TypeError: Unregistered type : std::vector<X> when trying to cast std::vector<X> to py::list

[naquad]

Hello,

I'm trying to return a vector of items, here's the code:

#include <pybind11/pybind11.h>
#include <pybind11/numpy.h>
#include <vector>
#include <format>

namespace bt {
    using namespace std;

    struct item {
        ssize_t entry;
        double value;

        item(const item&) = default;

        item(ssize_t _entry = -1, double _value = NAN):
            entry(_entry), value(_value)
        {}
    };

    vector<item> run(size_t len, const double *data) {
        vector<item> items;
        items.reserve(len);

        for (size_t i = 0; i < len; ++i) {
            items.emplace_back(i, data[i]);
        }

        return items;
    }
};

namespace py = pybind11;

py::list run(const py::array_t<double, py::array::c_style | py::array::forcecast> data) {
    if (data.ndim() != 1) {
        throw std::invalid_argument("Input must be 1-D array");
    }

    return py::cast(bt::run(data.size(), data.data()));
}

PYBIND11_MODULE(bt, m) {
    m.doc() = "pybind11 demo plugin";

    py::class_<bt::item>(m, "item")
        .def(
            py::init<ssize_t, double>(),
            py::arg("entry") = -1, py::arg("value") = NAN,
            "constructor with entry and value"
        )
        .def("__repr__", [](const bt::item& self) {
            return std::format(
                "<bt.item entry={}, value={}>",
                self.entry,
                self.value
            );
        })
        .def_readonly("entry", &bt::item::entry)
        .def_readonly("value", &bt::item::value);

    m.def("run", &run, py::arg("data"), "map elements to items");
}

It compiles but fails in the runtime:

Traceback (most recent call last):
  File "/home/naquad/projects/tests/pybinds/test.py", line 8, in <module>
    print(bt.run(data))
          ^^^^^^^^^^^^
TypeError: Unregistered type : std::vector<bt::item, std::allocator<bt::item> >

The error can be fixed if I do py::bind_vector<std::vector<bt::item>>(m, "ItemVector") but then I'm getting a useless class that I would like not to export. I'm somewhat confused as the docs state that std::vector conversion is supported and I assume that pybind is aware of my class after I've registered it.

What am I doing wrong and how do I fix this?

Thank you.

[naquad]

Ah, what a silly mistake. Adding:

#include <pybind11/stl.h>

Has solved the error.