[Python-Dev] PEP 297: Support for System Upgrades

[M.-A. Lemburg]

Guido van Rossum wrote:
>>Ok, I've started looking at adding support for this. Here's
>>a couple of things I found:
>>
>>* getpath.c:
>>    Some of the '/' path delimiters are hard coded; shouldn't
>>    these be replaced with SEP ?
> 
> All the platforms that I'm awware of that don't use '/' have their own
> getpath.c copy anyway (the one for Windows is PC/getpathp.c).

But can't hurt to change these in the standard getpath.c, right ?
(reduce() is looking for SEP, so on platforms which do use the
standard getpath.c but have a different os.sep could be mislead
by the hardcoded slash in some constants)

>>* There's no easy way to find the first item on sys.path which
>>   starts the default path added by Python at startup time. It seems
>>   that a suffix search for "python23.zip" gives the best hint.
>>   The only other possibility I see is writing the support code
>>   directly into getpath.c.
> 
> That's where I'd put it, yes.

You mean "put it into getpath.c" or "put it in front of
.../python23.zip" ?

>>* site.py contains code which prefixes "site-packages" with both
>>   sys.prefix and sys.exec_prefix. Is this really used anywhere ?
>>   (distutils and the old Makefile.pre.in both install to
>>   sys.prefix per default)
> 
> I thought they might install extension modules in exec_prefix.  But
> maybe it's a YAGNI.

Hmm, I've just built a Python interpreter with different
prefix and exec_prefix settings: using such an interpreter
lets distutils default to the exec_prefix subtree. However,
Python itself does not create a site-packages directory in
that tree (make install creates this directory in
$(prefix)/lib/pythonX.X/ and not $(exec_prefix)/lib/pythonX.X/).

-- 
Marc-Andre Lemburg
CEO eGenix.com Software GmbH
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