catch exception, closes #1565

Closes #1565

Merge request studip/studip!1264

lib/classes/sidebar/RoomSearchWidget.class.php

@@ -485,6 +485,7 @@ class RoomSearchWidget extends SidebarWidget
             }
         }
 
+        try {
             $this->rooms = RoomManager::findRooms(
                 $this->selected_criteria['special__room_name']['value'],
                 $this->location_id,
@@ -494,6 +495,9 @@ class RoomSearchWidget extends SidebarWidget
                 'name ASC, mkdate ASC',
                 false
             );
+        } catch (\InvalidArgumentException $e) {
+            PageLayout::postError($e->getMessage());
+        }
     }
 
     public function resetSearch()