Use underlying type converter for nullable type (#84208)

* Use underlying type converter for nullable type

* verify that we use underlying type converter for nullable types

* rollback a little change

* Update src/libraries/System.Text.Json/tests/System.Text.Json.SourceGeneration.Unit.Tests/JsonSourceGeneratorTests.cs

* Update src/libraries/System.Text.Json/tests/System.Text.Json.SourceGeneration.Unit.Tests/JsonSourceGeneratorTests.cs

* Use consistent indentation.

* Fix runtime support for nullable properties with custom converters.

---------

Co-authored-by: Eirik Tsarpalis <eirik.tsarpalis@gmail.com>

diff --git a/src/libraries/System.Text.Json/gen/JsonSourceGenerator.Emitter.cs b/src/libraries/System.Text.Json/gen/JsonSourceGenerator.Emitter.cs
index e329d01..14f66ef 100644 (file)
--- a/src/libraries/System.Text.Json/gen/JsonSourceGenerator.Emitter.cs
+++ b/src/libraries/System.Text.Json/gen/JsonSourceGenerator.Emitter.cs
@@ -33,6 +33,7 @@ namespace System.Text.Json.SourceGeneration
             private const string PropInitMethodNameSuffix = "PropInit";
             private const string TryGetTypeInfoForRuntimeCustomConverterMethodName = "TryGetTypeInfoForRuntimeCustomConverter";
             private const string ExpandConverterMethodName = "ExpandConverter";
+            private const string GetConverterForNullablePropertyMethodName = "GetConverterForNullableProperty";
             private const string SerializeHandlerPropName = "SerializeHandler";
             private const string OptionsLocalVariableName = "options";
             private const string ValueVarName = "value";
@@ -80,6 +81,11 @@ namespace System.Text.Json.SourceGeneration
             private readonly Dictionary<string, string> _propertyNames = new();
 
             /// <summary>
+            /// Indicates that the type graph contains a nullable property with a design-time custom converter declaration.
+            /// </summary>
+            private bool _emitGetConverterForNullablePropertyMethod;
+
+            /// <summary>
             /// The SourceText emit implementation filled by the individual Roslyn versions.
             /// </summary>
             private partial void AddSource(string hintName, SourceText sourceText);
@@ -88,6 +94,7 @@ namespace System.Text.Json.SourceGeneration
             {
                 Debug.Assert(_typeIndex.Count == 0);
                 Debug.Assert(_propertyNames.Count == 0);
+                Debug.Assert(!_emitGetConverterForNullablePropertyMethod);
 
                 foreach (TypeGenerationSpec spec in contextGenerationSpec.GeneratedTypes)
                 {
@@ -106,7 +113,7 @@ namespace System.Text.Json.SourceGeneration
                 string contextName = contextGenerationSpec.ContextType.Name;
 
                 // Add root context implementation.
-                AddSource($"{contextName}.g.cs", GetRootJsonContextImplementation(contextGenerationSpec));
+                AddSource($"{contextName}.g.cs", GetRootJsonContextImplementation(contextGenerationSpec, _emitGetConverterForNullablePropertyMethod));
 
                 // Add GetJsonTypeInfo override implementation.
                 AddSource($"{contextName}.GetJsonTypeInfo.g.cs", GetGetTypeInfoImplementation(contextGenerationSpec));
@@ -114,6 +121,7 @@ namespace System.Text.Json.SourceGeneration
                 // Add property name initialization.
                 AddSource($"{contextName}.PropertyNames.g.cs", GetPropertyNameInitialization(contextGenerationSpec));
 
+                _emitGetConverterForNullablePropertyMethod = false;
                 _propertyNames.Clear();
                 _typeIndex.Clear();
             }
@@ -539,7 +547,7 @@ namespace System.Text.Json.SourceGeneration
                 return CompleteSourceFileAndReturnText(writer);
             }
 
