scan-pull-request.yml

name: Scan Pull Request

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

  workflow_dispatch:

permissions:
  contents: read
  pull-requests: write
  repository-projects: read

jobs:
  lint-pr-title:
    name: 🏷️ Lint PR Title

    runs-on: ubuntu-latest

    steps:
      - name: Lint title
        uses: amannn/action-semantic-pull-request@v5
        id: lint-title
        env:
          GITHUB_TOKEN: ${{ github.token }}

      - name: Create error comment
        uses: marocchino/sticky-pull-request-comment@v2
        if: ${{ always() && steps.lint-title.outputs.error_message != null }}
        with:
          header: lint-title-error-comment
          message: |
            We require pull request titles to follow the [Conventional Commits specification](https://www.conventionalcommits.org/en/v1.0.0/) and it looks like this pull request's title needs to be adjusted.

            Details:

            ```
            ${{ steps.lint-title.outputs.error_message }}
            ```
      - name: Delete error comment
        uses: marocchino/sticky-pull-request-comment@v2
        if: ${{ steps.lint-title.outputs.error_message == null }}
        with:
          header: lint-title-error-comment
          delete: true

  set-labels:
    name: 🏷️ Set Labels

    runs-on: ubuntu-latest

    steps:
      - uses: actions/checkout@v4

      - name: Set labels
        uses: actions/labeler@v5
        with:
          configuration-path: ./.github/config/labeler.yml
          sync-labels: true

      - name: Assign Conventional Commit label
        shell: bash
        env:
          PR_CURRENT_LABELS_JSON: ${{ toJson(github.event.pull_request.labels) }}
          PR_TITLE: ${{ github.event.pull_request.title }}
          GITHUB_TOKEN: ${{ github.token }}
        run: |
          # Create a mapping between Conventional Commit prefixes and our labels:
          label_map='{
            "build": "type: build",
            "chore": "type: chore",
            "ci": "type: ci",
            "docs": "type: docs",
            "feat": "type: feature",
            "fix": "type: bugfix",
            "perf": "type: performance",
            "refactor": "type: refactor",
            "revert": "type: reversion",
            "style": "type: style",
            "test": "type: test"
          }'

          # Strip any surrounding whitespace from the sanitized PR title:
          pr_title="$(echo "$PR_TITLE" | tr -d '\n' | xargs)"

          # Parse the existing labels:
          pr_current_labels=$(echo "$PR_CURRENT_LABELS_JSON" | jq '.[].name')

          # Determine the Conventional Commit type based upon the PR title:
          commit_type="$(echo "$pr_title" | cut -d: -f1 | sed 's/(.*)//g; s/!//g')"
          echo "Detected Conventional Commit type: '$commit_type'"

          if [[ -z "$commit_type" ]]; then
            echo "Commit type could not be extracted from PR title: '$pr_title'"
            exit 1
          fi

          # Pull the appropriate label based on the detected Conventional Commit type:
          label_to_apply="$(echo "$label_map" | jq -r --arg type "$commit_type" '.[$type] // empty')"

          if [[ -z "$label_to_apply" ]]; then
            echo "Unrecognized Conventional Commit type: '$commit_type'"
            exit 1
          fi

          echo "Mapping Conventional Commit type '$commit_type' to label: '$label_to_apply'"

          # Determine whether any outdated Conventional Commit labels need to be
          # removed:
          labels_to_remove_csv=$(echo "$PR_CURRENT_LABELS_JSON" | jq -r --argjson label_map "$label_map" --arg current_label "$label_to_apply" '.[].name | select(. != $current_label and (. as $existing | $label_map | any(.[]; . == $existing)))' | paste -sd, -)
          echo "Removing incorrect Conventional Commit labels: '$labels_to_remove_csv'"

          # If the label to add is already applied, skip it:
          labels_to_add_csv=""
          if echo "$pr_current_labels" | grep -qw "$label_to_apply"; then
            echo "Label already exists on the PR: '$label_to_apply'"
          else
            echo "Label should be added to the PR: '$label_to_apply'"
            labels_to_add_csv+="$label_to_apply"
          fi

          # Apply the label changes:
          if [[ -n "$labels_to_remove_csv" || -n "$labels_to_add_csv" ]]; then
            gh pr edit \
              "${{ github.event.pull_request.number }}" \
              ${labels_to_add_csv:+--add-label "$labels_to_add_csv"} \
              ${labels_to_remove_csv:+--remove-label "$labels_to_remove_csv"}
          else
            echo "No label changes needed"
          fi