[vtkusers] Bug in vtkStripper on a very simple case ? (confirmed)

[pof]

Dear vtk'ers,

I confirm that I found a bug in vtkStripper, which in some cases does not produce the expected result.

In this simple example (polydata0.vtk file), 5 segments are defined, and they do define unambiguously a single polyline:
	///////
	# vtk DataFile Version 3.0
	vtk output
	ASCII
	DATASET POLYDATA
	POINTS 6 float
	1.7 0.5 0 2 0 0 1.7 -0.5 0
	1.6 -1 0 1.8 -0.2 0 1.6 1 0

	LINES 5 15
	2 0 1
	2 2 3
	2 4 2
	2 1 4
	2 5 0
	///////

When this polydata is processed through the vtkStripper, the first four segments are merged, but the last segment remains unmerged (see the last section of the polydata1.vtk file below) :
	LINES 2 9
	5 0 1 4 2 3
	2 5 0

Strangely, if the polydata is modified by defining the segment (2 5 0) as the first segment, then vtkStripper succeed to merge the 5 segments (see the last section below) :
	LINES 1 7
	6 5 0 1 4 2 3

Herebelow is the code used to reproduce this data and the described bug.

Any idea why vtkStripper does not behave correctly in this case?
Thanks
JD

--------------------------------------
#include <vtkPolyData.h>
#include <vtkPolyDataWriter.h>
#include <vtkSmartPointer.h>
#include <vtkCellArray.h>
#include <vtkStripper.h>

int main(int argc, char *argv[])
{
   vtkSmartPointer<vtkPoints> Points = vtkSmartPointer<vtkPoints>::New();
   // Create 6 points
   Points->InsertNextPoint(1.7,  0.5, 0);
   Points->InsertNextPoint(2.0,  0,    0);
   Points->InsertNextPoint(1.7, -0.5, 0);
   Points->InsertNextPoint(1.6, -1,    0);
   Points->InsertNextPoint(1.8, -0.2, 0);
   Points->InsertNextPoint(1.6,  1,    0);

   vtkSmartPointer<vtkCellArray> Segments = 
vtkSmartPointer<vtkCellArray>::New();
   // Create line segment #0
   Segments->InsertNextCell(2);
   Segments->InsertCellPoint(0);
   Segments->InsertCellPoint(1);
   // Create line segment #1
   Segments->InsertNextCell(2);
   Segments->InsertCellPoint(2);
   Segments->InsertCellPoint(3);
   // Create line segment #2
   Segments->InsertNextCell(2);
   Segments->InsertCellPoint(4);
   Segments->InsertCellPoint(2);
   // Create line segment #3
   Segments->InsertNextCell(2);
   Segments->InsertCellPoint(1);
   Segments->InsertCellPoint(4);
   // Create line segment #4
   Segments->InsertNextCell(2);
   Segments->InsertCellPoint(5);
   Segments->InsertCellPoint(0);

   // Create the polydata from points and faces
   vtkSmartPointer<vtkPolyData> SegPD = vtkSmartPointer<vtkPolyData>::New();
   SegPD->SetPoints(Points);
   SegPD->SetLines(Segments);
   SegPD->Update();

   // Try to get the polyline (there should be 1) from the segments
   vtkSmartPointer<vtkStripper> stripper = 
vtkSmartPointer<vtkStripper>::New();
   stripper->SetInputConnection(SegPD->GetProducerPort());
   stripper->Update();

   vtkSmartPointer<vtkPolyDataWriter> wr = 
vtkSmartPointer<vtkPolyDataWriter>::New();
   // Save the original polydata on a vtk file
   wr->SetFileName("D:\\polylines0.vtk");
   wr->SetInputConnection(SegPD->GetProducerPort());
   wr->Write();
   // Save the filtered polydata on a vtk file
   wr->SetFileName("D:\\polylines1.vtk");
   wr->SetInputConnection(stripper->GetOutputPort());
   wr->Write();

   return EXIT_SUCCESS;
}
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