This happens because:

• Py_ssize_t c_args_len = 0;
• But, PyEval_EvalCodeEx expects int:

   PyObject *
   PyEval_EvalCodeEx(PyObject *_co, PyObject *globals, PyObject *locals,
                  PyObject *const *args, int argcount,
                  PyObject *const *kws, int kwcount,
                  PyObject *const *defs, int defcount,
                  PyObject *kwdefs, PyObject *closure)

Looks like this is a side effect of ae62bdd

Possible solution is to use an explicit (int) converter.
I don't think that we should really worry about an overflow in the test code.
I will send a PR to check if this is a proper fix.

CC @ambv as the original PR reviewer.

Linked PRs

• gh-101656: Fix "conversion from Py_ssize_t to int" warning in _testcapimodule #101657
• [3.11] gh-101656: Fix "conversion from Py_ssize_t to int" warning in … #101680