pr-title.yml

name: Check Conventional Commits format

on:
  pull_request:
    branches: [ master ]
    # Revalidate if the title is corrected without a new code commit.
    types: [opened, reopened, synchronize, edited, ready_for_review]
  # The action does not support running on merge_group events,
  # but if the check succeeds in the PR there is no need to check it again.
  merge_group:
    types: [checks_requested]

permissions:
  pull-requests: read

jobs:
  main:
    name: Validate Conventional Commit PR title
    runs-on: ubuntu-latest
    # outputs:
    #   # Whether the PR title indicates a breaking change.
    #   breaking: ${{ steps.breaking.outputs.breaking }}
    #   # Whether the PR body contains a "BREAKING CHANGE:" footer describing the breaking change.
    #   has_breaking_footer: ${{ steps.breaking.outputs.has_breaking_footer }}

    # The following steps are only run on pull_request events. We add the
    # `if` statements to each individual step since we want the job to still
    # succeed in merge queues.
    steps:
      - name: Validate the PR title format
        uses: amannn/action-semantic-pull-request@v6
        if: github.event_name == 'pull_request'
        id: lint_pr_title
        with:
          # Configure which types are allowed (newline-delimited).
          # Default: https://github.com/commitizen/conventional-commit-types
          types: |
            feat
            fix
            docs
            refactor
            perf
            test
            ci
            chore
            revert
          # Configure that a scope must always be provided.
          requireScope: false
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

      # `action-semantic-pull-request` does not parse the title, so it cannot
      # detect if it is marked as a breaking change.
      #
      # Since at this point we know the PR title is a valid conventional commit,
      # we can use a simple regex that looks for a '!:' sequence. It could be
      # more complex, but we don't care about false positives.
      - name: Check for breaking change flag and footer
        if: github.event_name == 'pull_request'
        id: breaking
        run: |
          echo "=== Breaking change detection ==="

          if [[ "${PR_TITLE}" =~ ^.*\!:.*$ ]]; then
            BREAKING=true
            echo "ℹ️ PR title declares a breaking change (!)"
          else
            BREAKING=false
            echo "ℹ️ PR title does NOT declare a breaking change"
          fi

          if [[ "${PR_BODY}" == *"BREAKING CHANGE:"* ]]; then
            HAS_FOOTER=true
            echo "ℹ️ PR body contains BREAKING CHANGE footer"
          else
            HAS_FOOTER=false
            echo "ℹ️ PR body does NOT contain BREAKING CHANGE footer"
          fi

          echo "breaking=$BREAKING" >> "$GITHUB_OUTPUT"
          echo "has_breaking_footer=$HAS_FOOTER" >> "$GITHUB_OUTPUT"
        env:
          PR_TITLE: ${{ github.event.pull_request.title }}
          PR_BODY: ${{ github.event.pull_request.body }}

      - name: Require BREAKING CHANGE footer for breaking changes
        if: ${{ github.event_name == 'pull_request_target' && steps.breaking.outputs.breaking == 'true' && steps.breaking.outputs.has_breaking_footer == 'false' }}
        run: |
          echo "Hey there and thank you for opening this pull request! 👋"
          echo
          echo "It looks like your proposed title indicates a breaking change. If that's the case, please make sure to include a \"BREAKING CHANGE:\" footer in the body of the pull request describing the breaking change and any migration instructions."
          exit 1

      - name: Fail if the footer is required but missing
        if: ${{ github.event_name == 'pull_request_target' && steps.breaking.outputs.breaking == 'true' && steps.breaking.outputs.has_breaking_footer == 'false' }}
        run: exit 1

      - name: Post a comment if the PR badly formatted
        # When the previous steps fails, the workflow would stop. By adding this
        # condition you can continue the execution with the populated error message.
        if: always() && github.event_name == 'pull_request'  && (steps.lint_pr_title.outputs.error_message != null)
        run: |
          echo "Hey there and thank you for opening this pull request! 👋"
          echo ""
          echo "We require pull request titles to follow the [Conventional Commits specification](https://www.conventionalcommits.org/en/v1.0.0/) and it looks like your proposed title needs to be adjusted."
          echo ""
          echo "Your title should look like this. The scope field is optional."
          echo '```'
          echo "<type>(<scope>): <description>"
          echo '```'
          echo ""
          echo "If the PR includes a breaking change, mark it with an exclamation mark:"
          echo '```'
          echo "<type>!: <description>"
          echo '```'
          echo "and include a \"BREAKING CHANGE:\" footer in the body of the pull request."
          echo ""
          echo "Available types:"
          echo "- feat: A new feature"
          echo "- fix: A bug fix"
          echo "- docs: Documentation only changes"
          echo "- refactor: A code change that neither fixes a bug nor adds a feature"
          echo "- perf: A code change that improves performance"
          echo "- test: Adding missing tests or correcting existing tests"
          echo "- ci: Changes to the CI configuration files and scripts"
          echo "- chore: Other changes that don't affect the published crate"
          echo "- revert: Reverts a previous commit"
          exit 1