-            private static void GeneratePropMetadataInitFunc(SourceWriter writer, string propInitMethodName, TypeGenerationSpec typeGenerationSpec)
+            private void GeneratePropMetadataInitFunc(SourceWriter writer, string propInitMethodName, TypeGenerationSpec typeGenerationSpec)
             {
                 Debug.Assert(typeGenerationSpec.PropertyGenSpecs != null);
                 ImmutableEquatableArray<PropertyGenerationSpec> properties = typeGenerationSpec.PropertyGenSpecs;
@@ -585,9 +593,15 @@ namespace System.Text.Json.SourceGeneration
                         ? $"{JsonIgnoreConditionTypeRef}.{property.DefaultIgnoreCondition.Value}"
                         : "null";
 
-                    string converterInstantiationExpr = property.ConverterType != null
-                        ? $"({JsonConverterTypeRef}<{propertyTypeFQN}>){ExpandConverterMethodName}(typeof({propertyTypeFQN}), new {property.ConverterType.FullyQualifiedName}(), {OptionsLocalVariableName})"
-                        : "null";
+                    string? converterInstantiationExpr = null;
+                    if (property.ConverterType != null)
+                    {
+                        TypeRef? nullableUnderlyingType = _typeIndex[property.PropertyType].NullableUnderlyingType;
+                        _emitGetConverterForNullablePropertyMethod |= nullableUnderlyingType != null;
+                        converterInstantiationExpr = nullableUnderlyingType != null
+                            ? $"{GetConverterForNullablePropertyMethodName}<{nullableUnderlyingType.FullyQualifiedName}>(new {property.ConverterType.FullyQualifiedName}(), {OptionsLocalVariableName})"
+                            : $"({JsonConverterTypeRef}<{propertyTypeFQN}>){ExpandConverterMethodName}(typeof({propertyTypeFQN}), new {property.ConverterType.FullyQualifiedName}(), {OptionsLocalVariableName})";
+                    }
 
                     writer.WriteLine($$"""
                         var {{InfoVarName}}{{i}} = new {{JsonPropertyInfoValuesTypeRef}}<{{propertyTypeFQN}}>()
@@ -596,7 +610,7 @@ namespace System.Text.Json.SourceGeneration
                             IsPublic = {{FormatBool(property.IsPublic)}},
                             IsVirtual = {{FormatBool(property.IsVirtual)}},
                             DeclaringType = typeof({{property.DeclaringType.FullyQualifiedName}}),
-                            Converter = {{converterInstantiationExpr}},
+                            Converter = {{converterInstantiationExpr ?? "null"}},
                             Getter = {{getterValue}},
                             Setter = {{setterValue}},
                             IgnoreCondition = {{ignoreConditionNamedArg}},
@@ -1007,7 +1021,7 @@ namespace System.Text.Json.SourceGeneration
                     """);
             }
 
-            private static SourceText GetRootJsonContextImplementation(ContextGenerationSpec contextSpec)
+            private static SourceText GetRootJsonContextImplementation(ContextGenerationSpec contextSpec, bool emitGetConverterForNullablePropertyMethod)
             {
                 string contextTypeRef = contextSpec.ContextType.FullyQualifiedName;
                 string contextTypeName = contextSpec.ContextType.Name;
@@ -1048,7 +1062,7 @@ namespace System.Text.Json.SourceGeneration
 
                 writer.WriteLine();
 
-                GenerateConverterHelpers(writer);
+                GenerateConverterHelpers(writer, emitGetConverterForNullablePropertyMethod);
 
                 return CompleteSourceFileAndReturnText(writer);
             }
@@ -1082,7 +1096,7 @@ namespace System.Text.Json.SourceGeneration
                     """);
             }
 
