Fix variable precedence issue where set facts beat role params

Also updates doc on variable precedence, as it was incorrect for the
order of play vars/vars_prompt/vars_files in relation to set_fact and
registered variables.

Fixes #14702
Fixes #14826

docsite/rst/playbooks_variables.rst

@@ -803,11 +803,11 @@ In 2.x, we have made the order of precedence more specific (with the last listed
   * playbook group_vars
   * playbook host_vars
   * host facts
-  * registered vars
-  * set_facts
   * play vars
   * play vars_prompt
   * play vars_files
+  * registered vars
+  * set_facts
   * role and include vars
   * block vars (only for tasks in block)
   * task vars (only for the task)

lib/ansible/vars/__init__.py

@@ -327,20 +327,19 @@ class VariableManager:
                 for role in play.get_roles():
                     all_vars = combine_vars(all_vars, role.get_vars(include_params=False))
 
+        if host:
+            all_vars = combine_vars(all_vars, self._vars_cache.get(host.get_name(), dict()))
+            all_vars = combine_vars(all_vars, self._nonpersistent_fact_cache.get(host.name, dict()))
+
         if task:
             if task._role:
                 all_vars = combine_vars(all_vars, task._role.get_vars(include_params=False))
                 all_vars = combine_vars(all_vars, task._role.get_role_params(task._block.get_dep_chain()))
             all_vars = combine_vars(all_vars, task.get_vars())
 
-        if host:
+            # special case for include tasks, where the include params
-            all_vars = combine_vars(all_vars, self._vars_cache.get(host.get_name(), dict()))
+            # may be specified in the vars field for the task, which should
-            all_vars = combine_vars(all_vars, self._nonpersistent_fact_cache.get(host.name, dict()))
+            # have higher precedence than the vars/np facts above
-
-        # special case for include tasks, where the include params
-        # may be specified in the vars field for the task, which should
-        # have higher precedence than the vars/np facts above
-        if task:
             all_vars = combine_vars(all_vars, task.get_include_params())
 
         all_vars = combine_vars(all_vars, self._extra_vars)