STINNER Victor <vstin...@python.org> added the comment:
tl; dr I wrote PR 19902 to remove the "XXX" comment. -- Commit 21893fbb74e8fde2931fbed9b511e2a41362b1ab adds the following code: /* XXX It seems like we shouldn't have to check not equal to Py_None here because exc_type should only ever be a class. But not including this check was causing crashes on certain tests e.g. on Fedora. */ if (gen->gi_exc_state.exc_type && gen->gi_exc_state.exc_type != Py_None) { ... } I don't think that you should mention "Fedora" as a platform impacted by this issue: all platforms should be affected. It's just unclear why the issue was first seen on Fedora. gen_send_ex() copies tstate->exc_info to gen->gi_exc_state. tstate->exc_info->exc_type is set at least in the following 3 places in CPython code base: * ceval.c: POP_EXCEPT opcode: exc_info->exc_type = POP(); * ceval.c: UNWIND_EXCEPT_HANDLER() macro: exc_info->exc_type = POP(); * errors.c: PyErr_SetExcInfo() I saw in practice POP_EXCEPT and UNWIND_EXCEPT_HANDLER() setting exc_info->exc_type to Py_None (I didn't test PyErr_SetExcInfo()). _PyErr_GetTopmostException() also handles exc_info->exc_type == Py_None case: _PyErr_StackItem * _PyErr_GetTopmostException(PyThreadState *tstate) { _PyErr_StackItem *exc_info = tstate->exc_info; while ((exc_info->exc_type == NULL || exc_info->exc_type == Py_None) && exc_info->previous_item != NULL) { exc_info = exc_info->previous_item; } return exc_info; } -- So exc_type=None is not a bug, but it's done on purpose. If you don't want to get None in genobject.c, we should modify all places which set tstate->exc_info->exc_type. Problem: the structure currently exposed in the public C API (bpo-40429), and I wouldn't be surprised if Cython or greenlet modify tstate->exc_info directly. ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue29587> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com