Cannot save a RequestSpec object if nothing changed

[Balazs Gibizer]

If a RequestSpec.save() is called on an object that has no changed field the code blows up with UnboundLocalError:

      File "nova/tests/unit/objects/test_request_spec.py", line 622, in test_save_does_not_persist_requested_resources
        req_obj.save()
      File "/mnt/ssd/ebalgib/nova/py27/.tox/py27/local/lib/python2.7/site-packages/oslo_versionedobjects/base.py", line 226, in wrapper
        return fn(self, *args, **kwargs)
      File "nova/objects/request_spec.py", line 588, in save
        updates = self._get_update_primitives()
      File "nova/objects/request_spec.py", line 561, in _get_update_primitives
        return db_updates
    UnboundLocalError: local variable 'db_updates' referenced before assignment

It is because the db_updates local is only initialized if there is something to update but returned regardless
https://github.com/openstack/nova/blob/master/nova/objects/request_spec.py#L518
https://github.com/openstack/nova/blob/master/nova/objects/request_spec.py#L532

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/573768

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/573768
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=08fb09e878dcaedbb446e18502a6172fa4d43121
Submitter: Zuul
Branch: master

commit 08fb09e878dcaedbb446e18502a6172fa4d43121
Author: Balazs Gibizer <email address hidden>
Date: Fri Jun 8 17:57:07 2018 +0200

    Fix unbound local when saving an unchanged RequestSpec

    RequestSpec._get_update_primitives() tried to return the unitialized
    db_updates field when the object has no changes. This patch initalizes
    that local to None and handles that None in create() and save() where
    the RequestSpec._get_update_primitives() is called.

    Change-Id: Iad256079945bf8b5745ebdcc393c55115dbcab75
    Closes-Bug: #1775863

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/queens
Review: https://review.openstack.org/580309

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/580309
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=a31ebd87ba9a9c0ab0013fe59b6d5056c1193f4c
Submitter: Zuul
Branch: stable/queens

commit a31ebd87ba9a9c0ab0013fe59b6d5056c1193f4c
Author: Balazs Gibizer <email address hidden>
Date: Fri Jun 8 17:57:07 2018 +0200

    Fix unbound local when saving an unchanged RequestSpec

    RequestSpec._get_update_primitives() tried to return the unitialized
    db_updates field when the object has no changes. This patch initalizes
    that local to None and handles that None in create() and save() where
    the RequestSpec._get_update_primitives() is called.

    Change-Id: Iad256079945bf8b5745ebdcc393c55115dbcab75
    Closes-Bug: #1775863
    (cherry picked from commit 08fb09e878dcaedbb446e18502a6172fa4d43121)

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/pike
Review: https://review.openstack.org/580951

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/nova 18.0.0.0b3 development milestone.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/580951
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=6d60c74191f271c1fcea2ff1556a1f00baaa3f58
Submitter: Zuul
Branch: stable/pike

commit 6d60c74191f271c1fcea2ff1556a1f00baaa3f58
Author: Balazs Gibizer <email address hidden>
Date: Fri Jun 8 17:57:07 2018 +0200

    Fix unbound local when saving an unchanged RequestSpec

    RequestSpec._get_update_primitives() tried to return the unitialized
    db_updates field when the object has no changes. This patch initalizes
    that local to None and handles that None in create() and save() where
    the RequestSpec._get_update_primitives() is called.

    Change-Id: Iad256079945bf8b5745ebdcc393c55115dbcab75
    Closes-Bug: #1775863
    (cherry picked from commit 08fb09e878dcaedbb446e18502a6172fa4d43121)
    (cherry picked from commit a31ebd87ba9a9c0ab0013fe59b6d5056c1193f4c)

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/nova 16.1.5 release.

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/nova 17.0.6 release.