App: Bugfix for NULL-Pointer dereference of Property->getName()

src/Mod/Part/App/PartFeature.cpp

@@ -236,7 +236,7 @@ struct ShapeCache {
 
     void slotChanged(const App::DocumentObject &obj, const App::Property &prop) {
         const char *propName = prop.getName();
-        if(!propName)
+        if(!App::Property::isValidName(propName))
             return;
         if(strcmp(propName,"Shape")==0 
                 || strcmp(propName,"Group")==0 

src/Mod/PartDesign/Gui/TaskFeaturePick.cpp

@@ -340,7 +340,7 @@ App::DocumentObject* TaskFeaturePick::makeCopy(App::DocumentObject* obj, std::st
 
             App::Property* cprop = *it++;
 
-            if( strcmp(prop->getName(), "Label") == 0 ) {
+            if( prop->getName() && strcmp(prop->getName(), "Label") == 0 ) {
                 static_cast<App::PropertyString*>(cprop)->setValue(name.c_str());
                 continue;
             }

src/Mod/PartDesign/Gui/Utils.cpp

@@ -435,7 +435,7 @@ void relinkToBody (PartDesign::Feature *feature) {
                     }
                 }
 
-                if ( !valueStr.empty () ) {
+                if ( !valueStr.empty () && prop->hasName()) {
                     FCMD_OBJ_CMD(obj,prop->getName() << '=' << valueStr);
                 }
             }

src/Mod/Spreadsheet/Gui/DlgSheetConf.cpp

@@ -141,7 +141,7 @@ App::Property *DlgSheetConf::prepare(CellAddress &from, CellAddress &to,
                                 vexpr->getPath().getProperty());
             if(prop) {
                 auto obj = Base::freecad_dynamic_cast<DocumentObject>(prop->getContainer());
-                if(obj) {
+                if (obj && prop->hasName()) {
                     path = ObjectIdentifier(sheet);
                     path.setDocumentObjectName(obj,true);
                     path << ObjectIdentifier::SimpleComponent(prop->getName());