test_branch_conventions.yml

name: Fail on Malformed Commits in PR Branch

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

concurrency:
  group: ci-${{github.workflow}}-${{ github.ref }}
  cancel-in-progress: true

jobs:
  check-merge-commits:
    runs-on: ubuntu-latest
    container: ardupilot/ardupilot-dev-chibios:v0.1.3

    steps:
      - name: Checkout PR branch
        uses: actions/checkout@v6
        with:
          repository: ${{ github.event.pull_request.head.repo.full_name }}
          ref: ${{ github.event.pull_request.head.ref }}
          submodules: 'recursive'
          fetch-depth: 0

      - name: Fetch base branch
        run: |
          git remote -v
          git remote add upstream ${{ github.event.pull_request.base.repo.clone_url }}
          git fetch upstream ${{ github.event.pull_request.base.ref }}
          git show upstream/${{ github.event.pull_request.base.ref }}

      - name: Update submodules
        run: |
          git submodule update --init --recursive

      - name: Install aarch64 cross toolchain for Linux board checks
        shell: bash
        run: |
          apt-get update
          apt-get install -y g++-aarch64-linux-gnu

      - name: Test new boards compile
        shell: bash
        run: |
          Tools/scripts/test_new_boards.py --master-branch "upstream/${{ github.event.pull_request.base.ref }}"

      - name: Check for merge commits in PR branch
        shell: bash
        run: |
          # Find merge-base between base branch and (rebased) PR branch
          echo "Merge target is origin/${{ github.event.pull_request.base.ref }}"
          echo "github.event.pull_request.base.ref=${{ github.event.pull_request.base.ref }} "

          # Look for merge commits in PR branch only
          MERGE_COMMITS=$(git log upstream/${{ github.event.pull_request.base.ref }}..HEAD --merges --oneline)
          echo "Merge commits:"
          echo "$MERGE_COMMITS"

          if [[ -n "$MERGE_COMMITS" ]]; then
            echo "❌ Merge commits detected in the PR branch (not allowed):"
            echo "Please see https://ardupilot.org/dev/docs/submitting-patches-back-to-master.html"
            exit 1
          else
            echo "✅ No merge commits found in the PR branch."
          fi

          # Look for fixup! commits in PR branch only
          COMMITS=$(git log upstream/${{ github.event.pull_request.base.ref }}..HEAD --oneline)
          echo "Commits:"
          echo "$COMMITS"

          if [[ "$COMMITS" == *"fixup!"* ]]; then
            echo "❌ fixup commits detected in the PR branch (not allowed):"
            echo "$COMMITS"
            echo "Please see https://ardupilot.org/dev/docs/submitting-patches-back-to-master.html"
            exit 1
          else
            echo "✅ No fixup commits found in the PR branch."
          fi

          # require a well-formed subsystem tag before ":" in each commit message:
          while IFS= read x; do
            # strip leading hash from oneline format
            subject="${x#* }"
            # extract everything before the first colon
            prefix="${subject%%:*}"
            if [[ "$prefix" == "$subject" ]]; then
              echo "❌ Commit message ($x) missing subsystem tag on front.  Re-word your commit to reflect what subsystem it changes. E.g. 'AP_Compass: Added driver for XYZZY' (https://ardupilot.org/dev/docs/submitting-patches-back-to-master.html)"
              exit 1
            fi
            # spaces and quotes are allowed to support Revert commits e.g. 'Revert "AP_Periph: ...'
            if ! [[ "$prefix" =~ ^[A-Za-z0-9._/\ \"-]+$ ]]; then
              echo "❌ Commit message ($x) has malformed subsystem tag '$prefix'.  The subsystem prefix must contain only letters, digits, dots, underscores, slashes, hyphens, spaces, and quotes. E.g. 'AP_Compass: Added driver for XYZZY' (https://ardupilot.org/dev/docs/submitting-patches-back-to-master.html)"
              exit 1
            fi
          done <<< $COMMITS
          echo "✅ Commit messages have well-formed subsystem tags."

      - name: Lint changed markdown files
        shell: bash
        run: |
          # Get list of added or modified markdown files in the PR
          CHANGED_MD=$(git diff --name-only --diff-filter=AM upstream/${{ github.event.pull_request.base.ref }}...HEAD -- '*.md')

          if [[ -z "$CHANGED_MD" ]]; then
            echo "✅ No markdown files changed."
            exit 0
          fi

          echo "Changed markdown files:"
          echo "$CHANGED_MD"

          # Install markdownlint-cli2 (older version compatible with container's Node.js)
          apt-get update && apt-get install -y npm
          npm install -g markdownlint-cli2@0.4.0

          # Lint the changed files
          if markdownlint-cli2 $CHANGED_MD; then
            echo "✅ Markdown files pass linting."
          else
            echo "❌ Markdown linting errors found."
            exit 1
          fi

          # check that no commit subject line exceeds 160 characters:
          while IFS= read -r line; do
            if [[ ${#line} -gt 160 ]]; then
              echo "❌ Commit subject line exceeds 160 characters:"
              echo "$line"
              echo "Please keep the commit subject line to 160 characters or fewer."
              exit 1
            fi
          done <<< "$COMMITS"
          echo "✅ All commit subject lines are within 160 characters."