[SciPy-dev] Requiring Python 2.4

Robert Kern robert.kern@gmail....
Tue Aug 28 17:47:06 CDT 2007

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@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


> 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

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