I have a ns.pkg2 package that depends on ns.pkg1 package. I make a fork of it, publish it to git and want to install my version into my virtualenv. I use pip install -e mygit and end up with ns.pkg in <env>/local/lib/python2.7/site-packages/ns/pkg1 and ns.pkg2 in <env>/src/ns.pkg2 with an <env>/lib/python2.7/site-packages/ns.pkg2.egg-link. Now I can import ns and ns.pkg1 but not ns.pkg2. I couldn't find a way to install a package from git without pip install -e that calls setup.py develop. Also, I'm not sure it's not a problem with module code.

So, is it possible to co-install two modules from the same namespace from a tarball and directly from git?

There is an open issue in pip related to --editable and namespace installations: https://github.com/pypa/pip/issues/3

A workaround was merged, and maybe you can solve your problem by doing:

$ pip install -e mygit --egg