Message350264
I have been experimenting a little with the `abc` module in python. A la
>>> import abc
In the normal case you expect your ABC class to not be instantiated if it contains an unimplemented `abstractmethod`. You know like as follows:
>>> class MyClass(metaclass=abc.ABCMeta):
... @abc.abstractmethod
... def mymethod(self):
... return -1
...
>>> MyClass()
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: Can't instantiate abstract class MyClass with abstract methods mymethod
OR for any derived Class. It all seems to work fine until you inherit from something ... say `dict` or `list` as in the following:
>>> class YourClass(list, metaclass=abc.ABCMeta):
... @abc.abstractmethod
... def yourmethod(self):
... return -1
...
>>> YourClass()
[]
This is inconsistent because `type` is supposed to be the primary factory.
>>> type(abc.ABCMeta)
<class 'type'>
>>> type(list)
<class 'type'>
Why is the check for `__abstractmethods__` only implemented for `object_new` and not for other built-in types? |
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Date |
User |
Action |
Args |
2019-08-23 07:51:55 | Talha Ahmed | set | recipients:
+ Talha Ahmed |
2019-08-23 07:51:55 | Talha Ahmed | set | messageid: <1566546715.82.0.869555987333.issue37927@roundup.psfhosted.org> |
2019-08-23 07:51:55 | Talha Ahmed | link | issue37927 messages |
2019-08-23 07:51:55 | Talha Ahmed | create | |
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