[3.9] bpo-41909: Enable previously disabled recursion checks. (GH-22536) (GH-22550)
Enable recursion checks which were disabled when get __bases__ of
non-type objects in issubclass() and isinstance() and when intern
strings. It fixes a stack overflow when getting __bases__ leads
to infinite recursion.
Originally recursion checks was disabled for PyDict_GetItem() which
silences all errors including the one raised in case of detected
recursion and can return incorrect result. But now the code uses
PyDict_GetItemWithError() and PyDict_SetDefault() instead.
(cherry picked from commit 9ece9cd65cdeb0a1f6e60475bbd0219161c348ac)
4 files changed