Pybind11: pybind::vector doesnt compile with VS 15.9.x

[vdolbakyan]

Issue description

Simple pybind::vector usage doesn't compile with VS 15.9.x
PYBIND11_MAKE_OPAQUE(std::vector);
...
py::bind_vector(m, "BoolList");

stl_bind.h(386): error C2672: 'pybind11::detail::vector_buffer': no matching overloaded function found
core_submodule.cpp(19): note: see reference to function template instantiation 'pybind11::class_>,std::unique_ptr>>>> pybind11::bind_vector>,std::unique_ptr>>>,>(pybind11::handle,const std::string &)' being compiled
with
[
_Ty=bool,
Vector=std::vector>
]
include\pybind11\stl_bind.h(374): error C2893: Failed to specialize function template 'enable_if<_Test,_Ty>::type pybind11::detail::vector_buffer(Class_ &)'
with
[
_Ty=void
]
\include\pybind11\stl_bind.h(374): note: With the following template arguments:
\include\pybind11\stl_bind.h(374): note: 'Vector=Vector'
\include\pybind11\stl_bind.h(374): note: 'Class_=Class_'
\include\pybind11\stl_bind.h(374): note: 'Args={}'

Reproducible example code

PYBIND11_MAKE_OPAQUE(std::vector);

...
py::bind_vector>(m, "BoolList");

(The code should be minimal, have no external dependencies, isolate the function(s) that cause breakage. Submit matched and complete C++ and Python snippets that can be easily compiled and run to diagnose the issue.)

[petersteneteg]

I ran into the same issue,

For some unknown reason VS refuses to find this definition, even though there are now "buffer_protocol" tag types in the args list. If one does use "buffer_protocol" it works...

https://github.com/pybind/pybind11/blob/e2b884c33bcde70b2ea562ffa52dd7ebee276d50/include/pybind11/stl_bind.h#L365-L366

also just using

    if constexpr(detail::any_of<std::is_same<Args, buffer_protocol>...>::value) {
        detail::vector_buffer<Vector, Class_, Args...>(cl);
    }

instead of
https://github.com/pybind/pybind11/blob/e2b884c33bcde70b2ea562ffa52dd7ebee276d50/include/pybind11/stl_bind.h#L386

also works fine...

[petersteneteg]

Also just switching to

template <typename Vector, typename Class_, typename... Args>
typename std::enable_if<!detail::any_of<std::is_same<Args, buffer_protocol>...>::value>::type vector_buffer(Class_&) {}

makes it compile again :(

[petersteneteg]

just adding an extra doc string also makes it compile for me:

py::bind_vector<std::vector<bool>>(m, "BoolList", "doc string");

Love when the compiler is so stable and predictable ;)

[bstaletic]

The following works:

  py::bind_vector< std::vector< std::string > >( mod, "StringVector" );

Are you 100% sure passing std::vector instead of std::vector< somthing > is correct?

[petersteneteg]

Humm In my cast the "Something" was a glm vec type... and yes I use std::vector< somthing >, the other one with just std::vector, must be wrong in this context.

But no I think there might be an other issue at play here, std::vector is a special vector type... that might not play so nicely with pybind11...

[bstaletic]

I'm using quite a bit of std::vectors from python and it all works just fine once the "something" has appropriate binding. This issue, to me, really looks like a user error.

[vdolbakyan]

Are you using VS 15.9.2 or newer?

py::bind_vector>(m, "somelist", "description"); WORKS
py::bind_vector>(m, "somelist"); DOESNT WORK

[bstaletic]

Well, the Appveyor is running some version of MSVC 2017, but it looks like it is running 14.15.26726.

[petersteneteg]

Are you using VS 15.9.2 or newer?

py::bind_vector>(m, "somelist", "description"); WORKS
py::bind_vector>(m, "somelist"); DOESNT WORK

I have the exact same behaviour,
Im running VS 15.9.3.

Did use to work before, must be some kind of compiler regression...

[YannickJadoul]

Can't reproduce with VS 2017, MSVC 19.16.27041.0, Microsoft (R) Build Engine version 15.9.21+g9802d43bc3, for pybind11 2.5.0, and this code:

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

namespace py = pybind11;

PYBIND11_MAKE_OPAQUE(std::vector<std::string>);
PYBIND11_MAKE_OPAQUE(std::vector<bool>);

PYBIND11_MODULE(example, m) {
    py::bind_vector<std::vector<std::string>>(m, "StringVector");
    py::bind_vector<std::vector<bool>>(m, "BoolVector");
}

Maybe something got fixed? @vdolbakyan @petersteneteg Is this still an issue? If so, would you mind providing a complete minimal example, such that I can investigate? Please reopen if so.

[bstaletic]

With C++17 (/std:c++17), to get MSVC to behave, you need /permissive-. You should probably be compiling with that flag all the time, as it makes MSVC more strictly conforming.

EDIT: References: https://github.com/pybind/pybind11/issues/2089 and https://github.com/pybind/pybind11/pull/2292