5.0 RC1 - Copy_to serialization issues.

[niemyjski]

I'm still trying to get to the bottom of this issue but my app is unable to deserialize the mappings.

I get the following error

at Elasticsearch.Net.Transport`1.Request[TReturn](HttpMethod method, String path, PostData`1 data, IRequestParameters requestParameters) in C:\code\elasticsearch-net\src\Elasticsearch.Net\Transport\Transport.cs:line 93
   at Elasticsearch.Net.ElasticLowLevelClient.DoRequest[T](HttpMethod method, String path, PostData`1 data, IRequestParameters requestParameters) in C:\code\elasticsearch-net\src\Elasticsearch.Net\ElasticLowLevelClient.cs:line 61
   at Elasticsearch.Net.ElasticLowLevelClient.IndicesGetMapping[T](String index, String type, Func`2 requestParameters) in C:\code\elasticsearch-net\src\Elasticsearch.Net\ElasticLowLevelClient.Generated.cs:line 3560
   at Nest.LowLevelDispatch.IndicesGetMappingDispatch[T](IRequest`1 p) in C:\code\elasticsearch-net\src\Nest\_Generated\_LowLevelDispatch.generated.cs:line 1611
   at Nest.ElasticClient.<GetMapping>b__334_1(IGetMappingRequest p, PostData`1 d) in C:\code\elasticsearch-net\src\Nest\Indices\MappingManagement\GetMapping\ElasticClient-GetMapping.cs:line 43
   at Nest.ElasticClient.Nest.IHighLevelToLowLevelDispatcher.Dispatch[TRequest,TQueryString,TResponse](TRequest request, Func`3 responseGenerator, Func`3 dispatch) in C:\code\elasticsearch-net\src\Nest\ElasticClient.cs:line 57
   at Nest.ElasticClient.GetMapping(IGetMappingRequest request) in C:\code\elasticsearch-net\src\Nest\Indices\MappingManagement\GetMapping\ElasticClient-GetMapping.cs:line 40
   at Foundatio.Parsers.ElasticQueries.ElasticQueryParserConfigurationExtensions.<>c__DisplayClass0_0`1.<UseMappings>b__1() in C:\projects\foundatio-repositories\src\Foundatio.Repositories.Elasticsearch\Extensions\ElasticQueryParserConfigurationExtensions.cs:line 17
   at Foundatio.Parsers.ElasticQueries.ElasticQueryParserConfiguration.UpdateMapping()
   at Foundatio.Parsers.ElasticQueries.ElasticQueryParserConfiguration.GetMappingProperty(String field)
   at Foundatio.Parsers.ElasticQueries.Visitors.ElasticQueryVisitorContextExtensions.GetPropertyMapping(IElasticQueryVisitorContext context, String field)
   at Foundatio.Parsers.ElasticQueries.Visitors.ElasticQueryVisitorContextExtensions.GetNonAnalyzedFieldName(IElasticQueryVisitorContext context, String field)
   at Foundatio.Parsers.ElasticQueries.Visitors.GetSortFieldsVisitor.Visit(TermNode node, IQueryVisitorContext context)
   at Foundatio.Parsers.LuceneQueries.Visitors.QueryNodeVisitorBase.VisitAsync(TermNode node, IQueryVisitorContext context)
   at Foundatio.Parsers.LuceneQueries.Visitors.QueryNodeVisitorBase.VisitAsync(IQueryNode node, IQueryVisitorContext context)
   at Foundatio.Parsers.LuceneQueries.Visitors.QueryNodeVisitorBase.<VisitAsync>d__0.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Foundatio.Parsers.ElasticQueries.Visitors.GetSortFieldsVisitor.<AcceptAsync>d__2.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Foundatio.Parsers.ElasticQueries.ElasticQueryParser.<BuildSortAsync>d__8.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd(Task task)
   at Foundatio.Repositories.Elasticsearch.Queries.Builders.ParsedSearchQueryBuilder.<BuildAsync>d__2`1.MoveNext() in C:\projects\foundatio-repositories\src\Foundatio.Repositories.Elasticsearch\Queries\Builders\SearchQueryBuilder.cs:line 135
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Foundatio.Repositories.Elasticsearch.Queries.Builders.ElasticQueryBuilder.<BuildAsync>d__10`1.MoveNext() in C:\projects\foundatio-repositories\src\Foundatio.Repositories.Elasticsearch\Queries\Builders\ElasticQueryBuilder.cs:line 89
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Foundatio.Repositories.Elasticsearch.Queries.Builders.ElasticQueryBuilderExtensions.<BuildQueryAsync>d__0`1.MoveNext() in C:\projects\foundatio-repositories\src\Foundatio.Repositories.Elasticsearch\Queries\Builders\IElasticQueryBuilder.cs:line 52
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Foundatio.Repositories.Elasticsearch.Queries.Builders.ElasticQueryBuilderExtensions.<ConfigureSearchAsync>d__1`1.MoveNext() in C:\projects\foundatio-repositories\src\Foundatio.Repositories.Elasticsearch\Queries\Builders\IElasticQueryBuilder.cs:line 64
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Foundatio.Repositories.Elasticsearch.ElasticReadOnlyRepositoryBase`1.<ConfigureSearchDescriptorAsync>d__39.MoveNext() in C:\projects\foundatio-repositories\src\Foundatio.Repositories.Elasticsearch\Repositories\ElasticReadOnlyRepositoryBase.cs:line 435
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd(Task task)
   at Foundatio.Repositories.Elasticsearch.ElasticReadOnlyRepositoryBase`1.<FindAsAsync>d__15`1.MoveNext() in C:\projects\foundatio-repositories\src\Foundatio.Repositories.Elasticsearch\Repositories\ElasticReadOnlyRepositoryBase.cs:line 101
