[Distutils] patch: ez_setup.py: separate default version and minimum version of setuptools

[Phillip J. Eby]

At 12:56 PM 9/27/2007 -0600, zooko wrote:
>>>Thank you for setuptools!  We are using it in the Allmydata-Tahoe
>>>project [1].  We've patched ez_setup.py so that installation can
>>>proceed if an older version of setuptools is already present, as long
>>>as that version is not too old.  This allows ez_setup.py to work
>>>seamlessly in more situations.  Please apply.
>
>>It's not clear to me why the patch is necessary.  If you reference
>>a specific version of setuptools in your call to ez_setup(), the
>>behavior is almost identical.  The only difference is that if there
>>is no setuptools installed, then the version you specified in your
>>setup.py will be used for the installation.
>
>The situation was that a user had a version of setuptools installed
>(I think it was v0.6c5), and the ez_setup.py specified setuptools
>v0.6c6 (which was at that time the current version).  So, when the
>user executed "./setup.py", then he got an error saying that it
>wasn't possible to upgrade setuptools after setuptools was already
>loaded.
>
>With our patch, this is no longer a problem -- v0.6c5 is new enough
>to work, and so the setup.py execution proceeds after the check
>without attempting to install a newer version of setuptools.

If you invoke 'use_setuptools("0.6c5")', you would get the same 
behavior with an unpatched ez_setup.py.