issue #0002080: Attempt to remove FEM analysis result (displacement & stress) results in false warning

src/Gui/CommandDoc.cpp

@@ -1110,19 +1110,14 @@ void StdCmdDelete::activated(int iMsg)
                     if (!links.empty()) {
                         // check if the referenced objects are groups or are selected too
                         for (std::vector<App::DocumentObject*>::iterator lt = links.begin(); lt != links.end(); ++lt) {
-                            if (
-                                  (!(*lt)->hasExtension(App::GroupExtension::getExtensionClassTypeId())) &&
-                                  (!(*lt)->isDerivedFrom(App::Origin::getClassTypeId())) &&
-                                  (!rSel.isSelected(*lt))
-                                ){
-                                autoDeletion = false;
-                                affectedLabels.insert(QString::fromUtf8((*lt)->Label.getValue()));
+                            if (!rSel.isSelected(*lt)) {
+                                ViewProvider* vp = pGuiDoc->getViewProvider(*lt);
+                                if (!vp->canDelete(obj)) {
+                                    autoDeletion = false;
+                                    affectedLabels.insert(QString::fromUtf8((*lt)->Label.getValue()));
+                                }
                             }
                         }
-
-                        if (!autoDeletion) {
-                            break;
-                        }
                     }
                 }
 
@@ -1148,12 +1143,14 @@ void StdCmdDelete::activated(int iMsg)
                         Gui::ViewProvider* vp = pGuiDoc->getViewProvider(ft->getObject());
                         if (vp) {
                             // ask the ViewProvider if it wants to do some clean up
-                            if (vp->onDelete(ft->getSubNames()))
+                            if (vp->onDelete(ft->getSubNames())) {
                                 doCommand(Doc,"App.getDocument(\"%s\").removeObject(\"%s\")"
                                          ,(*it)->getName(), ft->getFeatName());
+                            }
                         }
                     }
                     (*it)->commitTransaction();
+
                     Gui::getMainWindow()->setUpdatesEnabled(true);
                     Gui::getMainWindow()->update();
                 }

src/Gui/ViewProvider.cpp

@@ -614,6 +614,11 @@ bool ViewProvider::onDelete(const vector< string >& subNames) {
     return del;
 }
 
+bool ViewProvider::canDelete(App::DocumentObject*) const
+{
+    return false;
+}
+
 bool ViewProvider::canDragObject(App::DocumentObject* obj) const {
 
     auto vector = getExtensionsDerivedFromType<Gui::ViewProviderExtension>();

src/Gui/ViewProvider.h

@@ -137,9 +137,16 @@ public:
      * Get called if the object is about to get deleted.
      * Here you can delete other objects, switch their visibility or prevent the deletion of the object.
      * @param subNames  list of selected subelements
-     * @return          true if the deletion is approoved by the view provider.
+     * @return          true if the deletion is approved by the view provider.
      */
     virtual bool onDelete(const std::vector<std::string> &subNames);
+    /**
+     * @brief Asks the view provider if the given object that is part of its
+     * outlist can be removed from there without breaking it.
+     * @param obj is part of the outlist of the object associated to the view provider
+     * @return true if the removal is approved by the view provider.
+     */
+    virtual bool canDelete(App::DocumentObject* obj) const;
     //@}
 
 

src/Gui/ViewProviderDocumentObject.cpp

@@ -35,7 +35,8 @@
 /// Here the FreeCAD includes sorted by Base,App,Gui......
 #include <Base/Console.h>
 #include <App/Material.h>
-#include <App/DocumentObject.h>
+#include <App/DocumentObjectGroup.h>
+#include <App/Origin.h>
 #include "Application.h"
 #include "Document.h"
 #include "Selection.h"
@@ -286,6 +287,16 @@ void ViewProviderDocumentObject::setActiveMode()
         ViewProvider::hide();
 }
 
+bool ViewProviderDocumentObject::canDelete(App::DocumentObject* obj) const
+{
+    Q_UNUSED(obj)
+    if (getObject()->hasExtension(App::GroupExtension::getExtensionClassTypeId()))
+        return true;
+    if (getObject()->isDerivedFrom(App::Origin::getClassTypeId()))
+        return true;
+    return false;
+}
+
 PyObject* ViewProviderDocumentObject::getPyObject()
 {
     if (!pyViewObject)

src/Gui/ViewProviderDocumentObject.h

@@ -77,6 +77,8 @@ public:
     void updateView();
     /// Get the object of this ViewProvider object
     App::DocumentObject *getObject(void) const {return pcObject;}
+    /// Asks the view provider if the given object can be deleted.
+    virtual bool canDelete(App::DocumentObject* obj) const;
     /// Get the GUI document to this ViewProvider object
     Gui::Document* getDocument() const;
     /// Get the python wrapper for that ViewProvider