Work in progress.

Author: rstam

src/MongoDB.Driver/Linq/Linq3Implementation/KnownSerializerFinders/KnownSerializerFinderHelperMethods.cs

@@ -108,30 +108,34 @@ private void DeduceBooleanSerializer(Expression node)
         }
     }
 
-    private void DeduceCollectionAndItemSerializers(Expression collectionExpression, Expression itemExpression)
-    {
-        DeduceItemAndCollectionSerializers(itemExpression, collectionExpression);
-    }
-
     private void DeduceCollectionAndCollectionSerializers(Expression collectionExpression1, Expression collectionExpression2)
     {
         IBsonSerializer collectionSerializer1;
         IBsonSerializer collectionSerializer2;
 
         if (IsNotKnown(collectionExpression1) && IsKnown(collectionExpression2, out collectionSerializer2))
         {
-            collectionSerializer1 = CreateCollectionSerializerFromCollectionSerializer(collectionExpression1.Type, collectionSerializer2);
+            collectionSerializer1 = collectionSerializer2 is IUnknowableSerializer ?
+                UnknowableSerializer.Create(collectionExpression1.Type) :
+                CreateCollectionSerializerFromCollectionSerializer(collectionExpression1.Type, collectionSerializer2);
             AddKnownSerializer(collectionExpression1, collectionSerializer1);
         }
 
         if (IsNotKnown(collectionExpression2) && IsKnown(collectionExpression1, out collectionSerializer1))
         {
-            collectionSerializer2 = CreateCollectionSerializerFromCollectionSerializer(collectionExpression2.Type, collectionSerializer1);
+            collectionSerializer2 = collectionSerializer1 is IUnknowableSerializer ?
+                UnknowableSerializer.Create(collectionExpression2.Type) :
+                CreateCollectionSerializerFromCollectionSerializer(collectionExpression2.Type, collectionSerializer1);
             AddKnownSerializer(collectionExpression2, collectionSerializer2);
         }
 
     }
 
+    private void DeduceCollectionAndItemSerializers(Expression collectionExpression, Expression itemExpression)
+    {
+        DeduceItemAndCollectionSerializers(itemExpression, collectionExpression);
+    }
+
     private void DeduceItemAndCollectionSerializers(Expression itemExpression, Expression collectionExpression)
     {
         if (IsNotKnown(itemExpression) && IsItemSerializerKnown(collectionExpression, out var itemSerializer))
@@ -141,7 +145,9 @@ private void DeduceItemAndCollectionSerializers(Expression itemExpression, Expre
 
         if (IsNotKnown(collectionExpression) && IsKnown(itemExpression, out itemSerializer))
         {
-            var collectionSerializer = CreateCollectionSerializerFromItemSerializer(collectionExpression.Type, itemSerializer);
+            var collectionSerializer = itemSerializer is IUnknowableSerializer ?
+                UnknowableSerializer.Create(collectionExpression.Type) :
+                CreateCollectionSerializerFromItemSerializer(collectionExpression.Type, itemSerializer);
             if (collectionSerializer != null)
             {
                 AddKnownSerializer(collectionExpression, collectionSerializer);
@@ -178,6 +184,15 @@ private void DeduceStringSerializer(Expression node)
         }
     }
 
+    private void DeduceUnknowableSerializer(Expression node)
+    {
+        if (IsNotKnown(node))
+        {
+            var unknowableSerializer = UnknowableSerializer.Create(node.Type);
+            AddKnownSerializer(node, unknowableSerializer);
+        }
+    }
+
     private bool IsItemSerializerKnown(Expression node, out IBsonSerializer itemSerializer)
     {
         if (IsKnown(node, out var serializer) &&

src/MongoDB.Driver/Linq/Linq3Implementation/KnownSerializerFinders/KnownSerializerFinderVisitBinary.cs

@@ -42,14 +42,11 @@ protected override Expression VisitBinary(BinaryExpression node)
         if (IsSymmetricalBinaryOperator(@operator) &&
             CanDeduceSerializer(leftExpression, rightExpression, out var unknownNode, out var knownSerializer))
         {
-            var isNull = unknownNode is ConstantExpression { Value: null };
-            if (!isNull && unknownNode.Type != knownSerializer.ValueType)
+            // expr1 op expr2 => expr1: expr2Serializer or expr2: expr1Serializer
+            if (knownSerializer.ValueType == unknownNode.Type)
             {
-                throw new ExpressionNotSupportedException(node, because: "operand types are not compatible with each other");
+                AddKnownSerializer(unknownNode, knownSerializer);
             }
-
-            // expr1 op expr2 => expr1: expr2Serializer or expr2: expr1Serializer
-            AddKnownSerializer(unknownNode, knownSerializer);
         }
 
         if (@operator == ExpressionType.ArrayIndex)

src/MongoDB.Driver/Linq/Linq3Implementation/KnownSerializerFinders/KnownSerializerFinderVisitMethodCall.cs

