Stop ignoring merge hash behaviour in inventory (#58460)

* stop ignoring merge hash behaviour in inventory

fixes #58120

* added porting note

Co-Authored-By: Alicia Cozine <879121+acozine@users.noreply.github.com>

changelogs/fragments/hash_behaviour_inventory.yml

@@ -0,0 +1,2 @@
+bugfixes:
+    - Inventory sources now respect setting ``hash_behaviour``. Previously each new inventory source would overwrite existing vars, even when ``hash_behavior`` was set to ``merge``.

docs/docsite/rst/porting_guides/porting_guide_2.9.rst

@@ -19,7 +19,7 @@ This document is part of a collection on porting. The complete list of porting g
 Playbook
 ========
 
-No notable changes
+ * ``hash_behaviour`` now affects inventory sources. If you have it set to ``merge``, the data you get from inventory might change and you will have to update playbooks accordingly. If you're using the default setting (``overwrite``), you will see no changes. Inventory was ignoring this setting.
 
 
 Command Line

lib/ansible/inventory/group.py

@@ -22,8 +22,9 @@ from itertools import chain
 from ansible import constants as C
 from ansible.errors import AnsibleError
 from ansible.module_utils._text import to_native, to_text
-
+from ansible.module_utils.common._collections_compat import Mapping, MutableMapping
 from ansible.utils.display import Display
+from ansible.utils.vars import combine_vars
 
 display = Display()
 
@@ -245,7 +246,10 @@ class Group:
         if key == 'ansible_group_priority':
             self.set_priority(int(value))
         else:
-            self.vars[key] = value
+            if key in self.vars and isinstance(self.vars[key], MutableMapping) and isinstance(value, Mapping):
+                self.vars[key] = combine_vars(self.vars[key], value)
+            else:
+                self.vars[key] = value
 
     def clear_hosts_cache(self):
 

lib/ansible/inventory/host.py

@@ -20,6 +20,7 @@ from __future__ import (absolute_import, division, print_function)
 __metaclass__ = type
 
 from ansible.inventory.group import Group
+from ansible.module_utils.common._collections_compat import Mapping, MutableMapping
 from ansible.utils.vars import combine_vars, get_unique_id
 
 __all__ = ['Host']
@@ -137,7 +138,10 @@ class Host:
                         self.remove_group(oldg)
 
     def set_variable(self, key, value):
-        self.vars[key] = value
+        if key in self.vars and isinstance(self.vars[key], MutableMapping) and isinstance(value, Mapping):
+            self.vars[key] = combine_vars(self.vars[key], value)
+        else:
+            self.vars[key] = value
 
     def get_groups(self):
         return self.groups