Alexander Belopolsky belopol...@users.sourceforge.net added the comment:
There seems to be a bug somewhere in 2.x cPickle. Here is a somewhat simpler
way to demonstrate the bug: the following code
from pickletools import dis
import cPickle
t = 1L, # use long for easy 3.x comparison
s1 =
Alexander Belopolsky belopol...@users.sourceforge.net added the comment:
OK, the 2.7 behavior is explainable and correct. cPickle checks the reference
count and does not generate PUT for objects that don't have references:
from pickletools import dis
from cPickle import dumps
Alexander Belopolsky belopol...@users.sourceforge.net added the comment:
I am speculating here while Alexandre probably knows the answer. The skip PUT
on unreferenced objects optimization was probably removed because doing so
makes _pickle module behave more like pickle and because
New submission from Alberto Planas DomÃnguez apla...@gmail.com:
Sometimes, when I use cPickle to serialize tuples of strings, I get different
dumps() result for the same tuple:
import cPickle
t = ('s', 'JOHN')
s1 = cPickle.dumps(t)
s2 = cPickle.dumps(cPickle.loads(cPickle.dumps(t)))
assert s1
Antoine Pitrou pit...@free.fr added the comment:
I don't think you can expect serialized results to always be equal. It can
depend on specifics of the internal algorithm, such as optimizations or dict
iteration order.
--
nosy: +alexandre.vassalotti, pitrou
priority: normal - low
