AutoDateHistogramAggregate Interval should be DateMathTime (#4725)

This commit fixes a bug with AutoDateHistogramAggregate Interval
property that uses the Time type to represent valid intervals. The Time
type however does not support Months and Years, which are valid units
for the AutoDateHistogram interval.

Fixes #4333

(cherry picked from commit a693da3)

Author: russcam

docs/aggregations/bucket/auto-date-histogram/auto-date-histogram-aggregation-usage.asciidoc

@@ -109,7 +109,7 @@ response.ShouldBeValid();
 
 var dateHistogram = response.Aggregations.AutoDateHistogram("projects_started_per_month");
 dateHistogram.Should().NotBeNull();
-dateHistogram.Interval.Should().NotBeNull();
+dateHistogram.AutoInterval.Should().NotBeNull();
 dateHistogram.Buckets.Should().NotBeNull();
 dateHistogram.Buckets.Count.Should().BeGreaterThan(1);
 foreach (var item in dateHistogram.Buckets)

docs/aggregations/pipeline/serial-differencing/serial-differencing-aggregation-usage.asciidoc

@@ -91,7 +91,7 @@ projectsPerMonth.Buckets.Count.Should().BeGreaterThan(0);
 
 var differenceCount = 0;
 
-bool atleastOneSecondDifference = false;
+var atleastOneSecondDifference = false;
 foreach (var item in projectsPerMonth.Buckets)
 {
     differenceCount++;

src/Nest/Aggregations/AggregateDictionary.cs

@@ -188,7 +188,7 @@ public AutoDateHistogramAggregate AutoDateHistogram(string key)
 			{
 				Buckets = bucket.Items.OfType<DateHistogramBucket>().ToList(),
 				Meta = bucket.Meta,
-				Interval = bucket.Interval
+				AutoInterval = bucket.AutoInterval
 			};
 		}
 

src/Nest/Aggregations/AggregateJsonConverter.cs

@@ -504,7 +504,7 @@ private IAggregate GetMultiBucketAggregate(JsonReader reader, JsonSerializer ser
 			if (reader.TokenType == JsonToken.PropertyName && (string)reader.Value == Parser.Interval)
 			{
 				var interval = reader.ReadAsString();
-				bucket.Interval = new Time(interval);
+				bucket.AutoInterval = new DateMathTime(interval);
 			}
 
 			return bucket;

src/Nest/Aggregations/Bucket/AutoDateHistogram/AutoDateHistogramBucket.cs

@@ -1,7 +1,16 @@
-namespace Nest
+// Licensed to Elasticsearch B.V under one or more agreements.
+// Elasticsearch B.V licenses this file to you under the Apache 2.0 License.
+// See the LICENSE file in the project root for more information
+
+using System;
+
+namespace Nest
 {
 	public class AutoDateHistogramAggregate : MultiBucketAggregate<DateHistogramBucket>
 	{
+		[Obsolete("Use AutoInterval. This property is incorrectly mapped to the wrong type")]
 		public Time Interval { get; internal set; }
+
+		public DateMathTime AutoInterval { get; internal set; }
 	}
 }

src/Nest/Aggregations/Bucket/BucketAggregate.cs

@@ -1,3 +1,7 @@
+// Licensed to Elasticsearch B.V under one or more agreements.
+// Elasticsearch B.V licenses this file to you under the Apache 2.0 License.
+// See the LICENSE file in the project root for more information
+
 using System;
 using System.Collections.Generic;
 
