fix 'return false' from parse

this was abandoned early on the manger side  but seems like we left behind on plugin side.
more flexible extensions with yaml plugin
validate data correctly for yaml/constructed
fixed issue with only adding one child to keyed, the group only got the host that forced it's creation

fixes #31382
fixes #31365

lib/ansible/plugins/inventory/constructed.py

@@ -10,7 +10,7 @@ DOCUMENTATION = '''
     version_added: "2.4"
     short_description: Uses Jinja2 to construct vars and groups based on existing inventory.
     description:
-        - Uses a YAML configuration file with a ``.config`` extension to define var expresisions and group conditionals
+        - Uses a YAML configuration file with a valid YAML or ``.config`` extension to define var expressions and group conditionals
         - The Jinja2 conditionals that qualify a host for membership.
         - The JInja2 exprpessions are calculated and assigned to the variables
         - Only variables already available from previous inventories or the fact cache can be used for templating.
@@ -54,6 +54,9 @@ EXAMPLES = '''
 
 import os
 
+from collections import MutableMapping
+
+from ansible import constants as C
 from ansible.errors import AnsibleParserError
 from ansible.plugins.inventory import BaseInventoryPlugin
 from ansible.module_utils._text import to_native
@@ -75,7 +78,7 @@ class InventoryModule(BaseInventoryPlugin):
         if super(InventoryModule, self).verify_file(path):
             file_name, ext = os.path.splitext(path)
 
-            if not ext or ext == '.config':
+            if not ext or ext in ['.config'] + C.YAML_FILENAME_EXTENSIONS:
                 valid = True
 
         return valid
@@ -92,6 +95,8 @@ class InventoryModule(BaseInventoryPlugin):
 
         if not data:
             raise AnsibleParserError("%s is empty" % (to_native(path)))
+        elif not isinstance(data, MutableMapping):
+            raise AnsibleParserError('inventory source has invalid structure, it should be a dictionary, got: %s' % type(data))
         elif data.get('plugin') != self.NAME:
             raise AnsibleParserError("%s is not a constructed groups config file, plugin entry must be 'constructed'" % (to_native(path)))