Re: PyCXX V6.2.6 Released

[Barry S. <ba...@ba...>]

> On 5 Jan 2015, at 23:41, π <sun...@gm...> wrote:
> 
> Hello PyCXX people,
> 
> I recently stumbled upon what I believed to be a minor PyCXX bug regarding allocation for new style classes.
> 
> http://stackoverflow.com/questions/27662074/how-to-tidy-fix-pycxxs-creation-of-new-style-python-extension-class

I'll have to check the memory alloc bug mentioned. If you can isolate the patch I'd appreciate it.

There is a lot of clutter in the SO articles.

> 
> The link proposes a fix. Amazingly, there is some anonymous engineer on SO who appears to understand every line of the PyCXX source code.
> My hat off to this individual! The technical complexity of this library has really stretched my mental capacity to its limits.

If you understand the python internals I think the PyCXX is not so hard to understand.

> A second concern I have is regarding...
> 
> http://sourceforge.net/p/cxx/code/HEAD/tree/trunk/CXX/Src/Python3/cxx_extensions.cxx
> 
> extern "C" PyObject *str_handler( PyObject *self )
> {
>    try
>    {
>        PythonExtensionBase *p = getPythonExtensionBase( self );
>        return new_reference_to( p->str() );
>    }
>    catch( Py::Exception & )
>    {
>        return NULL;    // indicate error
>    }
> }
> 
> There are about 50 functions of the same format and my concern applies to all of them.
> 
> What if somewhere in the p->str() C++ code an exception happens that is not of type Py::Exception ?

You mean a C++ exception?

That would be a bug in the C++ code which needs to map the C++ exception into a Python Exception.

> I don't think it will be caught.
> 
> Shouldn't there be an extra 'catch(...)' to catch the remaining errors?
> 
> I'm not too sure about the second one, the first one does appear to be a bug.
> 

Barry