buildout picks other (outdated) setuptools version than a simple "import setuptools" in system python (Mac OS X)

bin/buildout picks another setuptools version on my Mac OS X system than "import setuptools" in the system's /usr/bin/python. This seems unintuitive and from the conversations in the zope channel on freenode I believe this is probably a bug that should be fixed.

Basically, Mac OS X does have multiple versions of setuptools available:

/Library/Python/2.6/site-packages/setuptools-0.6c12dev_r85381-py2.6.egg/setuptools/__init__.py

/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/setuptools (0.6c9-py2.6)

Using the system python for a short test, everything seems to be fine:

    iMac01:~ jonasthiem$ python
    Python 2.6.1 (r261:67515, Feb 11 2010, 00:51:29)
    [GCC 4.2.1 (Apple Inc. build 5646)] on darwin
    Type "help", "copyright", "credits" or "license" for more information.
    >>> import setuptools
    >>> setuptools
    <module 'setuptools' from '/Library/Python/2.6/site-packages/setuptools-0.6c12dev_r85381-py2.6.egg/setuptools/__init__.py'>

Then using buildout, this happens:

    iMac01:p2.nosqlmyadmin jonasthiem$ bin/buildout -vvvv
    /Users/jonasthiem/p2.nosqlmyadmin/parts/buildout/site.py:262: UserWarning: Module pkg_resources was already imported from /System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/pkg_resources.pyc, but /Users/jonasthiem/p2.nosqlmyadmin/eggs/distribute-0.6.14-py2.6.egg is being added to sys.path
    import pkg_resources
    /Users/jonasthiem/p2.nosqlmyadmin/parts/buildout/site.py:262: UserWarning: Module site was already imported from /Users/jonasthiem/p2.nosqlmyadmin/parts/buildout/site.py, but /Users/jonasthiem/p2.nosqlmyadmin/eggs/distribute-0.6.14-py2.6.egg is being added to sys.path
    import pkg_resources
    Installing 'mr.developer', 'buildout.dumppickedversions'.
    We have the distribution that satisfies 'mr.developer==1.14'.
    We have the distribution that satisfies 'buildout.dumppickedversions==0.4'.
    While:
    Installing.
    Loading extensions.
    Error: There is a version conflict.
    We already have: setuptools 0.6c9
    iMac01:p2.nosqlmyadmin jonasthiem$