From 3bd448d1a88a21ccbcc99ef5a9499338a712bad6 Mon Sep 17 00:00:00 2001
From: Andreas Fabri <andreas.fabri@geometryfactory.com>
Date: Wed, 28 Feb 2024 14:28:00 +0000
Subject: [PATCH 1/4] Polygon: Avoid stackoverflow when summing exact numbers

---
 Polygon/include/CGAL/Polygon_2_algorithms.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Polygon/include/CGAL/Polygon_2_algorithms.h b/Polygon/include/CGAL/Polygon_2_algorithms.h
index 5c836466c11..dc8f9c8708f 100644
--- a/Polygon/include/CGAL/Polygon_2_algorithms.h
+++ b/Polygon/include/CGAL/Polygon_2_algorithms.h
@@ -24,6 +24,7 @@
 #include <CGAL/config.h>
 #include <CGAL/enum.h>
 #include <CGAL/Bbox_2.h>
+#include <CGAL/Lazy.h>
 #include <CGAL/Polygon_2/polygon_assertions.h>
 
 ///
@@ -153,6 +154,7 @@ area_2( ForwardIterator first, ForwardIterator last,
    ForwardIterator third = second;
    while (++third != last) {
         result = result + compute_area_2(*first, *second, *third);
+        exact(result);
         second = third;
    }
 }
@@ -190,6 +192,7 @@ polygon_area_2( ForwardIterator first, ForwardIterator last,
    ForwardIterator third = second;
    while (++third != last) {
         result = result + compute_area_2(*first, *second, *third);
+        exact(result);
         second = third;
    }
    return result;

From 2c8567ed16d16650e517cbba7688965f964ee313 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C3=A9bastien=20Loriot?= <sebastien.loriot@cgal.org>
Date: Wed, 6 Mar 2024 10:48:52 +0100
Subject: [PATCH 2/4] add overload for Quotent as specialization for
 std::arithmetic result in undefined behavior

---
 Filtered_kernel/include/CGAL/Lazy.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Filtered_kernel/include/CGAL/Lazy.h b/Filtered_kernel/include/CGAL/Lazy.h
index 463ef501b34..dcfb877ee8e 100644
--- a/Filtered_kernel/include/CGAL/Lazy.h
+++ b/Filtered_kernel/include/CGAL/Lazy.h
@@ -108,6 +108,10 @@ template<class T>inline std::enable_if_t<std::is_arithmetic<T>::value||std::is_e
 template<class T>inline std::enable_if_t<std::is_arithmetic<T>::value||std::is_enum<T>::value, T> exact (T d){return d;}
 template<class T>inline std::enable_if_t<std::is_arithmetic<T>::value||std::is_enum<T>::value, int> depth(T){return -1;}
 
+template<class T>inline std::enable_if_t<std::is_arithmetic<T>::value, Quotient<T>> approx(Quotient<T> d){return d;}
+template<class T>inline std::enable_if_t<std::is_arithmetic<T>::value, Quotient<T>> exact (Quotient<T> d){return d;}
+template<class T>inline std::enable_if_t<std::is_arithmetic<T>::value, int> depth(Quotient<T>){return -1;}
+
 // For tag classes: Return_base_tag, Homogeneous_tag, Null_vector, Origin
 template<class T>inline std::enable_if_t<std::is_empty<T>::value, T> exact(T){return {};}
 template<class T>inline std::enable_if_t<std::is_empty<T>::value, T> approx(T){return {};}

From 9b4f35dfa1ef528794360f501ead82594fff68d7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C3=A9bastien=20Loriot?= <sebastien.loriot@cgal.org>
Date: Wed, 6 Mar 2024 11:32:30 +0100
Subject: [PATCH 3/4] fix dependencies

