[IPython-dev] Dropping 2.4 support

[Fernando Perez]

On Fri, Aug 21, 2009 at 12:04 PM, Brian Granger<ellisonbg.net at gmail.com> wrote:

>> - Specific things we gain from being 2.5-only (not the "what's new in
>> 2.5" document, but which of those do *we* benefit from)
>
> * Absolute imports would allow us to ship enthought.traits in externals and
> avoid 1) the performance problems of namespace packages and 2) conflicting
> with other installed versions of enthought.traits.
>
> * Certain parts of twisted use the new generator features in 2.5.  Being
> able to use these features of twisted would probably dramatically simplify
> all of our twisted using test code.  This would be a *massive* improvement
> in maintainability.
>
> * Obviously there are all the other minor things like with and
> try/except/else/finally, but these are convenience things.
>
> * The faster we drop support for python 2.4 and 2.5, the easier moving to
> py3k will be.  I am not yet proposing that we drop 2.5 support though.


This is a good list for me.  Just to provide some context for the
others, here at scipy we've been having extensive discussions with
Enthought and the matplotlib team, on the possibility of using traits
without making it an external dependency.  For now we'll continue with
Brian's Traitlets work because:

- it gives us a pure-python implementation

- it serves as a 'review' of the Traits model, which is great in many
ways, but has accumulated some things that can probably be looked at
again with the benefit of hindsight.

But we'll enable the running of  our test suite both agianst Traitlets
AND against true Traits, to ensure we spot deviations in Traitlets
from the Traits API.

Once our own dust settles, we can revisit the question of whether to
swap out Traitlets for Traits, especially if it becomes possible to
remove the pure C dependencies in it after a cleanup and some possible
Cython work.

With this rationale, unless someone has a strong objection, I'm
inclined to allow Trunk to move forward to 2.5.  We can always
backport critical bugfixes to 0.10 and put out a 0.10.1 that would be
2.4-fixed, if such issues are reported (hopefully with patches).

We don't have to make this decision *now* though, so let's wait for a
few days in case someone has a valid objection that may force us to
revisit the question, before making a final commitment.

Thanks for the  feedback!

Cheers,

f