diff --git a/mypy/checker.py b/mypy/checker.py index cd23e74a8dac..8d7766a948c2 100644 --- a/mypy/checker.py +++ b/mypy/checker.py @@ -2022,22 +2022,29 @@ def check_method_override_for_base_with_name( if original_node and is_property(original_node): original_type = get_property_type(original_type) - if isinstance(typ, FunctionLike) and is_property(defn): - typ = get_property_type(typ) - if ( - isinstance(original_node, Var) - and not original_node.is_final - and (not original_node.is_property or original_node.is_settable_property) - and isinstance(defn, Decorator) - ): - # We only give an error where no other similar errors will be given. - if not isinstance(original_type, AnyType): - self.msg.fail( - "Cannot override writeable attribute with read-only property", - # Give an error on function line to match old behaviour. - defn.func, - code=codes.OVERRIDE, - ) + if is_property(defn): + inner: FunctionLike | None + if isinstance(typ, FunctionLike): + inner = typ + else: + inner = self.extract_callable_type(typ, context) + if inner is not None: + typ = inner + typ = get_property_type(typ) + if ( + isinstance(original_node, Var) + and not original_node.is_final + and (not original_node.is_property or original_node.is_settable_property) + and isinstance(defn, Decorator) + ): + # We only give an error where no other similar errors will be given. + if not isinstance(original_type, AnyType): + self.msg.fail( + "Cannot override writeable attribute with read-only property", + # Give an error on function line to match old behaviour. + defn.func, + code=codes.OVERRIDE, + ) if isinstance(original_type, AnyType) or isinstance(typ, AnyType): pass diff --git a/test-data/unit/check-functions.test b/test-data/unit/check-functions.test index b3df5fddafba..3aecbe065c27 100644 --- a/test-data/unit/check-functions.test +++ b/test-data/unit/check-functions.test @@ -2730,6 +2730,49 @@ f: Callable[[Sequence[TI]], None] g: Callable[[Union[Sequence[TI], Sequence[TS]]], None] f = g +[case testOverrideDecoratedProperty] +class Base: + @property + def foo(self) -> int: ... + +class decorator: + def __init__(self, fn): + self.fn = fn + def __call__(self, decorated_self) -> int: + return self.fn(decorated_self) + +class Child(Base): + @property + @decorator + def foo(self) -> int: + return 42 + +reveal_type(Child().foo) # N: Revealed type is "builtins.int" + +class BadChild1(Base): + @decorator + def foo(self) -> int: # E: Signature of "foo" incompatible with supertype "Base" \ + # N: Superclass: \ + # N: int \ + # N: Subclass: \ + # N: decorator + return 42 + +class not_a_decorator: + def __init__(self, fn): ... + +class BadChild2(Base): + @property + @not_a_decorator + def foo(self) -> int: # E: "not_a_decorator" not callable \ + # E: Signature of "foo" incompatible with supertype "Base" \ + # N: Superclass: \ + # N: int \ + # N: Subclass: \ + # N: not_a_decorator + return 42 +[builtins fixtures/property.pyi] + [case explicitOverride] # flags: --python-version 3.12 from typing import override