NullReferenceException in MappingWalker

[mausch]

Unhandled Exception: System.NullReferenceException: Object reference not set to an instance of an object.
   at Nest.DSL.Visitor.MappingWalker.Accept(RootObjectMapping mapping) in c:\code\elasticsearch-net\src\Nest\DSL\Visitor\MappingWalker.cs:line 21
   at Nest.GetMappingResponse.Accept(IMappingVisitor visitor) in c:\code\elasticsearch-net\src\Nest\Domain\Responses\GetMappingResponse.cs:line 54
   at NESTMapping.Program.Main(String[] args) in c:\Users\Mauricio\Documents\Visual Studio 2013\Projects\NESTMapping\NESTMapping\Program.cs:line 117

Repro:

using System;
using System.Collections.Generic;
using Nest;
using Nest.DSL.Visitor;

namespace NESTMapping
{
    public class UnwantedObject
    {
        public int DoNotWant { get; set; }
    }

    public class SomeObject
    {
        public UnwantedObject Unwanted { get; set; }

        public string Name;
    }

    class MappingVisitor: IMappingVisitor
    {
        private readonly int id;

        public MappingVisitor(int id)
        {
            this.id = id;
        }

        public int Depth
        {
            get
            {
                throw new NotImplementedException();
            }
            set
            {
                throw new NotImplementedException();
            }
        }

        public void Visit(AttachmentMapping mapping)
        {
            throw new NotImplementedException();
        }

        public void Visit(GeoShapeMapping mapping)
        {
            throw new NotImplementedException();
        }

        public void Visit(GeoPointMapping mapping)
        {
            throw new NotImplementedException();
        }

        public void Visit(IPMapping mapping)
        {
            throw new NotImplementedException();
        }

        public void Visit(MultiFieldMapping mapping)
        {
            throw new NotImplementedException();
        }

        public void Visit(NestedObjectMapping mapping)
        {
            throw new NotImplementedException();
        }

        public void Visit(ObjectMapping mapping)
        {
            throw new Exception("Object mapping detected " + id);
        }

        public void Visit(BinaryMapping mapping)
        {
            throw new NotImplementedException();
        }

        public void Visit(BooleanMapping mapping)
        {
            throw new NotImplementedException();
        }

        public void Visit(DateMapping mapping)
        {
            throw new NotImplementedException();
        }

        public void Visit(NumberMapping mapping)
        {
            throw new NotImplementedException();
        }

        public void Visit(StringMapping mapping)
        {
        }

        public void Visit(RootObjectMapping mapping)
        {
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            const string indexName = "someindex";
            var connectionSettings = new ConnectionSettings(uri: null, defaultIndex: indexName);
            var client = new ElasticClient(connectionSettings);
            client.DeleteIndex(x => x.AllIndices());
            client.CreateIndex(indexName);
            client.Map<SomeObject>(m => m.Type(indexName).Properties(p => p.String(d => d.Name(x => x.Name))));
            var mapping = client.GetMapping<SomeObject>(x => x);
            mapping.Accept(new MappingVisitor(1));
        }
    }
}

[gmarz]

@mausch Thanks for the clear repro, this has been fixed. 👍