Fix handler flushing to match how v1 worked

Also adds meta tasks to the list of tasks excluded from tag filtering

Fixes #11574

lib/ansible/playbook/block.py

@@ -322,7 +322,7 @@ class Block(Base, Become, Conditional, Taggable):
         def evaluate_and_append_task(target):
             tmp_list = []
             for task in target:
-                if task.action == 'include' or task.evaluate_tags(play_context.only_tags, play_context.skip_tags, all_vars=all_vars):
+                if task.action in ('meta', 'include') or task.evaluate_tags(play_context.only_tags, play_context.skip_tags, all_vars=all_vars):
                     tmp_list.append(task)
             return tmp_list
 

lib/ansible/playbook/play.py

@@ -26,10 +26,11 @@ from ansible.errors import AnsibleError, AnsibleParserError
 from ansible.playbook.attribute import Attribute, FieldAttribute
 from ansible.playbook.base import Base
 from ansible.playbook.become import Become
+from ansible.playbook.block import Block
 from ansible.playbook.helpers import load_list_of_blocks, load_list_of_roles
 from ansible.playbook.role import Role
 from ansible.playbook.taggable import Taggable
-from ansible.playbook.block import Block
+from ansible.playbook.task import Task
 
 from ansible.utils.vars import combine_vars
 
@@ -270,12 +271,25 @@ class Play(Base, Taggable, Become):
         tasks specified in the play.
         '''
 
+        # create a block containing a single flush handlers meta
+        # task, so we can be sure to run handlers at certain points
+        # of the playbook execution
+        flush_block = Block.load(
+            data={'meta': 'flush_handlers'},
+            play=self,
+            variable_manager=self._variable_manager,
+            loader=self._loader
+        )
+
         block_list = []
 
         block_list.extend(self.pre_tasks)
+        block_list.append(flush_block)
         block_list.extend(self._compile_roles())
         block_list.extend(self.tasks)
+        block_list.append(flush_block)
         block_list.extend(self.post_tasks)
+        block_list.append(flush_block)
 
         return block_list