delete_subnet since ipallocationranges has a foreign key to the subnet

[Akihiro Motoki]

After create_net and create_subnet , then delete_subnet fails with the following errors:
This bug can be reproduced by executing delete_subnet just after stack.sh has finished.

ubuntu@t1:~/devstack$ quantumv2 --os-token ADMIN --os-url http://localhost:9696/ delete_subnet 7e183f5b-e37f-4708-aecb-d6a555801678
ERROR: cliff.app (IntegrityError) (1451, 'Cannot delete or update a parent row: a foreign key constraint fails (`ovs_quantum`.`ipallocationranges`, CONSTRAINT `ipallocationranges_ibfk_1` FOREIGN KEY (`subnet_id`) REFERENCES `subnets` (`id`))') 'DELETE FROM subnets WHERE subnets.id = {'message': u"(IntegrityError) (1451, 'Cannot delete or update a parent row: a foreign key constraint fails (`ovs_quantum`.`ipallocationranges`, CONSTRAINT `ipallocationranges_ibfk_1` FOREIGN KEY (`subnet_id`) REFERENCES `subnets` (`id`))') 'DELETE FROM subnets WHERE subnets.id = %s' ('7e183f5b-e37f-4708-aecb-d6a555801678',)"}' ('7e183f5b-e37f-4708-aecb-d6a555801678',)

QuantumDbPluginV2:delete_subnet() in db/db_base_plugin_v2.py does not remove
an entry in IPAllocationRange tables that refers to the subnet to be deleted.

I also confirms that delete_subnet succeeded after I deleted the entry in IPAllocationRange tables that refers to the subnet.

(environment)
quantum: commit b0f43d7
devstack: commit 5a70e3f + https://review.openstack.org/#/c/9161 .

[dan wendlandt (danwent)]

Thanks for filing this bug and working on a fix!

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/9285

[dan wendlandt (danwent)]

Hi akihiro,

Since today is the last day to get fixes in for Folsom-2, garyk did a quick patch to fix this. However, gary did not yet explore why the unit tests did not catch this issue (it seems there is a gap in quantum/tests/unit/test_db_plugin.py that is not correctly testing delete_subnet). If you wanted to look into this and propose a fix, that would be very helpful.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/9285
Committed: http://github.com/openstack/quantum/commit/06900100ad6ddf81c7e5d48a17db079969dd80ce
Submitter: Jenkins
Branch: master

commit 06900100ad6ddf81c7e5d48a17db079969dd80ce
Author: Gary Kotton <email address hidden>
Date: Tue Jul 3 13:11:31 2012 -0400

    Delete IP allocation range for subnet when deleting subnet

    Fixes bug 1020563

    Change-Id: I034e490825603ab71662a0bbad9b325f419a9e43