Issue #2534: speed up isinstance() and issubclass() by 50-70%, so as to
match Python 2.5 speed despite the __instancecheck__ / __subclasscheck__
mechanism. In the process, fix a bug where isinstance() and issubclass(),
when given a tuple of classes as second argument, were looking up
__instancecheck__ / __subclasscheck__ on the tuple rather than on each
type object.
Reviewed by Benjamin Peterson and Raymond Hettinger.
diff --git a/Python/errors.c b/Python/errors.c
index 9c9eb2f..d7aac6d 100644
--- a/Python/errors.c
+++ b/Python/errors.c
@@ -160,11 +160,12 @@
int res = 0;
PyObject *exception, *value, *tb;
PyErr_Fetch(&exception, &value, &tb);
- res = PyObject_IsSubclass(err, exc);
+ /* PyObject_IsSubclass() can recurse and therefore is
+ not safe (see test_bad_getattr in test.pickletester). */
+ res = PyType_IsSubtype((PyTypeObject *)err, (PyTypeObject *)exc);
/* This function must not fail, so print the error here */
if (res == -1) {
PyErr_WriteUnraisable(err);
- /* issubclass did not succeed */
res = 0;
}
PyErr_Restore(exception, value, tb);