New submission from Shantanu <hauntsani...@gmail.com>:
Consider:
```
from typing import Protocol
class P(Protocol):
...
class C(P):
def __init__(self):
super().__init__()
C()
```
This code passes without error on 3.9.6.
With 3.9.7, we get:
```
Traceback (most recent call last):
File "/Users/shantanu/dev/test.py", line 10, in <module>
C()
File "/Users/shantanu/dev/test.py", line 8, in __init__
super().__init__()
File "/Users/shantanu/.pyenv/versions/3.9.7/lib/python3.9/typing.py", line
1083, in _no_init
raise TypeError('Protocols cannot be instantiated')
TypeError: Protocols cannot be instantiated
```
I bisected this to:
bpo-44806: Fix __init__ in subclasses of protocols (GH-27545) (GH-27559)
Note there is also an interaction with the later commit:
bpo-45081: Fix __init__ method generation when inheriting from Protocol
(GH-28121) (GH-28132)
This later commit actually causes a RecursionError:
```
File "/Users/shantanu/dev/cpython/Lib/typing.py", line 1103, in
_no_init_or_replace_init
cls.__init__(self, *args, **kwargs)
File "/Users/shantanu/dev/test.py", line 8, in __init__
super().__init__()
File "/Users/shantanu/dev/cpython/Lib/typing.py", line 1103, in
_no_init_or_replace_init
cls.__init__(self, *args, **kwargs)
File "/Users/shantanu/dev/test.py", line 8, in __init__
super().__init__()
```
Originally reported by @tyralla on Gitter.
----------
components: Library (Lib)
messages: 401184
nosy: hauntsaninja
priority: normal
severity: normal
status: open
title: Regression in 3.9.7 with typing.Protocol
versions: Python 3.9
_______________________________________
Python tracker <rep...@bugs.python.org>
<https://bugs.python.org/issue45121>
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