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Fix the annoying ‘Virtual environment already activated’ error

· 2 min read
Drew Ayling
Drew Ayling
Staff Software Engineer @ Ford

**shakes fist at poetry and zsh**​

If you’re like me, you spend a lot of time in the terminal window of your IDE. Sometimes, you do unrelated project things in this window instead of a system terminal. I appreciate how VS Code automatically loads the project’s virtualenv when I open the terminal window.

If you don’t, you still might need to do something like setting a key as an environment variable in your ~/.zshrc or, if you’re not a zsh user, you might need to load a new shell when your virtualenv is already active.

If you use poetry for your Python project management, you know what happens when you source the rc file.

poetry error

As you can see, the virtualenv can’t be activated with the poetry shell command anymore.

Simple Fix​

Add this to the bottom of your ~/.zshrc, depending on your shell configuration and system.

if [ -n $VIRTUAL_ENV ]; then
    echo “reactivating virtualenv”
    source “$VIRTUAL_ENV/bin/activate”
fi

See it in action:

poetry fix

Why does this work?​

The venv module in Python automatically sets the $VIRTUAL_ENV environment variable. So this works not just with poetry, but with anything using the built-in venv package.

When you source ~/.zshrc a new zsh shell is loaded, thus deactivating the virtual env. If you’re not using zsh, when you load a new shell, the virtualenv is also deactivated.

This works by simply checking for the virtualenv path that was active when the new shell launches and activates it again. Viola.

Hope this helps speed up your development!