---
 Bounding_volumes/package_info/Bounding_volumes/dependencies    | 1 +
 Generator/package_info/Generator/dependencies                  | 1 +
 Inscribed_areas/package_info/Inscribed_areas/dependencies      | 1 +
 Nef_2/package_info/Nef_2/dependencies                          | 1 +
 Polygon/package_info/Polygon/dependencies                      | 3 +++
 .../package_info/Set_movable_separability_2/dependencies       | 3 +++
 Stream_support/package_info/Stream_support/dependencies        | 1 +
 7 files changed, 11 insertions(+)

diff --git a/Bounding_volumes/package_info/Bounding_volumes/dependencies b/Bounding_volumes/package_info/Bounding_volumes/dependencies
index 99a12a27c82..6a7b86ebd72 100644
--- a/Bounding_volumes/package_info/Bounding_volumes/dependencies
+++ b/Bounding_volumes/package_info/Bounding_volumes/dependencies
@@ -4,6 +4,7 @@ Cartesian_kernel
 Circulator
 Distance_2
 Distance_3
+Filtered_kernel
 Installation
 Intersections_2
 Intersections_3
diff --git a/Generator/package_info/Generator/dependencies b/Generator/package_info/Generator/dependencies
index 04faaf3547d..925a743b87c 100644
--- a/Generator/package_info/Generator/dependencies
+++ b/Generator/package_info/Generator/dependencies
@@ -1,6 +1,7 @@
 Algebraic_foundations
 BGL
 Circulator
+Filtered_kernel
 Generator
 Installation
 Interval_support
diff --git a/Inscribed_areas/package_info/Inscribed_areas/dependencies b/Inscribed_areas/package_info/Inscribed_areas/dependencies
index da58f1b4f08..fc0704df443 100644
--- a/Inscribed_areas/package_info/Inscribed_areas/dependencies
+++ b/Inscribed_areas/package_info/Inscribed_areas/dependencies
@@ -1,6 +1,7 @@
 Algebraic_foundations
 Circulator
 Distance_2
+Filtered_kernel
 Inscribed_areas
 Installation
 Interval_support
diff --git a/Nef_2/package_info/Nef_2/dependencies b/Nef_2/package_info/Nef_2/dependencies
index cca2b94b65f..1abad5d8686 100644
--- a/Nef_2/package_info/Nef_2/dependencies
+++ b/Nef_2/package_info/Nef_2/dependencies
@@ -5,6 +5,7 @@ Cartesian_kernel
 Circulator
 Distance_2
 Distance_3
+Filtered_kernel
 HalfedgeDS
 Hash_map
 Homogeneous_kernel
diff --git a/Polygon/package_info/Polygon/dependencies b/Polygon/package_info/Polygon/dependencies
index 3312eb37e46..7ed360974c5 100644
--- a/Polygon/package_info/Polygon/dependencies
+++ b/Polygon/package_info/Polygon/dependencies
@@ -1,8 +1,11 @@
 Algebraic_foundations
 Circulator
+Filtered_kernel
 GraphicsView
 Installation
+Interval_support
 Kernel_23
+Modular_arithmetic
 Number_types
 Polygon
 Profiling_tools
diff --git a/Set_movable_separability_2/package_info/Set_movable_separability_2/dependencies b/Set_movable_separability_2/package_info/Set_movable_separability_2/dependencies
index e88f195eeab..c84b7694460 100644
--- a/Set_movable_separability_2/package_info/Set_movable_separability_2/dependencies
+++ b/Set_movable_separability_2/package_info/Set_movable_separability_2/dependencies
@@ -1,7 +1,10 @@
 Algebraic_foundations
 Circulator
+Filtered_kernel
 Installation
+Interval_support
 Kernel_23
+Modular_arithmetic
 Number_types
 Polygon
 Profiling_tools
diff --git a/Stream_support/package_info/Stream_support/dependencies b/Stream_support/package_info/Stream_support/dependencies
index 86fd53b13ac..f45a1a985bf 100644
--- a/Stream_support/package_info/Stream_support/dependencies
+++ b/Stream_support/package_info/Stream_support/dependencies
@@ -1,6 +1,7 @@
 Algebraic_foundations
 BGL
 Circulator
+Filtered_kernel
 Installation
 Interval_support
 Kernel_23

From f34745c4d87c94f954fe1e6b7a3a1b3dbdf85e62 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C3=A9bastien=20Loriot?= <sebastien.loriot@cgal.org>
Date: Thu, 14 Mar 2024 09:14:47 +0100
Subject: [PATCH 4/4] use a functor for collapsing the DAG to not depend on
 Filtered_kernel nor inclusion order

