Later specified environment with parameter_defaults values of 0 do not override earlier non-0 values

[James Slagle]

When using multiple environments with -e, and you have a parameter value specified via parameter_defaults, and it's value is 0 (the non-quoted number), it will not override earlier non-zero values.

Here is a test reproducer:

[root@tripleo-09 test]# cat template.yaml
heat_template_version: ocata

parameters:

  param1:
    type: number
    default: 0

resources:

  param1_value:
    type: OS::Heat::Value
    properties:
      value:
        {get_param: param1}

[root@tripleo-09 test]# cat env1.yaml
parameter_defaults:
  param1: 1

[root@tripleo-09 test]# cat env2.yaml
parameter_defaults:
  param1: 0

My create command:
[root@tripleo-09 test]# openstack stack create test --wait -t template.yaml -e env1.yaml -e env2.yaml

Notice env2.yaml is specified last.

The result:

[root@tripleo-09 test]# openstack stack resource show test param1_value
+------------------------+-------------------------------------------------------------------------------------+
| Field | Value |
+------------------------+-------------------------------------------------------------------------------------+
| attributes | {u'value': u'1'} |
| creation_time | 2017-03-02T14:01:42Z |
| description | |
| links | [{u'href': u'http://192.168.25.10:8004/v1/df4517693d6f44c8adc911f8ba0579d0/stacks/t |
| | est/49406476-bf1a-4abb-91ab-37fc6c3d0a4e/resources/param1_value', u'rel': u'self'}, |
| | {u'href': u'http://192.168.25.10:8004/v1/df4517693d6f44c8adc911f8ba0579d0/stacks/te |
| | st/49406476-bf1a-4abb-91ab-37fc6c3d0a4e', u'rel': u'stack'}] |
| logical_resource_id | param1_value |
| physical_resource_id | test-param1_value-wrxf72k66px2 |
| required_by | [] |
| resource_name | param1_value |
| resource_status | CREATE_COMPLETE |
| resource_status_reason | state changed |
| resource_type | OS::Heat::Value |
| updated_time | 2017-03-02T14:01:42Z |
+------------------------+-------------------------------------------------------------------------------------+

The value is 1, when it should be 0.

If you quote the value in env2.yaml so it looks like:
[root@tripleo-09 test]# cat env2.yaml
parameter_defaults:
  param1: "0"

Then you get the expected value of 0 after a stack create:
[root@tripleo-09 test]# openstack stack resource show test param1_value
+------------------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Field | Value |
+------------------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| attributes | {u'value': 0} |
| creation_time | 2017-03-02T14:06:03Z |
| description | |
| links | [{u'href': u'http://192.168.25.10:8004/v1/df4517693d6f44c8adc911f8ba0579d0/stacks/test/cd23f838-566b-4c9f-bc2f-2259753509b3/resources/param1_value', u'rel': u'self'}, {u'href': |
| | u'http://192.168.25.10:8004/v1/df4517693d6f44c8adc911f8ba0579d0/stacks/test/cd23f838-566b-4c9f-bc2f-2259753509b3', u'rel': u'stack'}] |
| logical_resource_id | param1_value |
| physical_resource_id | test-param1_value-6kh4vqc5vfhu |
| required_by | [] |
| resource_name | param1_value |
| resource_status | CREATE_COMPLETE |
| resource_status_reason | state changed |
| resource_type | OS::Heat::Value |
| updated_time | 2017-03-02T14:06:03Z |
+------------------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

I'd wager that there is some logic somewhere that is applying some "if" logic to the parameter's value to see if it was specified and the non-quoted 0 evalues to false, so the later value is ignored.

When I was debugging client side, I saw the later value of 0 working as expected after template_utils.process_multiple_environments_and_files had been called, in that 0 was shown as the value in parameter_defaults in the returned merged_env.

So, the bug must be server side. Note also that if you do a stack create with --dry-run, you will see the wrong value shown in the parameters of the output.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/440659

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/440659
Committed: https://git.openstack.org/cgit/openstack/heat/commit/?id=16999806e6a16548cdf87d9f475ef4dd16f28a5f
Submitter: Jenkins
Branch: master

commit 16999806e6a16548cdf87d9f475ef4dd16f28a5f
Author: Thomas Herve <email address hidden>
Date: Thu Mar 2 17:01:33 2017 +0100

    Handle zero values when merging environments

    When merging multiple envs, 0 values where ignored in later envs, not
    taking precedence. This fixes it by checking for None instead.

    Change-Id: Ia0da6988f92825bcc9a19dd3dcce771baa978a59
    Closes-Bug: #1669442

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/heat 9.0.0.0b1 development milestone.