From 45486176ea14884400188c604d5d3488f803ff2d Mon Sep 17 00:00:00 2001 From: Guido van Rossum Date: Thu, 30 Jan 2003 05:39:04 +0000 Subject: In save_newobj(), if an object's __getnewargs__ and __getstate__ are the same function, don't save the state or write a BUILD opcode. This is so that a type (e.g. datetime :-) can support protocol 2 using __getnewargs__ while also supporting protocol 0 and 1 using __getstate__. (Without this, the state would be pickled twice with protocol 2, unless __getstate__ is defined to return None, which breaks protocol 0 and 1.) --- Lib/pickle.py | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/Lib/pickle.py b/Lib/pickle.py index 9630d33..d62a5bd 100644 --- a/Lib/pickle.py +++ b/Lib/pickle.py @@ -416,6 +416,29 @@ class Pickler: write(SETITEM) getstate = getattr(obj, "__getstate__", None) + + # A class may define both __getstate__ and __getnewargs__. + # If they are the same function, we ignore __getstate__. + # This is for the benefit of protocols 0 and 1, which don't + # use __getnewargs__. Note that the only way to make them + # the same function is something like this: + # + # class C(object): + # def __getstate__(self): + # return ... + # __getnewargs__ = __getstate__ + # + # No tricks are needed to ignore __setstate__; it simply + # won't be called when we don't generate BUILD. + # Also note that when __getnewargs__ and __getstate__ are + # the same function, we don't do the default thing of + # looking for __dict__ and slots either -- it is assumed + # that __getnewargs__ returns all the state there is + # (which should be a safe assumption since __getstate__ + # returns the *same* state). + if getstate and getstate == getnewargs: + return + if getstate: try: state = getstate() -- cgit v0.12