Windows, activate_this assumes *nix path to site-packages

[vbabiy]

==== The problem

When I attempt to use the activate_this.py script to activate an environment on Windows, the script appears to have correctly reworked the python path through sys.path. However, I am unable to import any module installed to the virtualenv's site-packages.

==== The cause

I believe this is because the activate_this.py script assumes the path to the "site-packages" directory is the same on all platforms, but it is not. The location of the site-packages directory in virtualenvs on Windows is different from the location of the same directory on *nix type OSes.

On *nix type platforms, the location of site-packages is a directory on a path that is dependent on the Python version that was used to create the virtualenv.

So assuming the virtualenv was created with Python2.5, the activate_this.py script should use the location:

VIRTUALENV_BASE/lib/python2.5/site-packages/

On the other hand, with virtualenvs on Windows, the site-packages directory is located at:

*VIRTUALENV_BASE\Lib\site-packages*

==== Possible solution

I think this could be resolved with a simple check like:

#!python
if sys.platform == 'win32':
    # use windows site-packages path
else:
    # use *nix style site-packages path

==== Steps to re-create

Assumptions:

• Your development setup is a Windows box with Python (2.5 or 2.6) installed
• You have virtualenv<=1.4.6 installed

1. Create an isolated virtualenv and install a simple package in it:

#!console
> virtualenv --no-site-packages mytestenv
> mytestenv\Scripts\activate.bat
(mytestenv) > pip install Yolk
(mytestenv) > yolk --list
pip             - X.Y.Z        - active
setuptools      - X.Y.Z        - active
yolk            - X.Y.Z        - active
(mytestenv) > deactivate
>

2. Verify that you can import the module in the python shell when the virtualenv is activated with the batch file.

#!console
> mytestenv\Scripts\activate.bat
(mytestenv) > python



#!python
>>> import yolk
>>> 

3. Create a python test script to activate the environment in python and import the "Yolk" module

#!python
import os

# Activate the environment with activate_this.py
here = os.path.abspath(os.path.dirname(__file__))
activate_this = os.path.join(here, 'mytestenv', 'Scripts', 'activate_this.py')
execfile(activate_this, dict(__file__=activate_this))

import yolk

Save the file as smalltest.py and try to run it.

IMPORTANT -- to recreate this issue properly, ensure that your virtualenv has been deactivated prior to running the smalltest.py script.

#!console
> python smalltest.py
Traceback (most recent call last):
    ...
ImportError: No module named yolk

Observe that the import failed because the virtualenv was not properly activated by executing the activate_this.py script.

---

Local development environment:

• Python 2.5.4
• Virtualenv 1.4.6
• Windows XP (SP3)

---

If you are interested in how I discovered this problem, you may refer to :

• http://stackoverflow.com/questions/2643612/activate-a-python-virtual-environment-using-activate-this-py-in-a-fabfile-on-win

---

• Bitbucket: https://bitbucket.org/ianb/virtualenv/issue/31
• Originally Reported By: Rudy Lattae
• Originally Created At: 2010-04-20 05:12:31

[vbabiy]

• Changed title from The "activate_this.py" script assumes a *nix like path
  to site-packages on Windows to Windows, activate_this assumes a *nix like path
  to site-packages.

---

Original Comment By: Rudy Lattae

[vbabiy]

• Changed title from Windows, activate_this assumes a *nix like path to
  site-packages to Windows, activate_this assumes *nix path to site-packages.

---

Original Comment By: Rudy Lattae

[vbabiy]

To get the ball rolling on this issue, I implemented and tested what I hope is
a decent fix for the issue. The fix is to have activate_this.py check which
platform it is running on before it crafts the path to the site-packages
directory.

NOTE: I only tested this on Windows XP (32bit) I have not tested it on Vista,
7, or any 64 bit versions.

Hope it helps.

---

Original Comment By: Rudy Lattae

[vbabiy]

Fix #31, make activate_this.py work on Windows (use Lib/site-packages)

→ [Author: ianb

Age: 11 months ago

Fix 31, make activate_this.py work on Windows (use Lib/site-
packages)">r296:9d4f196d2bf4]2

assumes-nix-path-to

---

Original Comment By: Ian Bicking

[vbabiy]

Note I haven't tested this change myself, if it didn't fix the problem please
reopen this ticket.

---

Original Comment By: Ian Bicking