Comment 4 for bug 1760956

In an interesting and relevant twist, coincidentally the same day we're dealing with pip >= 10.0 and python-apt on a separate bug which affected test execution environments (bug #1760720):

At least in the tempest charm, if I leave use_venv True and set use_system_packages False, I get apt import errors at charm run time. The charms are clearly leaning on the fact that some system-installed libraries are installed outside of the virtualenv (via debs in this case). Lines, blurred. Wires, crossed.

This is just one example, but it is a clear example of how we have missed fully declaring dependencies from a pure python standpoint.

Further ideas, debate, conversation are of course welcome.