handle groups correctly when they are 'null' (#41698)

* handle groups correctly when they are 'null'

 - even if defined as mapping but having no keys, objects shoudl still be processed correctly
 - also add ansilbe_verbosity to vars not to display in ansible-inventory

fixes #41692

lib/ansible/cli/inventory.py

@@ -42,6 +42,7 @@ INTERNAL_VARS = frozenset(['ansible_diff_mode',
                            'ansible_playbook_python',
                            'ansible_run_tags',
                            'ansible_skip_tags',
+                           'ansible_verbosity',
                            'ansible_version',
                            'inventory_dir',
                            'inventory_file',

lib/ansible/plugins/inventory/yaml.py

@@ -59,6 +59,7 @@ all: # keys must be unique, i.e. only one 'hosts' per group
 '''
 
 import os
+
 from collections import MutableMapping
 
 from ansible.errors import AnsibleParserError
@@ -112,37 +113,38 @@ class InventoryModule(BaseFileInventoryPlugin):
 
     def _parse_group(self, group, group_data):
 
-        if isinstance(group_data, MutableMapping):
+        if isinstance(group_data, (MutableMapping, type(None))):
 
             self.inventory.add_group(group)
 
-            # make sure they are dicts
-            for section in ['vars', 'children', 'hosts']:
-                if section in group_data:
-                    # convert strings to dicts as these are allowed
-                    if isinstance(group_data[section], string_types):
-                        group_data[section] = {group_data[section]: None}
-
-                    if not isinstance(group_data[section], MutableMapping):
-                        raise AnsibleParserError('Invalid "%s" entry for "%s" group, requires a dictionary, found "%s" instead.' %
-                                                 (section, group, type(group_data[section])))
-
-            for key in group_data:
-                if key == 'vars':
-                    for var in group_data['vars']:
-                        self.inventory.set_variable(group, var, group_data['vars'][var])
-
-                elif key == 'children':
-                    for subgroup in group_data['children']:
-                        self._parse_group(subgroup, group_data['children'][subgroup])
-                        self.inventory.add_child(group, subgroup)
-
-                elif key == 'hosts':
-                    for host_pattern in group_data['hosts']:
-                        hosts, port = self._parse_host(host_pattern)
-                        self._populate_host_vars(hosts, group_data['hosts'][host_pattern] or {}, group, port)
-                else:
-                    self.display.warning('Skipping unexpected key (%s) in group (%s), only "vars", "children" and "hosts" are valid' % (key, group))
+            if group_data is not None:
+                # make sure they are dicts
+                for section in ['vars', 'children', 'hosts']:
+                    if section in group_data:
+                        # convert strings to dicts as these are allowed
+                        if isinstance(group_data[section], string_types):
+                            group_data[section] = {group_data[section]: None}
+
+                        if not isinstance(group_data[section], (MutableMapping, type(None))):
+                            raise AnsibleParserError('Invalid "%s" entry for "%s" group, requires a dictionary, found "%s" instead.' %
+                                                     (section, group, type(group_data[section])))
+
+                for key in group_data:
+                    if key == 'vars':
+                        for var in group_data['vars']:
+                            self.inventory.set_variable(group, var, group_data['vars'][var])
+
+                    elif key == 'children':
+                        for subgroup in group_data['children']:
+                            self._parse_group(subgroup, group_data['children'][subgroup])
+                            self.inventory.add_child(group, subgroup)
+
+                    elif key == 'hosts':
+                        for host_pattern in group_data['hosts']:
+                            hosts, port = self._parse_host(host_pattern)
+                            self._populate_host_vars(hosts, group_data['hosts'][host_pattern] or {}, group, port)
+                    else:
+                        self.display.warning('Skipping unexpected key (%s) in group (%s), only "vars", "children" and "hosts" are valid' % (key, group))
 
         else:
             self.display.warning("Skipping '%s' as this is not a valid group definition" % group)