Pipenv in emacs

org-mode is a really good and powerful interface for literate programming. It also forms a good substitute for Jupyter notebooks when collaboration isn’t particularly required on the project. Though, there is one problem that occurs when using python in org-mode - it uses the default system-wide python installation for running the code-blocks. Since using python for various projects requires using virtual environments, it becomes essential to be able to use them inside org-mode. I use pipenv for managing my virtual environments. To use that in emacs, I found the pipenv.el package that seems to provide all the necessary functionalities to use pipenv in emacs. It can be installed using straight.el directly

    (use-package pipenv
      :straight t
      :hook ((python-mode-hook . pipenv-mode)
             (org-mode-hook . pipenv-mode))
      )

This enables the pipenv-mode minor mode while using python-mode or org-mode. This should provide functions like pipenv-activate and pipenv-deactivate to activate the required virtual environment and pipenv-install to install any package and add it to the Pipfile.

When I enabled the pipenv-mode minor mode and ran M-x pipenv-activate in a directory that contained a Pipfile, it showed me an error Searching for program: No such file or directory, pipenv. I tried restarting the emacs session but it did not work.

1. Getting pipenv to work

After running into the issue, I decided going into the source code to see what’s going wrong. First important thing that I noticed was that the function pipenv-activate checks if the current directory or any of its parent directory is a pipenv project via the pipenv-project? function. This is done using the locate-dominating-file function and returns the path to the first found directory that contains Pipfile.

  (defun pipenv-project? ()
    "Are we in a Pipenv project?"
    (locate-dominating-file default-directory "Pipfile"))

pipenv-activate then waits for the pipenv-venv function to return the path to the virtual environment for the current project. On trying this function on a file in a pipenv project, I found out that it was this function that was throwing the error. This also made the error more clear as I realised that it is trying to run the pipenv --venv command and couldn’t find the pipenv executable. On further inspection, I found out that the pipenv executable was in ~/.local/bin/ which was not in the emacs exec-path variable. So, adding this path should potentially resolve this issue.

  (add-to-list 'exec-path "~/.local/bin")

Yay! pipenv-activate works now :)