pr-lint.yaml

name: Lint Pull Request Title

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

jobs:
  lint-pr-title:
    permissions:
      pull-requests: write
    runs-on: ubuntu-latest
    steps:
      - name: Lint PR title
        id: lint-pr-title
        uses: amannn/action-semantic-pull-request@v6
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        with:
          # chore(deps): bump <some dependency>
          #  ^     ^       ^
          #  |     |       | __Subject
          #  |     |_______ Scope
          #  |____________ Type

          # Configure which types are allowed (newline-delimited).
          # These are regex patterns auto-wrapped in `^ $`.
          # Default: https://github.com/commitizen/conventional-commit-types
          types: |
            ci
            chore
            docs
            feat
            fix
            refactor
            test

          # Configure which scopes are allowed (newline-delimited).
          # These are regex patterns auto-wrapped in `^ $`.
          scopes: |
            .*

          # Configure scope as optional.
          requireScope: false

          # Configure additional validation for the subject based on a regex.
          # This ensures the subject doesn't start with an uppercase character.
          subjectPattern: ^(?![A-Z]).+$

          # If `subjectPattern` is configured, you can use this property to override
          # the default error message that is shown when the pattern doesn't match.
          # The variables `subject` and `title` can be used within the message.
          subjectPatternError: |
            The subject "{subject}" found in the pull request title "{title}"
            didn't match the configured pattern. Please ensure that the subject
            doesn't start with an uppercase character.

        # Continue on error so we can leave a comment on the PR to give the author some guidance.
        continue-on-error: true

        # Delete previous lint failure comments if linting succeeded.
      - name: Delete previous lint failure comments
        if: steps.lint-pr-title.outcome == 'success'
        uses: actions/github-script@v8
        with:
          script: |
            const prNumber = context.payload.pull_request.number;

            // Get all comments on this PR
            const { data: comments } = await github.rest.issues.listComments({
              owner: context.repo.owner,
              repo: context.repo.repo,
              issue_number: prNumber,
            });

            // Find all bot comments that are lint failure comments
            const lintFailureComments = comments.filter(comment =>
              comment.user.type === 'Bot' &&
              comment.body.includes('PR Title Lint Failed')
            );

            // Delete each lint failure comment
            for (const comment of lintFailureComments) {
              await github.rest.issues.deleteComment({
                owner: context.repo.owner,
                repo: context.repo.repo,
                comment_id: comment.id,
              });
              console.log(`Deleted lint failure comment ${comment.id}`);
            }

        # Add a comment to the PR to provide guidance if the linting failed.
      - name: Leave guidance comment
        if: steps.lint-pr-title.outcome == 'failure'
        uses: actions/github-script@v8
        with:
          script: |
            const prNumber = context.payload.pull_request.number;
            const prTitle = context.payload.pull_request.title;

            const comment = `## PR Title Lint Failed ❌

            **Current Title:** \`${prTitle}\`

            Your PR title doesn't follow the expected format. Please update your PR title to follow one of these patterns:

            ### Conventional Commits Format:
            - \`feat: add new feature\` - for new features
            - \`fix: resolve bug in component\` - for bug fixes
            - \`docs: update README\` - for documentation changes
            - \`refactor: improve code structure\` - for refactoring
            - \`test: add unit tests\` - for test additions
            - \`chore: remove dead code\` - for maintenance tasks
            - \`chore(deps): update dependencies\` - for updating dependencies
            - \`ci: update build pipeline\` - for CI/CD changes

            ### Guidelines:
            - Use lowercase for the type and description
            - Keep the description concise but descriptive
            - Use imperative mood (e.g., "add" not "adds" or "added")
            - Don't end with a period

            ### Examples:
            - ✅ \`feat(windows): add secure TLS bootstrapping for Windows nodes\`
            - ✅ \`fix: resolve kubelet certificate rotation issue\`
            - ✅ \`docs: update installation guide\`
            - ❌ \`Added new feature\`
            - ❌ \`Fix bug.\`
            - ❌ \`Update docs\`

            Please update your PR title and the lint check will run again automatically.`;

            // Check if we already commented on this PR to avoid spam
            const { data: comments } = await github.rest.issues.listComments({
              owner: context.repo.owner,
              repo: context.repo.repo,
              issue_number: prNumber,
            });

            const botComment = comments.find(comment =>
              comment.user.type === 'Bot' &&
              comment.body.includes('PR Title Lint Failed')
            );

            if (botComment) {
              // Update existing comment
              await github.rest.issues.updateComment({
                owner: context.repo.owner,
                repo: context.repo.repo,
                comment_id: botComment.id,
                body: comment
              });
            } else {
              // Create new comment
              await github.rest.issues.createComment({
                owner: context.repo.owner,
                repo: context.repo.repo,
                issue_number: prNumber,
                body: comment
              });
            }

        # If linting failed, fail the workflow run.
      - name: Fail the workflow
        if: steps.lint-pr-title.outcome == 'failure'
        run: exit 1