ci.yml

name: CI

on: [push, pull_request]

jobs:

  # Changes that only touch the README or the .github directory can't affect the build or test
  # results. This job detects that situation so the expensive build and test steps below can be
  # skipped. Note that the "Build and Test" job itself always runs to completion (reporting success)
  # even when there's nothing to build, because it's a required status check and a skipped required
  # check blocks pull requests from merging.
  detect-changes:
    name: Detect relevant changes
    runs-on: ubuntu-latest
    outputs:
      run: ${{ steps.filter.outputs.run }}
    steps:
      - uses: actions/checkout@v5
        with:
          fetch-depth: 0
      - name: Check whether any files outside README / .github changed
        id: filter
        run: |
          if [ "${{ github.event_name }}" = "pull_request" ]; then
            base="${{ github.event.pull_request.base.sha }}"
            head="${{ github.event.pull_request.head.sha }}"
          else
            base="${{ github.event.before }}"
            head="${{ github.sha }}"
          fi
          # If the base commit isn't available (e.g. a brand new branch), build to be safe.
          if ! git cat-file -e "$base" 2>/dev/null; then
            echo "Base commit unavailable; running the build."
            echo "run=true" >> "$GITHUB_OUTPUT"
            exit 0
          fi
          changed="$(git diff --name-only "$base" "$head")"
          echo "Changed files:"
          echo "$changed"
          relevant="$(echo "$changed" | grep -vE '^(README\.md|\.github/)' || true)"
          if [ -n "$relevant" ]; then
            echo "Relevant changes found; running the build."
            echo "run=true" >> "$GITHUB_OUTPUT"
          else
            echo "Only README / .github changes found; skipping the build."
            echo "run=false" >> "$GITHUB_OUTPUT"
          fi

  build-and-test:
    name: Build and Test
    runs-on: ubuntu-latest
    needs: detect-changes
    if: ${{ github.event_name == 'pull_request' || github.actor != 'Copilot' }}
    steps:
      - if: needs.detect-changes.outputs.run == 'true'
        uses: actions/checkout@master
      - if: needs.detect-changes.outputs.run == 'true'
        uses: Bogdanp/setup-racket@v1.5
        with:
          version: stable
      - if: needs.detect-changes.outputs.run == 'true'
        run: raco pkg install --batch --auto --link --name resyntax
      - if: needs.detect-changes.outputs.run == 'true'
        run: raco test --drdr --package resyntax

  code-coverage:
    name: Code Coverage
    runs-on: ubuntu-latest
    needs: detect-changes
    if: needs.detect-changes.outputs.run == 'true'
    steps:
      - uses: actions/checkout@master
      - uses: Bogdanp/setup-racket@v1.5
        with:
          version: stable
      - run: raco pkg install --batch --auto cover cover-coveralls
      - run: raco pkg install --batch --auto --link --name resyntax
      - run: raco cover --format coveralls --suppress-log-execution --package resyntax
        env:
          COVERALLS_REPO_TOKEN: ${{ secrets.COVERALLS_REPO_TOKEN }}