Files
langgraph/libs/langgraph/tests/test_parent_command.py
T
Eugene YurtsevandGitHub f178eb821e fix(langgraph): correct ParentCommand bubbling when checkpoint_ns includes numeric task segments (#6864)
Fixes incorrect `Command.PARENT` bubbling when checkpoint namespaces
include numeric task-disambiguation segments like `|1`. In some
nested-invoke/fanout scenarios, the runtime inserts a purely-numeric
namespace segment between `name:task_id` segments (e.g.
`parent_first:<id>|1|node:<id>`). The previous ParentCommand rewrite
logic only handled numeric segments at the end of the namespace, which
could produce a malformed parent graph identifier (e.g.
`parent_first:<id>|1`) and prevent the command from routing to the
intended parent node.

This change normalizes checkpoint namespaces by dropping numeric
segments before computing the parent namespace in both sync and async
retry paths. Added a minimal regression test that exercises the
nested-invoke case and asserts that `Command(graph=Command.PARENT,
goto=...)` reliably routes to the parent graph, regardless of whether
the jump comes from the first or second nested invocation.
2026-02-26 13:26:48 -05:00

54 lines
1.7 KiB
Python

from __future__ import annotations
from typing_extensions import TypedDict
from langgraph.graph import END, START, StateGraph
from langgraph.types import Command
def test_parent_command_from_nested_subgraph() -> None:
class ParentState(TypedDict):
jump_from_idx: int
class ChildState(TypedDict):
jump: bool
child_builder: StateGraph[ChildState] = StateGraph(ChildState)
def child_node(state: ChildState) -> Command | ChildState:
if state["jump"]:
return Command(graph=Command.PARENT, goto="parent_second")
return state
child_builder.add_node("node", child_node)
child_builder.add_edge(START, "node")
child_0 = child_builder.compile()
child_1 = child_builder.compile()
parent_builder: StateGraph[ParentState] = StateGraph(ParentState)
def parent_first(state: ParentState) -> ParentState:
child_0.invoke({"jump": state["jump_from_idx"] == 1})
if state["jump_from_idx"] == 1:
raise AssertionError("Shouldn't be here")
child_1.invoke({"jump": state["jump_from_idx"] == 2})
if state["jump_from_idx"] == 2:
raise AssertionError("Shouldn't be here")
return state
def parent_second(state: ParentState) -> ParentState:
return state
parent_builder.add_node("parent_first", parent_first)
parent_builder.add_node("parent_second", parent_second)
parent_builder.add_edge(START, "parent_first")
parent_builder.add_edge("parent_second", END)
graph = parent_builder.compile()
assert graph.invoke({"jump_from_idx": 1}) == {"jump_from_idx": 1}
assert graph.invoke({"jump_from_idx": 2}) == {"jump_from_idx": 2}