Ability to add Interrupts to nodes within subgraphs

[hwchase17]

Ability to add Interrupts to nodes within subgraphs
Really loving using Interrupts for debugging and testing up to a certain node!
I just realized when I converted a group of nodes into a subgraph that the interrupts can only occur on the top-level nodes or the subgraph node itself, but not nodes within the subgraph. I think this was mentioned as a limitation when subgraph support was added to Studio

[bforbanks]

I have also experienced this.
This migth be related to #190

[anmol-aidora]

Langgraph Studio not working with subgraphs

We have built a graph which also has subgraphs in it. The subgraphs contain nodes at which they interrupt. When we run it in Langgraph Studio, we are facing a major roadblock. When the subgraph interrupts, the As Node option becomes empty (instead of indicating the node it should resume execution from).

When I try to resume execution, I pass human message into the messages state variable, but the graph doesn't resume.

I have tried three approaches when passing the message:
Letting the As Node empty. -> Graph starts from start node (of the main graph), which is not desired.
Setting the subgraph node name (subgraph_3:__start__) in As Node.
Setting the exact node inside the subgraph from which I know it should resume from (subgraph_3:human_input_subgraph_3) in As Node.

I am attaching the respective error messages below:
Case 2:

langgraph-api-1       | error | Bad Request Error | Traceback (most recent call last):
  File "/usr/local/lib/python3.12/site-packages/starlette/_exception_handler.py", line 42, in wrapped_app
    await app(scope, receive, sender)
  File "/api/langgraph_api/route.py", line 32, in app
  File "/usr/local/lib/python3.12/site-packages/langgraph_storage/retry.py", line 34, in wrapper
    return await func(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/api/langgraph_api/api/threads.py", line 137, in update_thread_state
  File "/usr/local/lib/python3.12/site-packages/langgraph_storage/ops.py", line 562, in post
    next_config = await graph.aupdate_state(
                  ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/site-packages/langgraph/pregel/__init__.py", line 1261, in aupdate_state
    raise InvalidUpdateError(f"Node {as_node} does not exist")
langgraph.errors.InvalidUpdateError: Node subgraph_3:__start__ does not exist

Case 3:

langgraph-api-1       | error | Bad Request Error | Traceback (most recent call last):
  File "/usr/local/lib/python3.12/site-packages/starlette/_exception_handler.py", line 42, in wrapped_app
    await app(scope, receive, sender)
  File "/api/langgraph_api/route.py", line 32, in app
  File "/usr/local/lib/python3.12/site-packages/langgraph_storage/retry.py", line 34, in wrapper
    return await func(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/api/langgraph_api/api/threads.py", line 137, in update_thread_state
  File "/usr/local/lib/python3.12/site-packages/langgraph_storage/ops.py", line 562, in post
    next_config = await graph.aupdate_state(
                  ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/site-packages/langgraph/pregel/__init__.py", line 1261, in aupdate_state
    raise InvalidUpdateError(f"Node {as_node} does not exist")
langgraph.errors.InvalidUpdateError: Node subgraph_3:human_input_subgraph_3 does not exist

It seems like the UI is directly passing the node name as subgraph_3:human_input_subgraph_3. But the node of the subgraph has a unique name human_input_subgraph_3. The node ID being passed to the backend is not correct.

By the way, I am able to resume from the exact subgraph node in backend (using the RemoteGraph object/ doing graph.stream directly by following this langgraph doc