Surrogate type with base class

[AlleSchonWeg]

Hi,
i have type which inherits from a base class. The base class and the derived class have a Marshaler:

  [DerivedTypeShape(typeof(DerivedClass), Tag = 1, Name = "DerivedClass")]
  [TypeShape(Marshaler = typeof(BaseClassMarshaler))]
  public class BaseClass
  {
      public string BaseProperty { set; get; }
  }

  [TypeShape(Marshaler = typeof(DerivedClassMarshaler))]
  public class DerivedClass : BaseClass
  {
      public string DerivedProperty { set; get; }
  }

  [GenerateShape]
  public partial class Container
  {
      public BaseClass Base { set; get; }
  }

And the IMarshaler implementations:

public class BaseClassMarshaler : IMarshaler<BaseClass, string>
{
    public string? Marshal(BaseClass? value)
    {
        Console.WriteLine("Marshaling BaseClass to string");
        return "To_MarshalledType";
    }
    public BaseClass? Unmarshal(string? value)
    {
        return new BaseClass();
    }
}

public class DerivedClassMarshaler : IMarshaler<DerivedClass, string>
{
    public string? Marshal(DerivedClass? value)
    {
        Console.WriteLine("Marshaling DerivedClass to string");
        return "To_MarshalledType";
    }
    public DerivedClass? Unmarshal(string? value)
    {
        return new DerivedClass();
    }
}

Th problem is on serialization:

var container = new Container()
{
    Base = new DerivedClass()
    {
        BaseProperty = "BaseValue",
        DerivedProperty = "DerivedValue"
    }
};  
var typeshape = TypeShapeProvider_Nb_MsgPack_Surrogate.Default.GetTypeShape(typeof(Container));
var bytes = serializier.SerializeObject(container, typeshape);

the DerivedClassMarshaler is never called. Only the BaseClassMarshaler. Is this a bug? I need different surrogate types for BaseClass and DerivedClass.

[AArnott]

Thank you for bringing this to my attention. I thought about mixing DerivedTypeAttribute with MessagePackConverter attribute, but not with marshalers. This is an oversight which I will fix. Filed #884.