Fix for smart pointers being loaded through the main load point with a default JSON object.

Code/Framework/AzCore/AzCore/Serialization/Json/BaseJsonSerializer.cpp

@@ -208,6 +208,11 @@ namespace AZ
     // BaseJsonSerializer
     //
 
+    BaseJsonSerializer::OperationFlags BaseJsonSerializer::GetOperationsFlags() const
+    {
+        return OperationFlags::None;
+    }
+
     JsonSerializationResult::ResultCode BaseJsonSerializer::ContinueLoading(void* object, const Uuid& typeId, const rapidjson::Value& value,
         JsonDeserializerContext& context, Flags flags)
     {

Code/Framework/AzCore/AzCore/Serialization/Json/BaseJsonSerializer.h

@@ -163,11 +163,17 @@ namespace AZ
         
         enum Flags
         {
-            None = 0, //! No extra flags.
+            None = 0,                //! No extra flags.
             ResolvePointer = 1 << 0, //! The pointer passed in contains a pointer. The (de)serializer will attempt to resolve to an instance.
             ReplaceDefault = 1 << 1  //! The default value provided for storing will be replaced with a newly created one.
         };
 
+        enum class OperationFlags
+        {
+            None = 0,               //! No flags that control how the custom json serializer is used.
+            ManualDefault = 1 << 0  //! Even if an (explicit) default is found the custom json serializer will still be called.
+        };
+
         virtual ~BaseJsonSerializer() = default;
 
         //! Transforms the data from the rapidjson Value to outputValue, if the conversion is possible and supported.
@@ -180,6 +186,9 @@ namespace AZ
         virtual JsonSerializationResult::Result Store(rapidjson::Value& outputValue, const void* inputValue, const void* defaultValue,
             const Uuid& valueTypeId, JsonSerializerContext& context) = 0;
 
+        //! Returns the operation flags which tells the Json Serialization how this custom json serializer can be used.
+        virtual OperationFlags GetOperationsFlags() const;
+
     protected:
         //! Continues loading of a (sub)value. Use this function to load member variables for instance. This is more optimal than 
         //! directly calling the json serialization.
@@ -239,5 +248,6 @@ namespace AZ
     };
 
     AZ_DEFINE_ENUM_BITWISE_OPERATORS(AZ::BaseJsonSerializer::Flags)
+    AZ_DEFINE_ENUM_BITWISE_OPERATORS(AZ::BaseJsonSerializer::OperationFlags)
 
 } // namespace AZ

Code/Framework/AzCore/AzCore/Serialization/Json/JsonDeserializer.cpp

@@ -33,17 +33,17 @@ namespace AZ
                 "Target object for Json Serialization is pointing to nothing during loading.");
         }
 
-        if (IsExplicitDefault(value))
-        {
-            return context.Report(Tasks::ReadField, Outcomes::DefaultsUsed, "Value has an explicit default.");
-        }
-
         BaseJsonSerializer* serializer = context.GetRegistrationContext()->GetSerializerForType(typeId);
         if (serializer)
         {
-            return serializer->Load(object, typeId, value, context);
+            bool isExplicitDefault = IsExplicitDefault(value);
+            bool manuallyDefaults = (serializer->GetOperationsFlags() & BaseJsonSerializer::OperationFlags::ManualDefault) ==
+                BaseJsonSerializer::OperationFlags::ManualDefault;
+            return !isExplicitDefault || (isExplicitDefault && manuallyDefaults)
+                ? serializer->Load(object, typeId, value, context)
+                : context.Report(Tasks::ReadField, Outcomes::DefaultsUsed, "Value has an explicit default.");
         }
-        
+
         const SerializeContext::ClassData* classData = context.GetSerializeContext()->FindClassData(typeId);
         if (!classData)
         {
@@ -56,9 +56,19 @@ namespace AZ
             serializer = context.GetRegistrationContext()->GetSerializerForType(classData->m_azRtti->GetGenericTypeId());
             if (serializer)
             {
-                return serializer->Load(object, typeId, value, context);
+                bool isExplicitDefault = IsExplicitDefault(value);
+                bool manuallyDefaults = (serializer->GetOperationsFlags() & BaseJsonSerializer::OperationFlags::ManualDefault) ==
+                    BaseJsonSerializer::OperationFlags::ManualDefault;
+                return !isExplicitDefault || (isExplicitDefault && manuallyDefaults)
+                    ? serializer->Load(object, typeId, value, context)
+                    : context.Report(Tasks::ReadField, Outcomes::DefaultsUsed, "Value has an explicit default.");
             }
         }
+
+        if (IsExplicitDefault(value))
+        {
+            return context.Report(Tasks::ReadField, Outcomes::DefaultsUsed, "Value has an explicit default.");
+        }
         
         if (classData->m_azRtti && (classData->m_azRtti->GetTypeTraits() & AZ::TypeTraits::is_enum) == AZ::TypeTraits::is_enum)
         {

Code/Framework/AzCore/AzCore/Serialization/Json/SmartPointerSerializer.cpp

@@ -159,4 +159,9 @@ namespace AZ
         return context.Report(result, result.GetProcessing() != JSR::Processing::Halted ?
             "Successfully processed smart pointer." : "A problem occurred while processing a smart pointer.");
     }
+
+    BaseJsonSerializer::OperationFlags JsonSmartPointerSerializer::GetOperationsFlags() const
+    {
+        return OperationFlags::ManualDefault;
+    }
 } // namespace AZ

Code/Framework/AzCore/AzCore/Serialization/Json/SmartPointerSerializer.h

@@ -28,5 +28,7 @@ namespace AZ
             JsonDeserializerContext& context) override;
         JsonSerializationResult::Result Store(rapidjson::Value& outputValue, const void* inputValue, const void* defaultValue,
             const Uuid& valueTypeId, JsonSerializerContext& context) override;
+
+        OperationFlags GetOperationsFlags() const override;
     };
 } // namespace AZ