# Buggy code
def _process_pending_results(self, iterator, one_pass=False, max_passes=None):
    """
    Reads results off the final queue and takes appropriate action
    based on the result (executing callbacks, updating state, etc.).
    """

    ret_results = []

    def get_original_host(host_name):
        host_name = to_text(host_name)
        if host_name in self._inventory._hosts_cache:
            return self._inventory._hosts_cache[host_name]
        else:
            return self._inventory.get_host(host_name)

    def search_handler_blocks_by_name(handler_name, handler_blocks):
        for handler_block in handler_blocks:
            for handler_task in handler_block.block:
                if handler_task.name:
                    handler_vars = self._variable_manager.get_vars(
                        loader=self._loader, play=iterator._play, task=handler_task
                    )
                    templar = Templar(loader=self._loader, variables=handler_vars)
                    try:
                        # first we check with the full result of get_name(), which may
                        # include the role name (if the handler is from a role). If that
                        # is not found, we resort to the simple name field, which doesn't
                        # have anything extra added to it.
                        target_handler_name = templar.template(handler_task.name)
                        if target_handler_name == handler_name:
                            return handler_task
                        else:
                            target_handler_name = templar.template(
                                handler_task.get_name()
                            )
                            if target_handler_name == handler_name:
                                return handler_task
                    except (UndefinedError, AnsibleUndefinedVariable):
                        # We skip this handler due to the fact that it may be using
                        # a variable in the name that was conditionally included via
                        # set_fact or some other method, and we don't want to error
                        # out unnecessarily
                        continue
        return None

    def search_handler_blocks_by_uuid(handler_uuid, handler_blocks):
        for handler_block in handler_blocks:
            for handler_task in handler_block.block:
                if handler_uuid == handler_task._uuid:
                    return handler_task
        return None

    def parent_handler_match(target_handler, handler_name):
        if target_handler:
            if isinstance(target_handler, (TaskInclude, IncludeRole)):
                try:
                    handler_vars = self._variable_manager.get_vars(
                        loader=self._loader, play=iterator._play, task=target_handler
                    )
                    templar = Templar(loader=self._loader, variables=handler_vars)
                    target_handler_name = templar.template(target_handler.name)
                    if target_handler_name == handler_name:
                        return True
                    else:
                        target_handler_name = templar.template(
                            target_handler.get_name()
                        )
                        if target_handler_name == handler_name:
                            return True
                except (UndefinedError, AnsibleUndefinedVariable):
                    pass
            return parent_handler_match(target_handler._parent, handler_name)
        else:
            return False

    cur_pass = 0
    while True:
        try:
            self._results_lock.acquire()
            task_result = self._results.pop()
        except IndexError:
            break
        finally:
            self._results_lock.release()

        # get the original host and task. We then assign them to the TaskResult for use in callbacks/etc.
        original_host = get_original_host(task_result._host)
        found_task = iterator.get_original_task(original_host, task_result._task)
        original_task = found_task.copy(exclude_parent=True, exclude_tasks=True)
        original_task._parent = found_task._parent
        original_task.from_attrs(task_result._task_fields)

        task_result._host = original_host
        task_result._task = original_task

        # get the correct loop var for use later
        if original_task.loop_control:
            loop_var = original_task.loop_control.loop_var or "item"
        else:
            loop_var = "item"

        # send callbacks for 'non final' results
        if "_ansible_retry" in task_result._result:
            self._tqm.send_callback("v2_runner_retry", task_result)
            continue
        elif "_ansible_item_result" in task_result._result:
            if task_result.is_failed() or task_result.is_unreachable():
                self._tqm.send_callback("v2_runner_item_on_failed", task_result)
            elif task_result.is_skipped():
                self._tqm.send_callback("v2_runner_item_on_skipped", task_result)
            else:
                if "diff" in task_result._result:
                    if self._diff:
                        self._tqm.send_callback("v2_on_file_diff", task_result)
                self._tqm.send_callback("v2_runner_item_on_ok", task_result)
            continue

        if original_task.register:
            host_list = self.get_task_hosts(iterator, original_host, original_task)

            clean_copy = strip_internal_keys(task_result._result)
            if "invocation" in clean_copy:
                del clean_copy["invocation"]

            for target_host in host_list:
                self._variable_manager.set_nonpersistent_facts(
                    target_host, {original_task.register: clean_copy}
                )

