Given that we typically need at least 4 bytes just for the PyObject * pointer for each item in a list, I guess real lists are safe.

But how about list-like objects, implementing __len__ and __getitem__?  The following appears to run forever on my machine:



class SquaresList(object):
    def __init__(self, length):
        self._length = length

    def __len__(self):
        return self._length

    def __getitem__(self, index):
        if not 0 <= index <= self._length:
            raise IndexError
        return index**2


import bisect, sys

squareslist = SquaresList(sys.maxsize)
print bisect.bisect(squareslist, (sys.maxsize - 3)**2)