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typing.Annotated fails for functions returning UUIDs #115165
Description
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.
Lines 1128 to 1131 in 17689e3
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
Activity
AlexWaygood commentedon Feb 8, 2024
Thanks for the report!
Arguably there are two bugs here:
uuidmodule raisingTypeErrorfrom a__setattr__method? That seems like an antipattern; it should probably be raisingAttributeError. We probably can't change that now, though, for backwards-compatibility reasonstypingmodule should indeed be more careful here. Feel free to send a PR — I thinkexcept Exceptionmight actually be better here than just addingTypeErrorto theexceptclause. Otherwise we'll just get this bug reported again when somebody tries to useAnnotatedwith a class that raises e.g.RuntimeError(or whatever) from its__setattr__methodfixup! pythongh-115165: Fix Annotated for immutable types
fixup! pythongh-115165: Fix Annotated for immutable types
fixup! pythongh-115165: Fix Annotated for immutable types
fixup! pythongh-115165: Fix Annotated for immutable types
gh-115165: Fix `typing.Annotated` for immutable types (#115213)
pythongh-115165: Fix `typing.Annotated` for immutable types (pythonGH…
pythongh-115165: Fix `typing.Annotated` for immutable types (pythonGH…
[3.12] gh-115165: Fix `typing.Annotated` for immutable types (GH-115213…
[3.11] gh-115165: Fix `typing.Annotated` for immutable types (GH-115213…
AlexWaygood commentedon Feb 9, 2024
Thanks for the report, and the fix!
pythongh-115165: Fix `typing.Annotated` for immutable types (python#1…
pythongh-115165: Fix Annotated for immutable types
Add UUID support