[rfc] six-month stable release cycles

[Stephen J. Turnbull]

Andrew Bennetts writes:
 > Stephen J. Turnbull wrote:
 > > Martin Pool writes:
 > > 
 > >  > The Python case is a lot like ours, unsurprisingly - they basically
 > >  > can't and don't make strong promises about stability from 2.x to 2.y -
 > > 
 > > IMO, they do.  They make a strong promise of backward compatibility,
 > 
 > That's not my experience at all.

Well, they may not keep the promise, but they certainly intend to make
it.  I don't know internals about frameworks like Twisted and Zope to
judge frequency of breakage, but anything that supports plug-ins and
user-provided call-backs is likely to run into compatibility issues, I
think, because those mechanisms themselves are often somewhat delicate
because they provide additional semantics around the pure Python call.

My own experience with true applications, specifically Mailman and
Roundup, however, is that backward compatibility issues with Python
usually turn out to be bugs in the application that were masked by
bugs in Python.

 > I think the fundamental problem for library authors is that Python
 > (Python 2, at least, I haven't used 3 enough to have an opinion
 > about it) as a language simply doesn't have good facilities for
 > managing API evolution.

I haven't noticed that Python 3 has changed in this respect; there's
certainly been no discussion on the python-dev or python-3000 lists
about it.  Python 3 is still a duck-typing, consenting adults language.

I think it would be quite hard to provide strong facilities for
managing API evolution in that context.