[Python-Dev] Python 4: don't remove anything, don't break backward compatibility

[R. David Murray]

On Mon, 10 Mar 2014 16:06:22 -0000, Brett Cannon <bcannon at gmail.com> wrote:
> On Mon Mar 10 2014 at 11:50:54 AM, Victor Stinner <victor.stinner at gmail.com>
> wrote:
> 
> > 2014-03-10 16:25 GMT+01:00 Stefan Richthofer <Stefan.Richthofer at gmx.de>:
> > > I don't see the point in this discussion.
> > > As far as I know, the major version is INTENDED to
> > > indicate backward-incompatible changes.
> >
> > This is not a strict rule. I would like to follow Linux 3 which didn't
> > break the API between Linux 2 and Linux 3.
> >
> 
> I disagree. I don't think 3->4 will be as drastic as it was for 2->3, but I
> view Python 4 as a chance to drop all deprecated APIs that we left in for
> convenience in porting from Python 2 (e.g. the imp module). We can't put a
> removal date as we can't really declare Python 2 dead for the whole
> community. But when Python 4 does come out next decade I would like to say
> that we have moved entirely beyond Python 2 as a team and thus don't turn
> into Java and support deprecated code forever.

We had this discussion a bit ago, and my sense was that we tentatively
decided that we were just going to deprecate and remove things as
appropriate, irregardless of version number.  I used "4.0" in my
message about 'U' as a shorthand for "some time after python2
is no longer an issue".  Sorry for the confusion.  (That said, I
do see some merit to doing some extra cleaning at the 4.0
boundary, just for mental convenience.)

--David