@@ -3621,7 +3621,7 @@ static void object_dealloc(PyObject *);
36213621static PyObject * object_new (PyTypeObject * ,PyObject * ,PyObject * );
36223622static int object_init (PyObject * ,PyObject * ,PyObject * );
36233623static int update_slot (PyTypeObject * ,PyObject * );
3624- static void fixup_slot_dispatchers (PyTypeObject * );
3624+ static int fixup_slot_dispatchers (PyTypeObject * );
36253625static int type_new_set_names (PyTypeObject * );
36263626static int type_new_init_subclass (PyTypeObject * ,PyObject * );
36273627
@@ -4577,7 +4577,9 @@ type_new_impl(type_new_ctx *ctx)
45774577 }
45784578
45794579// Put the proper slots in place
4580- fixup_slot_dispatchers (type );
4580+ if (fixup_slot_dispatchers (type )< 0 ) {
4581+ gotoerror ;
4582+ }
45814583
45824584if (!_PyDict_HasOnlyStringKeys (type -> tp_dict )) {
45834585if (PyErr_WarnFormat (
@@ -11329,10 +11331,12 @@ update_slot(PyTypeObject *type, PyObject *name)
1132911331
1133011332/* Store the proper functions in the slot dispatches at class (type)
1133111333 definition time, based upon which operations the class overrides in its
11332- dict. */
11333- static void
11334+ dict.Returns -1 and exception set on error or 0 otherwise. */
11335+ static int
1133411336fixup_slot_dispatchers (PyTypeObject * type )
1133511337{
11338+ int res = 0 ;
11339+
1133611340// This lock isn't strictly necessary because the type has not been
1133711341// exposed to anyone else yet, but update_ont_slot calls find_name_in_mro
1133811342// where we'd like to assert that the type is locked.
@@ -11341,10 +11345,11 @@ fixup_slot_dispatchers(PyTypeObject *type)
1134111345PyObject * mro = lookup_tp_mro (type );
1134211346assert (mro );
1134311347
11344- // Try to prebuild MRO dict. If we fails then clear mro_dict and
11345- // reset error flag because we don't expect any exceptions. If
11346- // fails to prebuild MRO dict then update_on_slot will use
11347- // previous version of find_name_in_mro.
11348+ // Try to prebuild MRO dict. We build it in bottom-top manner,
11349+ // from bottom base to the top one, because the bottommost base
11350+ // has more items then other and copying it is preferable than
11351+ // merging.
11352+ // If we fails, then stop init type.
1134811353PyObject * mro_dict = NULL ;
1134911354Py_ssize_t n = PyTuple_GET_SIZE (mro );
1135011355for (Py_ssize_t i = 0 ;i < n ;i ++ ) {
@@ -11355,26 +11360,31 @@ fixup_slot_dispatchers(PyTypeObject *type)
1135511360if (i == 0 ) {
1135611361mro_dict = PyDict_Copy (dict );
1135711362if (!mro_dict ) {
11358- PyErr_Clear () ;
11359- break ;
11363+ res = -1 ;
11364+ goto finish ;
1136011365 }
1136111366 }else {
1136211367if (PyDict_Merge (mro_dict ,dict ,1 )< 0 ) {
11363- Py_CLEAR (mro_dict );
11364- PyErr_Clear ();
11365- break ;
11368+ res = -1 ;
11369+ gotofinish ;
1136611370 }
1136711371 }
1136811372 }
1136911373
11374+ assert (!res );
11375+ assert (mro_dict );
1137011376assert (!PyErr_Occurred ());
1137111377for (pytype_slotdef * p = slotdefs ;p -> name ; ) {
1137211378p = update_one_slot (type ,p ,mro_dict );
1137311379 }
1137411380
11381+ assert (!PyErr_Occurred ());
11382+
11383+ finish :
1137511384Py_XDECREF (mro_dict );
1137611385
1137711386END_TYPE_LOCK ();
11387+ return res ;
1137811388}
1137911389
1138011390static void