[Python-Dev] Status of 2.7 and 3.2

["Martin v. Löwis"]

Nick Coghlan wrote:
> Martin v. Löwis wrote:
>>> I have thought that 2.7 was now to come out instead with 3.2 and would
>>> include backported 3.2 new features.  Others expect 2.7 to come out soon
>>> after 3.1 and to only contain new 3.1 features.  So Guido or someone,
>>> please clarify: is 2.7 to be the counterpart of 3.1 or 3.2?
>> Neither, nor. 2.7 will be released 18..24 months after 2.6, i.e. between
>> April 2010 and October 2010. I think it's too early to speculate about
>> a release schedule for 3.2.
> 
> I think Terry's underlying question is more basic than that. It can also
> be phrased as:
> 
> "Is 2.7 allowed to have new features which did not appear in 3.1?"

I don't think this is the question Terry meant to ask, and the answer
to this question is a clear "Certainly, but you are asking the wrong
question."

The question that Terry really meant to ask is "why is there no release
candidate for 2.7 already, when 3.1 is going to be released RSN?", and
that question arises from the (incorrect) understanding that 2.x
releases and 3.x releases will be lock-step.

The question that you posed should have been phrased as
"Is 2.7 allowed to have new features which don't also appear on
the 3k branch?", to which the answer is a clear "No."

> In previous discussions, a general policy has been articulated that
> having released Python 3.0, any new features should appear in a 3.x
> release before they appear in a 2.x release.

I don't think that the policy has been articulated in exactly that
way, and it certainly wasn't implemented for 2.6/3.0. 2.6 was released
with features that had not been released in any 3.x release, just
because 3.x had not been released at all.

> A. "No."
> 
>   This answer means that 2.7 will only contain new features that are
> part of 3.1. If 2.7 sticks to a normal 18-24 month release cycle the
> only activities on the trunk for the next 12 months or so should be
> backports from 3.1 and bug fixes. New features added to the py3k branch
> for 3.2 should not be backported until after 2.7 is released. The other
> alternative in this case is to release 2.7 earlier than normal, but that
> creates problems in terms of the absolute duration of maintenance branch
> support for 2.6.

I think this makes it clear that the answer can't possibly be "No".
Not allowing addition of new features even though the release is still
12 months away would be unreasonable, IMO - what's the point of freezing
development now, and where should new features to 2.x be added if not
to the trunk?

Likewise, releasing 2.7 now is completely unacceptable.

> B. "Yes."
> 
>   This answer means that the 3.1 to 3.2 development cycle will need to
> be truncated by roughly 6 months so that 3.2 can be released before 2.7
> with any new features of interest. The 3.2 and 2.7 releases should then
> occur within a few months of each other.

Assuming the policy "release new features for 2.x only after they got
released for 3.x". I don't think such a policy actually exists.

Regards,
Martin