-            private static void GenerateConverterHelpers(SourceWriter writer)
+            private static void GenerateConverterHelpers(SourceWriter writer, bool emitGetConverterForNullablePropertyMethod)
             {
                 // The generic type parameter could capture type parameters from containing types,
                 // so use a name that is unlikely to be used.
@@ -1109,15 +1123,20 @@ namespace System.Text.Json.SourceGeneration
                             {{JsonConverterTypeRef}}? converter = options.Converters[i];
                             if (converter?.CanConvert(type) == true)
                             {
-                                return {{ExpandConverterMethodName}}(type, converter, options);
+                                return {{ExpandConverterMethodName}}(type, converter, options, validateCanConvert: false);
                             }
                         }
 
                         return null;
                     }
 
-                    private static {{JsonConverterTypeRef}} {{ExpandConverterMethodName}}({{TypeTypeRef}} type, {{JsonConverterTypeRef}} converter, {{JsonSerializerOptionsTypeRef}} options)
+                    private static {{JsonConverterTypeRef}} {{ExpandConverterMethodName}}({{TypeTypeRef}} type, {{JsonConverterTypeRef}} converter, {{JsonSerializerOptionsTypeRef}} options, bool validateCanConvert = true)
                     {
+                        if (validateCanConvert && !converter.CanConvert(type))
+                        {
+                            throw new {{InvalidOperationExceptionTypeRef}}(string.Format("{{ExceptionMessages.IncompatibleConverterType}}", converter.GetType(), type));
+                        }
+                    
                         if (converter is {{JsonConverterFactoryTypeRef}} factory)
                         {
                             converter = factory.CreateConverter(type, options);
@@ -1126,15 +1145,29 @@ namespace System.Text.Json.SourceGeneration
                                 throw new {{InvalidOperationExceptionTypeRef}}(string.Format("{{ExceptionMessages.InvalidJsonConverterFactoryOutput}}", factory.GetType()));
                             }
                         }
-
-                        if (!converter.CanConvert(type))
-                        {
-                            throw new {{InvalidOperationExceptionTypeRef}}(string.Format("{{ExceptionMessages.IncompatibleConverterType}}", converter.GetType(), type));
-                        }
                     
                         return converter;
                     }
                     """);
+
+                if (emitGetConverterForNullablePropertyMethod)
+                {
+                    writer.WriteLine($$"""
+
+                        private static {{JsonConverterTypeRef}}<{{TypeParameter}}?> {{GetConverterForNullablePropertyMethodName}}<{{TypeParameter}}>({{JsonConverterTypeRef}} converter, {{JsonSerializerOptionsTypeRef}} options)
+                            where {{TypeParameter}} : struct
+                        {
+                            if (converter.CanConvert(typeof({{TypeParameter}}?)))
+                            {
+                                return ({{JsonConverterTypeRef}}<{{TypeParameter}}?>){{ExpandConverterMethodName}}(typeof({{TypeParameter}}?), converter, options, validateCanConvert: false);
+                            }
+                    
+                            converter = {{ExpandConverterMethodName}}(typeof({{TypeParameter}}), converter, options);
+                            {{JsonTypeInfoTypeRef}}<{{TypeParameter}}> typeInfo = {{JsonMetadataServicesTypeRef}}.{{CreateValueInfoMethodName}}<{{TypeParameter}}>(options, converter);
+                            return {{JsonMetadataServicesTypeRef}}.GetNullableConverter<{{TypeParameter}}>(typeInfo);
+                        }
+                        """);
+                }
             }
 
             private static SourceText GetGetTypeInfoImplementation(ContextGenerationSpec contextSpec)

