[vtk-developers] [vtkusers] More on VTK 5.0.4: hashing vtk class objects broken?

[David Gobbi]

I found a machine that could reproduce the bug.  I've submitted a
patch for VTK 6, and I attached a patch for VTK 5.10 to the bug
report.

 - David

On Mon, Apr 29, 2013 at 1:30 PM, David Gobbi <david.gobbi at gmail.com> wrote:
> I can't reproduce this on my system.  For me, the hash function works
> just fine on VTK classes and instances in VTK 5.10.1.
>
> Can a few other python users try this?
>
>  - David
>
>
> On Mon, Apr 29, 2013 at 1:14 PM, E. Tadeu <e.tadeu at gmail.com> wrote:
>> This problem is still happening, I've just tested it with Python 2.7.3 and
>> VTK 5.10.1.
>>
>> I've debugged it inside CPython, and this is what I found:
>>
>>     In object.c(1100): calling PyObject_Hash(PyObject *v = vtkObject)
>>
>>       PyTypeObject *tp = v->ob_type; // tp is 'vtkclass' from
>> 'vtkCommonPython'
>>
>>     It calls, in line 1111: PyType_Ready(tp)
>>
>>       (Which seems it should've been called before)
>>
>>     In PyType_Ready, typeobject.c(4028), it calls:
>>
>>       mro_internal(type)
>>
>>     Which fails, because the type does not have the 'mro' attribute.
>>
>>
>>   I've created an issue here: http://vtk.org/Bug/view.php?id=14037
>>
>>   Thanks!
>>
>>
>>
>> On Wed, May 27, 2009 at 10:56 AM, Berk Geveci <berk.geveci at kitware.com>
>> wrote:
>>>
>>> This is definitely not intentional. Furthermore, I can't reproduce it
>>> on cvs head. Do you know what caused the problem between 5.0.3 and
>>> 5.0.4. Also, can you try 5.4 as I don't think we support 5.0 anymore?
>>>
>>> -berk
>>>
>>> On Wed, May 27, 2009 at 1:19 AM, Carlos Scheidegger
>>> <cscheid at sci.utah.edu> wrote:
>>> > Here's a simpler way to trigger the issue I just mentioned. The core
>>> > problem
>>> > is related to generating a hash from the vtk class object. On VTK 5.0.3
>>> > (and
>>> > Python 2.5.2), I get this:
>>> >
>>> >>>> import vtk
>>> >>>> hash(vtk.vtkObject)
>>> > 140169743808624
>>> >>>> id(vtk.vtkObject)
>>> > 140169743808624
>>> >
>>> > This seems to me the correct behavior. On VTK 5.0.4 (and Python 2.6.2),
>>> > I
>>> > get this:
>>> >
>>> >>>> hash(vtk.vtkObject)
>>> > Traceback (most recent call last):
>>> >  File "<stdin>", line 1, in <module>
>>> > AttributeError: mro
>>> >>>> id(vtk.vtkObject)
>>> > 3083232608L
>>> >
>>> > Is this an intended change? It is very convenient to use vtk classes in
>>> > python dictionaries...
>>> >
>>> > Thanks!
>>> > -carlos