Pickled Object Versioning
The pickle format has no such proviso.  Why don't you just make the "serial version number" part of the object's attributes, to be pickled right along with the rest?  Then the "notification" can be trivially had by comparing actual and desired version -- don't see why it should be a PITA.
I am working on a project where we have a large number of objects being serialized and stored to disk using pickle/cPickle.
As the life of the project progresses (after release to customers in the field) it is likely that future features/fixes will require us to change the signature of some of our persisted objects.  This could be the addition of fields, removing of fields, or even just changing the invariants on a piece of data.
Is there a standard way to mark an object that will be pickled as having a certain version (like serialVersionUID in Java)?  Basically, if I am restoring an instance of Foo version 234 but the current code is 236 I want to receive some notification on unpickle.  Should I just go ahead and roll out my own solution (could be a PITA).
Thanks