diff --git a/src/libraries/System.Text.Json/tests/System.Text.Json.SourceGeneration.Tests/ContextClasses.cs b/src/libraries/System.Text.Json/tests/System.Text.Json.SourceGeneration.Tests/ContextClasses.cs
index 0d87b28..863d86b 100644 (file)
--- a/src/libraries/System.Text.Json/tests/System.Text.Json.SourceGeneration.Tests/ContextClasses.cs
+++ b/src/libraries/System.Text.Json/tests/System.Text.Json.SourceGeneration.Tests/ContextClasses.cs
@@ -49,6 +49,8 @@ namespace System.Text.Json.SourceGeneration.Tests
         public JsonTypeInfo<StructWithCustomConverterProperty> StructWithCustomConverterProperty { get; }
         public JsonTypeInfo<ClassWithCustomConverterFactoryProperty> ClassWithCustomConverterFactoryProperty { get; }
         public JsonTypeInfo<StructWithCustomConverterFactoryProperty> StructWithCustomConverterFactoryProperty { get; }
+        public JsonTypeInfo<ClassWithCustomConverterNullableProperty> ClassWithCustomConverterNullableProperty { get; }
+        public JsonTypeInfo<ClassWithCustomConverterFactoryNullableProperty> ClassWithCustomConverterFactoryNullableProperty { get; }
         public JsonTypeInfo<ClassWithBadCustomConverter> ClassWithBadCustomConverter { get; }
         public JsonTypeInfo<StructWithBadCustomConverter> StructWithBadCustomConverter { get; }
         public JsonTypeInfo<PersonStruct?> NullablePersonStruct { get; }

diff --git a/src/libraries/System.Text.Json/tests/System.Text.Json.SourceGeneration.Tests/MetadataAndSerializationContextTests.cs b/src/libraries/System.Text.Json/tests/System.Text.Json.SourceGeneration.Tests/MetadataAndSerializationContextTests.cs
index 8e37e93..8ebf4c2 100644 (file)
--- a/src/libraries/System.Text.Json/tests/System.Text.Json.SourceGeneration.Tests/MetadataAndSerializationContextTests.cs
+++ b/src/libraries/System.Text.Json/tests/System.Text.Json.SourceGeneration.Tests/MetadataAndSerializationContextTests.cs
@@ -45,6 +45,8 @@ namespace System.Text.Json.SourceGeneration.Tests
     [JsonSerializable(typeof(StructWithCustomConverterProperty))]
     [JsonSerializable(typeof(ClassWithCustomConverterFactoryProperty))]
     [JsonSerializable(typeof(StructWithCustomConverterFactoryProperty))]
+    [JsonSerializable(typeof(ClassWithCustomConverterNullableProperty))]
+    [JsonSerializable(typeof(ClassWithCustomConverterFactoryNullableProperty))]
     [JsonSerializable(typeof(ClassWithBadCustomConverter))]
     [JsonSerializable(typeof(StructWithBadCustomConverter))]
     [JsonSerializable(typeof(PersonStruct?))]

diff --git a/src/libraries/System.Text.Json/tests/System.Text.Json.SourceGeneration.Tests/MetadataContextTests.cs b/src/libraries/System.Text.Json/tests/System.Text.Json.SourceGeneration.Tests/MetadataContextTests.cs
index 4cb8394..562dba3 100644 (file)
--- a/src/libraries/System.Text.Json/tests/System.Text.Json.SourceGeneration.Tests/MetadataContextTests.cs
+++ b/src/libraries/System.Text.Json/tests/System.Text.Json.SourceGeneration.Tests/MetadataContextTests.cs
@@ -44,6 +44,8 @@ namespace System.Text.Json.SourceGeneration.Tests
     [JsonSerializable(typeof(StructWithCustomConverterProperty), GenerationMode = JsonSourceGenerationMode.Metadata)]
     [JsonSerializable(typeof(ClassWithCustomConverterFactoryProperty), GenerationMode = JsonSourceGenerationMode.Metadata)]
     [JsonSerializable(typeof(StructWithCustomConverterFactoryProperty), GenerationMode = JsonSourceGenerationMode.Metadata)]
+    [JsonSerializable(typeof(ClassWithCustomConverterNullableProperty), GenerationMode = JsonSourceGenerationMode.Metadata)]
+    [JsonSerializable(typeof(ClassWithCustomConverterFactoryNullableProperty), GenerationMode = JsonSourceGenerationMode.Metadata)]
     [JsonSerializable(typeof(ClassWithBadCustomConverter), GenerationMode = JsonSourceGenerationMode.Metadata)]
     [JsonSerializable(typeof(StructWithBadCustomConverter), GenerationMode = JsonSourceGenerationMode.Metadata)]
     [JsonSerializable(typeof(PersonStruct?), GenerationMode = JsonSourceGenerationMode.Metadata)]
@@ -144,6 +146,8 @@ namespace System.Text.Json.SourceGeneration.Tests
     [JsonSerializable(typeof(StructWithCustomConverterProperty))]
     [JsonSerializable(typeof(ClassWithCustomConverterFactoryProperty))]
     [JsonSerializable(typeof(StructWithCustomConverterFactoryProperty))]
+    [JsonSerializable(typeof(ClassWithCustomConverterNullableProperty))]
+    [JsonSerializable(typeof(ClassWithCustomConverterFactoryNullableProperty))]
     [JsonSerializable(typeof(ClassWithBadCustomConverter))]
     [JsonSerializable(typeof(StructWithBadCustomConverter))]
     [JsonSerializable(typeof(PersonStruct?))]

