Attempting to use _input will crash Godot

[lilizoey]

Attempting to use _input will crash Godot, because we attempt to construct a Gd<InputEvent> directly from the pointer Godot sends us in the virtual call. However the pointer Godot sends us is actually a Ref<InputEvent>, which needs to be dereferenced using ref_get_object first.

A function defined on Gd like this does that properly

pub unsafe fn from_ref_sys(ptr: sys::GDExtensionConstRefPtr) -> Self {
    let object_ptr = interface_fn!(ref_get_object)(ptr);
    Self::from_obj_sys(object_ptr)
}

My guess is that this is true for all objects inheriting from RefCounted in virtual methods. But it doesn't seem like there's a simple way to check this beyond just manually going through every virtual method and checking. The extension_api.json doesn't say anything.

There isn't a simple hotfix for this beyond just expanding the macros and manually replacing the relevant call for _input. However doing so does fix the issue.

[Bromeon]

Thanks! Do you know where that sys::GDExtensionConstRefPtr comes from?

The only place where this type appears in the FFI header is ref_get_object itself:

gdext/godot-codegen/input/gdextension_interface.h

Line 582 in cccf247

GDExtensionObjectPtr (*ref_get_object)(GDExtensionConstRefPtr p_ref);

[lilizoey]

Here:

gdext/godot-codegen/input/gdextension_interface.h

Line 157 in cccf247

typedef const struct TagExtensionRef *GDExtensionConstRefPtr;

[Bromeon]

Sorry, I meant not the type but the pointer value. You suggested Gd::from_ref_sys() -- but we don't have a pointer of type sys::GDExtensionConstRefPtr anywhere around, and there's no FFI function that returns one.

So I guess we would need to transmute a pointer from a different type (sys::GDExtensionTypePtr)...

[lilizoey]

yeah, just like how we currently just cast a pointer to ObjectPtr in the virtual method calls.

[lilizoey]

Actually it seems like we need to do this for all object pointers