New submission from Edward Yang <[email protected]>:
Consider the following program:
```
import inspect
from typing import Generic, TypeVar
T = TypeVar('T')
class A(Generic[T]):
def __init__(self) -> None:
pass
print(inspect.signature(A))
```
I expect inspect.signature to return () as the signature of the constructor of
this function. However, I get this:
```
$ python3 foo.py
(*args, **kwds)
```
Although it is true that one cannot generally rely on inspect.signature to
always give the most accurate signature (because there may always be decorator
or metaclass shenanigans getting in the way), in this particular case it seems
especially undesirable because Python type annotations are supposed to be
erased at runtime, and yet here inheriting from Generic (simply to add type
annotations) causes a very clear change in runtime behavior.
----------
components: Library (Lib)
messages: 370870
nosy: ezyang
priority: normal
severity: normal
status: open
title: Inheriting from Generic causes inspect.signature to always return
(*args, **kwargs) for constructor (and all subclasses)
type: behavior
versions: Python 3.9
_______________________________________
Python tracker <[email protected]>
<https://bugs.python.org/issue40897>
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