You might find this helpful. https://docs.python.org/3/reference/datamodel.html
Thank you 😊😙 On Thu, Feb 6, 2020, 6:29 PM Frank Millman <fr...@chagford.com> wrote: > Hi all > > I have noticed a change in behaviour in Python 3.8 compared with > previous versions of Python going back to at least 2.7. I am pretty sure > that it is not a problem, and is caused by my relying on a certain > sequence of events at shutdown, which of course is not guaranteed. > However, any change in behaviour is worth reporting, just in case it was > unintended, so I thought I would mention it here. > > I have a module (A) containing common objects shared by other modules. I > have a module (B) which imports one of these common objects - a set(). > > Module B defines a Class, and creates a global instance of this class > when the module is created. This instance is never explicitly deleted, > so I assume it gets implicitly deleted at shutdown. It has a __del__() > method (only for temporary debugging purposes, so will be removed for > production) and the __del__ method uses the set() object imported from > Module A. > > This has worked for years, but now when the __del__ method is called, > the common object, which was a set(), has become None. > > My assumption is that Module A gets cleaned up before Module B, and when > Module B tries to access the common set() object it no longer exists. > > I have a workaround, so I am just reporting this for the record. > > Frank Millman > > -- > https://mail.python.org/mailman/listinfo/python-list > -- https://mail.python.org/mailman/listinfo/python-list
