I can't upgrade the pip in a Python virtual environment

[sirgazil]

Hello,

I'm confused about using Python virtual environments in the GNU system. I used 
to do the following on Debian to create a virtual environment for writing 
documentation in Sphinx:


#+BEGIN_EXAMPLE
$ python3 -m venv ~/.virtualenvs/ezfinge
$ source ~/.virtualenvs/ezfinge/bin/activate
(ezfinge) $ pip install Sphinx
[...]
You are using pip version 18.1, however version 19.1.1 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.
#+END_EXAMPLE

After this, I can create Sphinx-based documentation and build it normally. 
However, when I try to upgrade pip following the recommendation above, I get 
the following message:


#+BEGIN_EXAMPLE
(ezfinge) $ pip install --upgrade pip
Collecting pip
  Using cached 
https://files.pythonhosted.org/packages/5c/e0/be401c003291b56efc55aeba6a80ab790d3d4cece2778288d65323009420/pip-19.1.1-py2.py3-none-any.whl
Installing collected packages: pip
  Found existing installation: pip 18.1
    Not uninstalling pip at 
/gnu/store/x67xvqx6jmgln1dxyvhvc7k9grbcdvy6-profile/lib/python3.7/site-packages,
 outside environment /home/sirgazil/.virtualenvs/ezfinge
    Can't uninstall 'pip'. No files were found to uninstall.
Successfully installed pip-19.1.1
You are using pip version 18.1, however version 19.1.1 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.
#+END_EXAMPLE


>From my Debian experience, I would expect pip to be upgraded and the message 
>at the end would disappear. I get this information about the pip in the Python 
>environment:


#+BEGIN_EXAMPLE
(ezfinge) $ which pip
/home/sirgazil/.virtualenvs/ezfinge/bin/pip
(ezfinge) $ pip --version
pip 10.0.1 from /home/sirgazil/.guix-profile/lib/python3.7/site-packages/pip 
(python 3.7)
#+END_EXAMPLE

I don't understand why the pip 19.1.1 is not seen. I also don't understand 
where the pip 10.0.1 comes from (the pip 18.1 is the one installed in my user 
profile).


I'm using this Guix:

#+BEGIN_EXAMPLE
$ LANG=C guix describe
Generation 3    Jun 15 2019 09:49:31    (current)
  guix ddd401d
    repository URL: https://git.savannah.gnu.org/git/guix.git
    branch: master
    commit: ddd401d28fb09f1f8ce96f2fc24226887a812412
#+END_EXAMPLE


Thanks,



---
https://sirgazil.bitbucket.io/