Enforcing Python imports’ order with isort, Makefiles, and Vim

I finally integrated isort into my toolbox. I think that the job of changing code files belongs to the editor (or an IDE), so I made Vim run isort automatically, while the import order enforcement in a project is done via Makefile (which can be run the same way by developers and the CI/CD pipeline).

This post may be a bit chaotic, but it should give a glimpse of how I like to set up automation around quality assurance (like tests, linting, static checks, etc.) in my projects. I’d like to produce more comprehensive write-ups at some point in the future.

isort installation

First, the isort Python package needs to be available for your editor and the make commands wherever you are working, so:

  • add isort to your project’s dependencies and virtualenv. I use poetry for that: poetry add --dev isort

  • make isort available outside of any virtualenv (e.g. for small scripts), by installing it for your user. I use pipx for that: pipx install isort

VIM (editor) setup

If you’re not using Vim you’ll probably still find an isort plugin for your editor. Or maybe your IDE has import ordering built-in, like Pycharm.

You’ll need a Vim plugin - ALE - to run isort. I recommend vim-plug as the plugin manager. You can see how I set it up at the top of my .vimrc.

You can add the plugin by adding Plug 'dense-analysis/ale' in the right place in your .vimrc, and then issuing the :PlugUpdate command to Vim.

Then, add some more config into .vimrc:

" make ALE use isort
let g:ale_fixers = { 'python': ['isort'] }

" this will make :ALEFix, and thus import fix to run on file save
let g:ale_fix_on_save = 1

Configuring isort

Know that you can configure some aspects of how isort works. For example, I like to sort all my imports alphabetically on the referenced packages, without separating import XXX and from XXX import YYY statements. So I put this in my pyproject.toml:

force_sort_within_sections = true

Use in project’s Makefile

I like to have a validate Makefile target that runs all tests and static code checks. That target should be run by developers and the CI/CD pipeline.

isort can work as one of the static checks, if used with -c flag.

So we can have a Makefile looking like this:

validate: static_checks test

    pytest -v tests/

    isort -c the_code
    pylint the_code

Bonus: automatic imports fixer for Vim

One of the features I’m missing from Pycharm is automatic adding of missing imports. There’s a plugin called vim-nayvy that can do that, but I wasn’t able to get it to work with anything other than standard library imports. That is, it wouldn’t fix imports of third-party packages from site-packages or project/local packages.

Maybe that has something to do with me not having a Python Language Server running with NeoVim… I’ll see about that some other time.


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