markdown-checks.yaml

name: Markdown linter

# What the execution context is:
# The creation of a pull request. Can also be triggered manually.

# What it does:
# Performs Markdown linting on the content of the pull request.

# Why we need it:
# To maintain a level of consistency in the markup content.

# What's important to know:
# As well as the rules defined in the configuration, a custom
# rule is also employed to check title case.

on:
  workflow_dispatch:
  pull_request:
    branches: [main]
    paths: 'docs/**'

jobs:
  main:
    if: contains(github.repositoryUrl, 'github.com')
    runs-on: ubuntu-20.04
    steps:

    - id: checkout_repo
      name: Check out the repository content
      uses: actions/checkout@v2

    - id: check_files_changed
      uses: dorny/paths-filter@v2
      with:
        list-files: 'escape'
        filters: |
          changed:
            - 'docs/**'

    - id: add_matcher
      name: Add the matcher for markdownlint style message output
      run: "echo ::add-matcher::.github/workflows/markdownlint/problem-matcher.json"

    - id: install_linter
      name: Install linting tool, custom rule and rule helpers
      run: |
        npm install \
          --no-package-lock \
          --no-save \
          markdownlint-cli@0.27 markdownlint-rule-titlecase markdownlint-rule-helpers@0.18

    - id: run_linter
      if: steps.check_files_changed.outputs.changed_files
      name: Run linter with specific rules, on the docs/ content
      run: |
        npx markdownlint \
          --config .github/workflows/markdownlint/config.yaml \
          --rules .github/workflows/markdownlint/md901 \
          --rules markdownlint-rule-titlecase \
          ${{ steps.check_files_changed.outputs.changed_files }}