Function cached_create_module

include/pybind11/pybind11.h:1535–1551

A Py_mod_create slot function which will return the previously created module from the cache if one exists, and otherwise will create a new module object. */

exists, and otherwise will create a new module object.
*/
inline PyObject *cached_create_module(PyObject *spec, PyModuleDef *) {
    (void) &cache_completed_module; // silence unused-function warnings, it is used in a macro

    auto nameobj = getattr(reinterpret_borrow<object>(spec), "name", none());
    if (nameobj.is_none()) {
        set_error(PyExc_ImportError, "module spec is missing a name");
        return nullptr;
    }

    auto *mod = get_cached_module(nameobj);
    if (mod) {
        Py_INCREF(mod);
    } else {
        mod = PyModule_NewObject(nameobj.ptr());
    }
    return mod;
}

/// Must be a POD type, and must hold enough entries for all of the possible slots PLUS ONE for
/// the sentinel (0) end slot.