How to get __import__ back after removing it with del __builtins__.__dict__["__import__"]

Question

I'm trying out a coding challange right now. I cannot change the code before del __builtins__.__dict__["__import__"] but must use import afterwards. I need a way to restore the default __builtins__. Its python 2.7.

I tryed __builtins__ = [x for x in (1).__class__.__base__.__subclasses__() if x.__name__ == 'catch_warnings'][0]()._module.__builtins__ but that doesn't work because the reference to builtins hasn't gone but the element from the dictionary of builtins are.

Answer 1

In Python 2, you can use the reload function to get a fresh copy of the __builtins__ module:

>>> del __builtins__.__dict__['__import__']
>>> reload(__builtins__)
<module '__builtin__' (built-in)>
>>> __import__
<built-in function __import__>
>>>

In Python 3, the reload function has been moved to the imp module (and in Python 3.4, importlib) so importing imp or importlib isn't option without __import__. Instead, you can use __loader__.load_module to load the sys module and delete the cached but ruined copy of the builtins module from the sys.modules dict, so that you can load a new copy of the builtins module with __loader__.load_module:

>>> del __builtins__.__dict__['__import__']
>>> del __loader__.load_module('sys').modules['builtins']
>>> __builtins__ = __loader__.load_module('builtins')
>>> __import__
<built-in function __import__>
>>>