On Sun, 01 Apr 2012 03:03:13 +1000, Nick Coghlan <ncogh...@gmail.com> wrote: > On Sun, Apr 1, 2012 at 2:09 AM, Guido van Rossum <gu...@python.org> wrote: > > Here's a different puzzle. Has anyone written a demo yet that provokes > > this RuntimeError, without cheating? (Cheating would be to mutate the > > dict from *inside* the __eq__ or __hash__ method.) If you're serious > > about revisiting this, I'd like to see at least one example of a > > program that is broken by the change. Otherwise I think the status quo > > in the 3.3 repo should prevail -- I don't want to be stymied by > > superstition. > > I attached an attempt to *deliberately* break the new behaviour to the > tracker issue. It isn't actually breaking for me, so I'd like other > folks to look at it to see if I missed something in my implementation, > of if it's just genuinely that hard to induce the necessary bad timing > of a preemptive thread switch.
Thanks, Nick. It looks reasonable to me, but I've only given it a quick look so far (I'll try to think about it more deeply later today). If it is indeed hard to provoke, then I'm fine with leaving the RuntimeError as a signal that the application needs to add some locking. My concern was that we'd have working production code that would start breaking. If it takes a *lot* of threads or a *lot* of mutation to trigger it, then it is going to be a lot less likely to happen anyway, since such programs are going to be much more careful about locking anyway. --David _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
