Use of uninitialized pointer in Argument Clinic generated code

[serhiy-storchaka]

The code generated for the Py_UNICODE converter (and derived converter LPCWSTR) looks like:

const Py_UNICODE *name;
...
if (!_PyArg_ParseXXX(..., name, ...)) {
    goto exit;
}
...
exit:
    PyMem_Free((void *)name);

If parsing fails, PyMem_Free() is called for uninitialized variable.

It is the only converter with non-trivial cleanup which does not have a mandatory initializer.

[serhiy-storchaka]

Seems that for now it only affects the Windows code.

I have found this bug when tried to use Argument Clinic for OS agnostic code which converts arguments to wchar_t * (in getpath.c).

[eryksun]

These needs to be fixed if _winapi.CreateJunction() is used as a fallback for os.symlink() when creating a compatibility link such as "bin -> Scripts". More here: #97586 (comment).