validate-pull-request.yml

name: Validate Pull Request

permissions:
  contents: read
  pull-requests: write

on:
  pull_request:
    branches:
      - main
    types:
      - opened
      - edited
      - synchronize
      - reopened

jobs:
  validate-title-and-commits:
    name: Validate Title and Commits
    runs-on: ubuntu-latest
    timeout-minutes: 5

    steps:
      - name: Checkout Code
        uses: actions/checkout@v4

      - name: Load valid tags
        id: load-tags
        run: |
          if [ ! -f ./.github/workflows/valid-tags.txt ]; then
            echo "::error::.github/workflows/valid-tags.txt file not found"
            exit 1
          fi

          echo "**Valid tags**: $(cat ./.github/workflows/valid-tags.txt | tr '\n' ',' | sed 's/,/, /g' | sed 's/, $//')" >> $GITHUB_STEP_SUMMARY

          TAG_REGEX=$(sed 's/[]\/$*.^|[]/\\&/g' ./.github/workflows/valid-tags.txt | paste -sd "|" -)

          # Matches:
          #   1) One or more valid tags at the beginning, directly adjacent, followed by at least one space, then text
          #   2) Text that does not start with '[' (i.e. no tags)
          echo "regex=^((($TAG_REGEX)){1,}[[:space:]]+.*|[^[]+.*)$" >> $GITHUB_OUTPUT

          echo "Built the regex: ^((($TAG_REGEX)){1,}[[:space:]]+.*|[^[]+.*)$"

      - name: Validate PR title
        id: validate_title
        run: |
          echo "### Validate PR Title" >> $GITHUB_STEP_SUMMARY
          REGEX="${{ steps.load-tags.outputs.regex }}"
          TITLE=$(jq -r '.pull_request.title // "No title found"' "$GITHUB_EVENT_PATH")

          ESCAPED_TITLE=$(echo "$TITLE" | sed 's/["\`\\$]/\\&/g')

          if [[ ! "$TITLE" =~ $REGEX ]]; then
            echo "- ❌ PR title \"$ESCAPED_TITLE\" is invalid." >> $GITHUB_STEP_SUMMARY
            echo "TITLE_VALID=false" >> $GITHUB_OUTPUT
          else
            echo "- ✅ PR title \"$ESCAPED_TITLE\" is valid." >> $GITHUB_STEP_SUMMARY
            echo "TITLE_VALID=true" >> $GITHUB_OUTPUT
          fi

      - name: Validate PR commits
        id: validate_commits
        run: |
          echo "### Validate PR Commits" >> $GITHUB_STEP_SUMMARY
          REGEX="${{ steps.load-tags.outputs.regex }}"
          git fetch --prune --unshallow origin ${{ github.base_ref }}
          COMMITS=$(git log origin/${{ github.base_ref }}..HEAD --pretty=format:"%s" --no-merges)

          INVALID_COMMITS=0

          while read -r COMMIT_MSG; do
          if [[ -z "$COMMIT_MSG" ]]; then
            continue
          fi
          ESCAPED_MSG=$(echo "$COMMIT_MSG" | sed 's/["\`\\$]/\\&/g')
          if [[ ! "$COMMIT_MSG" =~ $REGEX ]]; then
            echo "- ❌ Commit message \"$ESCAPED_MSG\" is invalid." >> $GITHUB_STEP_SUMMARY
            INVALID_COMMITS=$((INVALID_COMMITS+1))
          else
            echo "- ✅ Commit message \"$ESCAPED_MSG\" is valid." >> $GITHUB_STEP_SUMMARY
          fi
          done <<< "$COMMITS"

          if [[ $INVALID_COMMITS -gt 0 ]]; then
            echo "COMMITS_VALID=false" >> $GITHUB_OUTPUT
          else
            echo "COMMITS_VALID=true" >> $GITHUB_OUTPUT
          fi

      - name: Validation return code
        run: |
          if [[ "${{ steps.validate_title.outputs.TITLE_VALID }}" != "true" || "${{ steps.validate_commits.outputs.COMMITS_VALID }}" != "true" ]]; then
            exit 1
          fi