diff --git a/src/libraries/System.Text.Json/tests/System.Text.Json.SourceGeneration.Tests/MixedModeContextTests.cs b/src/libraries/System.Text.Json/tests/System.Text.Json.SourceGeneration.Tests/MixedModeContextTests.cs
index 98d3dfa..bd5a525 100644 (file)
--- a/src/libraries/System.Text.Json/tests/System.Text.Json.SourceGeneration.Tests/MixedModeContextTests.cs
+++ b/src/libraries/System.Text.Json/tests/System.Text.Json.SourceGeneration.Tests/MixedModeContextTests.cs
@@ -45,6 +45,8 @@ namespace System.Text.Json.SourceGeneration.Tests
     [JsonSerializable(typeof(StructWithCustomConverterProperty), GenerationMode = JsonSourceGenerationMode.Metadata | JsonSourceGenerationMode.Serialization)]
     [JsonSerializable(typeof(ClassWithCustomConverterFactoryProperty), GenerationMode = JsonSourceGenerationMode.Metadata | JsonSourceGenerationMode.Serialization)]
     [JsonSerializable(typeof(StructWithCustomConverterFactoryProperty), GenerationMode = JsonSourceGenerationMode.Metadata | JsonSourceGenerationMode.Serialization)]
+    [JsonSerializable(typeof(ClassWithCustomConverterNullableProperty), GenerationMode = JsonSourceGenerationMode.Metadata | JsonSourceGenerationMode.Serialization)]
+    [JsonSerializable(typeof(ClassWithCustomConverterFactoryNullableProperty), GenerationMode = JsonSourceGenerationMode.Metadata | JsonSourceGenerationMode.Serialization)]
     [JsonSerializable(typeof(ClassWithBadCustomConverter), GenerationMode = JsonSourceGenerationMode.Metadata | JsonSourceGenerationMode.Serialization)]
     [JsonSerializable(typeof(StructWithBadCustomConverter), GenerationMode = JsonSourceGenerationMode.Metadata | JsonSourceGenerationMode.Serialization)]
     [JsonSerializable(typeof(PersonStruct?), GenerationMode = JsonSourceGenerationMode.Metadata | JsonSourceGenerationMode.Serialization)]

diff --git a/src/libraries/System.Text.Json/tests/System.Text.Json.SourceGeneration.Tests/RealWorldContextTests.cs b/src/libraries/System.Text.Json/tests/System.Text.Json.SourceGeneration.Tests/RealWorldContextTests.cs
index 1d482e1..d0cef83 100644 (file)
--- a/src/libraries/System.Text.Json/tests/System.Text.Json.SourceGeneration.Tests/RealWorldContextTests.cs
+++ b/src/libraries/System.Text.Json/tests/System.Text.Json.SourceGeneration.Tests/RealWorldContextTests.cs
@@ -6,7 +6,6 @@ using System.IO;
 using System.Linq;
 using System.Text.Json.Serialization;
 using System.Text.Json.Serialization.Metadata;
-using System.Text.Json.Serialization.Tests;
 using Xunit;
 
 namespace System.Text.Json.SourceGeneration.Tests
@@ -258,6 +257,60 @@ namespace System.Text.Json.SourceGeneration.Tests
         }
 
