[Python-Dev] Distutils and Distribute roadmap (and some words on Virtualenv, Pip)

Masklinn masklinn at masklinn.net
Thu Oct 8 18:35:45 CEST 2009

On 8 Oct 2009, at 18:17 , Toshio Kuratomi wrote:
>> This is not at all how I use virtualenv. For me virtualenv is a
>> sandbox so that I don't have to become root whenever I need to  
>> install
>> a Python package for testing purposes
> This is needing to install multiple versions and use the newly  
> installed
> version for testing.
No it's not. It's keeping the python package *being tested* out of the  
system's or user's site-package because it's potentially unstable or  
unneeded. It provides a trivial way of *removing* the package to get  
rid of it: delete the virtualenv. No trace anywhere that the package  
was ever installed, no impact on the system  (apart from the potential  
side-effects of executing the system).

The issue here isn't "multiple installed packages", it will more than  
likely be the only version of itself: note that it's a package being  
tested, not an *upgrade* being tested.

The issues solved are:
* not having to become root (solved by PEP 370 if it ever lands)
* minimizing as much as possible the impact of testing the package on  
the system (not solved by any other solution)

>> and to allow me to hop between
>> sets of installed Python packages while developing on multiple Python
>> projects.
> This is the ability to install multiple versions and specify different
> versions for different projects you're working on.
No, this is the ability to not needlessly clutter site-packages, keep  
them clean, tight, focused; and the ability to keep a project's  
environment (such as its dependencies) clear and repeatable. Nowhere  
was it indicated that multiple versions were involved.

Both of those *might* imply issues of multiple versions concurrently  
installed on the system, and virtualenv would incidentally solve these  
issues, but these issues are *not* the core of either use case.  
They're at best peripheral and potential.

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