When the graph includes an async BaseCheckpointSaver and uses get_state_history, the program hangs

[gbaian10]

Checked other resources

• This is a bug, not a usage question. For questions, please use GitHub Discussions.
• I added a clear and detailed title that summarizes the issue.
• I read what a minimal reproducible example is (https://stackoverflow.com/help/minimal-reproducible-example).
• I included a self-contained, minimal example that demonstrates the issue INCLUDING all the relevant imports. The code run AS IS to reproduce the issue.

Example Code

import asyncio

from langgraph.checkpoint.sqlite.aio import AsyncSqliteSaver
from langgraph.graph import END, START, MessagesState, StateGraph


async def main() -> None:
    builder = StateGraph(MessagesState)
    builder.add_node("foo", lambda _: None)
    builder.add_edge(START, "foo")
    builder.add_edge("foo", END)

    async with AsyncSqliteSaver.from_conn_string(":memory:") as checkpointer:
        graph = builder.compile(checkpointer=checkpointer)
        config = {"configurable": {"thread_id": "1"}}
        await graph.ainvoke({"messages": []}, config)
        for state in graph.get_state_history(config):
            print(state)

        # async for state in graph.aget_state_history(config):
        #     print(state)


if __name__ == "__main__":
    asyncio.run(main())

Description

When using a graph with async checkpointer(sqlite / postgres) and calling sync method get_state_history, the program blocks and cannot continue running.

I expect the sync method to either throw a NotImplementedError exception or continue running, but without leveraging the benefits of async.

System Info

System Information

OS: Linux
Python Version: 3.13.1 (main, Dec 4 2024, 08:54:15) [GCC 13.2.0]

Package Information

langchain_core: 0.3.29
langgraph: 0.2.62
langgraph-checkpoint-sqlite: 2.0.1
langgraph-checkpoint-postgres: 2.0.10