gate-quickstart role failing depends-on 'UnboundLocalError: local variable 'remote_head' referenced before assignment'

[Harry Rybacki]

It appears that changes with a `Depends-on: <change id>` are presently breaking the gate-quickstart role. I first noted this when making a tripleo-quickstart-extras change[1] depend on a tripleo-quickstart change[2].

From the gate's console output[3] we see the following error:

```
TASK [gate-quickstart : Check out the gated change] ****************************
task path: /home/centos/workspace/tripleo-quickstart-extras-gate-mitaka-delorean-full-minimal/usr/local/share/ansible/roles/gate-quickstart/tasks/checkout.yml:6
Wednesday 11 January 2017 19:36:42 +0000 (0:00:00.058) 0:00:05.991 *****
An exception occurred during task execution. To see the full traceback, use -vvv. The error was: UnboundLocalError: local variable 'remote_head' referenced before assignment
fatal: [localhost]: FAILED! => {"changed": false, "failed": true, "module_stderr": "Traceback (most recent call last):\n File \"/tmp/ansible_wcP1Ev/ansible_module_git.py\", line 1040, in <module>\n main()\n File \"/tmp/ansible_wcP1Ev/ansible_module_git.py\", line 994, in main\n result.update(changed=True, after=remote_head, msg='Local modifications exist')\nUnboundLocalError: local variable 'remote_head' referenced before assignment\n", "module_stdout": "", "msg": "MODULE FAILURE"}
```

The failing task is calling Ansible's git module. This appears to be known issue[4] related to 'force: true'[5]. A fix was merged to devel and backported to stable-2.2[6]. We have pinned ansible to '2.2.0.0' in our requirements.txt[7] though -- so I'm not sure exactly what is going on. Need to verify exactly what 2.2 stable means with respect to 2.2.0.0

[1] - https://review.openstack.org/#/c/419007/3
[2] - https://review.openstack.org/#/c/418998/4
[3] - https://ci.centos.org/artifacts/rdo/jenkins-tripleo-quickstart-extras-gate-mitaka-delorean-full-minimal-558/console.txt.gz
[4] - https://github.com/ansible/ansible-modules-core/issues/5504
[5] - https://github.com/openstack/tripleo-quickstart-extras/blob/master/roles/gate-quickstart/tasks/checkout.yml#L11
[6] - https://github.com/ansible/ansible/pull/19057
[7] - https://github.com/openstack/tripleo-quickstart/blob/master/requirements.txt#L1

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/419135

[Harry Rybacki (hrybacki-h)]

It looks like 2.2 stable[1] is higher than our pinned version of 2.2.0.0[2]. Filing a review to bump to 2.2.1[3]

[1] - https://github.com/ansible/ansible/tree/stable-2.2
[2] - https://github.com/openstack/tripleo-quickstart/blob/master/requirements.txt#L1
[3] - https://review.openstack.org/419135

[Harry Rybacki (hrybacki-h)]

Although the fix has been merged into Ansible, it's not (presently) in a release. https://github.com/ansible/ansible/releases

[OpenStack Infra (hudson-openstack)]

Change abandoned by Harry Rybacki (<email address hidden>) on branch: master
Review: https://review.openstack.org/419135
Reason: Abandoning in lieu of https://review.openstack.org/#/c/419639

[Harry Rybacki (hrybacki-h)]

Fix has been reviewed and merged: https://review.openstack.org/#/c/419639

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/419135
Committed: https://git.openstack.org/cgit/openstack/tripleo-quickstart/commit/?id=fe7fcc45996e9e72b48caa6c5852236fd2743c6d
Submitter: Jenkins
Branch: master

commit fe7fcc45996e9e72b48caa6c5852236fd2743c6d
Author: Harry Rybacki <email address hidden>
Date: Wed Jan 11 16:15:08 2017 -0500

    Bump required ansible version pin to 2.2.1.0

    2.2.0.0 does not include an important fix that is breaking the
    depends-on functionality of the gate-quickstart role.

    Change-Id: I351e03293bdce9ba5acb301e4097b0ad2b95998f
    Closes-bug: 1655757

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/tripleo-quickstart 2.0.0 release.