        # all host status messages contain 2 entries: (msg, task_result)
        role_ran = False
        if task_result.is_failed():
            role_ran = True
            ignore_errors = original_task.ignore_errors
            if not ignore_errors:
                display.debug("marking %s as failed" % original_host.name)
                if original_task.run_once:
                    # if we're using run_once, we have to fail every host here
                    for h in self._inventory.get_hosts(iterator._play.hosts):
                        if h.name not in self._tqm._unreachable_hosts:
                            state, _ = iterator.get_next_task_for_host(h, peek=True)
                            iterator.mark_host_failed(h)
                            state, new_task = iterator.get_next_task_for_host(
                                h, peek=True
                            )
                else:
                    iterator.mark_host_failed(original_host)

                # increment the failed count for this host
                self._tqm._stats.increment("failures", original_host.name)

                # grab the current state and if we're iterating on the rescue portion
                # of a block then we save the failed task in a special var for use
                # within the rescue/always
                state, _ = iterator.get_next_task_for_host(original_host, peek=True)

                if (
                    iterator.is_failed(original_host)
                    and state
                    and state.run_state == iterator.ITERATING_COMPLETE
                ):
                    self._tqm._failed_hosts[original_host.name] = True

                if state and state.run_state == iterator.ITERATING_RESCUE:
                    self._variable_manager.set_nonpersistent_facts(
                        original_host,
                        dict(
                            ansible_failed_task=original_task.serialize(),
                            ansible_failed_result=task_result._result,
                        ),
                    )
            else:
                self._tqm._stats.increment("ok", original_host.name)
                if "changed" in task_result._result and task_result._result["changed"]:
                    self._tqm._stats.increment("changed", original_host.name)
            self._tqm.send_callback(
                "v2_runner_on_failed", task_result, ignore_errors=ignore_errors
            )
        elif task_result.is_unreachable():
            self._tqm._unreachable_hosts[original_host.name] = True
            iterator._play._removed_hosts.append(original_host.name)
            self._tqm._stats.increment("dark", original_host.name)
            self._tqm.send_callback("v2_runner_on_unreachable", task_result)
        elif task_result.is_skipped():
            self._tqm._stats.increment("skipped", original_host.name)
            self._tqm.send_callback("v2_runner_on_skipped", task_result)
        else:
            role_ran = True

            if original_task.loop:
                # this task had a loop, and has more than one result, so
                # loop over all of them instead of a single result
                result_items = task_result._result.get("results", [])
            else:
                result_items = [task_result._result]

            for result_item in result_items:
                if "_ansible_notify" in result_item:
                    if task_result.is_changed():
                        # The shared dictionary for notified handlers is a proxy, which
                        # does not detect when sub-objects within the proxy are modified.
                        # So, per the docs, we reassign the list so the proxy picks up and
                        # notifies all other threads
                        for handler_name in result_item["_ansible_notify"]:
                            found = False
                            # Find the handler using the above helper.  First we look up the
                            # dependency chain of the current task (if it's from a role), otherwise
                            # we just look through the list of handlers in the current play/all
                            # roles and use the first one that matches the notify name
                            target_handler = search_handler_blocks_by_name(
                                handler_name, iterator._play.handlers
                            )
                            if target_handler is not None:
                                found = True
                                if (
                                    original_host
                                    not in self._notified_handlers[target_handler._uuid]
                                ):
                                    self._notified_handlers[
                                        target_handler._uuid
                                    ].append(original_host)
                                    # FIXME: should this be a callback?
                                    display.vv("NOTIFIED HANDLER %s" % (handler_name,))
                            else:
                                # As there may be more than one handler with the notified name as the
                                # parent, so we just keep track of whether or not we found one at all
                                for target_handler_uuid in self._notified_handlers:
                                    target_handler = search_handler_blocks_by_uuid(
                                        target_handler_uuid, iterator._play.handlers
                                    )
                                    if target_handler and parent_handler_match(
                                        target_handler, handler_name
                                    ):
                                        found = True
                                        if (
                                            original_host
                                            not in self._notified_handlers[
                                                target_handler._uuid
                                            ]
                                        ):
                                            self._notified_handlers[
                                                target_handler._uuid
                                            ].append(original_host)
                                            display.vv(
                                                "NOTIFIED HANDLER %s"
                                                % (target_handler.get_name(),)
                                            )

