[BUG]: Binding two maps with two different integer key types failues due to duplicate KeyViews

[gatecat]

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What version (or hash if on master) of pybind11 are you using?

3cc7e42

Problem description

The attached example code binds two map types: std::map<uint16_t, uint16_t> and std::map<uint32_t, uint16_t>.

With recent pybind11 this fails when importing with:

ImportError: generic_type: cannot initialize type "KeysView[int]": an object with that name is already defined

Looking at the relevant code:

pybind11/include/pybind11/stl_bind.h

Line 733 in 3cc7e42

if (!detail::get_type_info(typeid(KeysView))) {

checks whether a matching key typeid has been wrapped already; but in this case two different typeids have the same string name in pybind11.

This is breaking a project that happens to use this; if there's a workaround other than unifying the map key types that fixes things with recent pybind11 releases that would also be useful to know.

Thanks for your help!

Reproducible example code

#include <pybind11/pybind11.h>
#include <pybind11/stl_bind.h>
#include <map>

namespace py = pybind11;

PYBIND11_MODULE(python_example, m) {
    py::bind_map<std::map<uint16_t, uint16_t>>(m, "u16u16map");
    py::bind_map<std::map<uint32_t, uint16_t>>(m, "u32u16map");
}

Is this a regression? Put the last known working version here if it is.

Believe this was broken by 9db9880. 2.10.0 was known working.

[lyskov]

The same issue also appear if one attempts to bind both map to float and double. Minimal code to replicate:

#include <map>
#include <pybind11/pybind11.h>
#include <pybind11/stl_bind.h>

PYBIND11_MODULE(example, m)
{
	// leads to ImportError: generic_type: cannot initialize type "ValuesView[float]": an object with that name is already defined
	pybind11::bind_map< std::map<std::string,float> >(m, "map_string_float" );
	pybind11::bind_map< std::map<std::string,double> >(m, "map_string_double" );
}

[mika-fischer]

I think this was broken by 9db9880 first released in v2.10.2, from #4353

[mika-fischer]

And needless to say this also breaks our build, so this is a real issue.

Interrestingly we also run into this:

ImportError: generic_type: cannot initialize type "ArrayInt2": an object with that name is already defined

ArrayInt2 is a binding for std::array<int, 2>. Not entirely sure if it's the same issue, but it also appears with 2.10.2...

Everything works fine in 2.10.1.

[Tobias-Fischer]

Are there any updates on this? It also breaks a few of my projects, see https://github.com/conda-forge/pycolmap-feedstock/issues