[C++-sig] Type conversion problem -- simplified

[Randall Hopper]

David Abrahams:
 |When a Python instance of a wrapped class T is converted to a T*,
 |Boost.Python searches through the list of instance_holders (plural, to
 |support MI) held by the Python instance for one that contains a T.
 |See find_instance_impl in libs/python/src/object/class.cpp
 |
 |In your case the search is failing where it should succeed.  I would
 |expect you to have a single instance_holder in the chain that is in
 |fact a python::objects::pointer_holder containing a
 |ref_ptr<Vec3Array>.  The only reasons I can think of for the match to
 |fail are:
 |
 |     a. some problem with typeid matching.
 |     b. the ref_ptr is in fact NULL.
 |
 |I think you could examine the execution of find_instance_impl in a
 |debugger and learn a lot.

Soon as I get this work project squared away, I'll do that.  Thanks for the
insight!  That's what I needed.

Randall