derived, Is.EqualTo("leaf"));
     }
 
+    [Test]
+    public void SerializeDeserialize_OverriddenProperties_RespectInheritedJsonPropertyName()
+    {
+        var original = new JsonNamedOverriddenDerivedOptions
+        {
+            Base = "shared",
+            Derived = "leaf",
+        };
+
+        var toml = TomlSerializer.Serialize(original);
+        var roundtrip = TomlSerializer.Deserialize<JsonNamedOverriddenDerivedOptions>(toml);
+
+        Assert.That(toml, Does.Contain("baseValue = \"shared\""));
+        Assert.That(toml, Does.Contain("derivedValue = \"leaf\""));
+        Assert.That(roundtrip, Is.Not.Null);
+        Assert.That(roundtrip!.Base, Is.EqualTo("shared"));
+        Assert.That(roundtrip.Derived, Is.EqualTo("leaf"));
+    }
+
     [Test]
     public void Deserialize_PrivateSetter_WithJsonInclude_Works()
     {

src/Tomlyn.Tests/NewApiSourceGenerationTests.cs

@@ -36,6 +36,20 @@ public sealed class GeneratedDerivedOptions : GeneratedBaseOptions
     public string? Derived { get; init; }
 }
 
+public abstract class GeneratedOverriddenBaseOptions
+{
+    [JsonPropertyName("baseValue")]
+    public virtual required string? Base { get; init; }
+}
+
+public sealed class GeneratedOverriddenDerivedOptions : GeneratedOverriddenBaseOptions
+{
+    [JsonPropertyName("derivedValue")]
+    public string? Derived { get; init; }
+
+    public override required string? Base { get; init; }
+}
+
 public sealed class GeneratedOptionsPerson
 {
     public string Name { get; set; } = "";
@@ -264,6 +278,12 @@ internal partial class TestTomlSerializerContextInheritedMembers : TomlSerialize
 {
 }
 
+[TomlSourceGenerationOptions(PropertyNamingPolicy = JsonKnownNamingPolicy.CamelCase)]
+[TomlSerializable(typeof(GeneratedOverriddenDerivedOptions))]
+internal partial class TestTomlSerializerContextOverriddenMembers : TomlSerializerContext
+{
+}
+
 [TomlSourceGenerationOptions(
     WriteIndented = false,
     IndentSize = 4,
@@ -813,6 +833,38 @@ public void GeneratedContext_CanSerializeAndDeserializeInheritedProperties()
         Assert.That(roundtrip.Derived, Is.EqualTo("leaf"));
     }
 
+    [Test]
+    public void GeneratedContext_CanDeserializeOverriddenProperties_WithInheritedJsonPropertyName()
+    {
+        var context = TestTomlSerializerContextOverriddenMembers.Default;
+        var toml = """
+            baseValue = "shared"
+            derivedValue = "leaf"
+            """;
+
+        var roundtrip = TomlSerializer.Deserialize<GeneratedOverriddenDerivedOptions>(toml, context);
+
+        Assert.That(roundtrip, Is.Not.Null);
+        Assert.That(roundtrip!.Base, Is.EqualTo("shared"));
+        Assert.That(roundtrip.Derived, Is.EqualTo("leaf"));
+    }
+
+    [Test]
+    public void GeneratedContext_CanSerializeOverriddenProperties_WithInheritedJsonPropertyName()
+    {
+        var context = TestTomlSerializerContextOverriddenMembers.Default;
+        var original = new GeneratedOverriddenDerivedOptions
+        {
+            Base = "shared",
+            Derived = "leaf",
+        };
+
+        var toml = TomlSerializer.Serialize(original, context);
+
+        Assert.That(toml, Does.Contain("baseValue = \"shared\""));
+        Assert.That(toml, Does.Contain("derivedValue = \"leaf\""));
+    }
+
     [Test]
     public void GeneratedContext_AppliesTomlSourceGenerationOptions()
     {