JsonSubtypes does not respect naming strategy for discriminator property value

[egovova11]

Description

The issue occurs when naming strategy other than CamelCase is used.

Source/destination types

public enum EnumType
{
    EnumMemberOne,
    EnumMemberTwo
}

public interface IMyType
{
    EnumType EnumValue {get;}
}

public class MyTypeOne : IMyType
{
    public EnumType EnumValue => EnumType.EnumMemberOne;
}

public class MyTypeTwo : IMyType
{
    public EnumType EnumValue => EnumType.EnumMemberTwo;
}

var serializerSettings = new JsonSerializerSettings
{
    ContractResolver = new DefaultContractResolver
            {
                NamingStrategy = new SnakeCaseNamingStrategy(),
            },
    Converters = new List<JsonConverter>
    {
          new StringEnumConverter
            {
                NamingStrategy = new SnakeCaseNamingStrategy()
            },
          JsonSubtypesConverterBuilder
                .Of(typeof(IMyType), nameof(IMyType.EnumValue))
                .RegisterSubtype(typeof(MyTypeOne), EnumType.EnumMemberOne)
                .RegisterSubtype(typeof(MyTypeTwo), EnumType.EnumMemberTwo)
                .Build()
    }
}

Source/destination JSON

{"enum_value":"enum_member_one"}

Expected behavior

JSON is deserialized correctly with regard to naming strategy settings.

Actual behavior

Deserialization fails with the following message:

System.ArgumentException: Could not convert 'enum_member_one' to EnumType. ---> Newtonsoft.Json.JsonSerializationException: Error converting value "enum_member_one" to type 'Namespace.EnumType'. Path 'enum_value', line 1, position 13. ---> System.ArgumentException: Requested value 'enum_member_one' was not found.

Steps to reproduce

var json = "{\"enum_value\":\"enum_member_one\"}";
var result = JsonConvert.DeserializeObject<IMyType>(jsonValue, serializerSettings);

[manuc66]

Hi @egovova11

Thanks for submitting this issue !

Please note that the code provided is only compatible with Newtonsoft.Json version 12 and that
you need to specify the json property name on the line .Of(typeof(IMyType) as follow:

var serializerSettings = new JsonSerializerSettings
{
    ContractResolver = new DefaultContractResolver
            {
                NamingStrategy = new SnakeCaseNamingStrategy(),
            },
    Converters = new List<JsonConverter>
    {
          new StringEnumConverter
            {
                NamingStrategy = new SnakeCaseNamingStrategy()
            },
          JsonSubtypesConverterBuilder
                .Of(typeof(IMyType), "enum_value") // <--- here you have to provide the json property name
                .RegisterSubtype(typeof(MyTypeOne), EnumType.EnumMemberOne)
                .RegisterSubtype(typeof(MyTypeTwo), EnumType.EnumMemberTwo)
                .Build()
    }
}

I can reproduce the bug described, it's due to the fact that reading the discriminator property doesn't seem to use the converter provided for the property.

The problem is located here:
https://github.com/manuc66/JsonSubTypes/blob/master/JsonSubTypes/JsonSubtypes.cs#L363

But I have no idea how use JsonSerializerSettings at that place

[egovova11]

Yeah, I used exactly the same approach to workaround the issue.
Also, the same applies to enum member values (i.e. EnumType.EnumMemberOne -> enum_member_one).

Thanks for pointing to the code location, I'll give it a thought. Maybe I will be able to come up with some solution for that.

[manuc66]

I've finally found a fix, see PR #93