Twenty questions about the GPL July 13th, 2009

foo.py is a Python library released under the GPLv3. bar.py is a library distributed commercially. If bar contains import foo, must bar.py be released under the GPL? Does the answer change if foo.py does not ship with bar.py, but nonetheless requires foo.py to function? Does the answer change if foo.py does not ship with bar.py and does not require its presence to function? libfoo.so is a C shared library released under the GPLv3.…