---
 .../Bounding_volumes/dependencies             |  1 -
 Filtered_kernel/include/CGAL/Lazy.h           | 11 +++++++++
 Generator/package_info/Generator/dependencies |  1 -
 .../Surface_mesh_geodesic_distances_3.h       |  2 ++
 .../package_info/Heat_method_3/dependencies   |  1 -
 .../package_info/Inscribed_areas/dependencies |  1 -
 Nef_2/package_info/Nef_2/dependencies         |  1 -
 Number_types/include/CGAL/utils_classes.h     | 11 +++++++++
 Polygon/include/CGAL/Polygon_2_algorithms.h   |  8 ++++---
 Polygon/package_info/Polygon/dependencies     |  3 ---
 .../CGAL/Polygon_mesh_processing/measure.h    | 24 ++++++++++++-------
 .../Set_movable_separability_2/dependencies   |  3 ---
 .../package_info/Stream_support/dependencies  |  1 -
 13 files changed, 44 insertions(+), 24 deletions(-)

diff --git a/Bounding_volumes/package_info/Bounding_volumes/dependencies b/Bounding_volumes/package_info/Bounding_volumes/dependencies
index 6a7b86ebd72..99a12a27c82 100644
--- a/Bounding_volumes/package_info/Bounding_volumes/dependencies
+++ b/Bounding_volumes/package_info/Bounding_volumes/dependencies
@@ -4,7 +4,6 @@ Cartesian_kernel
 Circulator
 Distance_2
 Distance_3
-Filtered_kernel
 Installation
 Intersections_2
 Intersections_3
diff --git a/Filtered_kernel/include/CGAL/Lazy.h b/Filtered_kernel/include/CGAL/Lazy.h
index dcfb877ee8e..95d79065451 100644
--- a/Filtered_kernel/include/CGAL/Lazy.h
+++ b/Filtered_kernel/include/CGAL/Lazy.h
@@ -117,6 +117,17 @@ template<class T>inline std::enable_if_t<std::is_empty<T>::value, T> exact(T){re
 template<class T>inline std::enable_if_t<std::is_empty<T>::value, T> approx(T){return {};}
 template<class T>inline std::enable_if_t<std::is_empty<T>::value, int> depth(T){return -1;}
 
+namespace internal{
+template <typename AT, typename ET, typename E2A>
+struct Evaluate<Lazy<AT,ET,E2A>>
+{
+  void operator()(const Lazy<AT,ET,E2A>& l)
+  {
+    exact(l);
+  }
+};
+} // internal namespace
+
 // For an iterator, exact/approx applies to the objects it points to
 template <class T, class=std::enable_if_t<is_iterator_type<T,std::input_iterator_tag>::value>>
 auto exact(T const& t) {return make_transforming_iterator(t,[](auto const&u)->decltype(auto){return CGAL::exact(u);});}
diff --git a/Generator/package_info/Generator/dependencies b/Generator/package_info/Generator/dependencies
index 925a743b87c..04faaf3547d 100644
--- a/Generator/package_info/Generator/dependencies
+++ b/Generator/package_info/Generator/dependencies
@@ -1,7 +1,6 @@
 Algebraic_foundations
 BGL
 Circulator
-Filtered_kernel
 Generator
 Installation
 Interval_support
diff --git a/Heat_method_3/include/CGAL/Heat_method_3/Surface_mesh_geodesic_distances_3.h b/Heat_method_3/include/CGAL/Heat_method_3/Surface_mesh_geodesic_distances_3.h
index 64c1782bb9c..46441d6f8e2 100644
--- a/Heat_method_3/include/CGAL/Heat_method_3/Surface_mesh_geodesic_distances_3.h
+++ b/Heat_method_3/include/CGAL/Heat_method_3/Surface_mesh_geodesic_distances_3.h
@@ -25,6 +25,8 @@
 #include <CGAL/squared_distance_3.h>
 #include <CGAL/Polygon_mesh_processing/measure.h>
 #include <CGAL/number_utils.h>
+#include <CGAL/Default.h>
+
 #ifdef CGAL_EIGEN3_ENABLED
 #include <CGAL/Eigen_solver_traits.h>
 #endif
diff --git a/Heat_method_3/package_info/Heat_method_3/dependencies b/Heat_method_3/package_info/Heat_method_3/dependencies
index 50488d5544f..f69807f53d7 100644
--- a/Heat_method_3/package_info/Heat_method_3/dependencies
+++ b/Heat_method_3/package_info/Heat_method_3/dependencies
@@ -4,7 +4,6 @@ Cartesian_kernel
 Circulator
 Distance_2
 Distance_3
-Filtered_kernel
 Heat_method_3
 Installation
 Interval_support
diff --git a/Inscribed_areas/package_info/Inscribed_areas/dependencies b/Inscribed_areas/package_info/Inscribed_areas/dependencies
index fc0704df443..da58f1b4f08 100644
--- a/Inscribed_areas/package_info/Inscribed_areas/dependencies
+++ b/Inscribed_areas/package_info/Inscribed_areas/dependencies
@@ -1,7 +1,6 @@
 Algebraic_foundations
 Circulator
 Distance_2
-Filtered_kernel
 Inscribed_areas
 Installation
 Interval_support
diff --git a/Nef_2/package_info/Nef_2/dependencies b/Nef_2/package_info/Nef_2/dependencies
index 1abad5d8686..cca2b94b65f 100644
--- a/Nef_2/package_info/Nef_2/dependencies
+++ b/Nef_2/package_info/Nef_2/dependencies
@@ -5,7 +5,6 @@ Cartesian_kernel
 Circulator
 Distance_2
 Distance_3
-Filtered_kernel
 HalfedgeDS
 Hash_map
 Homogeneous_kernel
diff --git a/Number_types/include/CGAL/utils_classes.h b/Number_types/include/CGAL/utils_classes.h
index 06a569a6d8b..1b4eb95ce89 100644
--- a/Number_types/include/CGAL/utils_classes.h
+++ b/Number_types/include/CGAL/utils_classes.h
@@ -266,6 +266,17 @@ class Is_valid
     };
 };
 
