deactivate not available in tmux session started from a virtual environment

[nakulj]

Bug report

In Fish, when starting tmux after activating a virtual environment, the deactivate command is not available in the tmux session.

$ python3 -m venv .venv
$ source .venv/bin/activate.fish
(.venv) $ tmux

This starts a tmux session with the virtual environment already activated, and working sort of correctly, but impossible to deactivate:

(.venv) $ echo $VIRTUAL_ENV
~/test/.venv
(.venv) $ which python
~/test/.venv/bin/python
(.venv) $ deactivate
fish: Unknown command: deactivate

Your environment

• CPython versions tested on: Python 3.11.2
• Operating system and architecture: macOS Ventura, M1
• Fish version- 3.6.1
• tmux version- 3.3a

Linked PRs

• gh-103291: Re-activate virtual environments in child processes #103447

[arhadthedev]

@vsajip (as a venv module expert)

[nakulj]

@thomasbbrunner any ideas on how to fix this? It appears related to #93858

[thomasbbrunner]

@nakulj I don't think venv supports having the virtual environment activated for child processes (e.g. tmux). It just happens to work, because the environment variables are exported to the child process.

You would have to activate the venv inside the tmux session again. With the fix in #93858, this shoud work :)

Either way, check if the implementation of virtualenv supports what you want to do. If it does, consider making a PR with the fix (the venv implementation is based on virtualenv).

[nakulj]

Thanks! That makes sense. I just confirmed that the same 'bug' happens with virtualenv.

I tried writing a fix anyway, please take a look! :)