On Tue, 23 Jun 2020, at 23:51, David Mathog wrote:
What I am after is some method of keeping exactly one copy of each package-version in the common area (ie, one might find foo-1.2, foo-1.7, and foo-2.3 there), while also presenting only the one version of each (let's say foo-1.7) to a particular installed program. On linux it might do that by making soft links to the common PYTHONPATH area from another directory for which it sets PYTHONPATH for the application. Finally, this has to be usable by any account which has read execute access to the main directory.
Conda environments work somewhat like this - all the packages are stored in a central place, and the structure of selected ones is replicated using hardlinks in a site-packages directory belonging to the environment. So if your concern is not to waste disk space by storing copies of the same packages, that might be an option.