         [Fact]
+        public virtual void RoundTripWithCustomConverterNullableProperty()
+        {
+            const string Json = "{\"TimeSpan\":42}";
+
+            var obj = new ClassWithCustomConverterNullableProperty
+            {
+                TimeSpan = TimeSpan.FromSeconds(42)
+            };
+
+            // Types with properties in custom converters do not support fast path serialization.
+            Assert.True(DefaultContext.ClassWithCustomConverterNullableProperty.SerializeHandler is null);
+
+            if (DefaultContext.JsonSourceGenerationMode == JsonSourceGenerationMode.Serialization)
+            {
+                Assert.Throws<InvalidOperationException>(() => JsonSerializer.Serialize(obj, DefaultContext.ClassWithCustomConverterNullableProperty));
+            }
+            else
+            {
+                string json = JsonSerializer.Serialize(obj, DefaultContext.ClassWithCustomConverterNullableProperty);
+                Assert.Equal(Json, json);
+
+                obj = JsonSerializer.Deserialize(Json, DefaultContext.ClassWithCustomConverterNullableProperty);
+                Assert.Equal(42, obj.TimeSpan.Value.TotalSeconds);
+            }
+        }
+
+        [Fact]
+        public virtual void RoundTripWithCustomConverterFactoryNullableProperty()
+        {
+            const string Json = "{\"MyEnum\":\"Two\"}";
+
+            var obj = new ClassWithCustomConverterFactoryNullableProperty
+            {
+                MyEnum = SourceGenSampleEnum.Two
+            };
+
+            // Types with properties in custom converters do not support fast path serialization.
+            Assert.True(DefaultContext.ClassWithCustomConverterFactoryNullableProperty.SerializeHandler is null);
+
+            if (DefaultContext.JsonSourceGenerationMode == JsonSourceGenerationMode.Serialization)
+            {
+                Assert.Throws<InvalidOperationException>(() => JsonSerializer.Serialize(obj, DefaultContext.ClassWithCustomConverterFactoryNullableProperty));
+            }
+            else
+            {
+                string json = JsonSerializer.Serialize(obj, DefaultContext.ClassWithCustomConverterFactoryNullableProperty);
+                Assert.Equal(Json, json);
+
+                obj = JsonSerializer.Deserialize(Json, DefaultContext.ClassWithCustomConverterFactoryNullableProperty);
+                Assert.Equal(SourceGenSampleEnum.Two, obj.MyEnum.Value);
+            }
+        }
+
+        [Fact]
         public virtual void RoundtripWithCustomConverterProperty_Struct()
         {
             const string ExpectedJson = "{\"Property\":42}";

