ansible - copy module returns different keys depending on change status - inconsistent

00_play.yml

---
- hosts: localhost
  gather_facts: False
  connection: local
  vars:
    foo: bar
  tasks:
    - name: first time - dest is changed, 'dest' is returned in results
      # yes I'm using template, not copy, but the template action plugin calls the copy module...
      template:
        src: 01_test.j2
        dest: /tmp/foobar
      register: template_result

    - debug:
        var: template_result

    - name: second time - nothing is changed, 'path' is returned in results
      template:
        src: 01_test.j2
        dest: /tmp/foobar
      register: template_result

    - debug:
        var: template_result

    - debug:
        msg: "To do a conditional, I need to handle both scenarios now - fugly"
      when: template_result.get('path', template_result.get('dest')) == '/tmp/foobar'

01_test.j2

{{ foo }}

02_output

PLAY [localhost] ***************************************************************************************************************************************************************************************************************************************************************

TASK [first time - dest is changed, 'dest' is returned in results] *************************************************************************************************************************************************************************************************************
changed: [localhost]

TASK [debug] *******************************************************************************************************************************************************************************************************************************************************************
ok: [localhost] => {
    "changed": false,
    "template_result": {
        "changed": true,
        "checksum": "e242ed3bffccdf271b7fbaf34ed72d089537b42f",
        "dest": "/tmp/foobar",
        "gid": 137676021,
        "group": "137676021",
        "md5sum": "c157a79031e1c40f85931829bc5fc552",
        "mode": "0644",
        "owner": "lynchg",
        "size": 4,
        "src": "/Users/lynchg/.ansible/tmp/ansible-tmp-1496845609.21-59671882598024/source",
        "state": "file",
        "uid": 1920260155
    }
}

TASK [second time - nothing is changed, 'path' is returned in results] *********************************************************************************************************************************************************************************************************
ok: [localhost]

TASK [debug] *******************************************************************************************************************************************************************************************************************************************************************
ok: [localhost] => {
    "changed": false,
    "template_result": {
        "changed": false,
        "diff": {
            "after": {
                "path": "/tmp/foobar"
            },
            "before": {
                "path": "/tmp/foobar"
            }
        },
        "gid": 137676021,
        "group": "137676021",
        "mode": "0644",
        "owner": "lynchg",
        "path": "/tmp/foobar",
        "size": 4,
        "state": "file",
        "uid": 1920260155
    }
}

TASK [debug] *******************************************************************************************************************************************************************************************************************************************************************
ok: [localhost] => {
    "changed": false,
    "msg": "To do a conditional, I need to handle both scenarios now - fugly"
}

PLAY RECAP *********************************************************************************************************************************************************************************************************************************************************************
localhost                  : ok=5    changed=1    unreachable=0    failed=0

Why does this matter?

I want to use assemble against a bunch of generated files, but only those generated.

- name: check contents of the temp dir
  find:
    paths: "{{ temp_dir }}"
  register: find_results
  changed_when: False

- name: configure the sections
  template:
    src: "{{ item.src }}.j2"
    dest: "{{ temp_dir }}/{{ item.order }}_{{ item.src }}.txt"
  with_items: "{{ templates }}"
  register: generated_templates

- name: remove any obsolete files
  file:
    path: "{{ item }}"
    state: absent
  # well this is awkward - dest or path, or both?
  with_items: "{{ find_results.files|map(attribute='path') | difference(generated_templates.results|map(attribute='dest')) }}"

- name: do something assembleeish
  assemble:
    ...

It would be nice if the bug I filed were fixed, but in the meantime, the workaround is

- name: purge invalid files step 1 - generate a list of expected filenames
  set_fact:
    expected_files: "{{ expected_files | default([]) + [item.order + '_' + item.src] }}"
  with_items: "{{ templates }}"
  run_once: True

- name: purge invalid files step 2 - check contents of the temp dir
  find:
    paths: "{{ temp_dir }}"
  register: find_results
  changed_when: False

- name: purge invalid files step 3 - remove any files that aren't in the expected list
  file:
    path: "{{ temp_dir }}/{{ item }}"
    state: absent
  with_items: "{{ find_results.files | map(attribute='path') | map('basename') | list | difference(expected_files) }}"