OK, I stop worring about thread safety and other implementation detail behavior on edge cases.
Thanks, INADA Naoki <songofaca...@gmail.com> On Wed, Sep 6, 2017 at 7:40 PM, Paul Moore <p.f.mo...@gmail.com> wrote: > On 6 September 2017 at 11:09, Antoine Pitrou <solip...@pitrou.net> wrote: >> On Wed, 6 Sep 2017 11:26:52 +0900 >> INADA Naoki <songofaca...@gmail.com> wrote: >>> >>> Like that, should we say "atomic & threadsafe __setitem__ for simple >>> key is implementation detail of CPython and PyPy. We recommend >>> using mutex when using OrderedDict from multiple thread."? >> >> I think you may be overstating the importance of making OrderedDict >> thread-safe. It's quite rare to be able to rely on the thread safety >> of a single structure, since most often your state is more complex than >> that and you have to use a lock anyway. >> >> The statu quo is that only experts rely on the thread-safety of list >> and dict, and they should be ready to reconsider if some day the >> guarantees change. > > Agreed. I wasn't even aware that list and dict were guaranteed > threadsafe (in the language reference). And even if they are, there's > going to be a lot of provisos that mean in practice you need to know > what you're doing to rely on that. Simple example: > > mydict[the_value()] += 1 > > isn't thread safe, no matter how thread safe dictionaries are. > > I don't have a strong opinion on making OrderedDict "guaranteed thread > safe" according to the language definition. But I'm pretty certain > that whether we do or not will make very little practical difference > to the vast majority of Python users. > > Paul > _______________________________________________ > Python-Dev mailing list > Python-Dev@python.org > https://mail.python.org/mailman/listinfo/python-dev > Unsubscribe: > https://mail.python.org/mailman/options/python-dev/songofacandy%40gmail.com _______________________________________________ Python-Dev mailing list Python-Dev@python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
