python and bpython using different PYTHONPATHs in Virtualenv

Question

Something strange and unexpected is happening with the sys.path of any virtual environment I set. For example, a clean env:

$ virtualenv test
$ source test/bin/activate
(test) $

This is the expected PYTHONPATH:

(test) $ python
>>> import sys
>>> print '\n'.join(sys.path)

/home/user/test/local/lib/python2.7/site-packages/setuptools-0.6c11-py2.7.egg
/home/user/test/local/lib/python2.7/site-packages/pip-1.1-py2.7.egg
/home/user/test/lib/python2.7/site-packages/setuptools-0.6c11-py2.7.egg
/home/user/test/lib/python2.7/site-packages/pip-1.1-py2.7.egg
/home/user/test/lib/python2.7
/home/user/test/lib/python2.7/plat-linux2
/home/user/test/lib/python2.7/lib-tk
/home/user/test/lib/python2.7/lib-old
/home/user/test/lib/python2.7/lib-dynload
/usr/lib/python2.7
/usr/lib/python2.7/plat-linux2
/usr/lib/python2.7/lib-tk
/home/user/test/local/lib/python2.7/site-packages
/home/user/test/lib/python2.7/site-packages

But this is the one I really get:

(test) $ bpython
>>> import sys
>>> print '\n'.join(sys.path)

/usr/bin
/usr/lib/python2.7
/usr/lib/python2.7/plat-linux2
/usr/lib/python2.7/lib-tk
/usr/lib/python2.7/lib-old
/usr/lib/python2.7/lib-dynload
/usr/local/lib/python2.7/dist-packages
/usr/lib/python2.7/dist-packages

I can't figure out the reason of the two different sys.paths. Because of that, no pip installation works! I'm using Virtualenv 1.7.2, Ubuntu 12.04, Python 2.7.3. Any help will be appreciated.

Answer 1

Rather than installing one copy of bpython per virtualenv, I've added this function to my shell profile (for example ~/.bashrc or ~/.zshrc). It wraps the bpython command with some logic to load the virtual environment's python path (if you have an active virtual environment).

bpython() {
    if test -n "$VIRTUAL_ENV"
    then
        PYTHONPATH="$(python -c 'import sys; print ":".join(sys.path)')" \
        command bpython "$@"
    else
        command bpython "$@"
    fi
}