Fixed CSHARP-263. Changed BsonBaseSerializer to require that all subc…

…lasses implement the overload of Deserialize that inludes an actualType parameter. When an array is serialized and nominalType is object it now wraps the array in a document that includes type information ("_t" and "_v" elements).

Bson/Serialization/Serializers/BsonBaseSerializer.cs

@@ -49,7 +49,8 @@ public abstract class BsonBaseSerializer : IBsonSerializer {
             Type nominalType,
             IBsonSerializationOptions options
         ) {
-            throw new NotSupportedException("Subclass must implement Deserialize.");
+            // override this method to determine actualType if your serializer handles polymorphic data types
+            return Deserialize(bsonReader, nominalType, nominalType, options);
         }
 
         /// <summary>
@@ -63,10 +64,10 @@ IBsonSerializationOptions options
         public virtual object Deserialize(
             BsonReader bsonReader,
             Type nominalType,
-            Type actualType, // ignored
+            Type actualType,
             IBsonSerializationOptions options
         ) {
-            return Deserialize(bsonReader, nominalType, options);
+            throw new NotSupportedException("Subclass must implement Deserialize.");
         }
 
         /// <summary>
@@ -114,5 +115,27 @@ object id
             throw new NotSupportedException("Subclass must implement SetDocumentId.");
         }
         #endregion
+
+        #region protected methods
+        /// <summary>
+        /// Verifies the nominal and actual types against the expected type.
+        /// </summary>
+        /// <param name="nominalType">The nominal type.</param>
+        /// <param name="actualType">The actual type.</param>
+        /// <param name="expectedType">The expected type.</param>
+        protected void VerifyTypes(
+            Type nominalType,
+            Type actualType,
+            Type expectedType
+        ) {
+            if (actualType != expectedType) {
+                var message = string.Format("{0} can only be used with type {1}, not with type {2}.", this.GetType().FullName, expectedType.FullName, actualType.FullName);
+                throw new BsonSerializationException(message);
+            }
+            if (!nominalType.IsAssignableFrom(actualType)) {
+                var message = string.Format("{0} can only be used with a nominal type that is assignable from the actual type {1}, but nominal type {2} is not.", this.GetType().FullName, actualType.FullName, nominalType.FullName);
+            }
+        }
+        #endregion
     }
 }

Bson/Serialization/Serializers/BsonPrimitiveSerializers.cs

@@ -58,13 +58,17 @@ public class BooleanSerializer : BsonBaseSerializer {
         /// </summary>
         /// <param name="bsonReader">The BsonReader.</param>
         /// <param name="nominalType">The nominal type of the object.</param>
+        /// <param name="actualType">The actual type of the object.</param>
         /// <param name="options">The serialization options.</param>
         /// <returns>An object.</returns>
         public override object Deserialize(
             BsonReader bsonReader,
             Type nominalType,
+            Type actualType,
             IBsonSerializationOptions options
         ) {
+            VerifyTypes(nominalType, actualType, typeof(bool));
+
             var bsonType = bsonReader.CurrentBsonType;
             switch (bsonType) {
                 case BsonType.Boolean:
@@ -156,13 +160,17 @@ public class DateTimeSerializer : BsonBaseSerializer {
         /// </summary>
         /// <param name="bsonReader">The BsonReader.</param>
         /// <param name="nominalType">The nominal type of the object.</param>
+        /// <param name="actualType">The actual type of the object.</param>
         /// <param name="options">The serialization options.</param>
         /// <returns>An object.</returns>
         public override object Deserialize(
             BsonReader bsonReader,
             Type nominalType,
+            Type actualType,
             IBsonSerializationOptions options
         ) {
+            VerifyTypes(nominalType, actualType, typeof(DateTime));
+
             var dateTimeOptions = (options == null) ? DateTimeSerializationOptions.Defaults : (DateTimeSerializationOptions) options;
             DateTime value;
 
