mypyc/lib-rt/module_shim.tmpl

#include <Python.h>

PyMODINIT_FUNC
PyInit_{modname}(void)
{{
    PyObject *tmp;
    // Use ImportModuleLevel with a non-empty fromlist so Python returns the
    // leaf submodule via sys.modules lookup, avoiding the top-down getattr
    // walk done by PyImport_ImportModule. That walk fails when the shim runs
    // during a parent package's __init__.py, because the parent's submodule
    // attribute isn't set until after __init__ returns.
    static PyObject *fromlist = NULL;
    if (!fromlist) {{
        fromlist = Py_BuildValue("(s)", "*");
        if (!fromlist) return NULL;
    }}
    tmp = PyImport_ImportModuleLevel("{libname}", NULL, NULL, fromlist, 0);
    if (!tmp) return NULL;
    // Populate cross-group export tables lazily, just before we instantiate
    // the per-module real init. Deferring this out of the shared lib's own
    // PyInit keeps separate-mode compiled modules from recursively triggering
    // sibling-package __init__.py mid-bootstrap.
    // PyObject_GetOptionalAttrString would be cleaner, but it's 3.13+ and the
    // shim deliberately #includes only <Python.h>, so we can't pull in the
    // pythoncapi_compat.h shim from lib-rt here. AttributeError + PyErr_Clear
    // is the portable form.
    PyObject *deps_capsule = PyObject_GetAttrString(tmp, "ensure_deps");
    if (deps_capsule != NULL) {{
        int (*deps_func)(void) = (int (*)(void))PyCapsule_GetPointer(
            deps_capsule, "{libname}.ensure_deps");
        Py_DECREF(deps_capsule);
        if (deps_func == NULL) {{
            Py_DECREF(tmp);
            return NULL;
        }}
        if (deps_func() < 0) {{
            Py_DECREF(tmp);
            return NULL;
        }}
    }} else {{
        PyErr_Clear();
    }}
    PyObject *capsule = PyObject_GetAttrString(tmp, "init_{full_modname}");
    Py_DECREF(tmp);
    if (capsule == NULL) return NULL;
    void *init_func = PyCapsule_GetPointer(capsule, "{libname}.init_{full_modname}");
    Py_DECREF(capsule);
    if (!init_func) {{
        return NULL;
    }}
    return ((PyObject *(*)(void))init_func)();
}}

// distutils sometimes spuriously tells cl to export CPyInit___init__,
// so provide that so it chills out
PyMODINIT_FUNC PyInit___init__(void) {{ return PyInit_{modname}(); }}