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
   at Exceptionless.Api.Tests.Repositories.EventIndexTests.<GetByFilterAsync>d__43.MoveNext() in C:\Code\Exceptionless\tests\Exceptionless.Api.Tests\Search\EventIndexTests.cs:line 462
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
   at Exceptionless.Api.Tests.Repositories.EventIndexTests.<GetByBotAsync>d__31.MoveNext() in C:\Code\Exceptionless\tests\Exceptionless.Api.Tests\Search\EventIndexTests.cs:line 328
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
----- Inner Stack Trace -----
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateNewList(JsonReader reader, JsonArrayContract contract, Boolean& createdFromNonDefaultCreator)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateList(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, Object existingValue, String id)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateValueInternal(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.SetPropertyValue(JsonProperty property, JsonConverter propertyConverter, JsonContainerContract containerContract, JsonProperty containerProperty, JsonReader reader, Object target)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.PopulateObject(Object newObject, JsonReader reader, JsonObjectContract contract, JsonProperty member, String id)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateObject(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateValueInternal(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Deserialize(JsonReader reader, Type objectType, Boolean checkAdditionalContent)
   at Newtonsoft.Json.JsonSerializer.DeserializeInternal(JsonReader reader, Type objectType)
   at Newtonsoft.Json.Linq.JToken.ToObject(Type objectType, JsonSerializer jsonSerializer)
   at Newtonsoft.Json.Linq.JToken.ToObject(Type objectType)
   at Newtonsoft.Json.Linq.JToken.ToObject[T]()
   at Nest.PropertyJsonConverter.ReadJson(JsonReader reader, Type objectType, Object existingValue, JsonSerializer serializer) in C:\code\elasticsearch-net\src\Nest\Mapping\Types\PropertyJsonConverter.cs:line 30
   at Nest.PropertiesJsonConverter.ReadJson(JsonReader reader, Type objectType, Object existingValue, JsonSerializer serializer) in C:\code\elasticsearch-net\src\Nest\Mapping\Types\PropertiesJsonConverter.cs:line 50
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.DeserializeConvertable(JsonConverter converter, JsonReader reader, Type objectType, Object existingValue)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.SetPropertyValue(JsonProperty property, JsonConverter propertyConverter, JsonContainerContract containerContract, JsonProperty containerProperty, JsonReader reader, Object target)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.PopulateObject(Object newObject, JsonReader reader, JsonObjectContract contract, JsonProperty member, String id)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateObject(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateValueInternal(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Deserialize(JsonReader reader, Type objectType, Boolean checkAdditionalContent)
   at Newtonsoft.Json.JsonSerializer.DeserializeInternal(JsonReader reader, Type objectType)
   at Newtonsoft.Json.Linq.JToken.ToObject(Type objectType, JsonSerializer jsonSerializer)
   at Newtonsoft.Json.Linq.JToken.ToObject(Type objectType)
   at Newtonsoft.Json.Linq.JToken.ToObject[T]()
   at Nest.PropertyJsonConverter.ReadJson(JsonReader reader, Type objectType, Object existingValue, JsonSerializer serializer) in C:\code\elasticsearch-net\src\Nest\Mapping\Types\PropertyJsonConverter.cs:line 30
   at Nest.PropertiesJsonConverter.ReadJson(JsonReader reader, Type objectType, Object existingValue, JsonSerializer serializer) in C:\code\elasticsearch-net\src\Nest\Mapping\Types\PropertiesJsonConverter.cs:line 50
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.DeserializeConvertable(JsonConverter converter, JsonReader reader, Type objectType, Object existingValue)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.SetPropertyValue(JsonProperty property, JsonConverter propertyConverter, JsonContainerContract containerContract, JsonProperty containerProperty, JsonReader reader, Object target)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.PopulateObject(Object newObject, JsonReader reader, JsonObjectContract contract, JsonProperty member, String id)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateObject(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateValueInternal(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Deserialize(JsonReader reader, Type objectType, Boolean checkAdditionalContent)
   at Newtonsoft.Json.JsonSerializer.DeserializeInternal(JsonReader reader, Type objectType)
