Comment 6 for bug 1802977

Steps for verify:
1. Create configs
repro.yaml

heat_template_version: 2015-04-30
resources:
  net:
    type: OS::Neutron::Net
    properties:
      name: repro
  grp:
    type: OS::Heat::ResourceGroup
    properties:
      count: 1
      resource_def:
        type: repro-nested.yaml
        properties:
          private_network_id: { get_resource: net }

repro-nested.yaml

heat_template_version: 2015-04-30
parameters:
  private_network_id:
    type: string
resources:
  unit:
    type: OS::Heat::TestResource
    properties:
      value: { get_param: private_network_id }

openstack stack create repro -t repro.yaml
openstack stack update repro -t repro.yaml --dry-run --show-nested

2. Run verify
heat stack-update repro --template-file repro.yaml --dry-run --show-nested
+-----------+---------------+--------------------------------+-----------------------------------------------------------+
| state | resource_name | resource_type | resource_identity |
+-----------+---------------+--------------------------------+-----------------------------------------------------------+
| unchanged | net | OS::Neutron::Net | { |
| | | | "stack_name": "repro", |
| | | | "stack_id": "4442b7fe-bb2b-4766-a6dd-4947603a213b", |
| | | | "tenant": "6fe6cd742c384eafa3f853dc7ecb995b", |
| | | | "path": "/resources/net" |
| | | | } |
| updated | grp | OS::Heat::ResourceGroup | { |
| | | | "stack_name": "repro", |
| | | | "stack_id": "4442b7fe-bb2b-4766-a6dd-4947603a213b", |
| | | | "tenant": "6fe6cd742c384eafa3f853dc7ecb995b", |
| | | | "path": "/resources/grp" |
| | | | } |
| updated | 0 | file:///root/repro-nested.yaml | { |
| | | | "stack_name": "repro-grp-zpvljfhha3zg", |
| | | | "stack_id": "e233c0dc-e355-4720-95f0-65ae68b30502", |
| | | | "tenant": "6fe6cd742c384eafa3f853dc7ecb995b", |
| | | | "path": "/resources/0" |
| | | | } |
| updated | unit | OS::Heat::TestResource | { |
| | | | "stack_name": "repro-grp-zpvljfhha3zg-0-3u5ylabj6wna", |
| | | | "stack_id": "cdf97e3f-fc17-4e17-9501-79ef3188af1c", |
| | | | "tenant": "6fe6cd742c384eafa3f853dc7ecb995b", |
| | | | "path": "/resources/unit" |
| | | | } |
+-----------+---------------+--------------------------------+-----------------------------------------------------------+