PartDesign: fixes for new body creation

Upon creation, new bodies used to steal bits from other parts and
bodies, if they were accidentally selected. Extra checks have been added
to make that much less likely.

src/Mod/PartDesign/Gui/CommandBody.cpp

@@ -133,10 +133,14 @@ void CmdPartDesignBody::activated(int iMsg)
 {
     if ( !PartDesignGui::assureModernWorkflow( getDocument() ) )
         return;
+    App::Part *actPart = PartDesignGui::getActivePart ();
+    App::Part* partOfBaseFeature = nullptr;
+
     std::vector<App::DocumentObject*> features =
         getSelection().getObjectsOfType(Part::Feature::getClassTypeId());
     App::DocumentObject* baseFeature = nullptr;
 
+
     if (!features.empty()) {
         if (features.size() == 1) {
             baseFeature = features[0];
@@ -146,15 +150,28 @@ void CmdPartDesignBody::activated(int iMsg)
                 QMessageBox::warning(Gui::getMainWindow(), QObject::tr("Bad base feature"),
                         QObject::tr("Body can't be based on a PartDesign feature."));
                 baseFeature = nullptr;
-
             }
-
-            if ( baseFeature->isDerivedFrom ( Part::BodyBase::getClassTypeId() ) )  {
+            else if (PartDesign::Body::findBodyOf ( baseFeature )){
+                QMessageBox::warning(Gui::getMainWindow(), QObject::tr("Bad base feature"),
+                        QObject::tr("%1 already belongs to a body, can't use it as base feature for another body.")
+                                     .arg(QString::fromUtf8(baseFeature->Label.getValue())));
+                baseFeature = nullptr;
+            }
+            else if ( baseFeature->isDerivedFrom ( Part::BodyBase::getClassTypeId() ) )  {
                 // Prevent creating bodies based on bodies
                 QMessageBox::warning(Gui::getMainWindow(), QObject::tr("Bad base feature"),
                         QObject::tr("Body can't be based on annother body."));
                 baseFeature = nullptr;
+            } else {
 
+                partOfBaseFeature = App::Part::getPartOfObject(baseFeature);
+                if (partOfBaseFeature != 0  &&  partOfBaseFeature != actPart){
+                    //prevent cross-part mess
+                    QMessageBox::warning(Gui::getMainWindow(), QObject::tr("Bad base feature"),
+                            QObject::tr("Base feature (%1) belongs to other part.")
+                                         .arg(QString::fromUtf8(baseFeature->Label.getValue())));
+                    baseFeature = nullptr;
+                };
             }
 
         } else {
@@ -164,8 +181,6 @@ void CmdPartDesignBody::activated(int iMsg)
         }
     }
 
-    // first check if Part is already created:
-    App::Part *actPart = PartDesignGui::getActivePart ();
 
     openCommand("Add a Body");
 
@@ -174,6 +189,11 @@ void CmdPartDesignBody::activated(int iMsg)
     // add the Body feature itself, and make it active
     doCommand(Doc,"App.activeDocument().addObject('PartDesign::Body','%s')", bodyName.c_str());
     if (baseFeature) {
+        if (partOfBaseFeature){
+            //withdraw base feature from Part, otherwise visibility mandess results
+            doCommand(Doc,"App.activeDocument().%s.removeObject(App.activeDocument().%s)",
+                    partOfBaseFeature->getNameInDocument(), baseFeature->getNameInDocument());
+        }
         doCommand(Doc,"App.activeDocument().%s.BaseFeature = App.activeDocument().%s",
                 bodyName.c_str(), baseFeature->getNameInDocument());
     }