On Wed, May 9, 2012 at 2:34 PM, Ian Kelly <ian.g.ke...@gmail.com> wrote: > On Wed, May 9, 2012 at 1:39 PM, Russell E. Owen <ro...@uw.edu> wrote: >> I was wondering. I override __new__ (and __init__) to print messages and >> was quite surprised to only see __new__being called when the object was >> first created, not when it was being unpickled. But maybe there's >> something funny about my override that caused unpickle to ignore it and >> use the default version. I hope so. I can't see how the object could be >> constructed during unpickle without calling __new__. But that's one >> reason I was curious about the unpickling sequence of operations. > > You're probably pickling with the default protocol. Unpickling calls > an overridden __new__ method only if the pickle protocol is at least > 2. Using protocol 0 or 1, new-style class instances are constructed > with the base object.__new__ instead.
BTW, in case you're wondering where all this is documented, pull up PEP 307 and read the sections "Case 2" and Case 3". Cheers, Ian -- http://mail.python.org/mailman/listinfo/python-list
