If you're switching from Ubuntu Oneiric to Ubuntu Precise and you're
python-virtualenv, you might be in for a surprise:
The default access to the global site-packages modules is reversed between virtualenv 1.6.x and 1.7.
When you were used to finding your apt-get installed python modules like
python-psycopg2 in your new virtualenv
environment, now they're suddenly unavailable.
--no-site-packages Ignored (the default). Don´t give access to the global site-packages modules to the virtual environment.
That was not the default before.
The new option to get the old behaviour:
--system-site-packages Give access to the global site-packages modules to the virtual environment.
By the way, if you already populated your new virtualenv directory with
the 1.7 version, you don't need to recreate it. Removing the
no-global-site-packages.txt is enough:
# find /srv/django-env -name no-global-site-packages.txt /srv/django-env/mysite/lib/python2.7/no-global-site-packages.txt