Python 3.14 defers annotation evaluation (PEP 649/749): don't read cls.__dict__['__annotations__'], use annotationlib

Fix

# before
hints = cls.__dict__.get('__annotations__', {})
hints = obj.__annotations__          # obj is an instance

# after (3.14+)
from annotationlib import get_annotations, Format
hints = get_annotations(cls, format=Format.FORWARDREF)  # tolerates undefined names
hints = get_annotations(type(obj))
# inside a metaclass __new__ during class construction:
annotate = annotationlib.get_annotate_from_class_namespace(ns)

Cross-version: typing_extensions backports Format and get_annotations(). from __future__ import annotations is unchanged in 3.14 but is now deprecated; removal will not happen before 3.13 reaches end of life in 2029. Quoted forward-reference strings are no longer required on 3.14+.

Symptom

On Python 3.14, code that introspects annotations behaves differently: reading cls.__dict__['__annotations__'] (the class namespace) no longer finds them, reading annotations via an instance of an annotated class stops working, and evaluating annotations that reference names defined later raises NameError at introspection time instead of at definition time. Libraries that read annotations (serializers, DI containers, ORMs) may need updates before they handle unquoted forward references.

Cause

Python 3.14 (2025-10-07): "The annotations on functions, classes, and modules are no longer evaluated eagerly. Instead, annotations are stored in special-purpose annotate functions and evaluated only when necessary (except if from __future__ import annotations is used)." The porting notes: "do not read annotations directly from the namespace dictionary attribute of type objects"; accessing class annotations from an instance "will no longer work in Python 3.14."

Verify

from annotationlib import get_annotations, Format
def f(x: Undefined): ...
print(get_annotations(f, format=Format.STRING))   # {'x': 'Undefined'}

Sources

https://docs.python.org/3/whatsnew/3.14.html

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Python 3.14 defers annotation evaluation (PEP 649/749): don't read cls.dict['annotations'], use annotationlib

Symptom

Cause

Verify

Sources

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