Group: ensure single group only

src/App/GeoFeatureGroupExtension.cpp

@@ -281,8 +281,6 @@ std::vector< DocumentObject* > GeoFeatureGroupExtension::getCSRelevantLinks(Docu
     return result;
 }
 
-
-
 // Python feature ---------------------------------------------------------
 
 namespace App {

src/App/GeoFeatureGroupExtension.h

@@ -111,6 +111,7 @@ public:
     /// obj and from obj excluding expressions and stopping the recursion at other geofeaturegroups. 
     /// The result is the combination of CSOutList and CSInList.
     static std::vector<App::DocumentObject*> getCSRelevantLinks(App::DocumentObject* obj);
+    
 private:
     Base::Placement recursiveGroupPlacement(GeoFeatureGroupExtension* group);
     static std::vector<App::DocumentObject*> getObjectsFromLinks(App::DocumentObject*);

src/App/GroupExtension.cpp

@@ -243,6 +243,30 @@ PyObject* GroupExtension::getExtensionPyObject(void) {
     return Py::new_reference_to(ExtensionPythonObject);
 }
 
+void GroupExtension::extensionOnChanged(const Property* p) {
+    
+    //we need to remove all object that have  other parent geofeature groups
+    if(strcmp(p->getName(), "Group")==0) {
+     
+        bool error = false;
+        auto corrected = Group.getValues();
+        for(auto obj : Group.getValues()) {
+            
+            auto grp = GroupExtension::getGroupOfObject(obj);
+            if(grp && (grp != getExtendedObject())) {
+                error = true;
+                corrected.erase(std::remove(corrected.begin(), corrected.end(), obj), corrected.end());
+            }
+        }  
+        if(error) {
+            Group.setValues(corrected);
+            throw Base::Exception("Object can only be in a single Group");
+        }
+    }
+    
+    App::Extension::extensionOnChanged(p);
+}
+
 
 namespace App {
 EXTENSION_PROPERTY_SOURCE_TEMPLATE(App::GroupExtensionPython, App::GroupExtension)

src/App/GroupExtension.h

@@ -100,6 +100,8 @@ public:
     
     virtual PyObject* getExtensionPyObject(void);
 
+    virtual void extensionOnChanged(const Property* p) override;
+    
     /// Properties
     PropertyLinkList Group;
 

src/Mod/Test/Document.py

@@ -869,6 +869,9 @@ class UndoRedoCases(unittest.TestCase):
     #adding the object to a geofeaturegroup, but not its group, should handle it automatically when used 
     #addObject
     
+    #to test: try add obj to second group, once by addObject, once by .Group = []
+    
+    
 
   def tearDown(self):
     # closing doc