Included the nested identity for inner hits on a nested type

See https://www.elastic.co/guide/en/elasticsearch/reference/2.0/search-aggregations-metrics-top-hits-aggregation.html#_top_hits_support_in_a_nested_or_reverse_nested_aggregator
Closes #2323

Author: russcam

src/Nest/CommonAbstractions/LazyDocument/LazyDocument.cs

@@ -7,7 +7,7 @@ namespace Nest
 	public interface ILazyDocument
 	{
 		/// <summary>
-		/// 
+		///
 		/// </summary>
 		/// <typeparam name="T"></typeparam>
 		/// <returns></returns>
@@ -21,7 +21,7 @@ public class LazyDocument : ILazyDocument
 		public T As<T>() where T : class
 		{
 			var jToken = this._Value;
-			return jToken != null ? jToken.ToObject<T>() : null;
+			return jToken?.ToObject<T>();
 		}
 	}
-}
+}

src/Nest/CommonAbstractions/LazyDocument/LazyDocumentJsonConverter.cs

@@ -9,7 +9,7 @@ internal class LazyDocumentJsonConverter : JsonConverter
 		public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
 		{
 			var d = value as LazyDocument;
-			if (d == null || d._Value == null)
+			if (d?._Value == null)
 				return;
 			writer.WriteToken(d._Value.CreateReader());
 		}
@@ -25,4 +25,4 @@ public override bool CanConvert(Type objectType)
 			return true;
 		}
 	}
-}
+}

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

@@ -92,7 +92,7 @@ private static void PopulateHit(JsonSerializer serializer, JsonReader reader, ob
 
 		private static JObject CreateIntermediateJObject(JsonReader reader)
 		{
-			JObject jObject = JObject.Load(reader);
+			var jObject = JObject.Load(reader);
 			return jObject;
 		}
 
@@ -112,26 +112,29 @@ internal static Type GetConcreteTypeUsingSelector<T>(
 			var baseType = realConcreteConverter._baseType;
 			var selector = realConcreteConverter._concreteTypeSelector;
 
-			//Hit<dynamic> hitDynamic = new Hit<dynamic>();
 			dynamic d = jObject;
 			var fields = jObject["fields"];
 			var fieldsDictionary = fields?.ToObject<IDictionary<string, object>>();
 			var fieldValues = new FieldValues(settings.Inferrer, fieldsDictionary);
-			var hitDynamic = new Hit<dynamic>();
-			//favor manual mapping over doing Populate twice.
-			hitDynamic.Fields = fieldValues;
-			hitDynamic.Source = d._source;
-			hitDynamic.Index = d._index;
-			hitDynamic.Score = d._score != null ? (double)d._score : 0;
-			hitDynamic.Type = d._type;
-			hitDynamic.Version = d._version;
-			hitDynamic.Id = d._id;
-			hitDynamic.Parent = d._parent;
-			hitDynamic.Routing = d._routing;
-			hitDynamic.Sorts = d.sort;
-			hitDynamic._Highlight = d.highlight is Dictionary<string, List<string>> ? d.highlight : null;
-			hitDynamic.Explanation = d._explanation is Explanation ? d._explanation : null;
-			object o = d._source ?? DynamicResponse.Create(fieldsDictionary) ?? new object {};
+			var hitDynamic = new Hit<dynamic>
+			{
+				//favor manual mapping over doing Populate twice.
+				Fields = fieldValues,
+				Source = d._source,
+				Index = d._index,
+				Score = d._score != null ? (double)d._score : 0,
+				Type = d._type,
+				Version = d._version,
+				Id = d._id,
+				Parent = d._parent,
+				Routing = d._routing,
+				Sorts = d.sort,
+				_Highlight = d.highlight is Dictionary<string, List<string>> ? d.highlight : null,
+				Explanation = d._explanation is Explanation ? d._explanation : null,
+				Nested = d._nested
+			};
+
+			object o = d._source ?? DynamicResponse.Create(fieldsDictionary) ?? new object();
 			var concreteType = selector(o, hitDynamic);
 			return concreteType;
 		}

src/Nest/Nest.csproj

@@ -1143,6 +1143,7 @@
     <Compile Include="Search\Search\Hits\HitsMetaData.cs" />
     <Compile Include="Search\Search\Hits\InnerHitsMetaData.cs" />
     <Compile Include="Search\Search\Hits\InnerHitsResult.cs" />
+    <Compile Include="Search\Search\Hits\NestedIdentity.cs" />
     <Compile Include="Search\Search\InnerHits\GlobalInnerHit.cs" />
     <Compile Include="Search\Search\InnerHits\InnerHits.cs" />
     <Compile Include="Search\Search\InnerHits\InnerHitsContainer.cs" />

src/Nest/Search/Search/Hits/Hit.cs

@@ -29,48 +29,50 @@ public interface IHit<out T> where T : class
 	public class Hit<T> : IHit<T>
 		where T : class
 	{
-		[JsonProperty(PropertyName = "fields")]
+		[JsonProperty("fields")]
 		public FieldValues Fields { get; internal set; }
 
