Can existing virtualenv be upgraded gracefully?

Question

I have a virtualenv created for Python 2.5 and want to "upgrade" it to Python 2.6.

Here is how it was originally set up:

virtualenv --no-site-packages -p python2.5 myenv

I now run virtualenv in the same directory to upgrade:

virtualenv --no-site-packages -p python2.6 myenv
...
Not overwriting existing python script myenv/bin/python (you must use myenv/bin/python2.6)
...
Overwriting myenv/bin/activate with new content

The default python is still 2.5, even though I can also specify 2.6. Is there any way to remove 2.5 entirely and have 'bin/python' point to 2.6 instead?

Answer 1

You should create a new virtualenv using python2.6 and then, after activating the new env, use its python2.6 and its easy_install to install new versions of any site packages you need. Beware that the path name to the virtualenv is hardwired into various files within the environment, so, when you are ready to switch over to it, either change your startup scripts et al to refer to the new virualenv path or be very careful about copying it over to the old directory and modifying the path names inside it.

Answer 2

You can use the Python 2.6 virtualenv to "revirtual" the existing directory. You will have to reinstall all the modules you installed though. I often have a virtual directory for developing a module, and virtualenv the same directory with many versions of Python, and it works just fine. :)