[FIXED] What is this 'bad:' label generated by Cython?

Issue

While cythonizing my Cython source code files, I can see a dozen of warnings about a label named 'bad:' generated by Cython, for example:

read_input.cpp:30037:3: warning: label ‘bad’ defined but not used [-Wunused-label]

The C++ generated function is like this:

static PyObject* __pyx_convert__to_py_struct__VehicleCaps(struct VehicleCaps s) {
  PyObject* res;
  PyObject* member;
  res = __Pyx_PyDict_NewPresized(0); if (unlikely(!res)) return NULL;
  return res;
  bad:
  Py_XDECREF(member);
  Py_DECREF(res);
  return NULL;
}

The 'bad:' label is in there, I don't get it why Cython is generating this unused label and it shows warnings.

Do I have really fix these warnings? or it's safe to leave them untouched?

Solution

It's for goto bad if something fails in the function, but it doesn't look like anything can fail, so it's unused.

It isn't a problem so you can ignore it. But Cython generally tries not to generate unused labels, so feel free to report it as a (small) bug

Answered By - DavidW

Answer Checked By - David Marino (PHPFixing Volunteer)