Unable to pickle abstract class (using `abc.ABC`) with type annotations

[Viicos]

Starting with Python 3.14a3, the following raises a TypeError:

from abc import ABC

import cloudpickle

def class_factory():
    class Model(ABC):
        field: int

    return Model

cloudpickle.dumps(class_factory())
"""
TypeError: cannot pickle '_abc._abc_data' object
when serializing dict item '_abc_impl'
when serializing tuple item 0
when serializing cell reconstructor arguments
when serializing cell object
when serializing tuple item 0
when serializing dict item '__closure__'
when serializing tuple item 1
when serializing function state
when serializing function object
when serializing dict item '__annotate_func__'
when serializing tuple item 0
when serializing abc.ABCMeta state
when serializing abc.ABCMeta object
"""

[ogrisel]

@Viicos thanks for the report. Would you be interested in investigating whether it's possible to add support for this?

[Viicos]

I reported the issue as I encountered it when adding support for Python 3.14 in Pydantic, and got tests failing. I won't have capacity to look into this.

[ogrisel]

I opened a mirror issue on CPython since this code used to work with CPython 3.13 and the resulting change of picklability status might not have been intended.

[glemaitre]

I'll give a shot at it and see where it goes.

[ogrisel]

Let me try to assign this to copilot to check its capabilities on a real life problem.