CSHARP-2622: IdGenerator not working for inserts after using oftype on collection.

Author: rstam

src/MongoDB.Driver/OfTypeSerializer.cs

@@ -13,12 +13,13 @@
 * limitations under the License.
 */
 
+using System;
 using MongoDB.Bson.Serialization;
 using MongoDB.Bson.Serialization.Serializers;
 
 namespace MongoDB.Driver
 {
-    internal sealed class OfTypeSerializer<TRootDocument, TDerivedDocument> : SerializerBase<TDerivedDocument>, IBsonDocumentSerializer
+    internal sealed class OfTypeSerializer<TRootDocument, TDerivedDocument> : SerializerBase<TDerivedDocument>, IBsonDocumentSerializer, IBsonIdProvider
         where TDerivedDocument : TRootDocument
     {
         private readonly IBsonSerializer<TDerivedDocument> _derivedDocumentSerializer;
@@ -34,12 +35,35 @@ public override TDerivedDocument Deserialize(BsonDeserializationContext context,
             return _derivedDocumentSerializer.Deserialize(context, args);
         }
 
+        public bool GetDocumentId(object document, out object id, out Type idNominalType, out IIdGenerator idGenerator)
+        {
+            if (_derivedDocumentSerializer is IBsonIdProvider idProvider)
+            {
+                return idProvider.GetDocumentId(document, out id, out idNominalType, out idGenerator);
+            }
+            else
+            {
+                id = null;
+                idNominalType = null;
+                idGenerator = null;
+                return false;
+            }
+        }
+
         public override void Serialize(BsonSerializationContext context, BsonSerializationArgs args, TDerivedDocument value)
         {
             args.NominalType = typeof(TRootDocument);
             _derivedDocumentSerializer.Serialize(context, args, value);
         }
 
+        public void SetDocumentId(object document, object id)
+        {
+            if (_derivedDocumentSerializer is IBsonIdProvider idProvider)
+            {
+                idProvider.SetDocumentId(document, id);
+            }
+        }
+
         public bool TryGetMemberSerializationInfo(string memberName, out BsonSerializationInfo serializationInfo)
         {
             var documentSerializer = _derivedDocumentSerializer as IBsonDocumentSerializer;

tests/MongoDB.Driver.Tests/Jira/CSharp2622Tests.cs

@@ -0,0 +1,59 @@
+/* Copyright 2019-present MongoDB Inc.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+using System;
+using FluentAssertions;
+using Xunit;
+
+namespace MongoDB.Driver.Tests.Jira
+{
+    public class CSharp2622Tests
+    {
+        // public methods
+        [Fact]
+        public void InsertOne_to_oftype_collection_should_generate_id()
+        {
+            var collectionNamespace = CoreTestConfiguration.GetCollectionNamespaceForTestClass(typeof(CSharp2622Tests));
+            var databaseName = collectionNamespace.DatabaseNamespace.DatabaseName;
+            var collectionName = collectionNamespace.CollectionName;
+            var client = DriverTestConfiguration.Client;
+            var database = client.GetDatabase(databaseName);
+            var collection = database.GetCollection<C>(collectionName);
+            var ofTypeCollection = collection.OfType<D>();
+            database.DropCollection(collectionName);
+            var document = new D { X = 1 };
+
+            ofTypeCollection.InsertOne(document);
+
+            var insertedDocuments = collection.FindSync("{}").ToList();
+            insertedDocuments.Count.Should().Be(1);
+            insertedDocuments[0].Should().BeOfType<D>();
+            var insertedDocument = (D)insertedDocuments[0];
+            insertedDocument.Id.Should().NotBeEmpty();
+            insertedDocument.X.Should().Be(1);
+        }
+
+        // nested types
+        public class C
+        {
+            public Guid Id { get; set; }
+        }
+
+        public class D : C
+        {
+            public int X { get; set; }
+        }
+    }
+}