                            if handler_name in self._listening_handlers:
                                for listening_handler_uuid in self._listening_handlers[
                                    handler_name
                                ]:
                                    listening_handler = search_handler_blocks_by_uuid(
                                        listening_handler_uuid, iterator._play.handlers
                                    )
                                    if listening_handler is not None:
                                        found = True
                                    else:
                                        continue
                                    if (
                                        original_host
                                        not in self._notified_handlers[
                                            listening_handler._uuid
                                        ]
                                    ):
                                        self._notified_handlers[
                                            listening_handler._uuid
                                        ].append(original_host)
                                        display.vv(
                                            "NOTIFIED HANDLER %s"
                                            % (listening_handler.get_name(),)
                                        )

                            # and if none were found, then we raise an error
                            if not found:
                                msg = (
                                    "The requested handler '%s' was not found in either the main handlers list nor in the listening handlers list"
                                    % handler_name
                                )
                                if C.ERROR_ON_MISSING_HANDLER:
                                    raise AnsibleError(msg)
                                else:
                                    display.warning(msg)

                if "add_host" in result_item:
                    # this task added a new host (add_host module)
                    new_host_info = result_item.get("add_host", dict())
                    self._add_host(new_host_info, iterator)

                elif "add_group" in result_item:
                    # this task added a new group (group_by module)
                    self._add_group(original_host, result_item)

                if "ansible_facts" in result_item:
                    # if delegated fact and we are delegating facts, we need to change target host for them
                    if (
                        original_task.delegate_to is not None
                        and original_task.delegate_facts
                    ):
                        host_list = self.get_delegated_hosts(result_item, original_task)
                    else:
                        host_list = self.get_task_hosts(
                            iterator, original_host, original_task
                        )

                    if original_task.action == "include_vars":
                        for var_name, var_value in iteritems(
                            result_item["ansible_facts"]
                        ):
                            # find the host we're actually referring too here, which may
                            # be a host that is not really in inventory at all
                            for target_host in host_list:
                                self._variable_manager.set_host_variable(
                                    target_host, var_name, var_value
                                )
                    else:
                        for target_host in host_list:
                            if original_task.action == "set_fact":
                                self._variable_manager.set_nonpersistent_facts(
                                    target_host, result_item["ansible_facts"].copy()
                                )
                            else:
                                self._variable_manager.set_host_facts(
                                    target_host, result_item["ansible_facts"].copy()
                                )

                if (
                    "ansible_stats" in result_item
                    and "data" in result_item["ansible_stats"]
                    and result_item["ansible_stats"]["data"]
                ):
                    if (
                        "per_host" not in result_item["ansible_stats"]
                        or result_item["ansible_stats"]["per_host"]
                    ):
                        host_list = self.get_task_hosts(
                            iterator, original_host, original_task
                        )
                    else:
                        host_list = [None]

                    data = result_item["ansible_stats"]["data"]
                    aggregate = (
                        "aggregate" in result_item["ansible_stats"]
                        and result_item["ansible_stats"]["aggregate"]
                    )
                    for myhost in host_list:
                        for k in data.keys():
                            if aggregate:
                                self._tqm._stats.update_custom_stats(k, data[k], myhost)
                            else:
                                self._tqm._stats.set_custom_stats(k, data[k], myhost)

            if "diff" in task_result._result:
                if self._diff:
                    self._tqm.send_callback("v2_on_file_diff", task_result)

            if original_task.action not in ["include", "include_role"]:
                self._tqm._stats.increment("ok", original_host.name)
                if "changed" in task_result._result and task_result._result["changed"]:
                    self._tqm._stats.increment("changed", original_host.name)

            # finally, send the ok for this task
            self._tqm.send_callback("v2_runner_on_ok", task_result)

        self._pending_results -= 1
        if original_host.name in self._blocked_hosts:
            del self._blocked_hosts[original_host.name]

