Python 子类装饰器。为什么我只能用父类限定装饰器一次

Question

我在 python 3.6 中尝试过这段代码

from abc import ABC, abstractmethod

class A(ABC):

  @property
  @abstractmethod
  def prop1(self):
    pass
    
  @prop1.setter
  @abstractmethod
  def prop1(self, val):
    pass

class B(A):
  def __init__(self, val=None):
    self._prop = val

  @A.prop1.setter
  def prop1(self, val):
    if val == "something":
      self._prop = val
    else:
      self._prop = "nothing"

  @A.prop1.getter
  def prop1(self):
    return self._prop

  def do_something(self):
    self.prop1 = "blah"

我收到错误 TypeError: Can't instantiate abstract class B with abstract methods prop1。但是，如果我像这样从覆盖的 getter 中删除 @A，则代码可以正常工作。

@prop1.getter
 def prop1(self):
   return self._prop

此外，getter 高于或低于 setter 并不重要。只有第一个似乎需要@A.。为什么会这样？

Answer 1

在子类中覆盖基类属性时，您根本不需要引用它们

from abc import ABC, abstractmethod


class A(ABC):

    @property
    @abstractmethod
    def prop1(self):
        pass

    @prop1.setter
    @abstractmethod
    def prop1(self, val):
        pass


class B(A):
    def __init__(self, val=None):
        self._prop = val

    @property
    def prop1(self):
        return self._prop

    @prop1.setter
    def prop1(self, val):
        if val == "something":
            self._prop = val
        else:
            self._prop = "nothing"

    def do_something(self):
        self.prop1 = "blah"