Add flag to Attributes to allow forcing parent inheritenceissue_18378_handler_environment_inheritance

In some situations, where the Base class defines an Attribute, the
BaseMeta class doesn't properly see the _get_parent_attribute or
_get_attr_<whatever> methods because of multiple layers of subclasses
(ie. Handler, which subclasses Task).

Fixes #18378

2 files changed, 37 insertions, 11 deletions

diff --git a/lib/ansible/playbook/attribute.py b/lib/ansible/playbook/attribute.py
index 3f55936ff6..f401eee3d7 100644
--- a/lib/ansible/playbook/attribute.py
+++ b/lib/ansible/playbook/attribute.py
@@ -23,17 +23,42 @@ from copy import deepcopy
 
 class Attribute:
 
-    def __init__(self, isa=None, private=False, default=None, required=False, listof=None, priority=0, class_type=None, always_post_validate=False, inherit=True):
+    def __init__(
+            self,
+            isa=None,
+            private=False,
+            default=None,
+            required=False,
+            listof=None,
+            priority=0,
+            class_type=None,
+            always_post_validate=False,
+            inherit=True,
+            force_parent=False,
+        ):
 
+        # the type of the field (string, bool, int, etc.)
         self.isa = isa
+        # whether the value of the attribute is private
         self.private = private
+        # the default value of the attribute, if not specified in the YAML
         self.default = default
+        # if required and not set, an error will be raised
         self.required = required
+        # if isa == 'list', this field can be used to control the types
+        # of each element in the list for validation purposes
         self.listof = listof
+        # the loading priority of the attribute
         self.priority = priority
+        # the class type of the attribute when isa == 'class'
         self.class_type = class_type
+        # whether or not the attribute should be post validated
         self.always_post_validate = always_post_validate
+        # whether or not the attribute should be inherited from the parent
         self.inherit = inherit
+        # force inheritence from the parent, even if _get_parent_attribute
+        # is not found in the class
+        self.force_parent = force_parent
 
         if default is not None and self.isa in ('list', 'dict', 'set'):
             self.default = deepcopy(default)
diff --git a/lib/ansible/playbook/base.py b/lib/ansible/playbook/base.py
index 77fd6890b5..f76927653f 100644
--- a/lib/ansible/playbook/base.py
+++ b/lib/ansible/playbook/base.py
@@ -111,7 +111,7 @@ class BaseMeta(type):
                     method = "_get_attr_%s" % attr_name
                     if method in src_dict or method in dst_dict:
                         getter = partial(_generic_g_method, attr_name)
-                    elif '_get_parent_attribute' in dst_dict and value.inherit:
+                    elif '_get_parent_attribute' in dst_dict and value.inherit or value.force_parent:
                         getter = partial(_generic_g_parent, attr_name)
                     else:
                         getter = partial(_generic_g, attr_name)
@@ -148,20 +148,20 @@ class BaseMeta(type):
 class Base(with_metaclass(BaseMeta, object)):
 
     # connection/transport
-    _connection          = FieldAttribute(isa='string')
-    _port                = FieldAttribute(isa='int')
-    _remote_user         = FieldAttribute(isa='string')
+    _connection          = FieldAttribute(isa='string', force_parent=True)
+    _port                = FieldAttribute(isa='int', force_parent=True)
+    _remote_user         = FieldAttribute(isa='string', force_parent=True)
 
     # variables
     _vars                = FieldAttribute(isa='dict', priority=100, inherit=False)
 
     # flags and misc. settings
-    _environment         = FieldAttribute(isa='list')
-    _no_log              = FieldAttribute(isa='bool')
-    _always_run          = FieldAttribute(isa='bool')
-    _run_once            = FieldAttribute(isa='bool')
-    _ignore_errors       = FieldAttribute(isa='bool')
-    _check_mode          = FieldAttribute(isa='bool')
+    _environment         = FieldAttribute(isa='list', force_parent=True)
+    _no_log              = FieldAttribute(isa='bool', force_parent=True)
+    _always_run          = FieldAttribute(isa='bool', force_parent=True)
+    _run_once            = FieldAttribute(isa='bool', force_parent=True)
+    _ignore_errors       = FieldAttribute(isa='bool', force_parent=True)
+    _check_mode          = FieldAttribute(isa='bool', force_parent=True)
 
     # param names which have been deprecated/removed
     DEPRECATED_ATTRIBUTES = [
@@ -535,3 +535,4 @@ class Base(with_metaclass(BaseMeta, object)):
         setattr(self, '_uuid', data.get('uuid'))
         self._finalized = data.get('finalized', False)
         self._squashed = data.get('squashed', False)
+