        # If this is a role task, mark the parent role as being run (if
        # the task was ok or failed, but not skipped or unreachable)
        if (
            original_task._role is not None and role_ran
        ):  # TODO:  and original_task.action != 'include_role':?
            # lookup the role in the ROLE_CACHE to make sure we're dealing
            # with the correct object and mark it as executed
            for entry, role_obj in iteritems(
                iterator._play.ROLE_CACHE[original_task._role._role_name]
            ):
                if role_obj._uuid == original_task._role._uuid:
                    role_obj._had_task_run[original_host.name] = True

        ret_results.append(task_result)

        if one_pass or max_passes is not None and (cur_pass + 1) >= max_passes:
            break

        cur_pass += 1

    return ret_results


# Traceback (KeyError)
ansible-playbook -vvvv playbook.yml
No config file found; using defaults
[WARNING]: Host file not found: /etc/ansible/hosts

[WARNING]: provided hosts list is empty, only localhost is available

Loading callback plugin default of type stdout, v2.0 from /usr/local/lib/python2.7/site-packages/ansible/plugins/callback/__init__.pyc

PLAYBOOK: playbook.yml *********************************************************
1 plays in playbook.yml

PLAY [localhost] ***************************************************************

TASK [include_role] ************************************************************
task path: /Users/xxx/workspace/xxx/playbook.yml:6

TASK [handlertest : command] ***************************************************
task path: /Users/xxx/workspace/xxx/roles/handlertest/tasks/main.yml:3
Using module file /usr/local/lib/python2.7/site-packages/ansible/modules/core/commands/command.py
<127.0.0.1> ESTABLISH LOCAL CONNECTION FOR USER: xxx
<127.0.0.1> EXEC /bin/sh -c '( umask 77 &amp;&amp; mkdir -p "` echo $HOME/.ansible/tmp/ansible-tmp-1478572148.78-187995060050975 `" &amp;&amp; echo ansible-tmp-1478572148.78-187995060050975="` echo $HOME/.ansible/tmp/ansible-tmp-1478572148.78-187995060050975 `" ) &amp;&amp; sleep 0'
<127.0.0.1> PUT /var/folders/62/pqgvprd11fb4k6shw2pdzkqm0000gq/T/tmpGA2Gau TO /Users/xxx/.ansible/tmp/ansible-tmp-1478572148.78-187995060050975/command.py
<127.0.0.1> EXEC /bin/sh -c 'chmod u+x /Users/xxx/.ansible/tmp/ansible-tmp-1478572148.78-187995060050975/ /Users/xxx/.ansible/tmp/ansible-tmp-1478572148.78-187995060050975/command.py &amp;&amp; sleep 0'
<127.0.0.1> EXEC /bin/sh -c '/usr/local/opt/python/bin/python2.7 /Users/xxx/.ansible/tmp/ansible-tmp-1478572148.78-187995060050975/command.py; rm -rf "/Users/xxx/.ansible/tmp/ansible-tmp-1478572148.78-187995060050975/" > /dev/null 2>&amp;1 &amp;&amp; sleep 0'
ERROR! Unexpected Exception: HANDLER: handlertest : Some handler
the full traceback was:

Traceback (most recent call last):
File "/usr/local/bin/ansible-playbook", line 103, in <module>
exit_code = cli.run()
File "/usr/local/lib/python2.7/site-packages/ansible/cli/playbook.py", line 159, in run
results = pbex.run()
File "/usr/local/lib/python2.7/site-packages/ansible/executor/playbook_executor.py", line 154, in run
result = self._tqm.run(play=play)
File "/usr/local/lib/python2.7/site-packages/ansible/executor/task_queue_manager.py", line 282, in run
play_return = strategy.run(iterator, play_context)
File "/usr/local/lib/python2.7/site-packages/ansible/plugins/strategy/linear.py", line 278, in run
results += self._wait_on_pending_results(iterator)
File "/usr/local/lib/python2.7/site-packages/ansible/plugins/strategy/__init__.py", line 534, in _wait_on_pending_results
results = self._process_pending_results(iterator)
File "/usr/local/lib/python2.7/site-packages/ansible/plugins/strategy/__init__.py", line 399, in _process_pending_results
if original_host not in self._notified_handlers[target_handler]:
KeyError: HANDLER: handlertest : Some handler

