[Python-Dev] Status of 2.7 and 3.2

Nick Coghlan ncoghlan at gmail.com
Mon Jun 8 04:21:11 CEST 2009

Martin v. Löwis wrote:
> 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.

I don't think the idea of "3.x first" was raised explicitly until the
discussions about having a short release cycle for 3.1 came up. Before
then there was an assumption that 3.1 and 2.7 would come out at roughly
the same time.

>> 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.

As RDM already mentioned, the potential problem such a policy is
intended to address is the idea of being able to write 2.7 code that
can't be forward ported to 3.x because no version with a corresponding
feature set has been released yet.

My last sentence above was actually deliberately ambiguous as to whether
2.7 or 3.2 ends up being released first - so long as the releases happen
within a few months of each other and any new features that appear in
2.7 also appear in 3.2, then the migration path for different 2.x
versions remains clear (i.e 2.6-only code can be migrated to 3.1, but
2.7 code may need to be migrated to 3.2 instead if it uses features that
aren't in 3.1).

The exact order and timing of 3.2/2.7 will no doubt depend on any
specific issues relating to the two releases around the time that they
come out. But in the interests of maintaining a coherent migration path
from 2.x to 3.x, it makes sense to plan to release them at roughly the
same time.


Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia

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