[Python-Dev] Order that site-packages is added to sys.path

[Barry A. Warsaw]

>>>>> "MAL" == M  <mal@lemburg.com> writes:

    MAL> I guess this is done for the same reason that e.g. /usr/local
    MAL> is last in PATH on Unix: system top level programs and libs
    MAL> should always have top priority. Otherwise, a user could
    MAL> easily override a system program/lib by placing a new version
    MAL> into the local dir which then gets picked up by other system
    MAL> programs.

Well, hopefully you'd control who can write into /usr/local so that
you could trust overrides being installed there.  On a single user
system, I usually do in fact put /usr/local/bin early in my path
specifically because I do want to override older, buggier, system
programs.

The analogy is similar in the Python situation.  When I'm the only
person using the system, and I'm in control of everything, being able
to override the standard library is a very useful thing to do.  When
there's less trust in the environment I'm running in, or more sharing
of common resources, it can be problematic.

-Barry