diff --git a/src/libraries/System.Text.Json/tests/System.Text.Json.SourceGeneration.Tests/SerializationContextTests.cs b/src/libraries/System.Text.Json/tests/System.Text.Json.SourceGeneration.Tests/SerializationContextTests.cs
index 837e896..4ff2b90 100644 (file)
--- a/src/libraries/System.Text.Json/tests/System.Text.Json.SourceGeneration.Tests/SerializationContextTests.cs
+++ b/src/libraries/System.Text.Json/tests/System.Text.Json.SourceGeneration.Tests/SerializationContextTests.cs
@@ -46,6 +46,8 @@ namespace System.Text.Json.SourceGeneration.Tests
     [JsonSerializable(typeof(StructWithCustomConverterProperty))]
     [JsonSerializable(typeof(ClassWithCustomConverterFactoryProperty))]
     [JsonSerializable(typeof(StructWithCustomConverterFactoryProperty))]
+    [JsonSerializable(typeof(ClassWithCustomConverterNullableProperty))]
+    [JsonSerializable(typeof(ClassWithCustomConverterFactoryNullableProperty))]
     [JsonSerializable(typeof(ClassWithBadCustomConverter))]
     [JsonSerializable(typeof(StructWithBadCustomConverter))]
     [JsonSerializable(typeof(PersonStruct?))]
@@ -95,6 +97,8 @@ namespace System.Text.Json.SourceGeneration.Tests
     [JsonSerializable(typeof(StructWithCustomConverterProperty), GenerationMode = JsonSourceGenerationMode.Serialization)]
     [JsonSerializable(typeof(ClassWithCustomConverterFactoryProperty), GenerationMode = JsonSourceGenerationMode.Serialization)]
     [JsonSerializable(typeof(StructWithCustomConverterFactoryProperty), GenerationMode = JsonSourceGenerationMode.Serialization)]
+    [JsonSerializable(typeof(ClassWithCustomConverterNullableProperty), GenerationMode = JsonSourceGenerationMode.Serialization)]
+    [JsonSerializable(typeof(ClassWithCustomConverterFactoryNullableProperty), GenerationMode = JsonSourceGenerationMode.Serialization)]
     [JsonSerializable(typeof(ClassWithBadCustomConverter), GenerationMode = JsonSourceGenerationMode.Serialization)]
     [JsonSerializable(typeof(StructWithBadCustomConverter), GenerationMode = JsonSourceGenerationMode.Serialization)]
     [JsonSerializable(typeof(PersonStruct?), GenerationMode = JsonSourceGenerationMode.Serialization)]
@@ -145,6 +149,8 @@ namespace System.Text.Json.SourceGeneration.Tests
     [JsonSerializable(typeof(StructWithCustomConverterProperty), GenerationMode = JsonSourceGenerationMode.Serialization)]
     [JsonSerializable(typeof(ClassWithCustomConverterFactoryProperty), GenerationMode = JsonSourceGenerationMode.Serialization)]
     [JsonSerializable(typeof(StructWithCustomConverterFactoryProperty), GenerationMode = JsonSourceGenerationMode.Serialization)]
+    [JsonSerializable(typeof(ClassWithCustomConverterNullableProperty), GenerationMode = JsonSourceGenerationMode.Serialization)]
+    [JsonSerializable(typeof(ClassWithCustomConverterFactoryNullableProperty), GenerationMode = JsonSourceGenerationMode.Serialization)]
     [JsonSerializable(typeof(ClassWithBadCustomConverter), GenerationMode = JsonSourceGenerationMode.Serialization)]
     [JsonSerializable(typeof(StructWithBadCustomConverter), GenerationMode = JsonSourceGenerationMode.Serialization)]
     [JsonSerializable(typeof(PersonStruct?), GenerationMode = JsonSourceGenerationMode.Serialization)]

diff --git a/src/libraries/System.Text.Json/tests/System.Text.Json.SourceGeneration.Tests/TestClasses.CustomConverters.cs b/src/libraries/System.Text.Json/tests/System.Text.Json.SourceGeneration.Tests/TestClasses.CustomConverters.cs
index 18762d2..7ed8c5e 100644 (file)
--- a/src/libraries/System.Text.Json/tests/System.Text.Json.SourceGeneration.Tests/TestClasses.CustomConverters.cs
+++ b/src/libraries/System.Text.Json/tests/System.Text.Json.SourceGeneration.Tests/TestClasses.CustomConverters.cs
@@ -257,6 +257,31 @@ namespace System.Text.Json.SourceGeneration.Tests
         public SourceGenSampleEnum MyEnum { get; set; }
     }
 