   at Newtonsoft.Json.Linq.JToken.ToObject(Type objectType, JsonSerializer jsonSerializer)
   at Newtonsoft.Json.Linq.JToken.ToObject(Type objectType)
   at Newtonsoft.Json.Linq.JToken.ToObject[T]()
   at Nest.PropertyJsonConverter.ReadJson(JsonReader reader, Type objectType, Object existingValue, JsonSerializer serializer) in C:\code\elasticsearch-net\src\Nest\Mapping\Types\PropertyJsonConverter.cs:line 30
   at Nest.PropertiesJsonConverter.ReadJson(JsonReader reader, Type objectType, Object existingValue, JsonSerializer serializer) in C:\code\elasticsearch-net\src\Nest\Mapping\Types\PropertiesJsonConverter.cs:line 50
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.DeserializeConvertable(JsonConverter converter, JsonReader reader, Type objectType, Object existingValue)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.SetPropertyValue(JsonProperty property, JsonConverter propertyConverter, JsonContainerContract containerContract, JsonProperty containerProperty, JsonReader reader, Object target)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.PopulateObject(Object newObject, JsonReader reader, JsonObjectContract contract, JsonProperty member, String id)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Populate(JsonReader reader, Object target)
   at Newtonsoft.Json.Serialization.JsonSerializerProxy.PopulateInternal(JsonReader reader, Object target)
   at Nest.FromJson.ReadAs[T](JsonReader reader, Type objectType, Object existingValue, JsonSerializer serializer) in C:\code\elasticsearch-net\src\Nest\CommonAbstractions\SerializationBehavior\GenericJsonConverters\FromJson.cs:line 14
   at Nest.ReadAsTypeJsonConverter`1.ReadJson(JsonReader reader, Type objectType, Object existingValue, JsonSerializer serializer) in C:\code\elasticsearch-net\src\Nest\CommonAbstractions\SerializationBehavior\GenericJsonConverters\ReadAsTypeJsonConverter.cs:line 19
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.DeserializeConvertable(JsonConverter converter, JsonReader reader, Type objectType, Object existingValue)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.PopulateDictionary(IDictionary dictionary, JsonReader reader, JsonDictionaryContract contract, JsonProperty containerProperty, String id)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateObject(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateValueInternal(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.PopulateDictionary(IDictionary dictionary, JsonReader reader, JsonDictionaryContract contract, JsonProperty containerProperty, String id)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateObject(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateValueInternal(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.PopulateDictionary(IDictionary dictionary, JsonReader reader, JsonDictionaryContract contract, JsonProperty containerProperty, String id)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateObject(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateValueInternal(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Deserialize(JsonReader reader, Type objectType, Boolean checkAdditionalContent)
   at Newtonsoft.Json.JsonSerializer.DeserializeInternal(JsonReader reader, Type objectType)
   at Nest.JsonNetSerializer.Deserialize[T](Stream stream) in C:\code\elasticsearch-net\src\Nest\CommonAbstractions\SerializationBehavior\JsonNetSerializer.cs:line 114
   at Nest.ElasticClient.DeserializeGetMappingResponse(IApiCallDetails response, IGetMappingRequest d, Stream stream) in C:\code\elasticsearch-net\src\Nest\Indices\MappingManagement\GetMapping\ElasticClient-GetMapping.cs:line 62
   at Nest.ElasticClient.<>c__DisplayClass334_0.<GetMapping>b__0(IApiCallDetails r, Stream s) in C:\code\elasticsearch-net\src\Nest\Indices\MappingManagement\GetMapping\ElasticClient-GetMapping.cs:line 42
   at Elasticsearch.Net.ResponseBuilder`1.SetBody(ElasticsearchResponse`1 response, Stream stream) in C:\code\elasticsearch-net\src\Elasticsearch.Net\Transport\Pipeline\ResponseBuilder.cs:line 78
   at Elasticsearch.Net.ResponseBuilder`1.ToResponse() in C:\code\elasticsearch-net\src\Elasticsearch.Net\Transport\Pipeline\ResponseBuilder.cs:line 31
   at Elasticsearch.Net.HttpConnection.Request[TReturn](RequestData requestData) in C:\code\elasticsearch-net\src\Elasticsearch.Net\Connection\HttpConnection.cs:line 153
   at Elasticsearch.Net.RequestPipeline.CallElasticsearch[TReturn](RequestData requestData) in C:\code\elasticsearch-net\src\Elasticsearch.Net\Transport\Pipeline\RequestPipeline.cs:line 411
   at Elasticsearch.Net.Transport`1.Request[TReturn](HttpMethod method, String path, PostData`1 data, IRequestParameters requestParameters) in C:\code\elasticsearch-net\src\Elasticsearch.Net\Transport\Transport.cs:line 69


