[Python-Dev] Backporting PEP 414

[Antoine Pitrou]

On Tue, 28 Feb 2012 16:23:40 -0500
Chris McDonough <chrism at plope.com> wrote:
> On Tue, 2012-02-28 at 15:54 -0500, Benjamin Peterson wrote:
> > 2012/2/28 Ethan Furman <ethan at stoneleaf.us>:
> > > Here's what I know:
> > >
> > > We don't add features to bug-fix releases.
> > > u'' is considered a feature.
> > > By not backporting to 3.1 and 3.2 we are not easing the migration pains from
> > > 2.x.
> > >
> > >
> > > Here's what I don't know:
> > >
> > > Why is readding u'' a feature and not a bug?  (Just had a thought about this
> > > -- because the removal of u'' is documented.)
> > 
> > Because it's a new "thing" which doesn't fix obviously broken behavior.
> > 
> > >
> > >
> > > If there is already a FAQ entry feel free to point me to it, but I would
> > > still be curious why, in this instance, practicality does not beat purity?
> > 
> > Because it's practical not to break bugfix releases with new features.
> 
> This change, by its nature, cannot break old programs.

Unless the implementation is buggy, or has unintended side-effects.
In theory, *most* changes done in feature releases cannot break old
programs. Reality is often a bit more surprising :)

Regards

Antoine.