CSHARP-3086: Hidden Indexes.

Author: DmitryLukyanov

src/MongoDB.Driver.Core/Core/Misc/Feature.cs

@@ -67,6 +67,7 @@ public class Feature
         private static readonly Feature __geoNearCommand = new Feature("GeoNearCommand", new SemanticVersion(1, 0, 0), new SemanticVersion(4, 1, 0, ""));
         private static readonly Feature __groupCommand = new Feature("GroupCommand", new SemanticVersion(1, 0, 0), new SemanticVersion(4, 1, 1, ""));
         private static readonly Feature __hedgedReads = new Feature("HedgedReads", new SemanticVersion(4, 3, 1, ""));
+        private static readonly Feature __hiddenIndex = new Feature("HiddenIndex", new SemanticVersion(4, 4, 0));
         private static readonly HintForDeleteOperationsFeature __hintForDeleteOperations = new HintForDeleteOperationsFeature("HintForDeleteOperations", new SemanticVersion(4, 3, 4));
         private static readonly HintForFindAndModifyFeature __hintForFindAndModifyFeature = new HintForFindAndModifyFeature("HintForFindAndModify", new SemanticVersion(4, 3, 4));
         private static readonly HintForUpdateAndReplaceOperationsFeature __hintForUpdateAndReplaceOperations = new HintForUpdateAndReplaceOperationsFeature("HintForUpdateAndReplaceOperations", new SemanticVersion(4, 2, 0));
@@ -321,6 +322,11 @@ public class Feature
         /// </summary>
         public static Feature HedgedReads => __hedgedReads;
 
+        /// <summary>
+        /// Gets the hidden index feature.
+        /// </summary>
+        public static Feature HiddenIndex => __hiddenIndex;
+
         /// <summary>
         /// Gets the hint for delete operations feature.
         /// </summary>

src/MongoDB.Driver.Core/Core/Operations/CreateIndexRequest.cs

@@ -32,6 +32,7 @@ public class CreateIndexRequest
         private Collation _collation;
         private string _defaultLanguage;
         private TimeSpan? _expireAfter;
+        private bool? _hidden;
         private string _languageOverride;
         private readonly BsonDocument _keys;
         private double? _max;
@@ -140,6 +141,15 @@ public TimeSpan? ExpireAfter
             set { _expireAfter = value; }
         }
 
+        /// <summary>
+        /// Gets or sets a value indicating whether the index is hidden.
+        /// </summary>
+        public bool? Hidden
+        {
+            get { return _hidden; }
+            set { _hidden = value; }
+        }
+
         /// <summary>
         /// Gets or sets the language override for text indexes.
         /// </summary>
@@ -346,6 +356,7 @@ internal BsonDocument CreateIndexDocument(SemanticVersion serverVersion)
                 { "collation", () => _collation.ToBsonDocument(), _collation != null },
                 { "default_language", () => _defaultLanguage, _defaultLanguage != null },
                 { "expireAfterSeconds", () => _expireAfter.Value.TotalSeconds, _expireAfter.HasValue },
+                { "hidden", () => _hidden.Value, _hidden.HasValue },
                 { "language_override", () => _languageOverride, _languageOverride != null },
                 { "max", () => _max.Value, _max.HasValue },
                 { "min", () => _min.Value, _min.HasValue },

src/MongoDB.Driver.Legacy/Builders/IndexOptionsBuilder.cs

@@ -90,6 +90,16 @@ public static IndexOptionsBuilder SetGeoSpatialRange(double min, double max)
             return new IndexOptionsBuilder().SetGeoSpatialRange(min, max);
         }
 
+        /// <summary>
+        /// Sets whether the index is hidden.
+        /// </summary>
+        /// <param name="value">Whether the index is hidden.</param>
+        /// <returns>The builder (so method calls can be chained).</returns>
+        public static IndexOptionsBuilder SetHidden(bool value)
+        {
+            return new IndexOptionsBuilder().SetHidden(value);
+        }
+
         /// <summary>
         /// Sets the name of the index.
         /// </summary>
@@ -277,6 +287,17 @@ public IndexOptionsBuilder SetGeoSpatialRange(double min, double max)
             return this;
         }
 
+        /// <summary>
+        /// Sets whether the index is hidden.
+        /// </summary>
+        /// <param name="value">Whether the index is hidden.</param>
+        /// <returns>The builder (so method calls can be chained).</returns>
+        public IndexOptionsBuilder SetHidden(bool value)
+        {
+            _document["hidden"] = value;
+            return this;
+        }
+
         /// <summary>
         /// Sets the name of the index.
         /// </summary>
@@ -481,6 +502,16 @@ public static IndexOptionsBuilder<TDocument> SetDropDups(bool value)
             return new IndexOptionsBuilder<TDocument>().SetDropDups(value);
         }
 
