Fixing bugs with {changed,failed}_when and until with registered vars

* Saving of the registered variable was occuring after the tests for
  changed/failed_when.
* Each of the above fields and until were being post_validated too early,
  so variables which were not defined at that time were causing task
  failures.

Fixes #13591

lib/ansible/executor/task_executor.py

@@ -387,7 +387,6 @@ class TaskExecutor:
 
         # make a copy of the job vars here, in case we need to update them
         # with the registered variable value later on when testing conditions
-        #vars_copy = variables.copy()
         vars_copy = variables.copy()
 
         display.debug("starting attempt loop")
@@ -404,6 +403,11 @@ class TaskExecutor:
                 return dict(unreachable=True, msg=to_unicode(e))
             display.debug("handler run complete")
 
+            # update the local copy of vars with the registered value, if specified,
+            # or any facts which may have been generated by the module execution
+            if self._task.register:
+                vars_copy[self._task.register] = result
+
             if self._task.async > 0:
                 # the async_wrapper module returns dumped JSON via its stdout
                 # response, so we parse it here and replace the result
@@ -433,11 +437,6 @@ class TaskExecutor:
                     return failed_when_result
                 return False
 
-            # update the local copy of vars with the registered value, if specified,
-            # or any facts which may have been generated by the module execution
-            if self._task.register:
-                vars_copy[self._task.register] = result
-
             if 'ansible_facts' in result:
                 vars_copy.update(result['ansible_facts'])
 

lib/ansible/playbook/task.py

@@ -260,6 +260,27 @@ class Task(Base, Conditional, Taggable, Become):
                 break
         return templar.template(value, convert_bare=True)
 
+    def _post_validate_changed_when(self, attr, value, templar):
+        '''
+        changed_when is evaluated after the execution of the task is complete,
+        and should not be templated during the regular post_validate step.
+        '''
+        return value
+
+    def _post_validate_failed_when(self, attr, value, templar):
+        '''
+        failed_when is evaluated after the execution of the task is complete,
+        and should not be templated during the regular post_validate step.
+        '''
+        return value
+
+    def _post_validate_until(self, attr, value, templar):
+        '''
+        until is evaluated after the execution of the task is complete,
+        and should not be templated during the regular post_validate step.
+        '''
+        return value
+
     def get_vars(self):
         all_vars = dict()
         if self._block: