New warning: `conversion from 'Py_ssize_t' to 'int', possible loss of data` in `Modules/_testcapimodule.c`

[sobolevn]

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

[ambv]

I think the fix is to replace the Py_ssize_t variables in the test function to ints as this is indeed what PyEval_EvalCodeEx expects.

[sobolevn]

@ambv can we do that? Because, for example, c_defaults_len uses this code:

cpython/Modules/_testcapimodule.c

Lines 3165 to 3170 in f87f6e2

	Py_ssize_t c_defaults_len = 0;
	if (defaults && PyTuple_Check(defaults)) {
	c_defaults = &PyTuple_GET_ITEM(defaults, 0);
	c_defaults_len = PyTuple_Size(defaults);
	}

And PyTuple_Size returns Py_ssize_t 🤔

[sobolevn]

Either way, we need to convert Py_ssize_t to int at some point. I propose to do it later on :)

[ambv]

OK, that makes sense to me, too. Let's go!