ci-generate.yaml

name: CI

on:
  pull_request:
     branches:
       - main

jobs:
  # Compare committed files with those generated from templates to ensure no differences occur.
  check-generated-files:
    runs-on: ubuntu-latest
    env:
      REPO: ${{ github.event.repository.name }}

    steps:
      - name: Checkout repository
        uses: actions/checkout@v4

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

      - name: Install cargo-generate
        uses: taiki-e/install-action@v2
        with:
          tool: cargo-generate

      - name: Retain pre-generated files
        run: |
          for template_file in $(find . -type f -name '*.template'); do
            generated_file="${template_file%.template}"
            if [[ -f "{$generated_file}" ]]; then
              # Keep a copy to diff with the output of the next step.
              cp "${generated_file}" "${generated_file}.check"
            fi
          done

      - name: Generate repository
        run: |
          # Note: we use cargo-generate itself here as bevy_cli's wrapping of the cargo-generate
          # library does not allow us to do useful things like --allow-commands and use local
          # templates.
          cargo generate --path . --name '${{ env.REPO }}' --allow-commands

      - name: Diff generated files
        run: |
          change_detected=false

          for check_file in $(find "{$REPO}" -type f -name '*.check'); do
            generated_file="${check_file%.check}"
            if ! diff "${check_file}" "${generated_file}"; then
              echo "File ${generated_file} has changed from ${generated_file}.template:"
              echo "::error file=${generated_file}::Template change detected."
              change_detected=true
            fi
          done

          if [[ "{$change_detected}" == true ]]; then
            exit 1
          fi