Hello!

This is a follow-up of this issue: https://www.gamedev.net/forums/topic/712952-strange-behavior-when-registering-method-with-template-specialization-types/5450698/​

The thread was closed because I didn't have time to work on the issue since I had to pause my scripting environment implementation. I went back working at it and I tried to understand the internals to see where the problem arises.

Just to recap what happens is that if I try to register 2 methods that return a specialized template type:

registerMethod("RecipeStep", "Slice<item::Stack> input()", CALL_METHOD_ARGS(RecipeStep, input, (void), DataSlice<ItemStack>), "");
registerMethod("RecipeStep", "Slice<item::Stack> output()", CALL_METHOD_ARGS(RecipeStep, output, (void), DataSlice<ItemStack>), "");

I get an error “Slice is not a template type”.

I debugged the implementation inside as_scriptengine.cpp and this is what happens:

First registration

• asCBuilder::CreateDataTypeFromNode(asCScriptNode *node, asCScriptCode *file, asSNameSpace *implicitNamespace, bool acceptHandleForScope, asCObjectType *currentType, bool reportError, bool *isValid) for return type is called
• it loops through engine→GetParentNameSpace(ns) because RecipeStep is in data namespace
• on second iteration ti = GetType(str.AddressOf(), ns, parentType) assign correct value
• this branch is taken if( ti->flags & asOBJ_TEMPLATE ) and everything works fine

Second registration

• asCBuilder::CreateDataTypeFromNode(asCScriptNode *node, asCScriptCode *file, asSNameSpace *implicitNamespace, bool acceptHandleForScope, asCObjectType *currentType, bool reportError, bool *isValid) for return type is called again
• This time ti = GetTypeFromTypesKnownByObject(str.AddressOf(), currentType); returns a asCTypeInfo* at first iteration (with different address than the previous one)
• this branch is NOT taken ti->flags & asOBJ_TEMPLATE
• method fails with msg.Format(TXT_TYPE_s_NOT_TEMPLATE, ti->name.AddressOf());

I hope this can help you pinpoint the issue. Some additional details:

• Slice is registered in global namespace as sizeof(void*), asOBJ_VALUE | asOBJ_TEMPLATE
• Slice<item::Stack> is registered as sizeof(type_t), asOBJ_VALUE | asOBJ_POD | asGetTypeTraits<DataSlice<T>>()
• RecipeStep is registered in data namespace