message: Detect stale file situation.
diff: @@ -215,6 +215,8 @@ def create_extension(ExtType, name, sources, dependencies, extra_link_args, extr
  class ONNXCpp2PyExtension(setuptools.Extension):
  def pre_run(self):
  self.sources = recursive_glob(SRC_DIR, '*.cc')
  + if os.path.join(SRC_DIR, "onnx.pb.cc") in self.sources:
  + raise RuntimeError("Stale onnx/onnx.pb.cc file detected. Please delete this file and rebuild.")
  cpp2py_deps = [Pybind11(), Python()]
  cpp2py_link_args = []
  