# langgraph/prebuilt/tool_node.py line ~951
except GraphBubbleUp:
    raise
except Exception as e:  # CancelledError bypasses this!
    # ... handle_tool_errors logic ...

import asyncio
from langchain_core.messages import AIMessage, HumanMessage, ToolMessage
from langchain_core.tools import tool
from langgraph.prebuilt import ToolNode


@tool
async def slow_tool(query: str) -> str:
    """A tool that takes time to complete."""
    await asyncio.sleep(10)
    return f"Result: {query}"


async def test_cancelled_error():
    tool_node = ToolNode(tools=[slow_tool], handle_tool_errors=True)

    ai_message = AIMessage(
        content="",
        tool_calls=[{"id": "call_1", "name": "slow_tool", "args": {"query": "test"}}]
    )
    state = {"messages": [HumanMessage(content="test"), ai_message]}
    config = {"configurable": {"thread_id": "test"}}

    task = asyncio.create_task(tool_node.ainvoke(state, config))
    await asyncio.sleep(0.1)
    task.cancel()

    try:
        await task
    except asyncio.CancelledError:
        print("CancelledError raised - no ToolMessage created!")
        # State now has AIMessage with tool_calls but no ToolMessage
        # This causes INVALID_CHAT_HISTORY on next LLM call


asyncio.run(test_cancelled_error())

except asyncio.CancelledError:
    if self._handle_tool_errors:
        return ToolMessage(
            content="Tool execution was cancelled",
            name=call["name"],
            tool_call_id=call["id"],
            status="error",
        )
    raise
except Exception as e:
    # existing handling...