Are you using the same machine for running automated tests (on several branches) *and* development (on several branches)?

Unless you are actually developing SQLAlchemy then you shouldn’t install it in development mode.

I would have all modules you depend on installed ‘normally’. Modules you are developing I personally wouldn’t have them installed at all, but keep them within my project structure and rely on the development / test environment to make sure they can be imported.

Polluting your test environment from your development environment should be avoided…

also, you should make sure you are using the same version of python for both the “python setup.py install” and running. If you have two versions, i.e. python2.4 and python2.5, you could by accident end up with a module installed for 2.4, but actually needed in 2.5.

as a debugging measure, start a python shell and do:
import sys
print sys.path

you’ll get the list of directories searched for your install. make sure to use the right python version like mentioned before.

PYTHONPATH should also work well (has for me). Have you exported it? i.e.
export PYTHONPATH=/home/me/pythonlibs
python myprog.py

or just prepend to the command line:
PYTHONPATH=/home/me/pythonlibs python myprog.py

If you want to you can just set the PYTHONPATH manually, the setup.py develop is just a convenience for you. I fail to see how Python package lookup is different from any other platform you are familiar with. It might work much better on Plan9 or some shit like that, but … … :-)

Using setuptool and setup.py develop it will install the package in your python packages folder, which on Debian is by default the system folder, which will be shared by all users.

Probably the easiest for you (And Jonathan told me he already recommended it to you) is to use virtualenv – http://pypi.python.org/pypi/virtualenv

Also this discussion probably belong in an internal mailing list of some sort :)

http://docs.python.org/dev/install/index.html#inst-search-path

Michael: No, that machine is only used for automated test runs. Several different projects though. BTW, I didn’t install SQLAlchemy in development mode, just with a regular easy_install… but for some reason Python sometimes “forgets” that it’s actually there (it gets lost from easy_install.pth somehow, but I have no idea why). When you say “installing normally”, do you mean in the system, like in /usr/lib/python/site-packages ? I’d rather not do that if possible, but installing in some “private directory” and using from there would be possible of course.

Sverre: PYTHONPATH didn’t work for me, maybe I did something wrong? Am I supposed to install things first so it works, or should I be able to just point PYTHONPATH to the directory with a fresh VCS checkout?

And thanks for the virtualenv thing, I’ll have a look!

Oh, and sorry for the comments not appearing, I was receiving tons of spam so I decided to make the comments invisible until I approved them… I didn’t really expect showing up on reddit :-P