[Distutils] Is there any harm in clearing sys.path_importer_cache from time to time?

[Phillip J. Eby]

At 11:37 AM 6/23/2006 -0400, Jim Fulton wrote:
>I have a script based on setuptools that invokes easy install to
>check for
>and download newer distributions.  I allow users to specify whether or
>not they want unzipped downloads.  As a result, easy_install will
>sometimes
>replace a zip file with a directory or the other way around.  This
>leads to
>problems in the invoking program because the sys.path_importer_cache
>is stale.  Does anyone know if it is safe to clear the cache from
>time to
>time?  If so, I'd be inclined to clear it any time I invoke
>easy_install.

Hm.  easy_install should be doing this itself...  oh wait, it's clearing 
the *zip directory cache*, which fixes the problem of overwriting a zip 
with a zip.  You're having a problem when overwriting a zip with a 
directory.  Now I understand why sometimes I still get reports of behavior 
that resembles this problem, but then they aren't reproducible.

I'll fix easy_install to also clear the path importer cache for a path 
entry when it clears the zip directory cache for that entry.

(And to answer your general question, it's fine to clear the 
path_importer_cache, per PEP 302's advice to do so whenever you add new 
import hooks.  It just slows down the next import search a bit.)