@@ -654,25 +654,11 @@ protected override Expression VisitMethodCall(MethodCallExpression node)
         var arguments = node.Arguments;
 
         DeduceMethodCallSerializers();
-        try
+        if (IsKnown(node, out var knownSerializer) && knownSerializer is IUnknowableSerializer)
         {
-            base.VisitMethodCall(node);
-        }
-        catch
-        {
-            if (node.Method.Is(QueryableMethod.Select) && (_translationOptions.EnableClientSideProjections ?? false))
-            {
-                var sourceExpression = arguments[0];
-                if (IsItemSerializerKnown(sourceExpression, out var sourceItemSerializer))
-                {
-                    AddKnownSerializer(node, IgnoreSubtreeSerializer.Create(node.Type));
-                }
-            }
-            else
-            {
-                throw;
-            }
+            return node; // don't visit node any further
         }
+        base.VisitMethodCall(node);
         DeduceMethodCallSerializers();
 
         return node;
@@ -840,7 +826,8 @@ void DeduceMethodCallSerializers()
                     break;
 
                 default:
-                    throw new ExpressionNotSupportedException(node, because: $"method {method.Name} is not supported");
+                    DeduceUnknowableSerializer(node);
+                    break;
             }
         }
 
@@ -2187,8 +2174,10 @@ void DeduceReturnsOneSourceItemSerializer()
 
             if (IsNotKnown(node) && IsKnown(sourceExpression, out var sourceSerializer))
             {
-                var sourceItemSerializer = ArraySerializerHelper.GetItemSerializer(sourceSerializer);
-                AddKnownSerializer(node, sourceItemSerializer);
+                var nodeSerializer = sourceSerializer is IUnknowableSerializer ?
+                    UnknowableSerializer.Create(node.Type) :
+                    ArraySerializerHelper.GetItemSerializer(sourceSerializer);
+                AddKnownSerializer(node, nodeSerializer);
             }
         }
 

src/MongoDB.Driver/Linq/Linq3Implementation/KnownSerializerFinders/KnownSerializerFinderVisitUnary.cs

@@ -192,11 +192,11 @@ static IBsonSerializer GetConvertEnumToEnumSerializer(UnaryExpression expression
                     throw new ExpressionNotSupportedException(expression, because: "target type is not an enum");
                 }
 
-                if (sourceSerializer is IHasRepresentationSerializer sourceHasRepresentationSerializer &&
-                    !SerializationHelper.IsNumericRepresentation(sourceHasRepresentationSerializer.Representation))
-                {
-                    throw new ExpressionNotSupportedException(expression, because: "source enum is not represented as a number");
-                }
+                // if (sourceSerializer is IHasRepresentationSerializer sourceHasRepresentationSerializer &&
+                //     !SerializationHelper.IsNumericRepresentation(sourceHasRepresentationSerializer.Representation))
+                // {
+                //     throw new ExpressionNotSupportedException(expression, because: "source enum is not represented as a number");
+                // }
 
                 return EnumSerializer.Create(targetType);
             }
@@ -214,17 +214,17 @@ static IBsonSerializer GetConvertFromNullableTypeSerializer(UnaryExpression expr
                     throw new ExpressionNotSupportedException(expression, because: $"sourceSerializer type {sourceSerializer.GetType()} does not implement nameof(INullableSerializer)");
                 }
 
-                var valueSerializer = nullableSourceSerializer.ValueSerializer;
+                var sourceValueSerializer = nullableSourceSerializer.ValueSerializer;
+                var sourceValueType = sourceValueSerializer.ValueType;
+
                 if (targetType.IsNullable(out var targetValueType))
                 {
-                    var sourceValueSerializer = nullableSourceSerializer.ValueSerializer;
-                    var sourceValueType = sourceValueSerializer.ValueType;
                     var targetValueSerializer = GetTargetSerializer(expression, sourceValueType, targetValueType, sourceValueSerializer);
                     return NullableSerializer.Create(targetValueSerializer);
                 }
                 else
                 {
-                    return valueSerializer;
+                    return GetTargetSerializer(expression, sourceValueType, targetType, sourceValueSerializer);
                 }
             }
 

src/MongoDB.Driver/Linq/Linq3Implementation/KnownSerializerFinders/KnownSerializerFinderVisitor.cs