# Fixed code
def _process_pending_results(self, iterator, one_pass=False, max_passes=None):
    """
    Reads results off the final queue and takes appropriate action
    based on the result (executing callbacks, updating state, etc.).
    """

    ret_results = []

    def get_original_host(host_name):
        host_name = to_text(host_name)
        if host_name in self._inventory._hosts_cache:
            return self._inventory._hosts_cache[host_name]
        else:
            return self._inventory.get_host(host_name)

    def search_handler_blocks_by_name(handler_name, handler_blocks):
        for handler_block in handler_blocks:
            for handler_task in handler_block.block:
                if handler_task.name:
                    handler_vars = self._variable_manager.get_vars(
                        loader=self._loader, play=iterator._play, task=handler_task
                    )
                    templar = Templar(loader=self._loader, variables=handler_vars)
                    try:
                        # first we check with the full result of get_name(), which may
                        # include the role name (if the handler is from a role). If that
                        # is not found, we resort to the simple name field, which doesn't
                        # have anything extra added to it.
                        target_handler_name = templar.template(handler_task.name)
                        if target_handler_name == handler_name:
                            return handler_task
                        else:
                            target_handler_name = templar.template(
                                handler_task.get_name()
                            )
                            if target_handler_name == handler_name:
                                return handler_task
                    except (UndefinedError, AnsibleUndefinedVariable):
                        # We skip this handler due to the fact that it may be using
                        # a variable in the name that was conditionally included via
                        # set_fact or some other method, and we don't want to error
                        # out unnecessarily
                        continue
        return None

    def search_handler_blocks_by_uuid(handler_uuid, handler_blocks):
        for handler_block in handler_blocks:
            for handler_task in handler_block.block:
                if handler_uuid == handler_task._uuid:
                    return handler_task
        return None

    def parent_handler_match(target_handler, handler_name):
        if target_handler:
            if isinstance(target_handler, (TaskInclude, IncludeRole)):
                try:
                    handler_vars = self._variable_manager.get_vars(
                        loader=self._loader, play=iterator._play, task=target_handler
                    )
                    templar = Templar(loader=self._loader, variables=handler_vars)
                    target_handler_name = templar.template(target_handler.name)
                    if target_handler_name == handler_name:
                        return True
                    else:
                        target_handler_name = templar.template(
                            target_handler.get_name()
                        )
                        if target_handler_name == handler_name:
                            return True
                except (UndefinedError, AnsibleUndefinedVariable):
                    pass
            return parent_handler_match(target_handler._parent, handler_name)
        else:
            return False

    cur_pass = 0
    while True:
        try:
            self._results_lock.acquire()
            task_result = self._results.pop()
        except IndexError:
            break
        finally:
            self._results_lock.release()

        # get the original host and task. We then assign them to the TaskResult for use in callbacks/etc.
        original_host = get_original_host(task_result._host)
        found_task = iterator.get_original_task(original_host, task_result._task)
        original_task = found_task.copy(exclude_parent=True, exclude_tasks=True)
        original_task._parent = found_task._parent
        original_task.from_attrs(task_result._task_fields)

        task_result._host = original_host
        task_result._task = original_task

        # get the correct loop var for use later
        if original_task.loop_control:
            loop_var = original_task.loop_control.loop_var or "item"
        else:
            loop_var = "item"

        # send callbacks for 'non final' results
        if "_ansible_retry" in task_result._result:
            self._tqm.send_callback("v2_runner_retry", task_result)
            continue
        elif "_ansible_item_result" in task_result._result:
            if task_result.is_failed() or task_result.is_unreachable():
                self._tqm.send_callback("v2_runner_item_on_failed", task_result)
            elif task_result.is_skipped():
                self._tqm.send_callback("v2_runner_item_on_skipped", task_result)
            else:
                if "diff" in task_result._result:
                    if self._diff:
                        self._tqm.send_callback("v2_on_file_diff", task_result)
                self._tqm.send_callback("v2_runner_item_on_ok", task_result)
            continue

        if original_task.register:
            host_list = self.get_task_hosts(iterator, original_host, original_task)

            clean_copy = strip_internal_keys(task_result._result)
            if "invocation" in clean_copy:
                del clean_copy["invocation"]

            for target_host in host_list:
                self._variable_manager.set_nonpersistent_facts(
                    target_host, {original_task.register: clean_copy}
                )

        # all host status messages contain 2 entries: (msg, task_result)
        role_ran = False
        if task_result.is_failed():
            role_ran = True
            ignore_errors = original_task.ignore_errors
            if not ignore_errors:
                display.debug("marking %s as failed" % original_host.name)
                if original_task.run_once:
                    # if we're using run_once, we have to fail every host here
                    for h in self._inventory.get_hosts(iterator._play.hosts):
                        if h.name not in self._tqm._unreachable_hosts:
                            state, _ = iterator.get_next_task_for_host(h, peek=True)
                            iterator.mark_host_failed(h)
                            state, new_task = iterator.get_next_task_for_host(
                                h, peek=True
                            )
                else:
                    iterator.mark_host_failed(original_host)

