[Distutils] Why is requiring version 0.0.1 when both 0.0.1 and 0.0.2 are available a conflict?

[P.J. Eby]

At 12:45 AM 8/17/2009 -0700, ryles wrote:
>Can someone explain what exactly the conflict is (I'm guessing
>pkg_resources is unhappy that 0.0.2 is already on sys.path)?

You guess correctly.

>I'd like for users to be able to explicitly use the older version if
>they're not yet comfortable with the new one. And a user just writing
>a simple script without wanting setuptools, or even simply trying
>something in the interactive interpreter, should be able to access the
>latest version without needing to know about pkg_resources.

Whichever version you install later will be the default in the 
interpreter, unless you use --multi-version.

Note, however, that a script whose setup.py requires a non-default 
version of the package will still work.  In other words, if you 
create another project with a setup.py that requires version 0.0.1, 
then upon installation that project's scripts will use 0.0.1, even 
though the interpreter's default will remain 0.0.2.