Question

I’ve written the following wrapper class. I want to define __setattr__ such that it redirects all attributes to the wrapped class. However, this prevents me from initializing the wrapper class. Any elegant way to fix this?

class Wrapper:
    def __init__(self, value):
        # How to use the default '__setattr__' inside '__init__'?
        self.value = value

    def __setattr__(self, name, value):
        setattr(self.value, name, value)

Answer 1

You are catching all assignments, which prevents the constructor from assigning self.value. You can use self.__dict__ to access the instance dictionary. Try:

class Wrapper:
    def __init__(self, value):
        self.__dict__['value'] = value

    def __setattr__(self, name, value):
        setattr(self.value, name, value)

Another way using object.__setattr__:

class Wrapper(object):
    def __init__(self, value):
        object.__setattr__(self, 'value', value)

    def __setattr__(self, name, value):
        setattr(self.value, name, value)