Fix BFS depth control in NetworkX graph traversal

lightrag/kg/networkx_impl.py

@@ -303,18 +303,20 @@ class NetworkXStorage(BaseGraphStorage):
             # Use BFS to get nodes
             bfs_nodes = []
             visited = set()
-            queue = [node_label]
+            queue = [(node_label, 0)]  # (node, depth) tuple
 
             # Breadth-first search
             while queue and len(bfs_nodes) < max_nodes:
-                current = queue.pop(0)
+                current, depth = queue.pop(0)
                 if current not in visited:
                     visited.add(current)
                     bfs_nodes.append(current)
 
-                    # Add neighbor nodes to queue
-                    neighbors = list(graph.neighbors(current))
-                    queue.extend([n for n in neighbors if n not in visited])
+                    # Only explore neighbors if we haven't reached max_depth
+                    if depth < max_depth:
+                        # Add neighbor nodes to queue with incremented depth
+                        neighbors = list(graph.neighbors(current))
+                        queue.extend([(n, depth + 1) for n in neighbors if n not in visited])
 
             # Check if graph is truncated - if we still have nodes in the queue
             # and we've reached max_nodes, then the graph is truncated