future 0.13 breaks with_metaclass(MetaClass, object)

[vdboor]

The following code worked in future 0.12.x, and breaks in future 0.13:

from future.builtins import object
from future.utils import with_metaclass

class MetaClass(type):
    pass

class TestClass(with_metaclass(MetaClass, object)):
    pass

That's because the newobject class got a metaclass.

Traceback:

Traceback (most recent call last):
  File "foo.py", line 7, in <module>
    class TestClass(with_metaclass(MetaClass, object)):
  File "env/lib/python2.7/site-packages/future/utils/__init__.py", line 133, in __new__
    return meta(name, bases, d)
TypeError: Error when calling the metaclass bases
    metaclass conflict: the metaclass of a derived class must be a (non-strict) subclass of the metaclasses of all its bases

[edschofield]

Thanks for reporting this bug, Diederik! A fix for this has gone into the v0.13.x branch. Please give it a test-run if you can. If all is well, this will make it into v0.13.1 soon.

[edschofield]

This should now be fixed in v0.13.1. If not, please feel free to re-open this issue.