id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
2016	wrong default arguments in boost/python/exec.hpp	schlotz <scholz@…>	Dave Abrahams	"Calling boost::python::exec, exec_file and eval without the second and third argument, makes the default arguments create 'object's where 'dict's are neccessary.

Consider this program:
{{{
#include <boost/python.hpp>
int main()
{
  using namespace boost::python;
  
  Py_Initialize();
  try {
    object foo = exec(""a=5; print(a);"");
  }
  catch(error_already_set const &) {
    PyErr_Print();
  }
  return 0;
}
}}}

Expected output:
{{{
5
}}}


Real output:
{{{
Traceback (most recent call last):
  File ""<string>"", line 1, in <module>
TypeError: 'NoneType' object does not support item assignment
}}}

A possible fix is to change the default arguments to exec, exec_file and eval in exec.hpp from ...=object() to ...=dict(), see the attached patch to boost/python/exec.hpp
I'm not sure if it would make sense to change the type of the arguments from object to dict as well.

Bye,
   Jan Scholz"	Bugs	closed	To Be Determined	python USE GITHUB	Boost Development Trunk	Problem	fixed	python exec exec_file eval default argument