@@ -41,9 +41,12 @@ public KnownSerializerFinderVisitor(ExpressionTranslationOptions translationOpti
 
     public override Expression Visit(Expression node)
     {
-        if (IsKnown(node, out var knownSerializer) && knownSerializer is IIgnoreSubtreeSerializer)
+        if (IsKnown(node, out var knownSerializer))
         {
-            return node; // don't visit subtree
+            if (knownSerializer is IIgnoreSubtreeSerializer or IUnknowableSerializer)
+            {
+                return node; // don't visit subtree
+            }
         }
 
         return base.Visit(node);

src/MongoDB.Driver/Linq/Linq3Implementation/KnownSerializerFinders/UnknownSerializerFinder.cs

@@ -41,9 +41,12 @@ public UnknownSerializerFinder(KnownSerializerMap knownSerializers)
 
     public override Expression Visit(Expression node)
     {
-        if (_knownSerializers.IsKnown(node, out var knownSerializer) && knownSerializer is IIgnoreSubtreeSerializer)
+        if (_knownSerializers.IsKnown(node, out var knownSerializer))
         {
-            return node; // don't visit subtree
+            if (knownSerializer is IIgnoreSubtreeSerializer or IUnknowableSerializer)
+            {
+                return node; // don't visit subtree
+            }
         }
 
         base.Visit(node);

src/MongoDB.Driver/Linq/Linq3Implementation/Serializers/NumericConversionSerializer.cs

@@ -69,6 +69,12 @@ private object Convert(Type from, Type to, object value)
         {
             (TypeCode.Decimal, TypeCode.Double) => (object)(double)(decimal)value,
             (TypeCode.Double, TypeCode.Decimal) => (object)(decimal)(double)value,
+            (TypeCode.Int16, TypeCode.Int32) => (object)(int)(short)value,
+            (TypeCode.Int16, TypeCode.Int64) => (object)(long)(short)value,
+            (TypeCode.Int32, TypeCode.Int16) => (object)(short)(int)value,
+            (TypeCode.Int32, TypeCode.Int64) => (object)(long)(int)value,
+            (TypeCode.Int64, TypeCode.Int16) => (object)(short)(long)value,
+            (TypeCode.Int64, TypeCode.Int32) => (object)(int)(long)value,
             _ => throw new NotSupportedException($"Cannot convert {from} to {to}"),
         };
     }

src/MongoDB.Driver/Linq/Linq3Implementation/Serializers/UnknowableSerializer.cs

@@ -0,0 +1,37 @@
+/* Copyright 2010-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 MongoDB.Bson.Serialization;
+using MongoDB.Bson.Serialization.Serializers;
+
+namespace MongoDB.Driver.Linq.Linq3Implementation.Serializers;
+
+internal static class UnknowableSerializer
+{
+    public static IBsonSerializer Create(Type valueType)
+    {
+        var serializerType = typeof(UnknowableSerializer<>).MakeGenericType(valueType);
+        return (IBsonSerializer)Activator.CreateInstance(serializerType);
+    }
+}
+
+internal interface IUnknowableSerializer
+{
+}
+
+internal class UnknowableSerializer<TValue> : SerializerBase<TValue>, IUnknowableSerializer
+{
+}

src/MongoDB.Driver/Linq/Linq3Implementation/Translators/ExpressionToAggregationExpressionTranslators/MemberInitExpressionWithKnownSerializerToAggregationExpressionTranslator.cs

@@ -46,7 +46,7 @@ public static TranslatedExpression TranslateWithKnownSerializer(
                     var argumentTranslation = ExpressionToAggregationExpressionTranslator.Translate(context, argument);
                     var matchingMemberSerializationInfo = matchingMemberSerializationInfos[i];
 
-                    if (!argumentTranslation.Serializer.Equals(matchingMemberSerializationInfo.Serializer))
+                    if (!argumentTranslation.Serializer.CanBeAssignedTo(matchingMemberSerializationInfo.Serializer))
                     {
                         throw new ExpressionNotSupportedException(argument, expression, because: "argument serializer is not equal to member serializer");
                     }