> That's good if it's so... can you explain why list_clear doesn't 
> guarantee that the list is empty? Why would XDECREF populate the list? 
> I don't quite understand it.


Does this mean that durning the Py_DECREF progress the list may be populated again? It's not a problem. Here is the simplest example(with applying eli's patch):


class A(object):
    def __init__(self, li):
        self._li = li
    def __del__(self):
        self._li.append(self)

li = []
li.append(A(li))
li.clear()
print(li)