Warning for image_locations.id being empty while running tests

[Nikhil Komawar]

sqlalchemy/sql/default_comparator.py:35: SAWarning: The IN-predicate on "image_locations.id" was invoked with an empty sequence. This results in a contradiction, which nonetheless can be expensive to evaluate. Consider alternative strategies for improved performance.
  return o[0](self, self.expr, op, *(other + o[1:]), **kwargs)

warning is shown.

Not sure if this is a bug, need some confirmation.

[Nikhil Komawar (nikhil-komawar)]

23:02:01 #openstack-glance: [ zhiyan] nikhil___: I had noticed that warning msg too before pushing the code. in short, I'm not sure if it's a bug in db.sqlalchemy implementation of location handling
                                      stuff, or it's just a particular case of fixture in testing.

[Harsh Shah (hshah)]

Looks like it could be due to this: https://github.com/openstack/glance/blob/master/glance/db/sqlalchemy/api.py#L880-883

[OpenStack Infra (hudson-openstack)]

Change abandoned by Harsh Shah (<email address hidden>) on branch: master
Review: https://review.openstack.org/206791

[Harsh Shah (hshah)]

Fixed as part of this patch: https://review.openstack.org/#/c/113880/