preserve same order as inventory manager when using host lookup (#55331)

* preserve same order as inventory manager when using inventory_hostnames lookup

add a test

* move generic code

1 files changed, 2 insertions, 2 deletions

diff --git a/lib/ansible/inventory/manager.py b/lib/ansible/inventory/manager.py
index 10785aa793..cc43e4e468 100644
--- a/lib/ansible/inventory/manager.py
+++ b/lib/ansible/inventory/manager.py
@@ -36,6 +36,7 @@ from ansible.module_utils.six import string_types
 from ansible.module_utils._text import to_bytes, to_text
 from ansible.parsing.utils.addresses import parse_address
 from ansible.plugins.loader import inventory_loader
+from ansible.utils.helpers import deduplicate_list
 from ansible.utils.path import unfrackpath
 from ansible.utils.display import Display
 
@@ -369,8 +370,7 @@ class InventoryManager(object):
                     # exclude hosts mentioned in any restriction (ex: failed hosts)
                     hosts = [h for h in hosts if h.name in self._restriction]
 
-                seen = set()
-                self._hosts_patterns_cache[pattern_hash] = [x for x in hosts if x not in seen and not seen.add(x)]
+                self._hosts_patterns_cache[pattern_hash] = deduplicate_list(hosts)
 
             # sort hosts list if needed (should only happen when called from strategy)
             if order in ['sorted', 'reverse_sorted']: