setup.py installs modules to a wrong place

[Michal Ludvig]

Hi,

I have recently seen some reports from users of my s3cmd script [1] who
installed the package using the provided distutils-based setup.py and
immediately after installation the script failed to run because it
couldn't find its modules.

Here's an example session from Mac OS X, but similar behaviour has been
observed on Ubuntu as well. Needless to say it works for me just fine so
I can't easily debug and fix it :-(

First is the reported setup.py output:

-----
~/bin/s3cmd $ sudo python setup.py install
Password:
....
running install_lib
creating /usr/lib/python2.5/site-packages
creating /usr/lib/python2.5/site-packages/S3
copying build/lib/S3/PkgInfo.py -> /usr/lib/python2.5/site-packages/S3
.... more modules, etc ...
-----

It decided to put the modules to /usr/lib/python2.5/site-packages/S3

Now, s3cmd should import from there, but fails:

~/bin/s3cmd $ s3cmd
Traceback (most recent call last):
File "/usr/bin/s3cmd", line 1207, in <module>
from S3 import PkgInfo
ImportError: No module named S3

sys.path at the time the script died had these entries:
/usr/bin
/System/Library/Frameworks/Python.framework/Versions/2.5/lib/python25.zip
/System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5
/System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/plat-darwin
/System/Library/Frameworks/Python.framework/Versions/2.5/...other_subdirs...
/Library/Python/2.5/site-packages

There is nothing special in setup.py. After all have a look yourself:
http://s3tools.svn.sourceforge.net/viewvc/s3tools/s3cmd/trunk/setup.py?view=markup

What could be the reason for distutils / setup.py to install the modules
to a directory that's not in sys.path? Can I detect it in setup.py and
prevent or workaround it somehow?

Thanks!

[1] http://s3tools.logix.cz/s3cmd -- Amazon S3 command line client

Michal