I got an error message while running setup.py develop that I don't understand: seems the error message claims an automatic install of a dependency failed, even though the dependency's egg actually did get installed and appears correct. (A bit tangential, but explanatory) background: Noting PJE's doc update repeating your recomendation to run setup.py develop. I wondered how setuptools would handle fetching a newer SVN revision of a dependency D installed with setup.py develop from an SVN checkout when running setup.py develop on a project P that depends on D. Would it use the .egg-link file to find and update the original working copy from which D was installed, or instead create a fresh SVN checkout? D == ClientForm P == mechanize So, I tried the following: 1. Installed ClientForm in site-packages from an SVN checkout using setup.py develop 2. Installed mechanize, which depends on Clientform, from an SVN checkout using setup.py develop 3. Modified my local copy of mechanize's setup.py to require a newer revision of ClientForm than I had installed in step 1. The modified dependency reads "ClientForm>=0.2.2-r21160, ==dev" 4. Ran python setup.py develop again for mechanize. That last step installed an egg with the right name (using a fresh checkout, which I guess answers the question above that motivated me), but also ended with this error message: error: Could not find required distribution ClientForm==dev,>=0.2.2-r21160 However, the ClientForm egg did in fact get installed and does indeed contain revision 21160. So, why the error message? Full output of step 4: mechanize[0]# python setup.py develop running develop running egg_info writing requirements to ./mechanize.egg-info/requires.txt writing ./mechanize.egg-info/PKG-INFO writing top-level names to ./mechanize.egg-info/top_level.txt running build_ext Creating /usr/lib/python2.3/site-packages/mechanize.egg-link (link to .) mechanize 0.0.12a.dev-r20866 is already the active version in easy-install.pth Installed /hda/usr/local/buf/comp/dev/wwwsearch/wwwsearch/mechanize Processing dependencies for mechanize==0.0.12a.dev-r20866 Searching for ClientForm==dev,>=0.2.2-r21160 Reading http://www.python.org/pypi/ClientForm/ Reading http://wwwsearch.sourceforge.net/ClientForm/ Best match: ClientForm dev Downloading http://codespeak.net/svn/wwwsearch/ClientForm/trunk#egg=ClientForm-dev Doing subversion checkout from http://codespeak.net/svn/wwwsearch/ClientForm/trunk to /tmp/easy_install-31mf3S/trunk Processing trunk Running setup.py -q bdist_egg --dist-dir /tmp/easy_install-31mf3S/trunk/egg-dist-tmp-qFDl23 Removing ClientForm 0.2.2.dev-r20620 from easy-install.pth file Adding ClientForm 0.2.2.dev-r21160 to easy-install.pth file Installed /usr/lib/python2.3/site-packages/ClientForm-0.2.2.dev_r21160-py2.3.egg error: Could not find required distribution ClientForm==dev,>=0.2.2-r21160 mechanize[0]# mechanize[0]# cd ../ClientForm ClientForm[0]# svn st -u ? README.html * 20620 README.html.in * 20620 test.py * 20620 setup.py M * 20620 ClientForm.py ? ClientForm.egg-info ? ClientForm.pyc X ez_setup Status against revision: 21261 Performing status on external item at 'ez_setup' ? ez_setup/__init__.pyc Status against revision: 2110 ClientForm[0]# cat /usr/lib/python2.3/site-packages/mechanize.egg-link /hda/usr/local/buf/comp/dev/wwwsearch/wwwsearch/mechanizeClientForm[0]# pwd /home/john/comp/dev/wwwsearch/wwwsearch/ClientForm ClientForm[0]# John