Get Python type name from C++ type?

[Jannik2099]

Hi

I am trying to look up the Python type that correlates to a C++ type, without having an instance of the C++ type at hand.

So far I have gotten to (simplified)

#include <string>
#include <iostream>
#include <typeindex>
#include <pybind11/pybind11.h>
#include <pybind11/detail/internals.h>

namespace py = pybind11;

template<typename T>
void lookup_type_name() {
const auto mapiter = py::detail::get_internals().registered_types_cpp.find(std::type_index(typeid(T)));
const py::detail::type_info *mapped_type = mapiter->second;
const std::string pyname = mapped_type->type->tp_name;
std::cout << "python type is " << pyname << std::endl;
}

This works fine for simple registered types, but e.g. for a std::variant<T1, T2> (where T1 and T2 have been registered, ofc) it yields Union[%, %]

How does pybind resolve these "nested type names" for the docstrings? Is it part of the public API?