Failed to update the allocation_pools for subnet

[huangtianhua]

After the bug fixed: https://bugs.launchpad.net/heat/+bug/1510338, user can update the 'allocation_pools' for neutron subnet resource, common cases are ok, but there is a problem for some special cases(if remove the allocation_pools from template when updating):
1. create a stack with subnet:
****************************
heat_template_version: 2014-10-16
resources:
  subnet:
    type: OS::Neutron::Subnet
    properties:
      network: 3447dd80-14ef-4059-8ea6-35f4fd60ba26
      cidr: 40.0.0.0/24
      allocation_pools: [{start: 40.0.0.10, end: 40.0.0.250}]

2. update the stack, remove the 'allocation_pools' from template
 ****************************
heat_template_version: 2014-10-16
resources:
  subnet:
    type: OS::Neutron::Subnet
    properties:
      network: 3447dd80-14ef-4059-8ea6-35f4fd60ba26
      cidr: 40.0.0.0/24

3. an error raised from neutron: BadRequest: Invalid input for allocation_pools. Reason: Invalid data format for IP pool: 'None'.

Seems neutron doesn't allow None value for allocation_pools, if we pass [] to neutron in this situation then will be ok.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/240654

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/240654
Committed: https://git.openstack.org/cgit/openstack/heat/commit/?id=b7d70c33d10a1357fd83b43a87d0d39fc1dd0c14
Submitter: Jenkins
Branch: master

commit b7d70c33d10a1357fd83b43a87d0d39fc1dd0c14
Author: huangtianhua <email address hidden>
Date: Sat Oct 31 17:55:54 2015 +0800

    Allow to update subnet without 'allocation_pools'

    Heat allow to update 'allocation_pools' for subnet
    resource in Change: I26f96f712dfa9405814e26a06668db7a608e84b8,
    but the patch introduced a problem: if user remove the
    'allocation_pools' from template when updating, heat will
    pass 'allocation_pools=None' to neutron, but neutron doesn't
    accept the None value for this property, an error will be
    raised: BadRequest: Invalid input for allocation_pools.
    Reason: Invalid data format for IP pool: 'None'. This patch
    will pass [] to neutron to fix this problem.

    Change-Id: I83e56d4494564de97717da6f6c0a9ae2cd9852dd
    Closes-Bug: #1511909

[Thierry Carrez (ttx)]

This issue was fixed in the openstack/heat 6.0.0.0b1 development milestone.