Unable to add custom middleware for mutations.

[jeremyraadttwins]

Is there an existing issue for this?

• [X] I have searched the existing issues

Describe the bug

When I add custom middleware to mutations I get an error block with the message "The type HotChocolate.Execution.Processing.ResultMapList is not supported as list value." and the extension code "EXEC_LIST_TYPE_NOT_SUPPORTED".

Steps to reproduce

Here is my basic test case. The middleware does nothing, but I still get the "EXEC_LIST_TYPE_NOT_SUPPORTED" error.

Mutation.cs:

    [ExtendObjectType(OperationTypeNames.Mutation)]
    public class CarMutations
    {
        [UseMyThing]
        public Car AddCar(
            AddCarInput input)
        {
            // save car into database.
        }
    }

Client Query:

  addCar(input: {
    make: "Ford"
  }) {
    car {
      make
    }
  }
}

Middleware:

    public class UseMyThingMiddleware
    {
        private readonly FieldDelegate _next;

        public UseMyThingMiddleware(FieldDelegate next)
        {
            _next = next;
        }

        public async Task InvokeAsync(IMiddlewareContext context)
        {
            await _next(context);
        }
    }

Relevant log output

No response

Additional Context?

No response

Product

Hot Chocolate

Version

12.15.0

[jeremyraadttwins]

I figured out my issue. In my UseMyThingAttribute class I had descriptor.Type<ListType<ObjectType<Look>>>(); when I needed descriptor.Type<ObjectType<Look>>();. I was using the same middleware for returning a list of cars and a single car.