vtkMultiBlockDataSet ShallowCopy is broken for 9.3
The following works before VTK 9.3 and is now broken.
This is an issue for PyVista's wrapping of vtkMultiBlockDataSet
and is causing testing failures in https://github.com/pyvista/pyvista/pull/4688
import vtk
source = vtk.vtkSphereSource()
source.Update()
a = source.GetOutput()
source = vtk.vtkConeSource()
source.Update()
b = source.GetOutput()
blocks = vtk.vtkMultiBlockDataSet()
blocks.SetNumberOfBlocks(2)
blocks.SetBlock(0, a)
blocks.SetBlock(1, b)
copy = vtk.vtkMultiBlockDataSet()
copy.ShallowCopy(blocks)
# Works prior to VTK 9.3
assert id(copy.GetBlock(0)) == id(a) # Should have same ID since ShallowCopy
assert id(copy.GetBlock(1)) == id(b) # Should have same ID since ShallowCopy