Pybind11 breaks Panda3d. Please, help

maxxim · October 11, 2019, 3:42pm

Hello. I am trying to embed some Python code in C++ Panda engine. I am using pybind11.
There’s a name conflict:

panda3d/panda3d/blob/371e60c768cfd1a1383c5b05f1cab2078014ccea/dtool/src/dtoolbase/register_type.h#L221


}


template<>
INLINE TypeHandle _get_type_handle(const void * const *) {
  return void_p_type_handle;
}




// The macro get_type_handle(type) is defined to make getting the type handle
// associated with a particular type a bit cleaner.
#define get_type_handle(type) _get_type_handle((const type *)0)




// The following template function and its specializations can be used to call
// init() on any unknown type.  Handy for use within a template class.


template<class T>
INLINE void _do_init_type(const T *) {
  T::init_type();
}

get_type_handle confilcts with pybind’s funciton with the same name:

github.com

pybind/pybind11/blob/6ca312b3bcdccdd55321dcf7111a50cad37a6c99/include/pybind11/cast.h#L201


        return gtype;


    if (throw_if_missing) {
        std::string tname = tp.name();
        detail::clean_type_id(tname);
        pybind11_fail("pybind11::detail::get_type_info: unable to find type info for \"" + tname + "\"");
    }
    return nullptr;
}


PYBIND11_NOINLINE inline handle get_type_handle(const std::type_info &tp, bool throw_if_missing) {
    detail::type_info *type_info = get_type_info(tp, throw_if_missing);
    return handle(type_info ? ((PyObject *) type_info->type) : nullptr);
}


struct value_and_holder {
    instance *inst = nullptr;
    size_t index = 0u;
    const detail::type_info *type = nullptr;
    void **vh = nullptr;

So, if pybind’s header gets included after the register_type.h (and it’s eventually does, e.g. in “config_MODULE_NAME.cxx” files), everything breaks.

I am not a C++ expert, so I don’t know solutions other than using a different design and avoiding including these two headers in one file. Maybe there’s an obvious solution that I am missing?

maxxim · October 11, 2019, 7:41pm

OK, since it’s my own fork of Panda3d, I’ve just replaced the macro in the source code.

Another strange thing is that panda.core fails to build if I include pybind, it results in error:

"pybind11 requires MSVC 2015 update 3 or newer"

and it fails the following check:

#  if _MSC_FULL_VER < 190024210
#    error pybind11 requires MSVC 2015 update 3 or newer
#  endif

Though I am using MSVC 2019. It seems that the build system replaces the _MSC_FULL_VER somewhere during this step?