                # increment the failed count for this host
                self._tqm._stats.increment("failures", original_host.name)

                # grab the current state and if we're iterating on the rescue portion
                # of a block then we save the failed task in a special var for use
                # within the rescue/always
                state, _ = iterator.get_next_task_for_host(original_host, peek=True)

                if (
                    iterator.is_failed(original_host)
                    and state
                    and state.run_state == iterator.ITERATING_COMPLETE
                ):
                    self._tqm._failed_hosts[original_host.name] = True

                if state and state.run_state == iterator.ITERATING_RESCUE:
                    self._variable_manager.set_nonpersistent_facts(
                        original_host,
                        dict(
                            ansible_failed_task=original_task.serialize(),
                            ansible_failed_result=task_result._result,
                        ),
                    )
            else:
                self._tqm._stats.increment("ok", original_host.name)
                if "changed" in task_result._result and task_result._result["changed"]:
                    self._tqm._stats.increment("changed", original_host.name)
            self._tqm.send_callback(
                "v2_runner_on_failed", task_result, ignore_errors=ignore_errors
            )
        elif task_result.is_unreachable():
            self._tqm._unreachable_hosts[original_host.name] = True
            iterator._play._removed_hosts.append(original_host.name)
            self._tqm._stats.increment("dark", original_host.name)
            self._tqm.send_callback("v2_runner_on_unreachable", task_result)
        elif task_result.is_skipped():
            self._tqm._stats.increment("skipped", original_host.name)
            self._tqm.send_callback("v2_runner_on_skipped", task_result)
        else:
            role_ran = True

            if original_task.loop:
                # this task had a loop, and has more than one result, so
                # loop over all of them instead of a single result
                result_items = task_result._result.get("results", [])
            else:
                result_items = [task_result._result]

            for result_item in result_items:
                if "_ansible_notify" in result_item:
                    if task_result.is_changed():
                        # The shared dictionary for notified handlers is a proxy, which
                        # does not detect when sub-objects within the proxy are modified.
                        # So, per the docs, we reassign the list so the proxy picks up and
                        # notifies all other threads
                        for handler_name in result_item["_ansible_notify"]:
                            found = False
                            # Find the handler using the above helper.  First we look up the
                            # dependency chain of the current task (if it's from a role), otherwise
                            # we just look through the list of handlers in the current play/all
                            # roles and use the first one that matches the notify name
                            target_handler = search_handler_blocks_by_name(
                                handler_name, iterator._play.handlers
                            )
                            if target_handler is not None:
                                found = True
                                if target_handler._uuid not in self._notified_handlers:
                                    self._notified_handlers[target_handler._uuid] = []
                                if (
                                    original_host
                                    not in self._notified_handlers[target_handler._uuid]
                                ):
                                    self._notified_handlers[
                                        target_handler._uuid
                                    ].append(original_host)
                                    # FIXME: should this be a callback?
                                    display.vv("NOTIFIED HANDLER %s" % (handler_name,))
                            else:
                                # As there may be more than one handler with the notified name as the
                                # parent, so we just keep track of whether or not we found one at all
                                for target_handler_uuid in self._notified_handlers:
                                    target_handler = search_handler_blocks_by_uuid(
                                        target_handler_uuid, iterator._play.handlers
                                    )
                                    if target_handler and parent_handler_match(
                                        target_handler, handler_name
                                    ):
                                        found = True
                                        if (
                                            original_host
                                            not in self._notified_handlers[
                                                target_handler._uuid
                                            ]
                                        ):
                                            self._notified_handlers[
                                                target_handler._uuid
                                            ].append(original_host)
                                            display.vv(
                                                "NOTIFIED HANDLER %s"
                                                % (target_handler.get_name(),)
                                            )

