STJ: Fix dynamic dispatch in deserialization

riganti · Apr 26, 2024 · e469e00 · e469e00
1 parent 63d8471
commit e469e00
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Showing 2 changed files with 32 additions and 8 deletions.
diff --git a/src/Framework/Framework/ViewModel/Serialization/ViewModelSerializationMap.cs b/src/Framework/Framework/ViewModel/Serialization/ViewModelSerializationMap.cs
@@ -813,27 +813,28 @@ private static void SerializeValue<TValue>(Utf8JsonWriter writer, JsonSerializer
         }
 
         public static readonly MethodInfo DeserializeViewModelDynamicMethod = typeof(JsonSerializationCodegenFragments).GetMethod(nameof(DeserializeViewModelDynamic), BindingFlags.NonPublic | BindingFlags.Static).NotNull();
-        private static TVM? DeserializeViewModelDynamic<TVM>(ref Utf8JsonReader reader, JsonSerializerOptions options, TVM? existingValue, bool populate, ViewModelJsonConverter factory, ViewModelJsonConverter.VMConverter<TVM>? defaultConverter, DotvvmSerializationState state)
+        private static TVM? DeserializeViewModelDynamic<TVM>(ref Utf8JsonReader reader, JsonSerializerOptions options, TVM? existingValue, bool populate, ViewModelJsonConverter factory, ViewModelJsonConverter.VMConverter<TVM> defaultConverter, DotvvmSerializationState state)
             where TVM: class
         {
             if (reader.TokenType == JsonTokenType.Null)
                 return default;
 
-            if (existingValue is null && defaultConverter is null)
+            if (existingValue is null)
             {
-                throw new Exception($"Cannot deserialize {typeof(TVM).ToCode()} dynamically, originalValue is null and type is abstract.");
+                return defaultConverter.Read(ref reader, typeof(TVM), options, state);
             }
 
-            if (defaultConverter is {} && (existingValue is null || existingValue.GetType() == typeof(TVM)))
+            var realType = existingValue?.GetType() ?? typeof(TVM);
+            if (defaultConverter is {} && realType == typeof(TVM))
             {
                 return populate && existingValue is {}
                         ? defaultConverter.Populate(ref reader, options, existingValue, state)
                         : defaultConverter.Read(ref reader, typeof(TVM), options, state);
             }
 
-            var converter = factory.GetConverterCached(typeof(TVM));
-            return populate ? (TVM?)converter.PopulateUntyped(ref reader, typeof(TVM), existingValue, options, state)
-                            : (TVM?)converter.ReadUntyped(ref reader, typeof(TVM), options, state);
+            var converter = factory.GetConverterCached(realType);
+            return populate ? (TVM?)converter.PopulateUntyped(ref reader, realType, existingValue, options, state)
+                            : (TVM?)converter.ReadUntyped(ref reader, realType, options, state);
         }
 
         public static readonly MethodInfo ReadEncryptedValueMethod = typeof(JsonSerializationCodegenFragments).GetMethod(nameof(ReadEncryptedValue), BindingFlags.NonPublic | BindingFlags.Static).NotNull();

diff --git a/src/Tests/ViewModel/SerializerTests.cs b/src/Tests/ViewModel/SerializerTests.cs
@@ -690,6 +690,29 @@ public void InterfaceSerialization_Static()
             XAssert.Equal(obj.Property2, obj2.Value.Property2);
         }
 
+        [TestMethod]
+        public void InterfaceSerialization_Dynamic()
+        {
+            var obj = new VMWithInterface() {
+                Property1 = "x",
+                Property2 = "y",
+                Property3 = "z"
+            };
+            var jsonStr = Serialize(new DefaultDispatchVMContainer<IVMInterface1> { Value = obj }, out var _, false);
+            Console.WriteLine(jsonStr);
+            var json = JsonNode.Parse(jsonStr).AsObject()["Value"].AsObject();
+            XAssert.Equal("x", (string)json["Property1"]);
+            XAssert.Equal("y", (string)json["Property2"]);
+            XAssert.Equal("z", (string)json["Property3"]);
+
+            var obj2 = new DefaultDispatchVMContainer<IVMInterface1> { Value = new VMWithInterface() };
+            var obj2Populated = PopulateViewModel(jsonStr, obj2);
+            Assert.AreSame(obj2, obj2Populated);
+            XAssert.Equal(obj.Property1, obj2.Value.Property1);
+            XAssert.Equal(obj.Property2, obj2.Value.Property2);
+            XAssert.Equal(obj.Property3, ((VMWithInterface)obj2.Value).Property3);
+        }
+
         class VMWithInterface: IVMInterface1
         {
             public string Property1 { get; set; }
@@ -935,7 +958,7 @@ class StaticDispatchVMContainer<TStatic>
 
     class DefaultDispatchVMContainer<TStatic>
     {
-        [Bind(AllowDynamicDispatch = false)]
+        [Bind(Name = "Value")] // make sure that the attribute presence does not affect the default behavior
         public TStatic Value { get; set; }
     }
 }