CSHARP-606: added support for type discriminated queries on fields.

Author: craiggwilson

Driver/Linq/Translators/PredicateTranslator.cs

@@ -27,6 +27,7 @@
 using MongoDB.Bson.Serialization.Options;
 using MongoDB.Driver.Builders;
 using MongoDB.Driver.Linq.Utils;
+using MongoDB.Bson.Serialization.Conventions;
 
 namespace MongoDB.Driver.Linq
 {
@@ -1291,14 +1292,7 @@ private IMongoQuery BuildTypeComparisonQuery(Expression variableExpression, Expr
                 return null;
             }
 
-            // TODO: would the object ever not be a ParameterExpression?
-            var parameterExpression = methodCallExpression.Object as ParameterExpression;
-            if (parameterExpression == null)
-            {
-                return null;
-            }
-
-            var serializationInfo = _serializationInfoHelper.GetSerializationInfo(parameterExpression);
+            var serializationInfo = _serializationInfoHelper.GetSerializationInfo(methodCallExpression.Object);
             var nominalType = serializationInfo.NominalType;
 
             var discriminatorConvention = BsonSerializer.LookupDiscriminatorConvention(nominalType);
@@ -1308,22 +1302,28 @@ private IMongoQuery BuildTypeComparisonQuery(Expression variableExpression, Expr
                 return BuildBooleanQuery(true);
             }
 
+            var elementName = discriminatorConvention.ElementName;
+            if (serializationInfo.ElementName != null)
+            {
+                elementName = string.Format("{0}.{1}", serializationInfo.ElementName, elementName);
+            }
+
             if (discriminator.IsBsonArray)
             {
                 var discriminatorArray = discriminator.AsBsonArray;
                 var queries = new IMongoQuery[discriminatorArray.Count + 1];
-                queries[0] = Query.Size(discriminatorConvention.ElementName, discriminatorArray.Count);
+                queries[0] = Query.Size(elementName, discriminatorArray.Count);
                 for (var i = 0; i < discriminatorArray.Count; i++)
                 {
-                    queries[i + 1] = Query.EQ(string.Format("{0}.{1}", discriminatorConvention.ElementName, i), discriminatorArray[i]);
+                    queries[i + 1] = Query.EQ(string.Format("{0}.{1}", elementName, i), discriminatorArray[i]);
                 }
                 return Query.And(queries);
             }
             else
             {
                 return Query.And(
-                    Query.NotExists(discriminatorConvention.ElementName + ".0"), // trick to check that element is not an array
-                    Query.EQ(discriminatorConvention.ElementName, discriminator));
+                    Query.NotExists(elementName + ".0"), // trick to check that element is not an array
+                    Query.EQ(elementName, discriminator));
             }
         }
 
@@ -1344,7 +1344,13 @@ private IMongoQuery BuildTypeIsQuery(TypeBinaryExpression typeBinaryExpression)
                 discriminator = discriminator.AsBsonArray[discriminator.AsBsonArray.Count - 1];
             }
 
-            return Query.EQ(discriminatorConvention.ElementName, discriminator);
+            var elementName = discriminatorConvention.ElementName;
+            var serializationInfo = _serializationInfoHelper.GetSerializationInfo(typeBinaryExpression.Expression);
+            if (serializationInfo.ElementName != null)
+            {
+                elementName = string.Format("{0}.{1}", serializationInfo.ElementName, elementName);
+            }
+            return Query.EQ(elementName, discriminator);
         }
 
         private string GetTrimCharsPattern(Expression trimCharsExpression)

DriverUnitTests/DriverUnitTests.csproj

@@ -129,6 +129,7 @@
     <Compile Include="GridFS\MongoGridFSSettingsTests.cs" />
     <Compile Include="GridFS\MongoGridFSStreamTests.cs" />
     <Compile Include="GridFS\MongoGridFSTests.cs" />
+    <Compile Include="Jira\CSharp606Tests.cs" />
     <Compile Include="Jira\CSharp598Tests.cs" />
     <Compile Include="Jira\CSharp538Tests.cs" />
     <Compile Include="Jira\CSharp532Tests.cs" />

DriverUnitTests/Jira/CSharp606Tests.cs

@@ -0,0 +1,65 @@
+/* Copyright 2010-2012 10gen 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 System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using NUnit.Framework;
+
+using MongoDB.Bson;
+using MongoDB.Driver;
+using MongoDB.Driver.Linq;
+using MongoDB.Bson.Serialization.Attributes;
+using MongoDB.Driver.Builders;
+
+namespace MongoDB.DriverUnitTests.Jira.CSharp606
+{
+    [TestFixture]
+    public class CSharp606Tests
+    {
+        [Test]
+        public void TestTypeIsOnProperty()
+        {
+            IMongoQuery query = Query<TestClass>.Where(x => x.Prop is B);
+
+            Assert.AreEqual("{ \"Prop._t\" : \"B\" }", query.ToString());
+        }
+
+        [Test]
+        public void TestTypeOfComparisonOnProperty()
+        {
+            IMongoQuery query = Query<TestClass>.Where(x => x.Prop.GetType() == typeof(B));
+
+            Assert.AreEqual("{ \"Prop._t.0\" : { \"$exists\" : false }, \"Prop._t\" : \"B\" }", query.ToString());
+        }
+
+        private class TestClass
+        {
+            public ObjectId Id { get; set; }
+
+            public A Prop { get; set; }
+        }
+        private class A
+        {
+            public string String { get; set; }
+        }
+
+        private class B : A
+        {
+            public int Int { get; set; }
+        }
+    }
+}