+namespace internal
+{
+// utility class to be used for calling exact(Lazy) when doing accumulation with EPECK
+template <class NT>
+struct Evaluate
+{
+  void operator()(const NT&)
+  {}
+};
+} // internal namespace
+
 } //namespace CGAL
 
 #endif // CGAL_UTILS_CLASSES_H
diff --git a/Polygon/include/CGAL/Polygon_2_algorithms.h b/Polygon/include/CGAL/Polygon_2_algorithms.h
index dc8f9c8708f..40b1e06a9c7 100644
--- a/Polygon/include/CGAL/Polygon_2_algorithms.h
+++ b/Polygon/include/CGAL/Polygon_2_algorithms.h
@@ -24,8 +24,8 @@
 #include <CGAL/config.h>
 #include <CGAL/enum.h>
 #include <CGAL/Bbox_2.h>
-#include <CGAL/Lazy.h>
 #include <CGAL/Polygon_2/polygon_assertions.h>
+#include <CGAL/utils_classes.h>
 
 ///
 namespace CGAL {
@@ -143,6 +143,7 @@ area_2( ForwardIterator first, ForwardIterator last,
         const PolygonTraits& traits)
 {
   typedef typename PolygonTraits::FT FT;
+  internal::Evaluate<FT> evaluate;
    result = FT(0);
    // check if the polygon is empty
    if (first == last) return;
@@ -154,7 +155,7 @@ area_2( ForwardIterator first, ForwardIterator last,
    ForwardIterator third = second;
    while (++third != last) {
         result = result + compute_area_2(*first, *second, *third);
-        exact(result);
+        evaluate(result);
         second = third;
    }
 }
@@ -181,6 +182,7 @@ polygon_area_2( ForwardIterator first, ForwardIterator last,
                 const PolygonTraits& traits)
 {
    typedef typename PolygonTraits::FT FT;
+   internal::Evaluate<FT> evaluate;
    FT result = FT(0);
    // check if the polygon is empty
    if (first == last) return result;
@@ -192,7 +194,7 @@ polygon_area_2( ForwardIterator first, ForwardIterator last,
    ForwardIterator third = second;
    while (++third != last) {
         result = result + compute_area_2(*first, *second, *third);
-        exact(result);
+        evaluate(result);
         second = third;
    }
    return result;
diff --git a/Polygon/package_info/Polygon/dependencies b/Polygon/package_info/Polygon/dependencies
index 7ed360974c5..3312eb37e46 100644
--- a/Polygon/package_info/Polygon/dependencies
+++ b/Polygon/package_info/Polygon/dependencies
@@ -1,11 +1,8 @@
 Algebraic_foundations
 Circulator
-Filtered_kernel
 GraphicsView
 Installation
-Interval_support
 Kernel_23
-Modular_arithmetic
 Number_types
 Polygon
 Profiling_tools
diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/measure.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/measure.h
index a0841748aee..87946231227 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/measure.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/measure.h
@@ -23,9 +23,7 @@
 #include <CGAL/boost/graph/properties.h>
 #include <CGAL/Named_function_parameters.h>
 #include <CGAL/Polygon_mesh_processing/internal/named_params_helper.h>
-
-
-#include <CGAL/Lazy.h> // needed for CGAL::exact(FT)/CGAL::exact(Lazy_exact_nt<T>)
+#include <CGAL/utils_classes.h>
 