+        /// <summary>
+        /// Sets whether the index is hidden.
+        /// </summary>
+        /// <param name="value">Whether the index is hidden.</param>
+        /// <returns>The builder (so method calls can be chained).</returns>
+        public static IndexOptionsBuilder<TDocument> SetHidden(bool value)
+        {
+            return new IndexOptionsBuilder<TDocument>().SetHidden(value);
+        }
+
         /// <summary>
         /// Sets the geospatial range.
         /// </summary>
@@ -685,6 +716,17 @@ public IndexOptionsBuilder<TDocument> SetGeoSpatialRange(double min, double max)
             return this;
         }
 
+        /// <summary>
+        /// Sets whether the index is hidden.
+        /// </summary>
+        /// <param name="value">Whether the index is hidden.</param>
+        /// <returns>The builder (so method calls can be chained).</returns>
+        public IndexOptionsBuilder<TDocument> SetHidden(bool value)
+        {
+            _indexOptionsBuilder.SetHidden(value);
+            return this;
+        }
+
         /// <summary>
         /// Sets the name of the index.
         /// </summary>

src/MongoDB.Driver.Legacy/GetIndexesResult.cs

@@ -140,6 +140,24 @@ public bool IsBackground
             }
         }
 
+        /// <summary>
+        /// Gets a value indicating whether the index is hidden.
+        /// </summary>
+        public bool IsHidden
+        {
+            get
+            {
+                if (_document.TryGetValue("hidden", out var value))
+                {
+                    return value.ToBoolean();
+                }
+                else
+                {
+                    return false;
+                }
+            }
+        }
+
         /// <summary>
         /// Gets a value indicating whether the index is sparse.
         /// </summary>

src/MongoDB.Driver/CreateIndexOptions.cs

@@ -30,6 +30,7 @@ public class CreateIndexOptions
         private Collation _collation;
         private string _defaultLanguage;
         private TimeSpan? _expireAfter;
+        private bool? _hidden;
         private string _languageOverride;
         private double? _max;
         private double? _min;
@@ -98,6 +99,15 @@ public TimeSpan? ExpireAfter
             set { _expireAfter = value; }
         }
 
+        /// <summary>
+        /// Gets or sets a value indicating whether the index is hidden.
+        /// </summary>
+        public bool? Hidden
+        {
+            get { return _hidden; }
+            set { _hidden = value; }
+        }
+
         /// <summary>
         /// Gets or sets the language override.
         /// </summary>
@@ -225,6 +235,7 @@ internal static CreateIndexOptions<TDocument> CoercedFrom(CreateIndexOptions opt
                     Collation = options.Collation,
                     DefaultLanguage = options.DefaultLanguage,
                     ExpireAfter = options.ExpireAfter,
+                    Hidden = options.Hidden,
                     LanguageOverride = options.LanguageOverride,
                     Max = options.Max,
                     Min = options.Min,

src/MongoDB.Driver/MongoCollectionImpl.cs

@@ -1566,6 +1566,7 @@ private IEnumerable<CreateIndexRequest> CreateCreateIndexRequests(IEnumerable<Cr
                         Collation = options.Collation,
                         DefaultLanguage = options.DefaultLanguage,
                         ExpireAfter = options.ExpireAfter,
+                        Hidden = options.Hidden,
                         LanguageOverride = options.LanguageOverride,
                         Max = options.Max,
                         Min = options.Min,

tests/MongoDB.Driver.Core.Tests/Core/Operations/CreateIndexRequestTests.cs

@@ -116,6 +116,7 @@ public void constructor_should_initialize_subject()
             subject.Collation.Should().BeNull();
             subject.DefaultLanguage.Should().BeNull();
             subject.ExpireAfter.Should().NotHaveValue();
+            subject.Hidden.Should().NotHaveValue();
             subject.LanguageOverride.Should().BeNull();
             subject.Max.Should().NotHaveValue();
             subject.Min.Should().NotHaveValue();
@@ -323,6 +324,27 @@ public void CreateIndexDocument_should_return_expected_result_when_ExpireAfter_i
             result.Should().Be(expectedResult);
         }
 
