Template value of debugger and then check for validity (#53587)

* Template value of debugger and then check for validity

* Removed if/else and forcing failure on undefined as per comments

* Added changelog

* changed colon to brackets so it appears as a string

changelogs/fragments/53587-allow_templated_debugger_value.yaml

@@ -0,0 +1,2 @@
+minor_changes:
+    - Allow debugger to take a templated value (https://github.com/ansible/ansible/pull/53587)

lib/ansible/playbook/base.py

@@ -254,7 +254,8 @@ class FieldAttributeBase(with_metaclass(BaseMeta, object)):
     def get_variable_manager(self):
         return self._variable_manager
 
-    def _validate_debugger(self, attr, name, value):
+    def _post_validate_debugger(self, attr, value, templar):
+        value = templar.template(value)
         valid_values = frozenset(('always', 'on_failed', 'on_unreachable', 'on_skipped', 'never'))
         if value and isinstance(value, string_types) and value not in valid_values:
             raise AnsibleParserError("'%s' is not a valid value for debugger. Must be one of %s" % (value, ', '.join(valid_values)), obj=self.get_ds())