Sketcher: Reduce ViewProviderUpdates when deleting Internal Alignment Geometry

==============================================================================

Deletion of a geometry having internal alignment geometry (B-Spline, Ellipse, ...)
involves calling a geometry deletion operation for each internal aligment constraint
in addition to the one of the geometry.

Before this commit, an update call was performed for each of these operations. Now,
there is a single update trigger operation after all the geometries are deleted.

src/Mod/Sketcher/App/SketchObject.cpp

@@ -146,6 +146,7 @@ SketchObject::SketchObject()
 
     internaltransaction=false;
     managedoperation=false;
+    deletinginternalgeometry=false;
 }
 
 SketchObject::~SketchObject()
@@ -955,6 +956,11 @@ int SketchObject::delGeometry(int GeoId, bool deleteinternalgeo)
              geo->getTypeId() == Part::GeomBSplineCurve::getClassTypeId())) {
 
             this->deleteUnusedInternalGeometry(GeoId, true);
+
+            Geometry.touch();
+
+            if(noRecomputes) // if we do not have a recompute, the sketch must be solved to update the DoF of the solver
+                solve();
             return 0;
         }
     }
@@ -997,10 +1003,12 @@ int SketchObject::delGeometry(int GeoId, bool deleteinternalgeo)
         this->Constraints.setValues(std::move(newConstraints));
     }
     // Update geometry indices and rebuild vertexindex now via onChanged, so that ViewProvider::UpdateData is triggered.
-    Geometry.touch();
+    if(!deletinginternalgeometry) {
+        Geometry.touch();
 
-    if(noRecomputes) // if we do not have a recompute, the sketch must be solved to update the DoF of the solver
-        solve();
+        if(noRecomputes) // if we do not have a recompute, the sketch must be solved to update the DoF of the solver
+            solve();
+    }
 
     return 0;
 }
@@ -4971,6 +4979,8 @@ int SketchObject::exposeInternalGeometry(int GeoId)
 
 int SketchObject::deleteUnusedInternalGeometry(int GeoId, bool delgeoid)
 {
+   Base::StateLocker lock(deletinginternalgeometry, true);
+
    if (GeoId < 0 || GeoId > getHighestCurveIndex())
         return -1;
 
@@ -5225,10 +5235,8 @@ int SketchObject::deleteUnusedInternalGeometry(int GeoId, bool delgeoid)
                         }
 
                     }
-                    // ignore weight constraints
-                    else if (((*itc)->Type!=Sketcher::Weight) && ( (*itc)->Second == (*it) || (*itc)->First == (*it) || (*itc)->Third == (*it)) ) {
-                        (*ita)++;
-                    }
+                    // We do not ignore weight constraints as we did with radius constraints, because the radius magnitude no longer makes sense
+                    // without the B-Spline.
                 }
 
                 if ( (*ita) < 2 ) { // IA

src/Mod/Sketcher/App/SketchObject.h

@@ -511,6 +511,8 @@ private:
     bool internaltransaction;
 
     bool managedoperation; // indicates whether changes to properties are the deed of SketchObject or not (for input validation)
+
+    bool deletinginternalgeometry; // sets a lock to deletinginternalgeometryoperation so that no individual triggers are perform on each element.
 };
 
 typedef App::FeaturePythonT<SketchObject> SketchObjectPython;