memoize decorator example has cache leak when used on an instance about decorator HOT 2 CLOSED

I would not call this a memory leak. It is intended behavior, the cache is keeping references as it should. I did not want to give a complex example with weak references. Still a warning for naive programmers with wrong expectations may be in order.

from decorator.

I understand the implementation is rather naive and if you look closely, it's obvious why you made these choices. I'm trying to point out that there are ways that will come to haunt you if you use this in production. Consider the following example:

class Something(object):
    @memoize
    def expensive_object(self):
        return generate_expensive_object()

Reading this code (without knowing what memoize does), I would expect that the expensive object is cleaned up after a "Something" object goes out of scope. But it does not.

a = Something().expensive_object()
b = Something().expensive_object()
c = Something().expensive_object()

del a
del b
del c

Now there's three expensive objects and three Something objects still in existence.

from decorator.