Fix parent attribute lookup to be default

Fixes #12526

lib/ansible/playbook/base.py

@@ -105,7 +105,10 @@ class Base:
         if hasattr(self, method):
             return getattr(self, method)()
 
-        return self._attributes[prop_name]
+        value = self._attributes[prop_name]
+        if value is None and hasattr(self, '_get_parent_attribute'):
+            value = self._get_parent_attribute(prop_name)
+        return value
 
     @staticmethod
     def _generic_s(prop_name, self, value):

lib/ansible/playbook/block.py

@@ -271,45 +271,50 @@ class Block(Base, Become, Conditional, Taggable):
         Generic logic to get the attribute or parent attribute for a block value.
         '''
 
-        value = self._attributes[attr]
-        if self._parent_block and (value is None or extend):
-            parent_value = getattr(self._parent_block, attr)
-            if extend:
-                value = self._extend_value(value, parent_value)
-            else:
-                value = parent_value
-        if self._task_include and (value is None or extend):
-            parent_value = getattr(self._task_include, attr)
-            if extend:
-                value = self._extend_value(value, parent_value)
-            else:
-                value = parent_value
-        if self._role and (value is None or extend):
-            parent_value = getattr(self._role, attr)
-            if extend:
-                value = self._extend_value(value, parent_value)
-            else:
-                value = parent_value
-
-            if len(self._dep_chain) and (not value or extend):
-                reverse_dep_chain = self._dep_chain[:]
-                reverse_dep_chain.reverse()
-                for dep in reverse_dep_chain:
-                    dep_value = getattr(dep, attr)
-                    if extend:
-                        value = self._extend_value(value, dep_value)
-                    else:
-                        value = dep_value
-
-                    if value is not None and not extend:
-                        break
-
-        if self._play and (value is None or extend):
-            parent_value = getattr(self._play, attr)
-            if extend:
-                value = self._extend_value(value, parent_value)
-            else:
-                value = parent_value
+        value = None
+        try:
+            value = self._attributes[attr]
+
+            if self._parent_block and (value is None or extend):
+                parent_value = getattr(self._parent_block, attr)
+                if extend:
+                    value = self._extend_value(value, parent_value)
+                else:
+                    value = parent_value
+            if self._task_include and (value is None or extend):
+                parent_value = getattr(self._task_include, attr)
+                if extend:
+                    value = self._extend_value(value, parent_value)
+                else:
+                    value = parent_value
+            if self._role and (value is None or extend):
+                parent_value = getattr(self._role, attr)
+                if extend:
+                    value = self._extend_value(value, parent_value)
+                else:
+                    value = parent_value
+
+                if len(self._dep_chain) and (not value or extend):
+                    reverse_dep_chain = self._dep_chain[:]
+                    reverse_dep_chain.reverse()
+                    for dep in reverse_dep_chain:
+                        dep_value = getattr(dep, attr)
+                        if extend:
+                            value = self._extend_value(value, dep_value)
+                        else:
+                            value = dep_value
+
+                        if value is not None and not extend:
+                            break
+
+            if self._play and (value is None or extend):
+                parent_value = getattr(self._play, attr)
+                if extend:
+                    value = self._extend_value(value, parent_value)
+                else:
+                    value = parent_value
+        except KeyError:
+            pass
 
         return value
 

lib/ansible/playbook/task.py

@@ -363,19 +363,25 @@ class Task(Base, Conditional, Taggable, Become):
         '''
         Generic logic to get the attribute or parent attribute for a task value.
         '''
-        value = self._attributes[attr]
-        if self._block and (value is None or extend):
-            parent_value = getattr(self._block, attr)
-            if extend:
-                value = self._extend_value(value, parent_value)
-            else:
-                value = parent_value
-        if self._task_include and (value is None or extend):
-            parent_value = getattr(self._task_include, attr)
-            if extend:
-                value = self._extend_value(value, parent_value)
-            else:
-                value = parent_value
+        value = None
+        try:
+            value = self._attributes[attr]
+
+            if self._block and (value is None or extend):
+                parent_value = getattr(self._block, attr)
+                if extend:
+                    value = self._extend_value(value, parent_value)
+                else:
+                    value = parent_value
+            if self._task_include and (value is None or extend):
+                parent_value = getattr(self._task_include, attr)
+                if extend:
+                    value = self._extend_value(value, parent_value)
+                else:
+                    value = parent_value
+        except KeyError:
+            pass
+
         return value
 
     def _get_attr_environment(self):