2009/6/19 <gl...@divmod.com>: > On 02:09 pm, benja...@python.org wrote: >> 2009/6/19 <gl...@divmod.com>: >>> What is "behavior"? Software is composed of behavior. If no behavior >>> changes, then nothing can ever happen. > >> I mean that if you pass X and Y into a function and get Z in 2.6, then >> you should be able to get Z from passing X and Y in 2.7 even if >> there's a new argument that returns Z' if you pass True to it. >> (Obviously, this is somewhat simplified, but I hope it helps.) > > This definition only makes sense if the interesting thing about a function > is its return value, and if the only sort of thing you have are functions. > What about side-effects, or exceptional conditions? What about > interactions with subclasses? (Changing a class in a library from old-style > to new-style has serious repercussions, as MRO conflicts can result in > applications that subclass it.)
I've added a little more about this to the PEP. See what you think. >>> >>> How do you propose to measure the benefit to breakage ratio? How do you >>> propose to define "trivial" to fix? Most projects, including Python, >>> Twisted, Django, and Zope, have an ever-increasing bug count, which means >>> that trivial issues fall off the radar pretty easily. >> >> Well, if you're tests aren't failing from it, is it an incompatibility? > > Well, let's say the tests do fail from it. Right now, even Twisted trunk > still doesn't *quite* support Python 2.6, but only on Windows, due to > stricter checking of the 'mode' argument for files. But this failing test > is just not that high priority, so our recommendation is "don't use python > 2.6 yet on Windows, 2.5 works fine". My point is that triviality is a > matter of perspective :). Eventually somebody will get around to it, but > 2.6 has been out for a while now. I understand. I think we will just have to provide guidelines for triviality and decide on a case by case basis. >>> There are a very large number of users of Python, the large percentage of >>> whom do not read python-dev. A posting on python-list is likely to >>> provoke >>> an unproductive pile-on. I suggest a dedicated list, which should >>> ideally >>> be low traffic, "python-incompatible-announce", or something like that, >>> so >>> that *everyone* who maintains Python software can subscribe to it, even >>> if >>> they're not otherwise interested in Python development. >> >> And that won't generate a pile-on? > > Well, the etiquette for that specific list could be "keep this low- traffic > unless you have a serious problem with this change". Or, better yet, make > it an announce-only list: the pile-on can still happen on python-list, but > only the results of the discussion will be announced on the > incompatible-announce list. I think that's a fine idea, but the PEP is dealing with policy as our mailing list infrastructure is now. -- Regards, Benjamin _______________________________________________ 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
