TypeError not cleared when handling complex arguments

[mhochsteger]

Since commit 496feac
the following code executes the right function but quits with an unhandled exception.

Failing code

test.cpp

#include <pybind11/pybind11.h>
#include <pybind11/complex.h>
#include <iostream>

namespace py = pybind11;

PYBIND11_PLUGIN(test) {
  py::module m("test");

  m.def("test", [] ( float x ) { 
      std::cout << x << std::endl;
      });
  m.def("test", [] ( std::complex<float> x ) { 
      std::cout << x << std::endl;
      });

  return m.ptr();
}

test.py

import test

test.test(1)
test.test(2j)

The output:

$ python3 test.py
1
(0,2)
TypeError: can't convert complex to int

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "test.py", line 4, in <module>
    test.test(2j)
SystemError: <built-in method test of PyCapsule object at 0x7fba58d193c0> returned a result with an error set

Suggested solution

In cast.h, line 453, it can happen that PyNumber_Long fails. In this case it leaves an unhandled TypeError.

 451             PyErr_Clear();
 452             if (type_error && PyNumber_Check(src.ptr()))
 453                 return load(object(PyNumber_Long(src.ptr()), true), false);
 454             return false;

My suggestion is to call PyErr_Clear() again after trying the conversion:

            if (type_error && PyNumber_Check(src.ptr())) {
                bool res = load(object(PyNumber_Long(src.ptr()), true), false);
                PyErr_Clear();
                return res; 
            }