PyCharm中自定义缓存属性的类型检查：行为解析与实用解决方案

from functools import cached_property
from collections.abc import Callable
from typing import TypeVar, Generic, Any, overload, Union

T = TypeVar("T")

class result_property(cached_property, Generic[T]):
    def __init__(self, func: Callable[[Any], T]) -> None:
        super().__init__(func)

    def __set_name__(self, owner: type[Any], name: str) -> None:
        super().__set_name__(owner, name)

    @overload
    def __get__(self, instance: None, owner: Union[type[Any], None] = None) -> 'result_property[T]': ...

    @overload
    def __get__(self, instance: object, owner: Union[type[Any], None] = None) -> T: ...

    def __get__(self, instance, owner=None):
        # 实际的获取逻辑由 cached_property 基类处理
        return super().__get__(instance, owner)

def func_str(s: str) -> None:
    print(s)

class Foo:
    @result_property
    def prop_int(self) -> int:
        return 1

foo = Foo()
# 尝试将一个整数类型的属性传递给一个期望字符串的函数
func_str(foo.prop_int)

tmp.py:38: error: Argument 1 to "func_str" has incompatible type "int"; expected "str"  [arg-type]
Found 1 error in 1 file (checked 1 source file)

# 这是一个简化的、可能不符合实际行为的 cached_property 描述符
def cached_property(func):
    def foo(self):
        # 这里的实现并不重要，关键在于名称
        pass
    return foo

def func_str(s: str) -> None:
    print(s)

class Foo:
    @cached_property
    def prop_int(self) -> int:
        return 1

foo = Foo()
# 即使是这个“虚假”的 cached_property，PyCharm 在此处会报告类型错误
func_str(foo.prop_int) # PyCharm 提示：Expected type 'str', got 'int' instead

import functools
from collections.abc import Callable
from typing import TypeVar, Generic, Any, overload, Union

T = TypeVar("T")

# 将自定义描述符类命名为 cached_property
class cached_property(functools.cached_property, Generic[T]):
    def __init__(self, func: Callable[[Any], T]) -> None:
        super().__init__(func)

    def __set_name__(self, owner: type[Any], name: str) -> None:
        super().__set_name__(owner, name)

    @overload
    def __get__(self, instance: None, owner: Union[type[Any], None] = None) -> 'cached_property[T]': ...

    @overload
    def __get__(self, instance: object, owner: Union[type[Any], None] = None) -> T: ...

    def __get__(self, instance, owner=None):
        return super().__get__(instance, owner)

def func_str(s: str) -> None:
    print(s)

class Foo:
    @cached_property # 使用重命名后的描述符
    def prop_int(self) -> int:
        return 1

foo = Foo()
# 现在 PyCharm 在此处会正确报告类型错误
func_str(foo.prop_int) # PyCharm 提示：Expected type 'str', got 'int' instead