@@ -72,6 +76,10 @@ public class BucketAggregate : IAggregate
 		public IReadOnlyCollection<IBucket> Items { get; set; } = EmptyReadOnly<IBucket>.Collection;
 		public IReadOnlyDictionary<string, object> Meta { get; set; } = EmptyReadOnly<string, object>.Dictionary;
 		public long? SumOtherDocCount { get; set; }
+
+		[Obsolete("Use AutoInterval. This property is incorrectly mapped to the wrong type")]
 		public Time Interval { get; set; }
+
+		public DateMathTime AutoInterval { get; set; }
 	}
 }

src/Tests/Tests.Reproduce/GitHubIssue4333.cs

@@ -0,0 +1,93 @@
+// Licensed to Elasticsearch B.V under one or more agreements.
+// Elasticsearch B.V licenses this file to you under the Apache 2.0 License.
+// See the LICENSE file in the project root for more information
+
+using System;
+using System.Text;
+using Elastic.Elasticsearch.Xunit.XunitPlumbing;
+using Elasticsearch.Net;
+using FluentAssertions;
+using Nest;
+
+namespace Tests.Reproduce
+{
+	public class GitHubIssue4333
+	{
+		[U]
+		public void CanDeserializeYearIntervalUnit()
+		{
+			var json = @"{
+			""took"" : 162,
+			""timed_out"" : false,
+			""_shards"" : {
+				""total"" : 3,
+				""successful"" : 3,
+				""skipped"" : 0,
+				""failed"" : 0
+			},
+			""hits"" : {
+				""total"" : 4089559,
+				""max_score"" : 0.0,
+				""hits"" : [ ]
+			},
+			""aggregations"" : {
+				""modDate"" : {
+					""buckets"" : [
+					{
+						""key_as_string"" : ""2013-01-01T00:00:00.000Z"",
+						""key"" : 1356998400000,
+						""doc_count"" : 32
+					},
+					{
+						""key_as_string"" : ""2014-01-01T00:00:00.000Z"",
+						""key"" : 1388534400000,
+						""doc_count"" : 617
+					},
+					{
+						""key_as_string"" : ""2015-01-01T00:00:00.000Z"",
+						""key"" : 1420070400000,
+						""doc_count"" : 183
+					},
+					{
+						""key_as_string"" : ""2016-01-01T00:00:00.000Z"",
+						""key"" : 1451606400000,
+						""doc_count"" : 3479
+					},
+					{
+						""key_as_string"" : ""2017-01-01T00:00:00.000Z"",
+						""key"" : 1483228800000,
+						""doc_count"" : 1948427
+					},
+					{
+						""key_as_string"" : ""2018-01-01T00:00:00.000Z"",
+						""key"" : 1514764800000,
+						""doc_count"" : 555748
+					},
+					{
+						""key_as_string"" : ""2019-01-01T00:00:00.000Z"",
+						""key"" : 1546300800000,
+						""doc_count"" : 1268034
+					},
+					{
+						""key_as_string"" : ""2020-01-01T00:00:00.000Z"",
+						""key"" : 1577836800000,
+						""doc_count"" : 313039
+					}
+					],
+					""interval"" : ""1y""
+				}
+			}
+		}";
+
+			var bytes = Encoding.UTF8.GetBytes(json);
+			var pool = new SingleNodeConnectionPool(new Uri("http://localhost:9200"));
+			var connectionSettings = new ConnectionSettings(pool, new InMemoryConnection(bytes)).DefaultIndex("default_index");
+			var client = new ElasticClient(connectionSettings);
+
+			var response = client.Search<object>();
+
+			var agg = response.Aggregations.AutoDateHistogram("modDate");
+			agg.AutoInterval.Should().Be("1y");
+		}
+	}
+}

src/Tests/Tests/Aggregations/Bucket/AutoDateHistogram/AutoDateHistogramAggregationUsageTests.cs

@@ -104,7 +104,7 @@ protected override void ExpectResponse(ISearchResponse<Project> response)
 
 			var dateHistogram = response.Aggregations.AutoDateHistogram("projects_started_per_month");
 			dateHistogram.Should().NotBeNull();
-			dateHistogram.Interval.Should().NotBeNull();
+			dateHistogram.AutoInterval.Should().NotBeNull();
 			dateHistogram.Buckets.Should().NotBeNull();
 			dateHistogram.Buckets.Count.Should().BeGreaterThan(1);
 			foreach (var item in dateHistogram.Buckets)