Can't get custom ContractResolver to work

[IvanSorokin]

NEST/Elasticsearch.Net version: 6.4.0

Elasticsearch version: 6.2.2

Description: I want to use $type only on root object. I tried to use ContractResolver from this
answer but it didn't work. Then I tried to modify this resolver, even threw exceptions from it but it didn't change anything. Seems like it is not used at all.

Client creation:

                         ConnectionSettings.SourceSerializerFactory sourceSerializerFactory = (builtin, setts) => new JsonNetSerializer(
                                                                                                                     builtin, setts,
                                                                                                                     () => new JsonSerializerSettings
                                                                                                                           {
                                                                                                                               TypeNameHandling = TypeNameHandling.All,
                                                                                                                               NullValueHandling = NullValueHandling.Ignore,
                                                                                                                               ContractResolver = SuppressItemTypeNameContractResolver.Instance,
                                                                                                                               TypeNameAssemblyFormatHandling = TypeNameAssemblyFormatHandling.Simple,
                                                                                                                               
                                                                                                                           }
                                                                                                                    );
                         var connectionSettings =
                             new ConnectionSettings(connectionPool, sourceSerializer: sourceSerializerFactory);

Resolver:

public class SuppressItemTypeNameContractResolver : DefaultContractResolver
        {
            static SuppressItemTypeNameContractResolver()
            {
                Instance = new SuppressItemTypeNameContractResolver();
            }

            public static SuppressItemTypeNameContractResolver Instance { get; }

            protected override JsonContract CreateContract(Type objectType)
            {
                var contract = base.CreateContract(objectType);

                if (contract is JsonContainerContract containerContract)
                {
                    if (containerContract.ItemTypeNameHandling == null)
                        containerContract.ItemTypeNameHandling = TypeNameHandling.None;
                }

                return contract;
            }
        }

[IvanSorokin]

okay, after inspecting source code I can conclude that this option really doesn't work because it is always overrided by elastic resolver afterwards. a bit misleading for me that you can pass an argument but have no changes in the final result.

[russcam]

Apologies for the super late response on this @IvanSorokin.

As you've found, the IContractResolver used by JsonNetSerializer is always set to ConnectionSettingsAwareContractResolver:

elasticsearch-net/src/Serializers/Nest.JsonNetSerializer/ConnectionSettingsAwareSerializerBase.Serializer.cs

Lines 63 to 68 in adc76e9

	private IContractResolver CreateContractResolver()
	{
	var contract = new ConnectionSettingsAwareContractResolver(ConnectionSettings);
	ModifyContractResolver(contract);
	return contract;
	}

The contract resolver needs to know how to handle certain NEST types and doesn't expose a way to change this currently.

[russcam]

I've opened #3599 for discussion

[russcam]

#3599 has been merged and will be in the next release (6.6.0), so am closing this issue.