[Python-Dev] Spreading the Python 3 religion

[Stefan Krah]

Merlijn van Deen <valhallasw at arctus.nl> wrote:
> Another cause for this is the painful merging in most version control systems.
> I'm guessing you all know the pain of 'svn merge' - and there are a lot of
> projects still using SVN or even CVS.
>
> As such, you need to impose the discipline to always apply changes to both
> branches. This is a reasonable thing for larger projects, but it is generally
> harder to implement it for smaller projects, as you're already lucky people are
> actually contributing.

What you say is all true, but I wonder if the additional work is really
that much of a problem.

Several people have said here that applying changes to both versions
becomes second nature, and this is also my experience. While mercurial
may be nicer, svnmerge.py isn't that bad.


Projects have different needs and priorities. From my own experience with
cdecimal I can positively say that the amount of work required to keep
two branches [1] in sync is completely dwarfed by first figuring out
what to write and then implementing it correctly.

After doing all that, the actual synchronization work feels like a vacation.


Another aspect, which may be again cdecimal-specific, is that keeping
2.5 compatibility is *at least* as bothersome as supporting 2.6/2.7 and 3.x.


As an example for a pretty large project, it looks like Antoine is making
good progress with Twisted:

https://bitbucket.org/pitrou/t3k/wiki/Home


I certainly can't say what's possible or best for other projects. I do
think though that choosing the separate branches strategy will pay off
eventually (at the very latest when Python-2.7 will reach the status
that Python-1.5 currently has).


Stefan Krah


[1] I don't even use two branches but 2.c/3.c and 2.py/3.py file name patterns.