Fix for covariant search date parsing

src/Nest/CommonAbstractions/SerializationBehavior/StatefulDeserialization/ConcreteTypeConverter.cs

@@ -94,7 +94,16 @@ private static void PopulateHit(JsonSerializer serializer, JsonReader reader, ob
 
 		private static JObject CreateIntermediateJObject(JsonReader reader)
 		{
+			var original = reader.DateParseHandling;
+			// Temporarily turn off DateTime parsing since we deserialize
+			// to a dynamic object and the date could be stored as a string
+			// in the users POCO and we need to preserve its format. This is
+			// side-effect free since we read the reader to completion using
+			// JObject.Load before handing off a new one to the deserialized
+			// hit object.
+			reader.DateParseHandling = DateParseHandling.None;
 			var jObject = JObject.Load(reader);
+			reader.DateParseHandling = original;
 			return jObject;
 		}
 

src/Tests/Reproduce/CovariantSearchDateParsing.cs

@@ -0,0 +1,56 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+using Elasticsearch.Net;
+using Nest;
+using FluentAssertions;
+using Newtonsoft.Json;
+using Tests.Framework;
+using Tests.Framework.ManagedElasticsearch.Clusters;
+using Xunit;
+
+namespace Tests.Reproduce
+{
+	public class CovariantSearchDateParsing : IClusterFixture<WritableCluster>
+	{
+		public interface ISearchResult
+		{
+			DateTime Date { get; set; }
+			string DateAsString { get; set; }
+		}
+
+		public class SearchResult : ISearchResult
+		{
+			public DateTime Date { get; set; }
+			public string DateAsString { get; set; }
+		}
+
+		private readonly WritableCluster _cluster;
+
+		public CovariantSearchDateParsing(WritableCluster cluster)
+		{
+			_cluster = cluster;
+		}
+
+		[I] public void CovariantSearchDateParsingTest()
+		{
+			var client = _cluster.Client;
+			var index = "convariantsearchconverstiontest";
+			if (client.IndexExists(index).Exists)
+				client.DeleteIndex(index);
+
+			var date = "2013-06-24T00:00:00.000";
+			var indexResult = client.Index(new SearchResult { DateAsString = date, Date = DateTime.Parse(date) }, i => i.Id(1).Index(index));
+			indexResult.IsValid.Should().BeTrue();
+			client.Refresh(Nest.Indices.All);
+			var response = client.Search<ISearchResult>(new SearchRequest<ISearchResult>(index, typeof(SearchResult)));
+			response.IsValid.Should().BeTrue();
+			response.Documents.Count.Should().Be(1);
+			var document = response.Documents.SingleOrDefault();
+			document.Should().NotBeNull();
+			document.DateAsString.Should().Be(date);
+			document.Date.ShouldBeEquivalentTo(DateTime.Parse(date));
+		}
+	}
+}

src/Tests/Tests.csproj

@@ -711,6 +711,7 @@
     <Compile Include="QueryDsl\NotConditionlessWhen.cs" />
     <Compile Include="QueryDsl\Specialized\Percolate\PercolateQueryUsageTests.cs" />
     <Compile Include="Reproduce\ConnectionReuseAndBalancing.cs" />
+    <Compile Include="Reproduce\CovariantSearchDateParsing.cs" />
     <Compile Include="Reproduce\DateSerialization.cs" />
     <Compile Include="Reproduce\GithubIssue2152.cs" />
     <Compile Include="Reproduce\GithubIssue2306.cs" />