Inherited interface messages won't process if conventions is used and handler only exists for base message

[janovesk]

Problem

The combination of

1. An interface based message inheriting another interface based message
2. Convention based definition of events
3. JsonSerializer

does not work correctly. :(

If you publish a interface based message that inherits from another interface based message, a subscriber of the base message will blow up with a deserialization message stating that it can not instanciate the inherited type at publish time.

Changing to the xmlserializer, removing the inheritance, using classes instead of interfaces or inheriting from IEvent fixes the problem.

Repro

Originally reported by user. Repro available here.

Code highlights

namespace Event
{
    public interface IBaseEvent
    {
        Guid Id { get; set; }
    }

    public interface IInheritedEvent : IBaseEvent
    {
    }
}

endpointConfiguration.UseSerialization<JsonSerializer>();
endpointConfiguration.Conventions().DefiningEventsAs(t => t.Namespace != null && t.Namespace.StartsWith("Event"));

public class BaseEventHandler : IHandleMessages<IBaseEvent>
{
    public Task Handle(IBaseEvent message, IMessageHandlerContext context)
    {
        return Task.CompletedTask;
    }
}

Error message on subscriber receiving IInheritedEvent

2017-03-22 14:12:14.799 ERROR NServiceBus.RecoverabilityExecutor Moving message '64e5a7f3-1092-480f-818b-a73e00d9974f' to the error queue 'error' because processing failed due to an exception:
NServiceBus.MessageDeserializationException: An error occurred while attempting to extract logical messages from transport message 64e5a7f3-1092-480f-818b-a73e00d9974f ---> Newtonsoft.Json.JsonSerializationException: Could not create an instance of type Event.IInheritedEvent. Type is an interface or abstract class and cannot be instantiated. Path 'Id', line 1, position 6.
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateNewObject(JsonReader reader, JsonObjectContract objectContract, JsonProperty containerMember, JsonProperty containerProperty, String id, Boolean& createdFromNonDefaultCreator) in C:\BuildAgent\work\3206e2123f54fce4\src\NServiceBus.Core\Transports\MessageContext.cs:line 0
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateObject(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue) in C:\BuildAgent\work\3206e2123f54fce4\src\NServiceBus.Core\Transports\MessageContext.cs:line 0
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Deserialize(JsonReader reader, Type objectType, Boolean checkAdditionalContent) in C:\BuildAgent\work\3206e2123f54fce4\src\NServiceBus.Core\Transports\MessageContext.cs:line 0
..

[janovesk]

Possibly related to #4452

[timbussmann]

@Particular/nservicebus-maintainers does this qualify as critical?
@janovesk are you investigating further on this issue?

[andreasohlund]

Talking this through with @timbussmann we decided to not rush the fix for this into 6.2 since its to risky.

The user have a workaround for now and the bug would be found during development. Assigning this to 6.3 since we still believe this needs to be addressed

[mluttrell]

@andreasohlund any idea when we can expect this? We're in the process of upgrading to NSB6 and running into this in a number of places.

[andreasohlund]

My best guestimate is that 6.3.0 will be released end of next week. Does that align with your deadline?

[mluttrell]

That general timeframe should be fine for us. Thank you!

[praveenkonduru]

I am running through the same issue. what is the work around for the issue

[timbussmann]

@praveenkonduru we recommend to upgrade to NServiceBus 6.3 or higher. Those versions should resolve the issue.