I try to upgrade pip within a virtualenv following the instructions here. The upgrade fails because the system python cannot import the name Message from the email module.
(newsfeed)myhost:newsfeed admin$ pip install --upgrade pip
Traceback (most recent call last):
File "/Users/admin/newsfeed/newsfeed/bin/pip", line 7, in <module>
from pip import main
File "/Library/Python/2.7/site-packages/pip/__init__.py", line 9, in <module>
from pip.log import logger
File "/Library/Python/2.7/site-packages/pip/log.py", line 8, in <module>
from pip import backwardcompat
File "/Library/Python/2.7/site-packages/pip/backwardcompat/__init__.py", line 69, in <module>
from email import Message as emailmessage
ImportError: cannot import name Message
This problem is not just with upgrading pip but with installing anything within the virtualenv. When new package installations are attempted the same error occurs.
In a python terminal outside the virtualenv Message cannot be imported, but inside the virtualenv it can.
Also, in a different virtualenv on the same machine, there is no error installing or upgrading packages.
Why can't this virtualenv upgrade or install packages?