A couple of years ago I wrote an article about dealing with typos in your source code. Today I’ll follow up with a simple recipe to automate this spell-checking process using GitHub Actions (GHA).1

Lately I’ve been adding the following GHA workflow to all of my OSS projects:

name: Spell Checking

on: [pull_request]

jobs:
  codespell:
    name: Check spelling with codespell
    runs-on: ubuntu-latest
    strategy:
      matrix:
        python-version: [3.8]
    steps:
      - uses: actions/checkout@v2
      - name: Set up Python $
        uses: actions/setup-python@v2
        with:
          python-version: $
      - name: Install dependencies
        run: |
          python -m pip install --upgrade pip
          pip install codespell
          if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
      - name: Check spelling with codespell
        run: codespell --ignore-words=codespell.txt || exit 1
  misspell:
    name: Check spelling with misspell
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v2
      - name: Install
        run: wget -O - -q https://git.io/misspell | sh -s -- -b .
      - name: Misspell
        run: ./misspell -error

There’s nothing fancy here. We’re just installing a couple of popular spell-checkers for code and we run them on everything within the Git repository. If they discover any problems the build will fail.

Just save the code above under .github/workflows/spell_checking.yml and you’re good to go. The workflow will get triggered for each subsequent pull request.

A couple of things to note:

  • This workflow uses both codespell and misspell. Using both might be an overkill for some of you. Personally, I like misspell more, as it’s super fast.
  • It’s a good idea to run both tools locally first and address any existing typos.
  • You may want to limit the checks only to files that were changed in the pull request.
  • You may want to specify a locale for misspell if you want to enforce a specific flavor of English (e.g. misspell -locale US).
  • This should probably be made a reusable workflow. I won’t be surprised if someone actually has created a public reusable workflow for spell-checking code already.

That’s all I have for you today. Big thanks to my fellow OSS hacker Koichi Ito, who came up with the idea of making spell-checking a CI step. In hindsight it seems like a very obvious thing to do, but it was always an afterthought for me. I’d be curious to hear how others are dealing with typos in their codebases.

  1. The outlined approach can easily be adapted for any other CI. ↩