[Paraview] "had to make up a value for selection": what am I doing wrong?

[Takuya OSHIMA]

Hi ParaView developers,

As I got no answer so far from the list, I did some digging with a
debugger. As a result it's looking more like a bug in ParaView, but
I'm not confident yet. So far what I found are threefold:

1. If I revert the following modification to
pqSignalAdaptorSelectionTreeWidget.cxx on 2008-07-02

Index: pqSignalAdaptorSelectionTreeWidget.cxx
===================================================================
RCS file: /cvsroot/ParaView3/ParaView3/Qt/Components/pqSignalAdaptorSelectionTreeWidget.cxx,v
retrieving revision 1.6
retrieving revision 1.7
diff -r1.6 -r1.7
187,188c187,190
<   
<   this->Internal->Property->ResetToDefault();
---
>  
>   // Domain changes should not change the property values. This is overriding
>   // the value loaded from state files etc.
>   // this->Internal->Property->ResetToDefault();

, the "had to make up a value" message disappeared and reader worked
as expected. This coincides with my thought that the problem started
at around a month ago.

2. After doing AddArray() to the selection object in the reader,
ParaView does seem to recognize the newly added item, since in

void vtkSMArraySelectionInformationHelper::UpdateProperty(
  vtkIdType connectionId,  int serverIds, vtkClientServerID objectId, 
  vtkSMProperty* prop)

numArrays turned out to have the expected number of arrays, and the
results of GetArgument() were precisely expected values. I could
confirm the new item is added to prop (the last argument in the
function prototype above) through SetElement(). The address prop
pointed to was 0x078c5b38 in the tracked case.

3. However, when

void pqSignalAdaptorSelectionTreeWidget::domainChanged()

was executed later, the address this->Internal->Property pointed to
was 0x078cd688, which was different from what prop pointed
to. Naturally, the object this->Internal->Property pointed to did not
contain the new item. Thus the missing item triggered the "had to make up
a value" message in

QList<QVariant> pqSMAdaptor::getSelectionProperty(vtkSMProperty*
  Property, unsigned int Index).

So my question after all is, where and why has prop (the object at
0x078c5b38) gone?  Even with a debugger, tracking what had been going
on behind 100+ call tree stack was simply out of my skill range. Can
you comment if this behavior is expected, or a bug?

Thanks,
Takuya

Takuya OSHIMA, Ph.D.
Faculty of Engineering, Niigata University
8050 Ikarashi-Ninocho, Nishi-ku, Niigata, 950-2181, JAPAN


From: Takuya OSHIMA <oshima at eng.niigata-u.ac.jp>
Subject: [Paraview] "had to make up a value for selection": what am I doing wrong?
Date: Fri, 25 Jul 2008 13:48:28 +0900 (JST)

> Hi,
> 
> My reader for the latest CVS head has a selection list within its UI
> panel associated with its corresponding vtkDataArraySelection object,
> as shown below in its XML representation. The selection list is
> initialized when RequestInformation() is called for the first time,
> and works perfectly as long as the contents of the list remain
> unchanged.
> 
> However if the reader try to add items to the selection list later
> within RequestData(), the newly added items always appear unchecked in
> the UI panel regardless of the status in its corresponding
> vtkDataArraySelection, and messages saying "had to make up a value for
> selection" are shown in the output window a number of times equal to
> the number of items added.
> 
> If I remember correctly this piece of code worked fine until rather
> recent CVS (within a month or so, but not so sure).
> 
> What am I doing wrong?
> 
>         <StringVectorProperty 
>             name="CellArrayInfo"
>             information_only="1">
>             <ArraySelectionInformationHelper attribute_name="Cell"/>
>         </StringVectorProperty>
>         <StringVectorProperty
>             name="CellArrays"
>             command="SetCellArrayStatus"
>             number_of_elements="0" 
>             repeat_command="1"
>             number_of_elements_per_command="2"
>             element_types="2 0"
>     	    information_property="CellArrayInfo">
>             <ArraySelectionDomain name="array_list">
>                 <RequiredProperties>
>                     <Property name="CellArrayInfo"
>                         function="ArrayList"/>
>                 </RequiredProperties>
>             </ArraySelectionDomain>
>         </StringVectorProperty>
> 
> Takuya OSHIMA, Ph.D.
> Faculty of Engineering, Niigata University
> 8050 Ikarashi-Ninocho, Nishi-ku, Niigata, 950-2181, JAPAN
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