Daniel J. Popowich wrote:
Nicolas Lehuen writes:
I've just checked in some changes to the Python source code in order
to support Python 2.2. Now the test suite runs successfully on Python
2.2.3 on Windows 2000. I've checked that no regressions were
introduced in later Python versions, too.
The changes are pretty simple : each Python module now features a
"from python22 import *". The mod_python.python22 module just
reimplements new builtins from Python 2.3. It turns out that the only
missing builtin for now is enumerate(). The tests module, containing a
few tests for generators, has to sport a "from __future__ import
generators" line.
I also had to change mod_python.cache which used time.strptime so that
it uses rfc822.parsedate, now.
I've did this because the guys from Nokia use Python 2.2 and
mod_python 3.1.3. They spotted memory leaks which are likely to be
fixed in mod_python 3.2.X, but they could not upgrade if Python 2.2
was not supported.
But does this scale over the life of a project? Every new python
module has to include 'from python22 import *'??
While never shying away from a decent hack myself, this is a hack that
affects everyone, not just those that need the hack, which, for me,
screams volumes.
Hmm, good points.
Certainly, which version of python mod_python is based on should not
be taken lightly. Was it formally decided to make mod_python
dependent on 2.3+? If not, then perhaps uses of enumerate,
etc. should not be used.
If a formal decision was made, then it's a done deal, right? If not
and uses of 2.3 have slipped in then perhaps it's a done deal anyway
because no one can stomach the thought of taking out the 2.3-isms at
this late date.
My impression is that there was never really a discussion on this issue.
Some 2.3-isms got used, so it was decided that 2.2 was not supported.
There likely should have been a more formal discussion on whether this
is right time to drop 2.2 support. Certainly we haven't done any testing
using python 2.2 so even with the hack I don't think we can comfortably
claim that that version is supported.
Regardless, I do not think it is within the scope of mod_python
developers to keep users forward-compatible with the underlying python
version. Sorry, but IMHO, this is not scalable software engineering.
I'll re-read this paragraph after a good sleep, but right now I'm not
sure if you mean we shouldn't be using features only available in newer
python versions, or we shouldn't worry about compatibilty with with
older python versions?
That said, I don't have a problem helping 2.2 users write their own
hacks. For example, let's take enumerate...another way of solving
this problem without touching any mod_python code would be a
suggestion in the FAQ to write a module, say, python22hacks.py:
------------------------------------------------------------
# python22hacks.py
#
# This is unsupported software offered to mod_python users who are
# stuck using python 2.2.
#
# Install by placing this module in the same directory with other
# mod_python modules and add the following to your apache config:
#
# PythonImport python22hacks INTERPRETER_NAME
#
# More disclaimers, blah, blah...
import __builtin__ as hack
hack.enumerate = lambda s: zip(xrange(len(s)), s)
------------------------------------------------------------
This way we don't have to touch every module of source code and the
onus is on the few who need it rather than the many who don't or those
who have to maintain it.
I like this solution.
Jim
