Hole_filter_2 erase hole with null ptr

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Issue Details

When I am using minkowski_sum_2 to calculate the minkowski sum of two polygons. The error jump out and interrupt the program.

It seems that the deque object is erasing an empty iterator.

Since I use the debug mode, I would like to update the vs2019 watch figure.

The local watch

The call stack

It seems that the to_erase variables contain error data.

class Hole_filter2 { private: typedef Kernel Kernel; typedef Container_ Container;

typedef CGAL::Polygon_2<Kernel, Container> Polygon_2; typedef CGAL::Polygon_with_holes_2<Kernel, Container> Polygon_with_holes_2; typedef typename Polygon_with_holes_2::Hole_iterator Hole_iterator; typedef std::vector Hole_iterator_vector;

public: /*! Filter out holes of a polygon with holes.

\param[in] pgn1 The polygon with holes to filter.
\param[in] pgn2 The reference polygon with holes.
\param[out] filtered_pgn1 the filterd polygon. */ void operator()(const Polygon_with_holes_2& pgn1, const Polygon_2& pgn2, Polygon_with_holes_2& filtered_pgn1) const

}

It seems the function operator() does not handle erase properly.

Source Code

Transformation_2 negative_scale(CGAL::SCALING, -1);
Polygon_2 inverse_item_polygon = transform(negative_scale, item_polygon_);
Polygon_with_holes_2 innfp_box = CGAL::minkowski_sum_2(inverse_item_polygon, flipped_container_polygon);

Environment

Operating system (Windows 64 bits):
Compiler: VS2019
Release or debug mode: Debug
Specific flags used (if any):
CGAL version: 5.5
Boost version: 1.78.0
Other libraries versions if used (Eigen, TBB, etc.):

void operator()(const Polygon_with_holes_2& pgn1,
                  const Polygon_2& pgn2,
                  Polygon_with_holes_2& filtered_pgn1) const
  {
    filtered_pgn1 = pgn1;

    Hole_iterator_vector to_erase;
    Bbox_2 boundary_bbox = pgn2.bbox();

    Hole_iterator it = filtered_pgn1.holes_begin();
    while (it != filtered_pgn1.holes_end()) {
      Bbox_2 hole_bbox = (*it).bbox();

      if ((hole_bbox.ymax()-hole_bbox.ymin() <
           boundary_bbox.ymax()-boundary_bbox.ymin()) ||
          (hole_bbox.xmax()-hole_bbox.xmin() <
           boundary_bbox.xmax()-boundary_bbox.xmin()))
      {
        to_erase.push_back(it);
      }
      ++it;
    }

    typename Hole_iterator_vector::iterator it2 = to_erase.begin();
    while (it2 != to_erase.end()) filtered_pgn1.erase_hole(*it2++);
  }

The implemtation of hole container is deque. How can we delete the iterator in this way?

Holes_container m_holes;

CGAL / cgal