endless loop when deleting region

[wanghong]

Reproduce:
1. create region A
2. create region B with parent A
3. update the parent of A to B
4. delete A or B

The error message:
{"error": {"message": "An unexpected error prevented the server from fulfilling your request: maximum recursion depth exceeded while getting the str of an object (Disable debug mode to suppress these details.)", "code": 500, "title": "Internal Server Error"}}

I have two solutions:
1. check circle when creating or updating region
2. do not allow the update of `parent_region_id`

I prefer the second one, it is simple enough. Any suggestion?

[Morgan Fainberg (mdrnstm)]

I would vote for the first option and include a circular deletion check as well - basically if you hit the first region in the list you're deleting, break out and perform the deletions.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/130445

[OpenStack Infra (hudson-openstack)]

Change abandoned by wanghong (<email address hidden>) on branch: master
Review: https://review.openstack.org/130445
Reason: I made a mistake that use the same branch for two patches.

@Morgan Fainberg, I will give another patch soon.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/130474

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/130474
Committed: https://git.openstack.org/cgit/openstack/keystone/commit/?id=35a2834aecdde5fff9a930c38dae678a91c7fa67
Submitter: Jenkins
Branch: master

commit 35a2834aecdde5fff9a930c38dae678a91c7fa67
Author: wanghong <email address hidden>
Date: Wed Oct 22 17:53:00 2014 +0800

    add circular check when updating region

    Now, we can make a circle in hierarchical regions via updating region,
    this can lead to endless loop when deleting region.
    Add a check when updating region to ensure no circle in hierarchical
    regions. And, add a circular deletion check as well to delete already
    exist circular hierarchies.

    Change-Id: I8e020bf4a63cabf653be95f46d70e8f58439d78d
    Closes-Bug: #1383676