"Paul Boddie" <[EMAIL PROTECTED]> wrote:
> Paul Rubin wrote:
>>
>> Right, the problem is if those methods start changing the "private"
>> variable. I should have been more explicit about that.
>>
>> class A:
>> def __init__(self):
>> self.__x = 3
>> def foo(self):
>> return self.__x
>>
>> class B(A): pass
>>
>> class A(B):
>> def bar(self):
>> self.__x = 5 # clobbers private variable of earlier class named A
>
> Has this ever been reported as a bug in Python? I could imagine more
> sophisticated "name mangling": something to do with the identity of the
> class might be sufficient, although that would make the tolerated
> "subversive" access to private attributes rather difficult.
>
> Paul
>
If it worries you then you can always check for it and disallow any
hierarchies where it could be a problem. For that matter PyChecker ought to
be able to catch this situation (maybe it already does, I haven't looked).
>>> class SafetyNet(type):
def __new__(cls, name, bases, dct):
print "new",name
c = type.__new__(cls, name, bases, dct)
assert not name in [b.__name__ for b in c.__mro__[1:]]
return c
>>> __metaclass__ = SafetyNet
>>> class A: pass
new A
>>> class B(A): pass
new B
>>> class A(B): pass
new A
Traceback (most recent call last):
File "<pyshell#24>", line 1, in <module>
class A(B): pass
File "<pyshell#17>", line 5, in __new__
assert not name in [b.__name__ for b in c.__mro__[1:]]
AssertionError
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