@@ -314,13 +322,17 @@ public class DoubleSerializer : BsonBaseSerializer {
         /// </summary>
         /// <param name="bsonReader">The BsonReader.</param>
         /// <param name="nominalType">The nominal type of the object.</param>
+        /// <param name="actualType">The actual type of the object.</param>
         /// <param name="options">The serialization options.</param>
         /// <returns>An object.</returns>
         public override object Deserialize(
             BsonReader bsonReader,
             Type nominalType,
+            Type actualType,
             IBsonSerializationOptions options
         ) {
+            VerifyTypes(nominalType, actualType, typeof(double));
+
             var representationOptions = (RepresentationSerializationOptions) options ?? defaultRepresentationOptions;
             var bsonType = bsonReader.CurrentBsonType;
             switch (bsonType) {
@@ -405,13 +417,17 @@ public class GuidSerializer : BsonBaseSerializer {
         /// </summary>
         /// <param name="bsonReader">The BsonReader.</param>
         /// <param name="nominalType">The nominal type of the object.</param>
+        /// <param name="actualType">The actual type of the object.</param>
         /// <param name="options">The serialization options.</param>
         /// <returns>An object.</returns>
         public override object Deserialize(
             BsonReader bsonReader,
             Type nominalType,
+            Type actualType,
             IBsonSerializationOptions options
         ) {
+            VerifyTypes(nominalType, actualType, typeof(Guid));
+
             var bsonType = bsonReader.CurrentBsonType;
             string message;
             switch (bsonType) {
@@ -509,13 +525,17 @@ public class Int32Serializer : BsonBaseSerializer {
         /// </summary>
         /// <param name="bsonReader">The BsonReader.</param>
         /// <param name="nominalType">The nominal type of the object.</param>
+        /// <param name="actualType">The actual type of the object.</param>
         /// <param name="options">The serialization options.</param>
         /// <returns>An object.</returns>
         public override object Deserialize(
             BsonReader bsonReader,
             Type nominalType,
+            Type actualType,
             IBsonSerializationOptions options
         ) {
+            VerifyTypes(nominalType, actualType, typeof(int));
+
             var representationOptions = (RepresentationSerializationOptions) options ?? defaultRepresentationOptions;
             var bsonType = bsonReader.CurrentBsonType;
             switch (bsonType) {
@@ -601,13 +621,17 @@ public class Int64Serializer : BsonBaseSerializer {
         /// </summary>
         /// <param name="bsonReader">The BsonReader.</param>
         /// <param name="nominalType">The nominal type of the object.</param>
+        /// <param name="actualType">The actual type of the object.</param>
         /// <param name="options">The serialization options.</param>
         /// <returns>An object.</returns>
         public override object Deserialize(
             BsonReader bsonReader,
             Type nominalType,
+            Type actualType,
             IBsonSerializationOptions options
         ) {
+            VerifyTypes(nominalType, actualType, typeof(long));
+
             var representationOptions = (RepresentationSerializationOptions) options ?? defaultRepresentationOptions;
             var bsonType = bsonReader.CurrentBsonType;
             switch (bsonType) {
@@ -692,13 +716,17 @@ public class ObjectIdSerializer : BsonBaseSerializer {
         /// </summary>
         /// <param name="bsonReader">The BsonReader.</param>
         /// <param name="nominalType">The nominal type of the object.</param>
+        /// <param name="actualType">The actual type of the object.</param>
         /// <param name="options">The serialization options.</param>
         /// <returns>An object.</returns>
         public override object Deserialize(
             BsonReader bsonReader,
             Type nominalType,
+            Type actualType,
             IBsonSerializationOptions options
         ) {
+            VerifyTypes(nominalType, actualType, typeof(ObjectId));
+
             BsonType bsonType = bsonReader.CurrentBsonType;
             switch (bsonType) {
                 case BsonType.ObjectId:
@@ -776,13 +804,17 @@ public class StringSerializer : BsonBaseSerializer {
         /// </summary>
         /// <param name="bsonReader">The BsonReader.</param>
         /// <param name="nominalType">The nominal type of the object.</param>
+        /// <param name="actualType">The actual type of the object.</param>
         /// <param name="options">The serialization options.</param>
         /// <returns>An object.</returns>
         public override object Deserialize(
             BsonReader bsonReader,
             Type nominalType,
+            Type actualType,
             IBsonSerializationOptions options
         ) {
+            VerifyTypes(nominalType, actualType, typeof(string));
+
             var bsonType = bsonReader.CurrentBsonType;
             if (bsonType == BsonType.Null) {
                 bsonReader.ReadNull();