Result Message:	
Elasticsearch.Net.UnexpectedElasticsearchClientException : Cannot create and populate list type Nest.Fields. Path 'copy_to', line 1, position 238.
---- Newtonsoft.Json.JsonSerializationException : Cannot create and populate list type Nest.Fields. Path 'copy_to', line 1, position 238.

GET http://127.0.0.1:9200/test-events/_mapping/events

{"test-events-v1-201412":{"mappings":{"events":{"dynamic":"false","_size":{"enabled":true},"properties":{"created_utc":{"type":"date"},"data":{"properties":{"@environment":{"properties":{"o_s_name":{"type":"text","index":false,"copy_to":["os"]}}}}},"id":{"type":"keyword"},"os":{"type":"text","fields":{"keyword":{"type":"keyword","ignore_above":256}}}}}}},"test-events-v1-201502":{"mappings":{"events":{"dynamic":"false","_size":{"enabled":true},"properties":{"created_utc":{"type":"date"},"data":{"properties":{"@environment":{"properties":{"o_s_name":{"type":"text","index":false,"copy_to":["os"]}}}}},"id":{"type":"keyword"},"os":{"type":"text","fields":{"keyword":{"type":"keyword","ignore_above":256}}}}}}}}

[niemyjski]

My mappings are pretty simple.

.Properties(p => p
    .Text(f => f.Name(Alias.OperatingSystem).AddKeywordField())
    .AddDataDictionaryMappings()

public static PropertiesDescriptor<PersistentEvent> AddDataDictionaryMappings(this PropertiesDescriptor<PersistentEvent> descriptor) {
            return descriptor.Object<DataDictionary>(f => f.Name(e => e.Data).Properties(p2 => p2
                .AddEnvironmentInfoMapping()));
        }
        
     public static PropertiesDescriptor<DataDictionary> AddEnvironmentInfoMapping(this PropertiesDescriptor<DataDictionary> descriptor) {
            return descriptor.Object<EnvironmentInfo>(f2 => f2.Name(Event.KnownDataKeys.EnvironmentInfo).Properties(p3 => p3
                .Text(f3 => f3.Name(r => r.OSName).CopyTo(fd => fd.Field(EventIndexType.Alias.OperatingSystem)).Index(false))
                ));
        }

[niemyjski]

I've gotten rid of our custom serializer so I've narrowed that out of the mix. I'm looking at the docs for copy_to and everything seems to ok

[russcam]

Thanks @niemyjski, I can repro this, looking at a fix now.

[niemyjski]

For some reason I can't run any tests in VS2017. This test may reproduce this issue:

	public class GithubIssue2409 : IClusterFixture<ReadOnlyCluster> {
		private readonly ReadOnlyCluster _cluster;

		public GithubIssue2409(ReadOnlyCluster cluster) {
			_cluster = cluster;
		}

		[I]
		public void ShouldRoundTripCopyTo() {
			var client = _cluster.Client;
			var response = client.CreateIndex(typeof(MyEvent), c => c
				.Mappings(map => map
					.Map<MyEvent>(m => m.Properties(p => p
					.Text(f => f.Name("os"))
					.Object<Dictionary<string, object>>(f => f.Name(e => e.Data).Properties(p2 => p2
						.Object<EnvironmentInfo>(f2 => f2.Name("EnvironmentInfo").Properties(p3 => p3
							.Text(f3 => f3.Name(r => r.OperatingSystem).CopyTo(fd => fd.Field("os"))))))))))
			);

			response.ShouldBeValid();

			var mappingResponse = client.GetMapping<MyEvent>();
			mappingResponse.ShouldBeValid();
		}

		public class MyEvent {
			public Dictionary<string, object> Data { get; set; } = new Dictionary<string, object>();
		}

		public class EnvironmentInfo {
			public string OperatingSystem { get; set; }
		}
	}

[russcam]

Fixed in 1fb762e. Will go into 5.0.0-rc2.

Thanks for reporting @niemyjski 👍