nullptr as default argument results in unreported exception during import

[mamoll]

The code at the bottom can be compiled like so:

clang++ -std=c++11 -I/opt/local/include -I/opt/local/Library/Frameworks/Python.framework/Versions/3.5/include/python3.5m  -shared -o foo.so nullptr_error.cpp -L/opt/local/Library/Frameworks/Python.framework/Versions/3.5/lib -lpython3.5 -L/opt/local/lib -lboost_python

When importing the resulting module in Python I see the following error:

>>> import foo
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
SystemError: initialization of foo raised unreported exception

If I replace nullptr with NULL, then there is no error. This is with Boost 1.59 installed via MacPorts on the latest version of OS X with the latest version of Xcode.

#include <boost/python.hpp>

struct Foo
{
    Foo() : foo_(1) {}
    void setFoo(int * foo = nullptr) { foo_ = foo ? *foo : 1; }
    int getFoo() { return foo_; }
    int foo_;
};

BOOST_PYTHON_MODULE(foo)
{
    boost::python::class_<Foo>("Foo", boost::python::init<>())
        .def("setFoo", &Foo::setFoo, ( boost::python::arg("foo")=nullptr))
        .def("getFoo", &Foo::getFoo)
        ;
}

[ofloveandhate]

i am getting the same or a similar unhelpful error using python3 when i import if i add bases<BaseT> to a certain class in my library...

initialization of _pybertini raised unreported exception

literally all i add is a bases to my class_, and i cannot import my library any more. this is with boost & boost.python versions 1.66; and Xcode Version 8.0 (8A218a), with

clang version 4.0.0 (trunk 289544)
Target: x86_64-apple-darwin15.6.0
Thread model: posix

my python3 line to compile your example is

g++ -std=c++11 -I/usr/local/include -I/Users/ofloveandhate/anaconda/include/python3.6m  -shared -o foo.so nullptr_error.cpp -L/Users/ofloveandhate/anaconda/lib -lpython3.6m -L/usr/local/lib -lboost_python3-mt

with boost and boost.python installed from homebrew, and some anaconda install on the path.

to check my sanity, i compiled your above test example, and get the same problem, 22 months later. pretty sure it is the same problem as i am experiencing.

if i compile my code with python2 installed at /usr/local/bin which resolves to version 2.7.13 installed from brew using this

g++ -std=c++11 -I/usr/local/include -I/usr/local/Cellar/python/2.7.13/Frameworks/Python.framework/Versions/2.7/include/python2.7  -shared -o foo.so nullptr_error.cpp -L/usr/local/opt/python/Frameworks/Python.framework/Versions/2.7/lib -lpython2.7 -L/usr/local/lib -lboost_python

i get the following much better error message:

RuntimeError: extension class wrapper for base class bertini::Observer<bertini::tracking::AMPTracker> has not been created yet

in fact, compiling your example using python2 yields this error:

TypeError: No to_python (by-value) converter found for C++ type: std::nullptr_t

why does python2 yield much better error reporting?
is there a way to make the python3 error message more helpful? what are the circumstances in which this particular error can be generated?

[ofloveandhate]

i again encountered this just now (feb 10 2018). i got

initialization of _pybertini raised unreported exception

upon import of my "successfully" built library. and the issue was that i had not yet exposed an enum. would have been clearly reported by python2, not with python3.

[dfaure-kdab]

I think the lack of precise error reporting was fixed in #280.
But I'm not sure if the problem with nullptr was fixed.