Random failures (memory corruption?) in BRepOffsetAPI_MakeFilling

[blechta]

Original downstream issue: https://gitlab.onelab.info/gmsh/gmsh/issues/596 Version: OCE-0.18.3 MWE:

from OCC.Core.BRepBuilderAPI import BRepBuilderAPI_MakeVertex
from OCC.Core.BRepBuilderAPI import BRepBuilderAPI_MakeEdge
from OCC.Core.BRepBuilderAPI import BRepBuilderAPI_MakeWire
from OCC.Core.BRepOffsetAPI import BRepOffsetAPI_MakeFilling
from OCC.Core.TopExp import TopExp_Explorer
from OCC.Core.TopAbs import TopAbs_EDGE
from OCC.Core.GeomAbs import GeomAbs_C0
from OCC.Core.gp import gp_Pnt
from OCC.Core.TColgp import TColgp_Array1OfPnt
from OCC.Core.Geom import Geom_BezierCurve
from OCC.Core.BRep import BRep_Tool


p1 = gp_Pnt(0,0,2)
p2 = gp_Pnt(1,0,2)
p3 = gp_Pnt(0,1,2)
p4 = gp_Pnt(5.000000e-01,0,1.500000e+00)
p5 = gp_Pnt(0,5.000000e-01,2.500000e+00)
p6 = gp_Pnt(5.000000e-01,5.000000e-01,1.500000e+00)
p7 = gp_Pnt(5.000000e-01,0,1)
p8 = gp_Pnt(0,5.000000e-01,3)
p9 = gp_Pnt(5.000000e-01,5.000000e-01,1)

v1 = BRepBuilderAPI_MakeVertex(p1).Vertex()
v2 = BRepBuilderAPI_MakeVertex(p2).Vertex()
v3 = BRepBuilderAPI_MakeVertex(p3).Vertex()

ctrl1 = TColgp_Array1OfPnt(1, 3)
ctrl1.SetValue(1, p1)
ctrl1.SetValue(2, p7)
ctrl1.SetValue(3, p2)

ctrl2 = TColgp_Array1OfPnt(1, 3)
ctrl2.SetValue(1, p3)
ctrl2.SetValue(2, p8)
ctrl2.SetValue(3, p1)

ctrl3 = TColgp_Array1OfPnt(1, 3)
ctrl3.SetValue(1, p2)
ctrl3.SetValue(2, p9)
ctrl3.SetValue(3, p3)

curve1 = Geom_BezierCurve(ctrl1)
curve2 = Geom_BezierCurve(ctrl2)
curve3 = Geom_BezierCurve(ctrl3)

edge1 = BRepBuilderAPI_MakeEdge(curve1, v1, v2).Edge()
edge2 = BRepBuilderAPI_MakeEdge(curve2, v3, v1).Edge()
edge3 = BRepBuilderAPI_MakeEdge(curve3, v2, v3).Edge()

wire = BRepBuilderAPI_MakeWire()
wire.Add(edge1)
wire.Add(edge2)
wire.Add(edge3)

wire = wire.Wire()
assert wire.Closed()

filling = BRepOffsetAPI_MakeFilling()
exp0 = TopExp_Explorer()
exp0.Init(wire, TopAbs_EDGE)

while exp0.More():
    filling.Add(exp0.Current(), GeomAbs_C0)
    exp0.Next()

print(BRep_Tool.Pnt(v1).Coord())

try:
    filling.Build()
finally:
    print(BRep_Tool.Pnt(v1).Coord())

Expected behavior: print

(0.0, 0.0, 2.0)
(0.0, 0.0, 2.0)

and exit.

Observed behavior: randomly one of the following:

(0.0, 0.0, 2.0)
(0.276393202249936, 0.361803398875032, 2.0)
Traceback (most recent call last):
  File "gmsh-issue-596.py", line 70, in <module>
    filling.Build()
RuntimeError: Standard_NoSuchObject
TCollection_List::Remove
wrapper details:
  * symname: BRepBuilderAPI_MakeShape_Build
  * wrapname: _wrap_BRepBuilderAPI_MakeShape_Build
  * fulldecl: void BRepBuilderAPI_MakeShape::Build()

or

(0.0, 0.0, 2.0)
(0.0, 0.0, 2.0)
Traceback (most recent call last):
  File "gmsh-issue-596.py", line 70, in <module>
    filling.Build()
RuntimeError: Standard_Failure
Wire is not closed
wrapper details:
  * symname: BRepBuilderAPI_MakeShape_Build
  * wrapname: _wrap_BRepBuilderAPI_MakeShape_Build
  * fulldecl: void BRepBuilderAPI_MakeShape::Build()

[blechta]

Note that changing p1 to

p1 = gp_Pnt(0.1,0,2)

makes the problem miraculously go away.