id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
5803	MPL assertion does not allow python to override protected virtual methods	mathstuf@…	Ralf W. Grosse-Kunstleve	"When wrapping a class with virtual protected methods, the following MPL assertion is hit in boost::python::detail::error::virtual_function_default<> (python/class.hpp:141):

{{{
assertion<mpl::not_<is_same<Default,Fn> > >
}}}

The way I've been exposing the protected method so that the Python can override it is:

{{{
class Base { protected: virtual void foo(); };
class BaseWrap : public Base, public wrapper<Base> { public: void foo(); void base_foo(); };
// ...
class_<BaseWrap, boost::noncopyable>(""PythonBase"")
    .def(""foo"", &BaseWrap::foo, &BaseWrap::base_foo);
}}}

The assertion is *supposed* to be (following the function names) testing that ``&BaseWrap::base_foo`` is a method of the wrapped class (``BaseWrap``), but it does it in a way that precludes the main overriding function from *also* being from ``BaseWrap`` which isn't really correct."	Bugs	closed	To Be Determined	python USE GITHUB	Boost 1.47.0	Problem	fixed