-		[JsonProperty(PropertyName = "_source")]
+		[JsonProperty("_source")]
 		public T Source { get; internal set; }
 
-		[JsonProperty(PropertyName = "_index")]
+		[JsonProperty("_index")]
 		public string Index { get; internal set; }
 
-		[JsonProperty(PropertyName = "inner_hits")]
+		[JsonProperty("inner_hits")]
 		[JsonConverter(typeof(VerbatimDictionaryKeysJsonConverter))]
 		public IDictionary<string, InnerHitsResult> InnerHits { get; internal set; }
 
-		// TODO make this nullable for 5.0
-		[JsonProperty(PropertyName = "_score")]
+		[JsonProperty("_score")]
 		public double Score { get; set; }
 
-		[JsonProperty(PropertyName = "_type")]
+		[JsonProperty("_type")]
 		public string Type { get; internal set; }
 
-		[JsonProperty(PropertyName = "_version")]
+		[JsonProperty("_version")]
 		public long? Version { get; internal set; }
 
-		[JsonProperty(PropertyName = "_id")]
+		[JsonProperty("_id")]
 		public string Id { get; internal set; }
 
-		[JsonProperty(PropertyName = "_parent")]
+		[JsonProperty("_nested")]
+		public NestedIdentity Nested { get; internal set; }
+
+		[JsonProperty("_parent")]
 		public string Parent { get; internal set; }
 
-		[JsonProperty(PropertyName = "_routing")]
+		[JsonProperty("_routing")]
 		public string Routing { get; internal set; }
 
-		[JsonProperty(PropertyName = "_timestamp")]
+		[JsonProperty("_timestamp")]
 		public long? Timestamp { get; internal set; }
 
-		[JsonProperty(PropertyName = "_ttl")]
+		[JsonProperty("_ttl")]
 		public long? Ttl { get; internal set; }
 
-		[JsonProperty(PropertyName = "sort")]
+		[JsonProperty("sort")]
 		public IEnumerable<object> Sorts { get; internal set; }
 
-		[JsonProperty(PropertyName = "highlight")]
+		[JsonProperty("highlight")]
 		[JsonConverter(typeof(VerbatimDictionaryKeysJsonConverter))]
 		internal Dictionary<string, List<string>> _Highlight { get; set; }
 
@@ -92,10 +94,10 @@ public HighlightFieldDictionary Highlights
 			}
 		}
 
-		[JsonProperty(PropertyName = "_explanation")]
+		[JsonProperty("_explanation")]
 		public Explanation Explanation { get; internal set; }
 
-		[JsonProperty(PropertyName = "matched_queries")]
+		[JsonProperty("matched_queries")]
 		public IEnumerable<string> MatchedQueries { get; internal set; }
 	}
 }

src/Nest/Search/Search/Hits/NestedIdentity.cs

@@ -0,0 +1,17 @@
+using Newtonsoft.Json;
+
+namespace Nest
+{
+	[JsonObject]
+	public class NestedIdentity
+	{
+		[JsonProperty("field")]
+		public Field Field { get; internal set; }
+
+		[JsonProperty("offset")]
+		public int Offset { get; internal set; }
+
+		[JsonProperty("_nested")]
+		public NestedIdentity Nested { get; internal set; }
+	}
+}

src/Tests/Reproduce/GithubIssue2323.cs

@@ -0,0 +1,53 @@
+using System.Linq;
+using FluentAssertions;
+using Nest;
+using Tests.Framework;
+using Tests.Framework.Integration;
+using Tests.Framework.MockData;
+using Xunit;
+
+namespace Tests.Reproduce
+{
+	public class GithubIssue2323 : IClusterFixture<ReadOnlyCluster>
+	{
+		private readonly ReadOnlyCluster _cluster;
+
+		public GithubIssue2323(ReadOnlyCluster cluster)
+		{
+			_cluster = cluster;
+		}
+
+		[I]
+		public void NestedInnerHitsShouldIncludedNestedProperty()
+		{
+			var client = _cluster.Client;
+			var response = client.Search<Project>(s => s
+				.Query(q => q
+					.Nested(n => n
+						.Path(p => p.Tags)
+						.Query(nq => nq
+							.MatchAll()
+						)
+						.InnerHits(i => i
+							.Source(false)
+						)
+					)
+				)
+			);
+
+			response.ShouldBeValid();
+
+			var innerHits = response.Hits.Select(h => h.InnerHits).ToList();
+
+			innerHits.Should().NotBeNullOrEmpty();
+
+			var innerHit = innerHits.First();
+			innerHit.Should().ContainKey("tags");
+			var hitMetadata = innerHit["tags"].Hits.Hits.First();
+
+			hitMetadata.Nested.Should().NotBeNull();
+			hitMetadata.Nested.Field.Should().Be(Field.Create("tags"));
+			hitMetadata.Nested.Offset.Should().BeGreaterOrEqualTo(0);
+		}
+	}
+}