pr-check_markdownlint.yml

name: Markdownlint (PR files)

on:
  pull_request:
    branches:
      - main
    paths:
      - .nvmrc
      - "**/*.md"

jobs:
  lint-docs:
    runs-on: ubuntu-latest

    steps:
      - uses: actions/checkout@v3

      - name: Get changed files
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          BASE_SHA: ${{ github.event.pull_request.base.sha }}
          HEAD_SHA: ${{ github.event.pull_request.head.sha }}
        run: |
          # Use the GitHub API to get the list of changed files
          # documenation: https://docs.github.com/rest/commits/commits#compare-two-commits
          DIFF_DOCUMENTS=$(gh api repos/{owner}/{repo}/compare/${{ env.BASE_SHA }}...${{ env.HEAD_SHA }} \
            --jq '.files | .[] | select(.status|IN("added", "modified", "renamed", "copied", "changed")) | .filename')
          # filter out files that are not markdown
          DIFF_DOCUMENTS=$(echo "${DIFF_DOCUMENTS}" | egrep -i "^files/.*\.md$" | xargs)
          echo "DIFF_DOCUMENTS=${DIFF_DOCUMENTS}" >> $GITHUB_ENV

      - name: Setup Node.js environment
        uses: actions/setup-node@v3
        with:
          node-version-file: ".nvmrc"
          cache: yarn

      - name: Install all yarn packages
        run: yarn --frozen-lockfile

      - name: Lint markdown files
        run: |
          echo "::add-matcher::.github/workflows/markdownlint-problem-matcher.json"
          files_to_lint="${{ env.DIFF_DOCUMENTS }}"
          yarn markdownlint-cli2 ${files_to_lint}