Cache field attributes list on the playbook classes (#79091)

* Cache field attributes list on the playbook classes

2 files changed, 11 insertions, 1 deletions

diff --git a/changelogs/fragments/cache-fa-on-pb-cls.yml b/changelogs/fragments/cache-fa-on-pb-cls.yml
new file mode 100644
index 00000000000..ab06b03559f
--- /dev/null
+++ b/changelogs/fragments/cache-fa-on-pb-cls.yml
@@ -0,0 +1,2 @@
+minor_changes:
+  - Cache field attributes list on the playbook classes
diff --git a/lib/ansible/playbook/base.py b/lib/ansible/playbook/base.py
index 5504645a126..bf007581308 100644
--- a/lib/ansible/playbook/base.py
+++ b/lib/ansible/playbook/base.py
@@ -10,6 +10,7 @@ import operator
 import os
 
 from copy import copy as shallowcopy
+from functools import cache
 
 from jinja2.exceptions import UndefinedError
 
@@ -74,7 +75,14 @@ class FieldAttributeBase:
     @classmethod
     @property
     def fattributes(cls):
-        # FIXME is this worth caching?
+        return cls._fattributes()
+
+    # mypy complains with "misc: Decorated property not supported"
+    # when @property and @cache are used together,
+    # split fattributes above into two methods
+    @classmethod
+    @cache
+    def _fattributes(cls):
         fattributes = {}
         for class_obj in reversed(cls.__mro__):
             for name, attr in list(class_obj.__dict__.items()):