MyPy doesn't raise a warning if you pass in an class implementation that enforces positional arguments on a method, for a protocol that does not.
To Reproduce
Example of a false negative. Executing this code leads to a runtime error, as ActualReadable.read will raise an error when trying to pass in a key-word argument.
from typing import Protocol
class Readable(Protocol):
def read(self, n: int = -1) -> bytes: ...
class ActualReadable:
def read(self, n: int = -1, /) -> bytes:
return b""
def foo(readable: Readable) -> None:
readable.read(n=1)
foo(ActualReadable())
Pyright's behavior would be good to model off of in terms of expected behavior. That is, raising a warning that the implementation isn't compatible with the protocol, and that n must not be positional-only.
Bug Report
MyPy doesn't raise a warning if you pass in an class implementation that enforces positional arguments on a method, for a protocol that does not.
To Reproduce
Example of a false negative. Executing this code leads to a runtime error, as
ActualReadable.readwill raise an error when trying to pass in a key-word argument.MyPy Playground
Expected Behavior
Pyright's behavior would be good to model off of in terms of expected behavior. That is, raising a warning that the implementation isn't compatible with the protocol, and that
nmust not be positional-only.Pyright Playground
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