>>>>> "NS" == Neil Schemenauer <nas@python.ca> writes: NS> There is insidious bug here. Andrew helped me walk through it NS> and I think we figured it out. First here's the code to NS> trigger it: A simpler example: import gc class Ouch: def __del__(self): gc.collect() def f(): gc.set_threshold(5) while 1: t = () # <-- here for i in range(300): t = [t, Ouch()] f() -Barry