Pass std::string as read_write to python

[luis605]

Hi there!

I am facing an issue while working on a project that involves passing an std::string attribute from a C++ class to Python using pybind11. Specifically, I am attempting to use def_readwrite to create a Python wrapper for this attribute with read-write access.

Here is a snippet of my code:

class Entity {
public:
    string name = "Entity";
    
    // Some code....
            py::module entity_module("entity_module");
            py::class_<Entity>(entity_module, "Entity")
                .def(py::init<>())
                .def_readwrite("name", &Entity::name, py::call_guard<py::gil_scoped_release>())
                // Etc...
                
        py::object entity_obj = py::cast(&this_entity);

        thread_local py::dict locals = py::dict(
            "entity"_a = entity_obj,

The name attribute is of type std::string, and I intend to make it accessible in Python with read-write capabilities. However, I am encountering an error message: "SystemError: Negative size passed to PyUnicode_New." when I try to print the entity.name, print(entity.name)

Is it normal, how do I fix it?

I searched lots of pages including this one https://pybind11.readthedocs.io/en/stable/advanced/cast/strings.html but I couldn't find an answer to my problem.

Thank you in advance!