Import bugs seem to be especially difficult to reduce the testcase, since it's often unclear what the hell is going on. Reduced from some large bunch o' code: $ ipy test.py False $ python test.py True File contents follow: # test.py import a print hasattr(a, 'c') # a/__init__.py import b # a/b.py import c # a/c.py #empty -- Seo Sanghyeon