[Boost-bugs] [Boost C++ Libraries] #5803: MPL assertion does not allow python to override protected virtual methods

Subject: [Boost-bugs] [Boost C++ Libraries] #5803: MPL assertion does not allow python to override protected virtual methods
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2011-08-22 18:02:48

#5803: MPL assertion does not allow python to override protected virtual methods
--------------------------------+-------------------------------------------
 Reporter:  mathstuf@…          |       Owner:  rwgk   
     Type:  Bugs                |      Status:  new    
Milestone:  To Be Determined    |   Component:  Python 
  Version:  Boost 1.47.0        |    Severity:  Problem
 Keywords:                      |  
--------------------------------+-------------------------------------------
 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.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/5803>
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