Comment 5 for bug 1842913

I have reproduced something similar:

---
- hosts: localhost
  tasks:
    - command: 'true'
      when: none_var is not none and none_var.changed
      vars:
        none_var: "{{ {} if foo is defined else none }}"

ansible-playbook t.yml

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

TASK [Gathering Facts] *************************************************************************************************************************************************************************************
ok: [localhost]

TASK [command] *********************************************************************************************************************************************************************************************
fatal: [localhost]: FAILED! => {"msg": "The conditional check 'none_var is not none and none_var.changed' failed. The error was: error while evaluating conditional (none_var is not none and none_var.changed): 'unicode object' has no attribute 'changed'\n\nThe error appears to be in '/tmp/t.yml': line 4, column 7, but may\nbe elsewhere in the file depending on the exact syntax problem.\n\nThe offending line appears to be:\n\n tasks:\n - command: 'true'\n ^ here\n"}

PLAY RECAP *************************************************************************************************************************************************************************************************
localhost

If I change it to this, it works:

---
- hosts: localhost
  tasks:
    - command: 'true'
      when: none_var is mapping and none_var.changed
      vars:
        none_var: "{{ foo if foo is defined else '' }}"