Odd one here. This worked before, but something has changed, perhaps upstream, perhaps in how source or the shell works.
If we go into a directory (lets call it foo) and do a python -m venv venv or virtualenv venv (if installed), the venv directory is created and contains venv/bin/activate. While in this terminal, can do source venv/bin/activate and it works (the python virtual environment is loaded and we get the (venv) prompt.) Then deactivate works.
But if a bash script named start is created here in foo, set executable, and contains source venv/bin/activate, this silently fails and we do not get the (venv) prompt. Tried many combinations of no/relative/full path, no/bash/env bash shebang, etc. It always just silently fails.
This worked awhile ago. Any ideas what changed, and what we can do to start a venv from a script?