Deserialize error property on MultiGetHit

Closes #2871

(cherry picked from commit dbcfd94)

Author: russcam

src/Nest/Document/Multiple/MultiGet/Response/MultiGetHit.cs

@@ -1,4 +1,7 @@
-using Newtonsoft.Json;
+using System;
+using Elasticsearch.Net;
+using System;
+using Newtonsoft.Json;
 
 namespace Nest
 {
@@ -20,6 +23,8 @@ public interface IMultiGetHit<out T> where T : class
 
 		string Routing { get; }
 
+		ServerError Error { get; }
+
 		long? Timestamp { get; }
 
 		long? Ttl { get; }
@@ -55,6 +60,9 @@ public class MultiGetHit<T> : IMultiGetHit<T>
 		[JsonProperty("_routing")]
 		public string Routing { get; internal set; }
 
+		[JsonProperty("error")]
+		public ServerError Error { get; internal set; }
+
 		[JsonProperty("_timestamp")]
 		public long? Timestamp { get; internal set; }
 

src/Nest/Document/Multiple/MultiGet/Response/MultiGetResponse.cs

@@ -25,6 +25,8 @@ public interface IMultiGetResponse : IResponse
 	[ContractJsonConverter(typeof(MultiGetHitJsonConverter))]
 	public class MultiGetResponse : ResponseBase, IMultiGetResponse
 	{
+		public override bool IsValid => base.IsValid && !this._Documents.HasAny(d => d.Error != null);
+		
 		public MultiGetResponse()
 		{
 			this._Documents = new List<IMultiGetHit<object>>();

src/Tests/Reproduce/GithubIssue2871.cs

@@ -0,0 +1,92 @@
+using System;
+using System.Linq;
+using Elasticsearch.Net;
+using FluentAssertions;
+using Nest;
+using Tests.Framework;
+using Tests.Framework.ManagedElasticsearch.Clusters;
+using Tests.Framework.MockData;
+using Xunit;
+
+namespace Tests.Reproduce
+{
+	public class GithubIssue2871 : IClusterFixture<WritableCluster>
+	{
+		private readonly WritableCluster _cluster;
+
+		public GithubIssue2871(WritableCluster cluster) => _cluster = cluster;
+
+		[I]
+		public void IsValidFalseAndDeserializedErrorsWhenMultiGetDocHasErrors()
+		{
+			var index1 = "index1";
+			var index2 = "index2";
+			var alias = "my_alias";
+			var client = _cluster.Client;
+
+			client.CreateIndex(index1, c=> c
+				.Mappings(m => m
+					.Map<Project>(mm => mm
+						.AutoMap()
+					)
+				)
+			);
+
+			client.CreateIndex(index2, c => c
+				.Mappings(m => m
+					.Map<Project>(mm => mm
+						.AutoMap()
+					)
+				)
+			);
+
+			var projects = new[]
+			{
+				new Project { Name = "project1" },
+				new Project { Name = "project2" },
+			};
+
+			client.Bulk(b => b
+				.IndexMany(projects, (bi, p) => bi.Index(index1).Document(p))
+				.IndexMany(projects, (bi, p) => bi.Index(index2).Document(p))
+				.Refresh(Refresh.WaitFor)
+			);
+
+			client.Alias(a => a
+				.Add(add => add
+					.Alias(alias)
+					.Index(index1)
+				)
+				.Add(add => add
+					.Alias(alias)
+					.Index(index2)
+				)
+			);
+
+			var multiGetRequest = new MultiGetRequest
+			{
+				Documents = new[] {
+					new MultiGetOperation<Project>("project1") {Index = alias },
+					new MultiGetOperation<Project>("project2") {Index = alias }
+				}
+			};
+
+			var response = client.MultiGet(multiGetRequest);
+			response.ShouldNotBeValid();
+
+			var firstMultiGetHit = response.Documents.First();
+			firstMultiGetHit.Error.Should().NotBeNull();
+			firstMultiGetHit.Error.Error.Should().NotBeNull();
+			firstMultiGetHit.Error.Error.Type.Should().NotBeNullOrEmpty();
+			firstMultiGetHit.Error.Error.Reason.Should().NotBeNullOrEmpty();
+			firstMultiGetHit.Error.Error.RootCause.Should().NotBeNull().And.HaveCount(1);
+
+			var lastMultiGetHit = response.Documents.Last();
+			lastMultiGetHit.Error.Should().NotBeNull();
+			lastMultiGetHit.Error.Error.Should().NotBeNull();
+			lastMultiGetHit.Error.Error.Type.Should().NotBeNullOrEmpty();
+			lastMultiGetHit.Error.Error.Reason.Should().NotBeNullOrEmpty();
+			lastMultiGetHit.Error.Error.RootCause.Should().NotBeNull().And.HaveCount(1);
+		}
+	}
+}