[Python-Dev] Re: Patch level versions and new features (Was: Some dull gc stats)

[Barry A. Warsaw]

>>>>> "MvL" == Martin v Loewis <martin@v.loewis.de> writes:

    >> For cases like the email package or distutils, I think it's
    >> perfectly OK to only provide the updates for older Python
    >> releases as separate download. Both have their own way of life,
    >> so IMHO this is acceptable.

    MvL> In neither case, this is really possible: Once you have the
    MvL> package in the Python core, a separate installation in
    MvL> site-packages cannot override the core implementation.

    MvL> I believe that was the motivation for Barry to consider
    MvL> backporting large amounts of changes. The same holds for
    MvL> distutils, except that there aren't that many major changes.

Exactly.  For my own purposes (e.g. Mailman) it's no problem; I
provide my own email package and arrange for MM to use it before the
Python standard one.  I actually think it's the right thing for a
normal distutils install to not override the standard version.

But I also think there is a use case for allowing a standard package
to be separately upgraded for a particular Python installation.  As
more and more standard Python libraries are packagized, they will
probably have life-cycles separate from the Python core themselves
(this will only be more true once we evolve toward a CPAN-like
arrangement).  So I think we will eventually need a way to upgrade
(not override :) a standard library package.

My suggestion would be to prepend a new directory on the standard
search path, let's call it site-upgrade for now.  A normal "python
setup.py install" would still install to site-packages, but we'd add a
"python setup.py upgrade" command that would install to site-upgrade.

-Barry