Comment 0 for bug 1524041

Example of error:

2015-12-08 14:07:48.276 | class RequestContextSerializer(messaging.RequestContextSerializer):
2015-12-08 14:07:48.276 | File "/home/jenkins/workspace/gate-ironic-python27/.tox/py27/lib/python2.7/abc.py", line 87, in __new__
2015-12-08 14:07:48.276 | cls = super(ABCMeta, mcls).__new__(mcls, name, bases, namespace)
2015-12-08 14:07:48.276 | TypeError: Error when calling the metaclass bases
2015-12-08 14:07:48.276 | metaclass conflict: the metaclass of a derived class must be a (non-strict) subclass of the metaclasses of all its bases

More logs: http://logs.openstack.org/59/254759/1/check/gate-ironic-python27/9e4a526/console.html

Cause:

oslo.messaging was using debtcollector to decorate the RequestContextSerializer as deprecated and ran into this debt collector bug: https://bugs.launchpad.net/debtcollector/+bug/1520397

More:

This patch fixed the problem before the oslo.messaging release in Ironic https://review.openstack.org/#/c/250571/1