 #include <boost/container/small_vector.hpp>
 #include <boost/graph/graph_traits.hpp>
@@ -261,12 +259,14 @@ face_border_length(typename boost::graph_traits<PolygonMesh>::halfedge_descripto
                    const PolygonMesh& pmesh,
                    const NamedParameters& np = parameters::default_values())
 {
-  typename GetGeomTraits<PolygonMesh, NamedParameters>::type::FT result = 0;
+  using FT = typename GetGeomTraits<PolygonMesh, NamedParameters>::type::FT;
+  ::CGAL::internal::Evaluate<FT> evaluate;
+  FT result = 0;
 
   for(typename boost::graph_traits<PolygonMesh>::halfedge_descriptor haf : halfedges_around_face(h, pmesh))
   {
     result += edge_length(haf, pmesh, np);
-    exact(result);
+    evaluate(result);
   }
 
   return result;
@@ -559,11 +559,14 @@ area(FaceRange face_range,
 {
   typedef typename boost::graph_traits<TriangleMesh>::face_descriptor face_descriptor;
 
-  typename GetGeomTraits<TriangleMesh, CGAL_NP_CLASS>::type::FT result = 0;
+  using FT = typename GetGeomTraits<TriangleMesh, CGAL_NP_CLASS>::type::FT;
+  FT result = 0;
+  ::CGAL::internal::Evaluate<FT> evaluate;
+
   for(face_descriptor f : face_range)
   {
     result += face_area(f, tmesh, np);
-    exact(result);
+    evaluate(result);
   }
 
   return result;
@@ -676,7 +679,10 @@ volume(const TriangleMesh& tmesh,
 
   typedef typename boost::graph_traits<TriangleMesh>::face_descriptor face_descriptor;
 
-  typename GetGeomTraits<TriangleMesh, CGAL_NP_CLASS>::type::FT volume = 0;
+  using FT = typename GetGeomTraits<TriangleMesh, CGAL_NP_CLASS>::type::FT;
+  ::CGAL::internal::Evaluate<FT> evaluate;
+
+  FT volume = 0;
   typename CGAL::Kernel_traits<typename property_map_value<TriangleMesh,
       CGAL::vertex_point_t>::type>::Kernel::Compute_volume_3 cv3;
 
@@ -686,7 +692,7 @@ volume(const TriangleMesh& tmesh,
                   get(vpm, target(halfedge(f, tmesh), tmesh)),
                   get(vpm, target(next(halfedge(f, tmesh), tmesh), tmesh)),
                   get(vpm, target(prev(halfedge(f, tmesh), tmesh), tmesh)));
-    exact(volume);
+    evaluate(volume);
   }
 
   return volume;
diff --git a/Set_movable_separability_2/package_info/Set_movable_separability_2/dependencies b/Set_movable_separability_2/package_info/Set_movable_separability_2/dependencies
index c84b7694460..e88f195eeab 100644
--- a/Set_movable_separability_2/package_info/Set_movable_separability_2/dependencies
+++ b/Set_movable_separability_2/package_info/Set_movable_separability_2/dependencies
@@ -1,10 +1,7 @@
 Algebraic_foundations
 Circulator
-Filtered_kernel
 Installation
-Interval_support
 Kernel_23
-Modular_arithmetic
 Number_types
 Polygon
 Profiling_tools
diff --git a/Stream_support/package_info/Stream_support/dependencies b/Stream_support/package_info/Stream_support/dependencies
index f45a1a985bf..86fd53b13ac 100644
--- a/Stream_support/package_info/Stream_support/dependencies
+++ b/Stream_support/package_info/Stream_support/dependencies
@@ -1,7 +1,6 @@
 Algebraic_foundations
 BGL
 Circulator
-Filtered_kernel
 Installation
 Interval_support
 Kernel_23