add job to check samples for changes

.github/workflows/check-samples.yml

@@ -0,0 +1,84 @@
+name: Check samples
+
+# avoiding duplicate jobs on push with open pull_request: https://github.com/orgs/community/discussions/26940#discussioncomment-6656489
+on: [push, pull_request]
+
+jobs:
+
+  check:
+    if: (github.event_name != 'pull_request' && ! github.event.pull_request.head.repo.fork) || (github.event_name == 'pull_request' && github.event.pull_request.head.repo.fork)
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        include:
+          - package_name: ros2_cpp_pkg
+            template: ros2_cpp_pkg
+            is_component: false
+            is_lifecycle: false
+            has_launch_file: true
+            has_params: true
+            has_subscriber: true
+            has_publisher: true
+            has_service_server: false
+            has_action_server: false
+            has_timer: false
+          - package_name: ros2_cpp_component_pkg
+            template: ros2_cpp_pkg
+            is_component: true
+            is_lifecycle: false
+            has_launch_file: true
+            has_params: true
+            has_subscriber: true
+            has_publisher: true
+            has_service_server: false
+            has_action_server: false
+            has_timer: false
+          - package_name: ros2_cpp_lifecycle_pkg
+            template: ros2_cpp_pkg
+            is_component: false
+            is_lifecycle: true
+            has_launch_file: true
+            has_params: true
+            has_subscriber: true
+            has_publisher: true
+            has_service_server: false
+            has_action_server: false
+            has_timer: false
+          - package_name: ros2_interfaces_pkg
+            template: ros2_interfaces_pkg
+            interface_types: Message,Service,Action
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.10"
+      - name: Install dependencies
+        run: |
+          pip install "copier~=9.2.0" "jinja2-strcase~=0.0.2"
+      - name: Generate packages
+        run: |
+          copier copy --trust --use-local-templates --defaults \
+            -d template=${{ matrix.template }} \
+            -d package_name=${{ matrix.package_name }} \
+            -d is_component=${{ matrix.is_component }} \
+            -d is_lifecycle=${{ matrix.is_lifecycle }} \
+            -d has_launch_file=${{ matrix.has_launch_file }} \
+            -d has_params=${{ matrix.has_params }} \
+            -d has_subscriber=${{ matrix.has_subscriber }} \
+            -d has_publisher=${{ matrix.has_publisher }} \
+            -d has_service_server=${{ matrix.has_service_server }} \
+            -d has_action_server=${{ matrix.has_action_server }} \
+            -d has_timer=${{ matrix.has_timer }} \
+            -d interface_types=${{ matrix.interface_types }} \
+            . packages
+      - name: Check for repository changes
+        run: |
+          rm -rf samples
+          mv packages samples
+          if [[ ! -z "$(git status --porcelain)" ]]; then
+            echo "Sample generation resulted in changes to the repository"
+            git diff
+            exit 1
+          fi