[issue42979] _zoneinfo: zoneinfomodule_exec() doesn't check for PyDateTime_IMPORT failure

[STINNER Victor]

New submission from STINNER Victor <vstinner at python.org>:

_zoneinfo starts with:

static int
zoneinfomodule_exec(PyObject *m)
{
    PyDateTime_IMPORT;

with:

#define PyDateTime_CAPSULE_NAME "datetime.datetime_CAPI"
#define PyDateTime_IMPORT \
    PyDateTimeAPI = (PyDateTime_CAPI *)PyCapsule_Import(PyDateTime_CAPSULE_NAME, 0)

If PyCapsule_Import() fails, zoneinfomodule_exec() returns 0 (success) with an exception raised.

It should check if the import succeeded or not. Concrete example on AIX where datetime cannot be imported:
https://bugs.python.org/issue42604#msg385347

"./python setup.py build" fails with:

Assertion failed: (item != NULL) ^ (PyErr_Occurred() != NULL), file  Objects/abstract.c, line 163

--

By the way, the import machinery should raise a SystemError if a module exec function raises an exception *and* reports a success: see _Py_CheckFunctionResult().

----------
components: Extension Modules
messages: 385355
nosy: vstinner
priority: normal
severity: normal
status: open
title: _zoneinfo: zoneinfomodule_exec() doesn't check for PyDateTime_IMPORT failure
versions: Python 3.10

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue42979>
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