test invalid normals 2

Utilities.cxx

@@ -63,6 +63,10 @@ void ComputeNormal (vtkPoints *pts, double *n, vtkIdType num, const vtkIdType *p
 }
 
 bool CheckNormal (vtkPoints *pts, vtkIdType num, const vtkIdType *poly, const double *n, double d) {
+    if (n[0] == 0 && n[1] == 0 && n[2] == 0) {
+        return false;
+    }
+
     const double *pt;
     vtkIdType i;
 

testing/test_filter.py

@@ -808,3 +808,58 @@ def test_branched_6(tmp_path):
 
     write_result(bf, tmp_path)
     check_result(bf, [6, 5])
+
+@pytest.mark.xfail
+def test_bad_shaped():
+    cube = vtkCubeSource()
+    cube.SetBounds(-2.5, 2.5, 0, 5, 0, 5)
+
+    z = 4.999
+
+    pts = [
+        [2.5, -2.5, 0],
+        [2.5, -2.5, 5],
+        [0, -2.5, z],
+        [-2.5, -2.5, 5],
+        [-2.5, -2.5, 0],
+
+        [-2.5, 2.5, 0],
+        [-2.5, 2.5, 5],
+        [0, 2.5, z],
+        [2.5, 2.5, 5],
+        [2.5, 2.5, 0],
+    ]
+
+    polys = [
+        [0, 1, 2, 3, 4],
+        [5, 6, 7, 8, 9],
+        [9, 8, 1, 0],
+        [4, 3, 6, 5],
+        [9, 0, 4, 5],
+        [1, 8, 7, 6, 3, 2]
+    ]
+
+    _pts = vtkPoints()
+
+    for pt in pts:
+        _pts.InsertNextPoint(*pt)
+
+    pd = vtkPolyData()
+    pd.Allocate(1)
+    pd.SetPoints(_pts)
+
+    for poly in polys:
+        cell = vtkIdList()
+        [ cell.InsertNextId(i) for i in poly ]
+        pd.InsertNextCell(VTK_POLYGON, cell)
+
+    prod = vtkTrivialProducer()
+    prod.SetOutput(pd)
+
+    bf = vtkPolyDataBooleanFilter()
+    bf.SetInputConnection(0, cube.GetOutputPort())
+    bf.SetInputConnection(1, prod.GetOutputPort())
+    bf.SetOperModeToNone()
+    bf.Update()
+
+    check_result(bf)