Pycharm静态分析并没有如我所愿推断子类类型

Question

在下面的Python代码中，

TruckDriver

类继承自

Driver

类，

Truck

类继承于

Vehicle

类。

driver

类的

Truck

属性是

TruckDriver

类型（在类型提示中指定），并传递给

Vehicle

类的构造函数（接受通用

Driver

类型） .

但是，Pycharm 在

Truck

类中警告我

driver

不具有

TruckDriver

特定属性。具体来说，它在

company

行中强调了

print(f"Company: {self.driver.company}")

属性，并带有以下警告：

“Driver”类的未解析属性引用“company”

有什么方法可以解决此类警告吗？我还在我的项目中使用 Ruff 作为 linter，但它在这里似乎没有帮助。

class Driver:
    def __init__(self, name: str):
        self.name = name

class TruckDriver(Driver):
    def __init__(self, name: str, company: str):
        super().__init__(name)
        self.company = company

class Vehicle:
    def __init__(self, driver: Driver):
        self.driver = driver

    def drive(self):
        print(f"{self.driver.name} is driving.")

class Truck(Vehicle):
    def __init__(self, driver: TruckDriver):
        super().__init__(driver)

    def drive(self):
        super().drive()
        print(f"Company: {self.driver.company}")

Answer 1

使用通用车辆：

from typing import Generic, TypeVar

D = TypeVar("D", bound="Driver")

class Driver:
    def __init__(self, name: str):
        self.name = name

class TruckDriver(Driver):
    def __init__(self, name: str, company: str):
        super().__init__(name)
        self.company = company

class Vehicle(Generic[D]):
    def __init__(self, driver: D):
        self.driver = driver

    def drive(self):
        print(f"{self.driver.name} is driving.")

class Truck(Vehicle[TruckDriver]):
    def __init__(self, driver: TruckDriver):
        super().__init__(driver)

    def drive(self):
        super().drive()
        print(f"Company: {self.driver.company}")

alice = Driver("Alice")
carol = TruckDriver("Carol", "Acme Truck Co.")

car = Vehicle(alice)
truck = Truck(carol)

car.drive()
truck.drive()