New submission from Devin Jeanpierre:
If a subclass has abstract methods, it fails to instantiate... unless it's a
metaclass, and then it succeeds.
>>> import abc
>>> class A(metaclass=abc.ABCMeta):
... @abc.abstractmethod
... def foo(self): pass
...
>>> class B(A): pass
...
>>> B()
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: Can't instantiate abstract class B with abstract methods foo
>>> class C(A, type): pass
...
>>> class c(metaclass=C): pass
...
>>> C('', (), {})
<class '__main__.'>
>>>
----------
components: Library (Lib)
messages: 243540
nosy: Devin Jeanpierre
priority: normal
severity: normal
status: open
title: ABCs don't fail metaclass instantiation
versions: Python 2.7, Python 3.4
_______________________________________
Python tracker <rep...@bugs.python.org>
<http://bugs.python.org/issue24235>
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