tripleo_container_manage: set empty default to systemd registers

If the tasks are skipped the variables are empty and should be default
to an empty list; which will return empty services when figuring out
what services need a restart.

Change-Id: I852066179c86b97a7f775a7babb4e44e89a0d9a3

tripleo_ansible/ansible_plugins/filter/helpers.py

@@ -420,11 +420,12 @@ class FilterModule(object):
         part of the list already.
         """
         return_list = []
-        for i in data['results']:
-            loop_var = i.get('ansible_loop_var', 'item')
-            for k, v in i[loop_var].items():
-                if ('changed' in i and i['changed']) or k in extra:
-                    return_list.append(k)
+        if 'results' in data:
+            for i in data['results']:
+                loop_var = i.get('ansible_loop_var', 'item')
+                for k, v in i[loop_var].items():
+                    if ('changed' in i and i['changed']) or k in extra:
+                        return_list.append(k)
         return return_list
 
     def dict_to_list(self, data):

tripleo_ansible/roles/tripleo_container_manage/tasks/podman/systemd.yml

@@ -77,8 +77,8 @@
 - name: Create fact for container_systemd_changes
   set_fact:
     container_systemd_changes: >-
-      {{ ((systemd_file|get_changed_async_task_names) + (systemd_healthcheck|get_changed_async_task_names) +
-      (systemd_timer|get_changed_async_task_names)|default([])|unique) }}
+      {{ ((systemd_file|default([])|get_changed_async_task_names) + (systemd_healthcheck|default([])|get_changed_async_task_names) +
+      (systemd_timer|default([])|get_changed_async_task_names)|unique) }}
 
 - name: "Force systemd daemon reload if a systemd file changed"
   systemd:

tripleo_ansible/tests/plugins/filter/test_helpers.py

@@ -952,3 +952,7 @@ class TestHelperFilters(tests_base.TestCase):
         ]
         result = self.filters.dict_to_list(data=dict)
         self.assertEqual(result, expected_list)
+
+    def test_get_changed_async_task_names_empty(self):
+        result = self.filters.get_changed_async_task_names(data=[])
+        self.assertEqual(result, [])