commit.yml

name: Custom Commit Message Validator

on:
  pull_request:
    types: [opened, reopened, synchronize]

jobs:
  validate_COMMIT_MESSAGEs:
    runs-on: ubuntu-latest

    permissions:
      contents: read
      pull-requests: read

    steps:
      - name: Checkout Repository
        uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Get PR Commits SHAs
        id: get_pr_commits
        run: |
          # Fetch all commit SHAs associated with the current Pull Request
          PR_COMMIT_SHAS=$(gh pr view ${{ github.event.pull_request.number }} --json commits --jq '[.commits[].oid] | join(" ")')
          echo "PR_COMMITS_LIST=${PR_COMMIT_SHAS}" >> "$GITHUB_OUTPUT"
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

      - name: Validate Each Commit Message
        env:
          TARGET_DATE: "2025-07-22"  # Only check commits after this date
          SKIP_KEYWORDS: "Merge,Revert,Release"  # Comma-separated keywords to skip validation
        run: |
          # Read commit SHAs into array
          IFS=' ' read -r -a commit_shas <<< "${{ steps.get_pr_commits.outputs.PR_COMMITS_LIST }}"
          has_validation_failed=false

          # Convert skip keywords to array
          IFS=',' read -r -a skip_keywords <<< "$SKIP_KEYWORDS"
          
          for commit_sha in "${commit_shas[@]}"; do
            echo "--- Checking commit: ${commit_sha} ---"
            
            # Get commit timestamps for date filtering
            COMMIT_DATE_UNIX=$(git log -n 1 --format=%at "${commit_sha}")
            TARGET_DATE_UNIX=$(date -d "${TARGET_DATE}" +"%s")
            COMMIT_DATE_HUMAN=$(git log -n 1 --format=%ad --date=iso-strict "${commit_sha}")

            # Skip older commits
            if (( COMMIT_DATE_UNIX < TARGET_DATE_UNIX )); then
              echo "Skipping commit ${commit_sha} (Date: ${COMMIT_DATE_HUMAN}) as it is older than ${TARGET_DATE}."
              continue
            fi

            echo "Processing commit ${commit_sha} (Date: ${COMMIT_DATE_HUMAN}) as it is on or after ${TARGET_DATE}."
            COMMIT_MESSAGE=$(git log --format=%B -n 1 "${commit_sha}")
            echo "Message content:"
            echo "${COMMIT_MESSAGE}"
            echo ""

            # Check for skip keywords
            skip_this_commit=false
            for keyword in "${skip_keywords[@]}"; do
              # Trim whitespace from keyword
              trimmed_keyword=$(echo "$keyword" | xargs)
              
              if [[ -n "$trimmed_keyword" ]] && 
                 [[ "${COMMIT_MESSAGE}" == *"$trimmed_keyword"* ]]; then
                echo "Skipping validation for commit ${commit_sha} due to skip keyword: ${trimmed_keyword}"
                skip_this_commit=true
                break
              fi
            done
            
            if [ "$skip_this_commit" = true ]; then
              continue
            fi

            # --- Validation Logic Start ---
            
            # 1. Check Conventional Commit format
            if [[ ! "${COMMIT_MESSAGE}" =~ ^(feat|fix|docs|chore|style|refactor|perf|test|build|ci|revert)(\([a-zA-Z0-9_-]+\))?(!?): ]]; then
              echo "::error file=COMMIT_MESSAGE::Commit ${commit_sha} does not start with a conventional commit type. Message: '${COMMIT_MESSAGE}'"
              has_validation_failed=true
              continue
            fi

            # Extract commit subject (first line)
            commit_subject=$(echo "${COMMIT_MESSAGE}" | head -n 1)

            # 2. NEW: Check minimum subject length (15 characters)
            if [[ ${#commit_subject} -lt 15 ]]; then
              echo "::error file=COMMIT_MESSAGE::Commit ${commit_sha} subject is too short (min 15 characters). Length: ${#commit_subject}. Subject: '${commit_subject}'"
              has_validation_failed=true
              continue
            fi

            # 3. Check maximum subject length (72 characters)
            if [[ ${#commit_subject} -gt 72 ]]; then
              echo "::warning file=COMMIT_MESSAGE::Commit ${commit_sha} subject line exceeds 72 characters. Length: ${#commit_subject}. Subject: '${commit_subject}'"
            fi

            # 4. Check empty line between subject and body
            if [[ $(echo "${COMMIT_MESSAGE}" | wc -l) -gt 1 ]]; then
              second_line=$(echo "${COMMIT_MESSAGE}" | awk 'NR==2 {print}' | xargs)
              if [[ -n "${second_line}" ]]; then
                echo "::error file=COMMIT_MESSAGE::Commit ${commit_sha} is missing an empty line between subject and body. Message: '${COMMIT_MESSAGE}'"
                has_validation_failed=true
                continue
              fi
            fi

          done

          # Fail job if any validation errors occurred
          if [ "$has_validation_failed" = true ]; then
            echo "::error::One or more commit messages failed validation. Please review the errors above."
            exit 1
          fi

          echo "All relevant commit messages in the PR passed validation."