                            if handler_name in self._listening_handlers:
                                for listening_handler_uuid in self._listening_handlers[
                                    handler_name
                                ]:
                                    listening_handler = search_handler_blocks_by_uuid(
                                        listening_handler_uuid, iterator._play.handlers
                                    )
                                    if listening_handler is not None:
                                        found = True
                                    else:
                                        continue
                                    if (
                                        original_host
                                        not in self._notified_handlers[
                                            listening_handler._uuid
                                        ]
                                    ):
                                        self._notified_handlers[
                                            listening_handler._uuid
                                        ].append(original_host)
                                        display.vv(
                                            "NOTIFIED HANDLER %s"
                                            % (listening_handler.get_name(),)
                                        )

                            # and if none were found, then we raise an error
                            if not found:
                                msg = (
                                    "The requested handler '%s' was not found in either the main handlers list nor in the listening handlers list"
                                    % handler_name
                                )
                                if C.ERROR_ON_MISSING_HANDLER:
                                    raise AnsibleError(msg)
                                else:
                                    display.warning(msg)

                if "add_host" in result_item:
                    # this task added a new host (add_host module)
                    new_host_info = result_item.get("add_host", dict())
                    self._add_host(new_host_info, iterator)

                elif "add_group" in result_item:
                    # this task added a new group (group_by module)
                    self._add_group(original_host, result_item)

                if "ansible_facts" in result_item:
                    # if delegated fact and we are delegating facts, we need to change target host for them
                    if (
                        original_task.delegate_to is not None
                        and original_task.delegate_facts
                    ):
                        host_list = self.get_delegated_hosts(result_item, original_task)
                    else:
                        host_list = self.get_task_hosts(
                            iterator, original_host, original_task
                        )

                    if original_task.action == "include_vars":
                        for var_name, var_value in iteritems(
                            result_item["ansible_facts"]
                        ):
                            # find the host we're actually referring too here, which may
                            # be a host that is not really in inventory at all
                            for target_host in host_list:
                                self._variable_manager.set_host_variable(
                                    target_host, var_name, var_value
                                )
                    else:
                        for target_host in host_list:
                            if original_task.action == "set_fact":
                                self._variable_manager.set_nonpersistent_facts(
                                    target_host, result_item["ansible_facts"].copy()
                                )
                            else:
                                self._variable_manager.set_host_facts(
                                    target_host, result_item["ansible_facts"].copy()
                                )

                if (
                    "ansible_stats" in result_item
                    and "data" in result_item["ansible_stats"]
                    and result_item["ansible_stats"]["data"]
                ):
                    if (
                        "per_host" not in result_item["ansible_stats"]
                        or result_item["ansible_stats"]["per_host"]
                    ):
                        host_list = self.get_task_hosts(
                            iterator, original_host, original_task
                        )
                    else:
                        host_list = [None]

                    data = result_item["ansible_stats"]["data"]
                    aggregate = (
                        "aggregate" in result_item["ansible_stats"]
                        and result_item["ansible_stats"]["aggregate"]
                    )
                    for myhost in host_list:
                        for k in data.keys():
                            if aggregate:
                                self._tqm._stats.update_custom_stats(k, data[k], myhost)
                            else:
                                self._tqm._stats.set_custom_stats(k, data[k], myhost)

            if "diff" in task_result._result:
                if self._diff:
                    self._tqm.send_callback("v2_on_file_diff", task_result)

            if original_task.action not in ["include", "include_role"]:
                self._tqm._stats.increment("ok", original_host.name)
                if "changed" in task_result._result and task_result._result["changed"]:
                    self._tqm._stats.increment("changed", original_host.name)

            # finally, send the ok for this task
            self._tqm.send_callback("v2_runner_on_ok", task_result)

        self._pending_results -= 1
        if original_host.name in self._blocked_hosts:
            del self._blocked_hosts[original_host.name]

        # If this is a role task, mark the parent role as being run (if
        # the task was ok or failed, but not skipped or unreachable)
        if (
            original_task._role is not None and role_ran
        ):  # TODO:  and original_task.action != 'include_role':?
            # lookup the role in the ROLE_CACHE to make sure we're dealing
            # with the correct object and mark it as executed
            for entry, role_obj in iteritems(
                iterator._play.ROLE_CACHE[original_task._role._role_name]
            ):
                if role_obj._uuid == original_task._role._uuid:
                    role_obj._had_task_run[original_host.name] = True

        ret_results.append(task_result)

        if one_pass or max_passes is not None and (cur_pass + 1) >= max_passes:
            break

        cur_pass += 1

    return ret_results