""" Tests the handling of explicit protocol classes. """ # Specification: https://typing.readthedocs.io/en/latest/spec/protocol.html#explicitly-declaring-implementation from abc import ABC, abstractmethod from typing import ClassVar, Protocol class PColor(Protocol): @abstractmethod def draw(self) -> str: ... def complex_method(self) -> int: return 1 class NiceColor(PColor): def draw(self) -> str: return "deep blue" class BadColor(PColor): def draw(self) -> str: return super().draw() # E: no default implementation class ImplicitColor: # Note no 'PColor' base here def draw(self) -> str: return "probably gray" def complex_method(self) -> int: return 0 v1: PColor = NiceColor() # OK v2: PColor = ImplicitColor() # OK class RGB(Protocol): rgb: tuple[int, int, int] other: int @abstractmethod def intensity(self) -> int: return 1 def transparency(self) -> int: ... class Point(RGB): def __init__(self, red: int, green: int, blue: str) -> None: self.rgb = red, green, blue # E: 'blue' must be 'int' self.other = 0 p = Point(0, 0, "") # E: Cannot instantiate abstract class class Proto1(Protocol): cm1: ClassVar[int] cm2: ClassVar[int] = 0 im1: int im2: int = 2 im3: int def __init__(self): self.im3 = 3 class Proto2(Protocol): cm10: int class Proto3(Proto2, Protocol): cm11: int class Concrete1(Proto1): def __init__(self): self.im1 = 1 self.im3 = 3 c1 = Concrete1() # E: cannot instantiate abstract class class Concrete2(Proto1): cm1 = 3 im1 = 0 c2 = Concrete2() class Concrete3(Proto1, Proto3): cm1 = 3 def __init__(self): self.im1 = 0 self.cm10 = 10 self.cm11 = 11 c3 = Concrete3() class Concrete4(Proto1, Proto3): cm1 = 3 cm10 = 3 def __init__(self): self.im1 = 3 self.im10 = 10 self.cm11 = 3 c4 = Concrete4() class Proto5(Protocol): def method1(self) -> int: ... class Concrete5(Proto5): pass c5 = Concrete5() # E: cannot instantiate abstract class class Proto6(Protocol): x: int class Mixin: x = 3 class Concrete6(Mixin, Proto6): pass class Proto7(Protocol): @abstractmethod def method1(self): ... class Mixin7(Proto7, ABC): def method1(self) -> None: pass class Concrete7A(Proto7): pass c7a = Concrete7A() # E: cannot instantiate abstract class class Concrete7B(Mixin7, Proto7): pass c7b = Concrete7B()