Bug report

Bug description:

typing.Annotated tries to set an attribute on the return value of calling an annotated callable. This fails when the returned object is immutable. I believe that adding TypeError to the except clause in typing. _BaseGenericAlias.__call__ will fix the problem. I'm not sure if there are more cases of the same pattern or not.

Example

import typing import uuid class MyAnnotation: def __init__(self, **properties) -> None: self.properties = properties def uuid_from_str(s: str) -> uuid.UUID: return uuid.UUID(f'urn:uuid:{s}') coercion = typing.Annotated[uuid_from_str, MyAnnotation(type='str', format='uuid')] coercion('00000000-0000-0000-0000-000000000000')

Result

Traceback (most recent call last): File "/Users/.../foo.py", line 12, in <module> coercion('00000000-0000-0000-0000-000000000000') File "/Users/.../lib/python3.12/typing.py", line 1142, in __call__ result.__orig_class__ = self ^^^^^^^^^^^^^^^^^^^^^ File "/Users/.../lib/python3.12/uuid.py", line 278, in __setattr__ raise TypeError('UUID objects are immutable') TypeError: UUID objects are immutable 

CPython versions tested on:

3.9, 3.10, 3.11, 3.12

Operating systems tested on:

macOS

Linked PRs

• gh-115165: Fix Annotated for immutable types #115213
• [3.12] gh-115165: Fix typing.Annotated for immutable types (GH-115213) #115227
• [3.11] gh-115165: Fix typing.Annotated for immutable types (GH-115213) #115228