Comment 6 for bug 619294

Turns out the __init__.py file is needed when trying to use uninstalled zope packages, or virtualenv without --no-site-packages option.

setuptools.find_packages does not recurse into packages that do not have an __init__.py file, so they are not included in results, and that may cause problems, but I do not have a test case to demonstrate that. One problem is that z3c.autoinclude does not find the target package. schooltool uses it to automatically include plugins, but I get a KeyError: 'schooltool' if schooltool/__init__.py is not installed.

A dependency on the namespace package may force the packager to create one.