Shared Commit Lint

name: Shared - Commit Lint

on:
  workflow_call:
    inputs:
      runner:
        description: 'Runner type'
        required: false
        type: string
        default: 'ubuntu-latest'

# Least privilege for what this workflow actually does. Without it the
# job inherits whatever the calling repository's default happens to be,
# which on older repositories is write-all.
permissions:
  contents: read

jobs:
  commitlint:
    name: Lint Commit Messages
    runs-on: ${{ inputs.runner }}
    # npm install plus lint; a hung install should not hold the runner for
    # GitHub's six-hour default, and this job runs in every consumer at once.
    timeout-minutes: 10
    steps:
      - name: Checkout
        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7.0.1
        with:
          fetch-depth: 0

      - name: Install commitlint
        run: |
          npm install --save-dev @commitlint/config-conventional @commitlint/cli

      # commitlint resolves its rules from the *consumer* repository. With no
      # config there it loads an empty rule set and exits 9 (`[empty-rules]`)
      # before reading a single commit, so the gate fails for reasons that have
      # nothing to do with the commits. Supply the conventional preset in that
      # case; a repo that ships its own config is left untouched.
      - name: Provide a default config when the repository has none
        run: |
          for f in commitlint.config.js commitlint.config.cjs commitlint.config.mjs \
                   commitlint.config.ts commitlint.config.json commitlint.config.yaml \
                   commitlint.config.yml .commitlintrc .commitlintrc.js .commitlintrc.cjs \
                   .commitlintrc.mjs .commitlintrc.ts .commitlintrc.json .commitlintrc.yaml \
                   .commitlintrc.yml; do
            if [ -f "$f" ]; then
              echo "Using the repository's own config: $f"
              exit 0
            fi
          done

          if [ -f package.json ] && grep -q '"commitlint"' package.json; then
            echo "Using the commitlint key in package.json"
            exit 0
          fi

          echo "No commitlint config found; falling back to @commitlint/config-conventional"
          echo "module.exports = { extends: ['@commitlint/config-conventional'] };" > commitlint.config.js

      - name: Validate PR commits
        if: github.event_name == 'pull_request'
        run: npx commitlint --from ${{ github.event.pull_request.base.sha }} --to ${{ github.event.pull_request.head.sha }} --verbose

      - name: Validate last commit
        if: github.event_name != 'pull_request'
        run: npx commitlint --from HEAD~1 --to HEAD --verbose