+    public class ClassWithCustomConverterFactoryNullableProperty
+    {
+        [JsonConverter(typeof(JsonStringEnumConverter))] // This converter is a JsonConverterFactory
+        public SourceGenSampleEnum? MyEnum { get; set; }
+    }
+
+    public class ClassWithCustomConverterNullableProperty
+    {
+        [JsonConverter(typeof(TimeSpanSecondsConverter))]
+        public TimeSpan? TimeSpan { get; set; }
+    }
+
+    public class TimeSpanSecondsConverter : JsonConverter<TimeSpan>
+    {
+        public override TimeSpan Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+        {
+            return TimeSpan.FromSeconds(reader.GetDouble());
+        }
+
+        public override void Write(Utf8JsonWriter writer, TimeSpan value, JsonSerializerOptions options)
+        {
+            writer.WriteNumberValue(value.TotalSeconds);
+        }
+    }
+
     [JsonConverter(typeof(CustomConverter_StructWithCustomConverter))] // Invalid
     public class ClassWithBadCustomConverter
     {

diff --git a/src/libraries/System.Text.Json/tests/System.Text.Json.SourceGeneration.Unit.Tests/JsonSourceGeneratorTests.cs b/src/libraries/System.Text.Json/tests/System.Text.Json.SourceGeneration.Unit.Tests/JsonSourceGeneratorTests.cs
index a0e038a..4287e16 100644 (file)
--- a/src/libraries/System.Text.Json/tests/System.Text.Json.SourceGeneration.Unit.Tests/JsonSourceGeneratorTests.cs
+++ b/src/libraries/System.Text.Json/tests/System.Text.Json.SourceGeneration.Unit.Tests/JsonSourceGeneratorTests.cs
@@ -695,6 +695,65 @@ namespace System.Text.Json.SourceGeneration.UnitTests
         }
 
         [Fact]
+        public void UseUnderlyingTypeConverterForNullableType()
+        {
+            // Compile the referenced assembly first.
+            Compilation referencedCompilation = CompilationHelper.CreateReferencedLocationCompilation();
+
+            // Emit the image of the referenced assembly.
+            byte[] referencedImage = CompilationHelper.CreateAssemblyImage(referencedCompilation);
+
+            string source = """
+                using ReferencedAssembly;
+                using System;
+                using System.Text.Json;
+                using System.Text.Json.Serialization;
+                namespace Test
+                {
+                    [JsonSourceGenerationOptions]
+                    [JsonSerializable(typeof(Sample))]
+                    public partial class SourceGenerationContext : JsonSerializerContext
+                    {
+                    }
+                    public class Sample
+                    {
+                        [JsonConverter(typeof(DateTimeOffsetToTimestampJsonConverter))]
+                        public DateTimeOffset Start { get; set; }
+                        [JsonConverter(typeof(DateTimeOffsetToTimestampJsonConverter))]
+                        public DateTimeOffset? End { get; set; } // Without this property, this is fine
+                    }
+                    public class DateTimeOffsetToTimestampJsonConverter : JsonConverter<DateTimeOffset>
+                    {
+                        internal const long TicksPerMicroseconds = 10;
+                        public override DateTimeOffset Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+                        {
+                            var value = reader.GetInt64();
+                            return new DateTimeOffset(value * TicksPerMicroseconds, TimeSpan.Zero);
+                        }
+                        public override void Write(Utf8JsonWriter writer, DateTimeOffset value, JsonSerializerOptions options)
+                        {
+                            writer.WriteNumberValue(value.Ticks / TicksPerMicroseconds);
+                        }
+                    }
+                }
+                """;
+
+            MetadataReference[] additionalReferences = { MetadataReference.CreateFromImage(referencedImage) };
+
+            Compilation compilation = CompilationHelper.CreateCompilation(source, additionalReferences);
+
+            JsonSourceGeneratorResult result = CompilationHelper.RunJsonSourceGenerator(compilation);
+
+            // Make sure compilation was successful.
+            CheckCompilationDiagnosticsErrors(result.NewCompilation.GetDiagnostics());
+
+            Assert.Equal(3, result.AllGeneratedTypes.Count());
+            result.AssertContainsType("global::Test.Sample");
+            result.AssertContainsType("global::System.DateTimeOffset");
+            result.AssertContainsType("global::System.DateTimeOffset?");
+        }
+
+        [Fact]
         public void VariousGenericSerializableTypesAreSupported()
         {
             string source = """