Python pickle通過getattr獲得了acycle遞歸？

Question

class Test(object): 
    def __init__(self, a): 
     self.a = a 

    def __getattr__(self, name): 
     return getattr(self.a, name) 

from pickle import loads, dumps 
loads(dumps((Test(something),))) 

我：

 7  def __getattr__(self, name): 
----> 8   return getattr(self.a, name) 

RuntimeError: maximum recursion depth exceeded 

任何暗示？

我可以通過改變像代碼解決這個問題：

if 'a' in self.__dict__: 
    return getattr(self.a, name) 

，但我不想。有更好的解決方案

謝謝

Answer 1

這應該工作，但我懷疑這是一個好主意......

class Test(object): 
    def __init__(self, a): 
     self.a = a 

    def __getattr__(self, name): 
     a = object.__getattribute__(self, 'a') 
     return a.__getattr__(a, name) 

from pickle import loads, dumps 
loads(dumps((Test({})))) 
# <__main__.Test at 0x7f6beb8> 

Answer 2

我會使用getattr()代替__getattr__。這相當於撥打getattr(Test(a).a, name)。這首先轉向a.__getattribute__，如果失敗，然後a.__getattr__

class Test(object): 
    def __init__(self, a): 
     self._a = a 

    def __getattr__(self, name): 
     a = object.__getattribute__(self, '_a') 
     return getattr(a, name)