[Anthony Baxter]
The release23-maint branch (for bugfixes on the 2.3 train of code) is now open for your bugfixing pleasure.
Yay!
My next (planned) release off that branch will be May-June, assuming Tim doesn't create^H^H^H^H^H "find" any more critical bugs before then.
(Oh sure, he'll claim that the bugs were there already...)
Alas, Jim Fulton already did: in typeobject.c's reduce_2(), if the object doesn't have __getstate__ but does have __dict__, the AttributeError from failing to find __getstate__ isn't cleared, so ceval ends up with a pending exception set after a call that returns normally. That's Bad (an utterly mysterious AttributeError gets raised after some later opcode notices the pending exception). That bug is in all flavors of 2.3, and on the head -- alas, there's no sane workaround for something like this.