semver-checks.yml

name: Rust semver-checks

on:
    pull_request:
        branches:
            - master
    workflow_dispatch:
        inputs:
            base:
                description: 'Base branch or tag to run the semver checks against.'
                required: true
                default: 'master'

permissions:
  pull-requests: read

jobs:
  semver-checks:
    name: semver-checks 🦀
    runs-on: ubuntu-latest
    env:
      GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
    steps:
      - uses: actions/checkout@v7
        with:
          ref: ${{ github.event.pull_request.head.sha || github.ref }}
          path: PR_BRANCH
          fetch-depth: 0

      # Remove repo toolchain pin so we can specify toolchain manually
      - name: Remove toolchain pin
        run: rm -f rust-toolchain.toml rustup-toolchain.toml

      - name: Install stable toolchain
        uses: dtolnay/rust-toolchain@stable

      - name: Build caching
        uses: Swatinem/rust-cache@v2

      # Run cargo-semver-checks against the PR's target branch.
      - name: Check semver changes
        id: semver
        uses: obi1kenobi/cargo-semver-checks-action@v2
        with:
          feature-group: all-features
          manifest-path: PR_BRANCH/Cargo.toml
          baseline-rev: ${{ github.event.pull_request.base.sha || github.event.inputs.base }}
          release-type: minor
        continue-on-error: true
      
      - name: Evaluate semver result
        run: |
          echo "=== cargo-semver-checks result ==="

          if [ "${{ steps.semver.outcome }}" = "failure" ]; then
            BREAKING=true
            echo "❌ Breaking changes detected in public Rust API"
          else
            BREAKING=false
            echo "✅ No breaking changes detected"
          fi

          echo
          echo "=== cargo-semver-checks summary ==="
          echo
          printf "%s\n" "${{ steps.semver.outputs.semver-checks-output }}"
          echo

          # Check PR title for conventional-commit breaking marker
          if [[ "${{ github.event.pull_request.title }}" =~ ^.*\!:.*$ ]]; then
            DECLARED=true
            echo "ℹ️ PR title declares a breaking change (!)"
          else
            DECLARED=false
            echo "ℹ️ PR title does NOT declare a breaking change"
          fi

          echo
          echo "=== Decision ==="

          if [ "$BREAKING" = true ] && [ "$DECLARED" = false ]; then
            echo "🚨 ERROR: Undeclared breaking changes detected."
            echo "Hey there and thank you for opening this pull request! 👋 Please deprecate the old API instead (if possible), or mark the PR with a `!` following the [conventional commits](https://www.conventionalcommits.org/en/v1.0.0/) format to indicate a breaking change."
            exit 1
          fi

          if [ "$BREAKING" = true ] && [ "$DECLARED" = true ]; then
            echo "⚠️ Breaking changes detected but correctly declared."
            echo "Workflow will succeed."
          fi

          if [ "$BREAKING" = false ]; then
            echo "✅ No breaking changes; workflow will succeed."
          fi