Restore duplicate-label guard while keeping docker subdir fix scoped

Author: Titas-Ghosh

mkconcore.py

@@ -284,7 +284,7 @@ def cleanup_script_files():
 nodes_dict = dict()
 node_id_to_label_map = dict() # Helper to get clean node labels from GraphML ID
 
-for node in nodes_text:
+for node in nodes_text:
     try:
         data = node.find('data', recursive=False)
         if data:
@@ -306,9 +306,15 @@ def cleanup_script_files():
 
                 nodes_dict[node['id']] = node_label
                 node_id_to_label_map[node['id']] = node_label.split(':')[0]
-    except (IndexError, AttributeError):
-        logging.debug('A node with no valid properties encountered and ignored')
-
+    except (IndexError, AttributeError):
+        logging.debug('A node with no valid properties encountered and ignored')
+
+label_values = list(nodes_dict.values())
+duplicates = {label for label in label_values if label_values.count(label) > 1}
+if duplicates:
+    logging.error(f"Duplicate node labels found: {sorted(duplicates)}")
+    quit()
+
 for edge in edges_text:
     try:
         data = edge.find('data', recursive=False)