commit-messages.yml

name: Commit messages

# release-please builds versions and release notes from commit subjects, so
# every non-merge commit must follow Conventional Commits (see CONTRIBUTING.md).

on:
  push:
  pull_request:

permissions:
  contents: read

jobs:
  conventional-commits:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0
      - name: Check commit subjects
        env:
          EVENT: ${{ github.event_name }}
          PUSH_BEFORE: ${{ github.event.before }}
          PUSH_AFTER: ${{ github.event.after }}
          PR_BASE: ${{ github.event.pull_request.base.sha }}
          PR_HEAD: ${{ github.event.pull_request.head.sha }}
        run: |
          if [ "$EVENT" = "pull_request" ]; then
            range="$PR_BASE..$PR_HEAD"
          elif [ -z "${PUSH_BEFORE//0/}" ]; then
            echo "New branch or tag push: no previous head to compare against; skipping."
            exit 0
          elif ! git cat-file -e "$PUSH_BEFORE^{commit}" 2>/dev/null; then
            echo "Previous head $PUSH_BEFORE is not in history (force push); skipping."
            exit 0
          else
            range="$PUSH_BEFORE..$PUSH_AFTER"
          fi
          pattern='^(feat|fix|docs|chore|ci|build|refactor|test|perf|style|revert)(\([A-Za-z0-9._/-]+\))?!?: [^ ].*$'
          bad=0
          while IFS= read -r line; do
            sha="${line%% *}"
            subject="${line#* }"
            if ! printf '%s\n' "$subject" | grep -Eq "$pattern"; then
              echo "::error::${sha:0:12} does not follow Conventional Commits: $subject"
              bad=1
            fi
          done < <(git log --no-merges --format='%H %s' "$range")
          if [ "$bad" -ne 0 ]; then
            echo "Expected 'type(scope)?!?: subject' with type one of feat, fix, docs, chore, ci, build, refactor, test, perf, style, revert." >&2
            exit 1
          fi
          echo "All commit subjects in $range follow Conventional Commits."
          # Commit messages become release notes: hold them to the public-copy rules.
          set -o pipefail
          git log --no-merges --format=%B "$range" | python3 scripts/check_public_copy.py --stdin "commit messages"