systemd facts: Handle AttributeError (#83684)

* Handle AttributeError raised while running systemd facts on
  non-systemd hosts

Signed-off-by: Abhijeet Kasurde <akasurde@redhat.com>

changelogs/fragments/systemd_facts.yml

@@ -0,0 +1,3 @@
+---
+bugfixes:
+   - systemd facts - handle AttributeError raised while gathering facts on non-systemd hosts.

lib/ansible/module_utils/facts/collector.py

@@ -90,6 +90,8 @@ class BaseFactCollector:
     def _transform_dict_keys(self, fact_dict):
         '''update a dicts keys to use new names as transformed by self._transform_name'''
 
+        if fact_dict is None:
+            return {}
         for old_key in list(fact_dict.keys()):
             new_key = self._transform_name(old_key)
             # pop the item by old_key and replace it using new_key

lib/ansible/module_utils/facts/system/systemd.py

@@ -29,19 +29,19 @@ class SystemdFactCollector(BaseFactCollector):
 
     def collect(self, module=None, collected_facts=None):
         systemctl_bin = module.get_bin_path("systemctl")
+        systemd_facts = {}
         if systemctl_bin and ServiceMgrFactCollector.is_systemd_managed(module):
-            rc, stdout, stderr = module.run_command(
+            rc, stdout, dummy = module.run_command(
                 [systemctl_bin, "--version"],
                 check_rc=False,
             )
 
-            systemd_facts = {}
-
             if rc != 0:
                 return systemd_facts
 
-            systemd_facts["systemd"] = {}
-            systemd_facts["systemd"]["features"] = str(stdout.split("\n")[1])
-            systemd_facts["systemd"]["version"] = int(stdout.split(" ")[1])
+            systemd_facts["systemd"] = {
+                "features": str(stdout.split("\n")[1]),
+                "version": int(stdout.split(" ")[1]),
+            }
 
-            return systemd_facts
+        return systemd_facts

test/units/module_utils/facts/test_ansible_collector.py

@@ -378,7 +378,7 @@ class TestCollectorDepsWithFilter(unittest.TestCase):
         facts_dict = fact_collector.collect(module=_mock_module,
                                             collected_facts=collected_facts)
         self.assertIn('concat_fact', facts_dict)
-        self.assertTrue('THE_NEEDED_FACT_VALUE' in facts_dict['concat_fact'])
+        self.assertIn('THE_NEEDED_FACT_VALUE', facts_dict['concat_fact'])
 
     def test_concat_collector_with_filter_on_concat(self):
         _mock_module = mock_module(gather_subset=['all', '!facter', '!ohai'],
@@ -396,8 +396,8 @@ class TestCollectorDepsWithFilter(unittest.TestCase):
         facts_dict = fact_collector.collect(module=_mock_module,
                                             collected_facts=collected_facts)
         self.assertIn('concat_fact', facts_dict)
-        self.assertTrue('THE_NEEDED_FACT_VALUE' in facts_dict['concat_fact'])
-        self.assertTrue('compound' in facts_dict['concat_fact'])
+        self.assertIn('THE_NEEDED_FACT_VALUE', facts_dict['concat_fact'])
+        self.assertIn('compound', facts_dict['concat_fact'])
 
     def _collect(self, _mock_module, collected_facts=None):
         _collectors = self._collectors(_mock_module)
@@ -439,6 +439,21 @@ class TestOnlyExceptionCollector(TestCollectedFacts):
         return [ExceptionThrowingCollector()]
 
 
+class NoneReturningCollector(collector.BaseFactCollector):
+    def collect(self, module=None, collected_facts=None):
+        return None
+
+
+class TestOnlyNoneCollector(TestCollectedFacts):
+    expected_facts = []
+    min_fact_count = 0
+
+    def _collectors(self, module,
+                    all_collector_classes=None,
+                    minimal_gather_subset=None):
+        return [NoneReturningCollector(namespace='ansible')]
+
+
 class TestMinimalCollectedFacts(TestCollectedFacts):
     gather_subset = ['!all']
     min_fact_count = 1