Fix #971: FilteredQuery not properly handling conditionless query or filter

Author: gmarz

src/Nest/DSL/Query/QueryDescriptor.cs

@@ -57,6 +57,7 @@ private QueryDescriptor<T> New(IQuery query, Action<IQueryContainer> fillPropert
 
 			if (fillProperty != null)
 				fillProperty(q);
+
 			return q;
 		}
 
@@ -463,6 +464,14 @@ public QueryContainer Filtered(Action<FilteredQueryDescriptor<T>> selector)
 			var query = new FilteredQueryDescriptor<T>();
 			selector(query);
 
+			var filtered = query as IFilteredQuery;
+			
+			if (filtered.Query.IsConditionless)
+				filtered.Query = null;
+			
+			if (filtered.Filter.IsConditionless)
+				filtered.Filter = null;
+
 			return this.New(query, q => q.Filtered = query);
 		}
 

src/Tests/Nest.Tests.Integration/Nest.Tests.Integration.csproj

@@ -186,6 +186,7 @@
     <Compile Include="Search\Filter\PrefixFilterTests.cs" />
     <Compile Include="Search\Filter\RangeFilterTests.cs" />
     <Compile Include="Search\Query\BoolQueryResults.cs" />
+    <Compile Include="Search\Query\FilteredQueryTests.cs" />
     <Compile Include="Search\Query\SpanQueryTests.cs" />
     <Compile Include="Search\Query\TermToString.cs" />
     <Compile Include="Core\UpdateTests.cs" />

src/Tests/Nest.Tests.Integration/Search/Query/FilteredQueryTests.cs

@@ -0,0 +1,84 @@
+using Nest.Tests.MockData.Domain;
+using NUnit.Framework;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using FluentAssertions;
+
+namespace Nest.Tests.Integration.Search.Query
+{
+	[TestFixture]
+	public class FilteredQueryTests : IntegrationTests
+	{
+		[Test]
+		public void QueryIsConditionless()
+		{
+			var response = this.Client.Search<ElasticsearchProject>(s => s
+				.Query(q => q
+					.Filtered(ff => ff
+						.Query(qq => qq
+							.Match(m => m
+								.OnField(p => p.Name)
+								.Query(null)
+							)
+						)
+						.Filter(f => f
+							.Term(p => p.Id, 1)
+						)
+					)
+				)
+			);
+
+			response.IsValid.Should().BeTrue();
+			response.Total.ShouldBeEquivalentTo(1);
+		}
+
+		[Test]
+		public void FilterIsConditionless()
+		{
+			var response = this.Client.Search<ElasticsearchProject>(s => s
+				.Query(q => q
+					.Filtered(ff => ff
+						.Query(qq => qq
+							.Match(m => m
+								.OnField(p => p.Name)
+								.Query("elasticsearch")
+							)
+						)
+						.Filter(f => f
+							.Term(p => p.Id, null)
+						)
+					)
+				)
+			);
+
+			response.IsValid.Should().BeTrue();
+			response.Total.Should().BeGreaterThan(1);
+		}
+
+		[Test]
+		public void QueryAndFilterAreConditionless()
+		{
+			var response = this.Client.Search<ElasticsearchProject>(s => s
+				.Query(q => q
+					.Filtered(ff => ff
+						.Query(qq => qq
+							.Match(m => m
+								.OnField(p => p.Name)
+								.Query(null)
+							)
+						)
+						.Filter(f => f
+							.Term(p => p.Id, null)
+						)
+					)
+				)
+			);
+
+			response.IsValid.Should().BeTrue();
+			response.Total.Should().BeGreaterThan(10);
+		}
+	}
+}