+        [Theory]
+        [ParameterAttributeData]
+        public void CreateIndexDocument_should_return_expected_result_when_Hidden_is_set([Values(null, false, true)] bool? hidden)
+        {
+            var keys = new BsonDocument("x", 1);
+            var subject = new CreateIndexRequest(keys)
+            {
+                Hidden = hidden
+            };
+
+            var result = subject.CreateIndexDocument(null);
+
+            var expectedResult = new BsonDocument
+            {
+                { "key", keys },
+                { "name", "x_1" },
+                { "hidden", () => hidden.Value, hidden.HasValue }
+            };
+            result.Should().Be(expectedResult);
+        }
+
         [Theory]
         [ParameterAttributeData]
         public void CreateIndexDocument_should_return_expected_result_when_LanguageOverride_is_set(
@@ -689,6 +711,19 @@ public void ExpireAfter_get_and_set_should_work(
             result.Should().Be(value);
         }
 
+        [Theory]
+        [ParameterAttributeData]
+        public void Hidden_get_and_set_should_work(
+            [Values(null, false, true)] bool? value)
+        {
+            var subject = new CreateIndexRequest(new BsonDocument("x", 1));
+
+            subject.Hidden = value;
+            var result = subject.Hidden;
+
+            result.Should().Be(value);
+        }
+
         [Theory]
         [ParameterAttributeData]
         public void LanguageOverride_get_and_set_should_work(

tests/MongoDB.Driver.Core.Tests/Core/Operations/CreateIndexesOperationTests.cs

@@ -254,6 +254,33 @@ public void Execute_should_work_when_expireAfter_has_value(
             index["expireAfterSeconds"].ToDouble().Should().Be(expireAfter.TotalSeconds);
         }
 
+        [SkippableTheory]
+        [ParameterAttributeData]
+        public void Execute_should_work_when_hidden_has_value(
+            [Values(null, false, true)] bool? hidden,
+            [Values(false, true)] bool async)
+        {
+            RequireServer.Check().Supports(Feature.HiddenIndex);
+            DropCollection();
+            var requests = new[] { new CreateIndexRequest(new BsonDocument("x", 1)) { Hidden = hidden} };
+            var subject = new CreateIndexesOperation(_collectionNamespace, requests, _messageEncoderSettings);
+
+            var result = ExecuteOperation(subject, async);
+
+            result["ok"].ToBoolean().Should().BeTrue();
+
+            var indexes = ListIndexes();
+            var index = indexes.Single(i => i["name"].AsString == "x_1");
+            if (hidden.GetValueOrDefault())
+            {
+                index["hidden"].AsBoolean.Should().BeTrue();
+            }
+            else
+            {
+                index.Contains("hidden").Should().BeFalse();
+            }
+        }
+
         [SkippableTheory]
         [ParameterAttributeData]
         public void Execute_should_work_when_unique_is_true(

tests/MongoDB.Driver.Core.Tests/Core/Operations/CreateIndexesUsingCommandOperationTests.cs

@@ -431,6 +431,31 @@ public void Execute_should_work_when_expireAfter_has_value(
             index["expireAfterSeconds"].ToDouble().Should().Be(expireAfter.TotalSeconds);
         }
 
+        [SkippableTheory]
+        [ParameterAttributeData]
+        public void Execute_should_work_when_hidden_has_value(
+            [Values(null, false, true)] bool? hidden,
+            [Values(false, true)] bool async)
+        {
+            RequireServer.Check().Supports(Feature.HiddenIndex);
+            DropCollection();
+            var requests = new[] { new CreateIndexRequest(new BsonDocument("x", 1)) { Hidden = hidden } };
+            var subject = new CreateIndexesUsingCommandOperation(_collectionNamespace, requests, _messageEncoderSettings);
+
+            ExecuteOperation(subject, async);
+
+            var indexes = ListIndexes();
+            var index = indexes.Single(i => i["name"].AsString == "x_1");
+            if (hidden.GetValueOrDefault())
+            {
+                index["hidden"].AsBoolean.Should().BeTrue();
+            }
+            else
+            {
+                index.Contains("hidden").Should().BeFalse();
+            }
+        }
+
         [SkippableTheory]
         [ParameterAttributeData]
         public void Execute_should_work_when_unique_is_true(

tests/MongoDB.Driver.Legacy.Tests/Builders/IndexOptionsBuilderTests.cs

@@ -55,6 +55,13 @@ public void TestGeoSpatialRange()
             Assert.Equal(expected, options.ToJson());
         }
 
+        [Fact]
+        public void TestHidden()
+        {
+            var options = IndexOptions.SetHidden(true);
+            options.ToBsonDocument().Should().Be("{ hidden : true }");
+        }
+
         [Fact]
         public void TestName()
         {