Fixing issue #1864 (Copy & paste allows creating a recursive hierarchy)

src/db/db/dbClipboardData.cc

@@ -156,6 +156,11 @@ ClipboardData::add (const db::Layout &layout, const db::Cell &cell, unsigned int
 std::vector<unsigned int>
 ClipboardData::do_insert (db::Layout &layout, const db::ICplxTrans *trans, db::Cell *cell, std::vector<db::cell_index_type> *new_tops, ClipboardDataInsertReceiver *insert_receiver) const
 {
+  //  identify the cells our target is eventually called from, including itself
+  std::set<db::cell_index_type> callers;
+  cell->collect_caller_cells (callers);
+  callers.insert (cell->cell_index ());
+
   std::vector <unsigned int> new_layers;
   PropertyMapper prop_id_map (&layout, &m_layout);
 
@@ -279,14 +284,21 @@ ClipboardData::do_insert (db::Layout &layout, const db::ICplxTrans *trans, db::C
 
       for (db::Cell::const_iterator inst = c->begin (); ! inst.at_end (); ++inst) {
 
-        tl::const_map<db::cell_index_type> im (cell_map.find (inst->cell_index ())->second);
-        db::Instance new_inst = t.insert (*inst, im, prop_id_map);
-        if (trans) {
-          new_inst = t.transform (new_inst, *trans);
-        }
+        db::cell_index_type inst_cell = cell_map.find (inst->cell_index ())->second;
+        if (callers.find (inst_cell) == callers.end ()) {
+
+          tl::const_map<db::cell_index_type> im (inst_cell);
+          db::Instance new_inst = t.insert (*inst, im, prop_id_map);
+          if (trans) {
+            new_inst = t.transform (new_inst, *trans);
+          }
 
-        if (insert_receiver) {
-          insert_receiver->instance_inserted (cp->second, new_inst);
+          if (insert_receiver) {
+            insert_receiver->instance_inserted (cp->second, new_inst);
+          }
+
+        } else {
+          tl::warn << tl::sprintf (tl::to_string (tr ("Refusing to paste an instance for cell %s, as this would create a recursive hierarchy")), layout.cell_name (inst_cell));
         }
 
       }

src/edt/edt/edtMainService.cc

@@ -2667,8 +2667,22 @@ MainService::paste ()
 {
   if (view ()->is_editable ()) {
 
+    //  skip, if there is nothing to insert
+    bool any = false;
+    for (db::Clipboard::iterator c = db::Clipboard::instance ().begin (); c != db::Clipboard::instance ().end () && ! any; ++c) {
+      const db::ClipboardValue<edt::ClipboardData> *value = dynamic_cast<const db::ClipboardValue<edt::ClipboardData> *> (*c);
+      any = (value != 0);
+    }
+    if (! any) {
+      return;
+    }
+
     int cv_index = view ()->active_cellview_index ();
+
     const lay::CellView &cv = view ()->cellview (cv_index);
+    if (! cv.is_valid ()) {
+      throw tl::Exception (tl::to_string (tr ("No cell selected to paste something into")));
+    }
 
     NewObjectsSelection insert_notification (cv_index, cv.cell_index (), view ());
 
@@ -2678,14 +2692,8 @@ MainService::paste ()
     for (db::Clipboard::iterator c = db::Clipboard::instance ().begin (); c != db::Clipboard::instance ().end (); ++c) {
       const db::ClipboardValue<edt::ClipboardData> *value = dynamic_cast<const db::ClipboardValue<edt::ClipboardData> *> (*c);
       if (value) {
-
-        if (! cv.is_valid ()) {
-          throw tl::Exception (tl::to_string (tr ("No cell selected to paste something into")));
-        }
-
         std::vector<unsigned int> nl = value->get ().insert (cv->layout (), cv.context_trans ().inverted (), &cv->layout ().cell (cv.cell_index ()), 0 /*new_tops*/, &insert_notification);
         new_layers.insert (new_layers.end (), nl.begin (), nl.end ());
-
       }
     }