remove circular dependency and corresponding fwd declarations

include in helpers.h was introduced by 0528592011
in 2019 for backward compatibility, it can now be removed

BGL/include/CGAL/boost/graph/generators.h

@@ -29,30 +29,6 @@
 #include <unordered_map>
 
 namespace CGAL {
-namespace Euler {
-
-// Some forward declarations to break the helpers.h > generators.h > Euler_operations.h cycle
-template< typename Graph>
-void fill_hole(typename boost::graph_traits<Graph>::halfedge_descriptor h,
-               Graph& g);
-
-template<typename Graph , typename VertexRange >
-typename boost::graph_traits<Graph>::face_descriptor add_face(const VertexRange& vr,
-                                                              Graph& g);
-
-template<typename Graph>
-typename boost::graph_traits<Graph>::halfedge_descriptor
-split_face(typename boost::graph_traits<Graph>::halfedge_descriptor h1,
-           typename boost::graph_traits<Graph>::halfedge_descriptor h2,
-           Graph& g);
-
-} // namespace Euler
-
-template <typename SourceMesh, typename TargetMesh,
-          typename NamedParameters1, typename NamedParameters2>
-void copy_face_graph(const SourceMesh& sm, TargetMesh& tm,
-                     const NamedParameters1& np1,
-                     const NamedParameters2& np2);
 
 namespace internal {
 

BGL/include/CGAL/boost/graph/helpers.h

@@ -1081,8 +1081,5 @@ int halfedge_index_in_face(typename boost::graph_traits<Graph>::halfedge_descrip
 
 } // namespace CGAL
 
-// Here at the bottom because helpers.h must include generators (for backward compatibility reasons),
-// and Euler_operations.h needs helpers.h
-#include <CGAL/boost/graph/generators.h>
 
 #endif // CGAL_BOOST_GRAPH_HELPERS_H

Convex_hull_3/include/CGAL/convex_hull_3.h

@@ -33,6 +33,7 @@
 
 #include <CGAL/Number_types/internal/Exact_type_selector.h>
 #include <CGAL/boost/graph/copy_face_graph.h>
+#include <CGAL/boost/graph/generators.h>
 #include <CGAL/Named_function_parameters.h>
 #include <CGAL/boost/graph/graph_traits_Triangulation_data_structure_2.h>
 #include <CGAL/boost/graph/properties_Triangulation_data_structure_2.h>

Optimal_bounding_box/include/CGAL/Optimal_bounding_box/oriented_bounding_box.h

@@ -24,6 +24,7 @@
 #include <CGAL/boost/graph/helpers.h>
 #include <CGAL/Named_function_parameters.h>
 #include <CGAL/boost/graph/named_params_helper.h>
+#include <CGAL/boost/graph/generators.h>
 #include <CGAL/convex_hull_3.h>
 #include <CGAL/Convex_hull_traits_3.h>
 #include <CGAL/Default.h>

Polyhedron/demo/Polyhedron/Plugins/PCA/Basic_generator_plugin.cpp

@@ -8,6 +8,7 @@
 
 #include <CGAL/boost/graph/helpers.h>
 #include <CGAL/boost/graph/Euler_operations.h>
+#include <CGAL/boost/graph/generators.h>
 
 #include <CGAL/subdivision_method_3.h>
 #include <CGAL/Kernel_traits.h>

Polyhedron/demo/Polyhedron/Plugins/PCA/Clipping_box_plugin.cpp

@@ -15,6 +15,7 @@
 #include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
 #include <CGAL/Polyhedron_3.h>
 #include <CGAL/Polygon_mesh_processing/compute_normal.h>
+#include <CGAL/boost/graph/generators.h>
 #include "Selection_visualizer.h"
 #include "Scene_plane_item.h"
 

Polyhedron/demo/Polyhedron/Plugins/PCA/Create_bbox_mesh_plugin.cpp

@@ -3,6 +3,8 @@
 #include <CGAL/Three/Scene_item.h>
 #include <CGAL/Three/Scene_interface.h>
 
+#include <CGAL/boost/graph/generators.h>
+
 #include <QAction>
 #include <QMainWindow>
 #include <QMessageBox>

Polyhedron/demo/Polyhedron/Plugins/PCA/Edit_box_plugin.cpp

@@ -7,6 +7,7 @@
 #include <CGAL/Three/Viewer_interface.h>
 #include <CGAL/Three/Three.h>
 #include <CGAL/boost/graph/helpers.h>
+#include <CGAL/boost/graph/generators.h>
 #include <QAction>
 #include <QMainWindow>
 #include <QApplication>

Polyhedron/demo/Polyhedron/Plugins/PCA/Pca_plugin.cpp

@@ -11,6 +11,7 @@
 #include <CGAL/bounding_box.h>
 #include <CGAL/linear_least_squares_fitting_3.h>
 #include <CGAL/boost/graph/helpers.h>
+#include <CGAL/boost/graph/generators.h>
 
 #include "Kernel_type.h"
 #include <CGAL/Three/Three.h>