[SciPy-dev] Requiring Python 2.4

[Robert Kern]

Stefan van der Walt wrote:
> On Tue, Aug 28, 2007 at 11:24:43AM -0700, Jarrod Millman wrote:
>> On 8/28/07, Robert Kern <robert.kern at gmail.com> wrote:
>>>> I noticed that some Python 2.4-only features crept into parts of SciPy
>>>> (yes, I'm guilty, too).  Has Python 2.5 been out for long enough that
>>>> we can drop support for 2.3?
>> What 2.4 features are being used?
> 
> Mostly list comprehension (should be easy to find using a regular
> expression search). No decorators (those you don't use by accident).
> I hope that ParametricTest is still compatible with 2.3, but I don't
> have 2.3 around to test anymore.

What 2.4 features do you think you might have used? The list of such features is
here:

  http://www.python.org/doc/2.4.4/whatsnew/whatsnew24.html

> Robert says we should still support 2.3 -- but is there a time limit
> or a migration plan?

To the extent that I have a say in the matter (and a survey of recent checkin
activity would suggest "significantly less than others in this discussion"), I
would like to maintain compatibility with as old a Python as we can for as long
as we can. I think we should have a compelling reason to drop support for a
version of Python that is more than just the age of that version. People are
still actively using Python 2.3. People are still actively using Python 1.5.2,
for that matter; and the people that still maintain their libraries for that
platform are highly regarded for it (e.g. Fredrik Lundh). We should drop
compatibility when there is a significant new feature that we need to use. If
scipy had a lot of places where it used popen, the subprocess module in 2.4
would be a good reason to switch, in my opinion. However, I don't see many 2.4
features that are really critical, just conveniences.

On the other hand, if there were a great influx of developers who had never seen
a Python older than 2.4, that might be a good reason to switch, too. But until
then, I think the rest of us can have the discipline to use only features from
2.3. It's not that hard.

-- 
Robert Kern

"I have come to believe that the whole world is an enigma, a harmless enigma
 that is made terrible by our own mad attempt to interpret it as though it had
 an underlying truth."
  -- Umberto Eco