Gracefully handle ctor parameters named by the serialized name

src/Nerdbank.MessagePack/Converters/CommonRecords.cs

@@ -111,7 +111,8 @@ internal record struct PropertyAccessors<TDeclaringType>(
 /// <typeparam name="TDeclaringType">The data type whose constructor is to be visited.</typeparam>
 /// <param name="Serializers">Serializable properties on the data type.</param>
 /// <param name="Deserializers">Deserializable properties on the data type.</param>
-internal record MapConstructorVisitorInputs<TDeclaringType>(MapSerializableProperties<TDeclaringType> Serializers, MapDeserializableProperties<TDeclaringType> Deserializers);
+/// <param name="ParametersByName">A collection of constructor parameters, with any conflicting names removed.</param>
+internal record MapConstructorVisitorInputs<TDeclaringType>(MapSerializableProperties<TDeclaringType> Serializers, MapDeserializableProperties<TDeclaringType> Deserializers, Dictionary<string, IConstructorParameterShape> ParametersByName);
 
 /// <summary>
 /// Encapsulates the data passed through <see cref="ITypeShapeVisitor.VisitConstructor{TDeclaringType, TArgumentState}(IConstructorShape{TDeclaringType, TArgumentState}, object?)"/> state arguments

src/Nerdbank.MessagePack/StandardVisitor.cs

@@ -80,8 +80,23 @@ internal StandardVisitor(ConverterCache owner, TypeGenerationContext context)
 
 		IConstructorShape? ctorShape = objectShape.Constructor;
 
-		Dictionary<string, IConstructorParameterShape>? ctorParametersByName =
-			ctorShape?.Parameters.ToDictionary(p => p.Name, StringComparer.OrdinalIgnoreCase);
+		Dictionary<string, IConstructorParameterShape>? ctorParametersByName = null;
+		if (ctorShape is not null)
+		{
+			ctorParametersByName = new(StringComparer.Ordinal);
+			foreach (IConstructorParameterShape ctorParameter in ctorShape.Parameters)
+			{
+				// Keep the one with the Kind that we prefer.
+				if (ctorParameter.Kind == ConstructorParameterKind.ConstructorParameter)
+				{
+					ctorParametersByName[ctorParameter.Name] = ctorParameter;
+				}
+				else if (!ctorParametersByName.ContainsKey(ctorParameter.Name))
+				{
+					ctorParametersByName.Add(ctorParameter.Name, ctorParameter);
+				}
+			}
+		}
 
 		List<SerializableProperty<T>>? serializable = null;
 		List<DeserializableProperty<T>>? deserializable = null;
@@ -147,9 +162,9 @@ internal StandardVisitor(ConverterCache owner, TypeGenerationContext context)
 
 			MapSerializableProperties<T> serializableMap = new(serializable?.ToArray());
 			MapDeserializableProperties<T> deserializableMap = new(propertyReaders);
-			MapConstructorVisitorInputs<T> inputs = new(serializableMap, deserializableMap);
 			if (ctorShape is not null)
 			{
+				MapConstructorVisitorInputs<T> inputs = new(serializableMap, deserializableMap, ctorParametersByName!);
 				converter = (MessagePackConverter<T>)ctorShape.Accept(this, inputs)!;
 			}
 			else
@@ -279,7 +294,7 @@ internal StandardVisitor(ConverterCache owner, TypeGenerationContext context)
 
 					List<SerializableProperty<TDeclaringType>> propertySerializers = inputs.Serializers.Properties.Span.ToList();
 
-					SpanDictionary<byte, DeserializableProperty<TArgumentState>> parameters = constructorShape.Parameters
+					SpanDictionary<byte, DeserializableProperty<TArgumentState>> parameters = inputs.ParametersByName.Values
 						.SelectMany<IConstructorParameterShape, (string Name, DeserializableProperty<TArgumentState> Deserialize)>(p =>
 						{
 							var prop = (DeserializableProperty<TArgumentState>)p.Accept(this)!;
@@ -316,7 +331,7 @@ internal StandardVisitor(ConverterCache owner, TypeGenerationContext context)
 						return new ObjectArrayConverter<TDeclaringType>(inputs.GetJustAccessors(), constructorShape.GetDefaultConstructor(), !this.owner.SerializeDefaultValues);
 					}
 
-					Dictionary<string, int> propertyIndexesByName = new(StringComparer.OrdinalIgnoreCase);
+					Dictionary<string, int> propertyIndexesByName = new(StringComparer.Ordinal);
 					for (int i = 0; i < inputs.Properties.Count; i++)
 					{
 						if (inputs.Properties[i] is { } property)

test/Nerdbank.MessagePack.Tests/MessagePackSerializerTests.cs

@@ -294,6 +294,26 @@
 		Assert.Equal(value, deserialized);
 	}
 
+	[Fact]
+	public void CtorParameterNameMatchesSerializedInsteadOfDeclaredName_Roundtrips()
+	{
+		this.AssertRoundtrip(new TypeWithConstructorParameterMatchingSerializedPropertyName(2));
+	}
+
+	[Fact]
+	public void CtorParameterNameMatchesSerializedInsteadOfDeclaredName_DefaultValueWorks()
+	{
+		Sequence<byte> seq = new();
+		MessagePackWriter writer = new(seq);
+		writer.WriteMapHeader(0);
+		writer.Flush();
+
+		TypeWithConstructorParameterMatchingSerializedPropertyName? deserialized =
+			this.Serializer.Deserialize<TypeWithConstructorParameterMatchingSerializedPropertyName>(seq, TestContext.Current.CancellationToken);
+		Assert.NotNull(deserialized);
+		Assert.Equal(8, deserialized.Marshaled);
+	}
+
 	/// <summary>
 	/// Carefully writes a msgpack-encoded array of bytes.
 	/// </summary>
@@ -496,6 +516,16 @@
 		public int Sum => this.A + this.B;
 	}
 
+	[GenerateShape]
+	internal partial record TypeWithConstructorParameterMatchingSerializedPropertyName
+	{
+		public TypeWithConstructorParameterMatchingSerializedPropertyName(int otherName = 8)
+			=> this.Marshaled = otherName;
+
+		[PropertyShape(Name = "otherName")]
+		public int Marshaled { get; set; }
+	}
+
 	[GenerateShape<UnannotatedPoco>]
 	[GenerateShape<object>]
 	[GenerateShape<string>]