getattr is enough but you can make it more explicit

@PrettyWood Sure. Do you think bool(getattr(cls, '__deprecated__')) is fine?

LGTM once we decide on the syntax for this line!

I just made a remark regarding the code with hasattr + getattr.
I now took a bit of time to understand the context and reading https://peps.python.org/pep-0702/ it seems you only care about the presence of the field
I can decide to write

@deprecated("")
class A: ...

and I'll have A.__deprecated__ = "", which will be falsy and still valid.

So in the end I guess the initial approach with just return hasattr(cls, '__deprecated__') is the best

What about a hasattr and then a false check? @NeevCohen @PrettyWood

I guess that's reasonable, though @deprecated takes a str as a parameter, if anything else is passed in an exception is raised. The following doesn't work

from typing import deprecated
from pydantic import BaseModel

@deprecated(False)
class Model(BaseModel):
    pass

Raises the following exception

TypeError: Expected an object of type str for 'message', not 'bool'

I guess someone could manually set a __deprecated__ attribute on the class to False, though I'm not sure that's a use case as far as we're concerned.

I guess just the simple hasattr check is the best choice here.

@sydney-runkle @PrettyWood thoughts?

+1. As I said earlier "So in the end I guess the initial approach with just return hasattr(cls, 'deprecated') is the best"