chore(broker): simplify subscribe code path

apps/emqx/src/emqx_broker.erl

@@ -139,6 +139,7 @@ subscribe(Topic, SubId, SubOpts0) when ?IS_TOPIC(Topic), ?IS_SUBID(SubId), is_ma
         %% New
         false ->
             ok = emqx_broker_helper:register_sub(SubPid, SubId),
+            true = ets:insert(?SUBSCRIPTION, {SubPid, Topic}),
             do_subscribe(Topic, SubPid, with_subid(SubId, SubOpts));
         %% Existed
         true ->
@@ -153,11 +154,7 @@ with_subid(undefined, SubOpts) ->
 with_subid(SubId, SubOpts) ->
     maps:put(subid, SubId, SubOpts).
 
-do_subscribe(Topic, SubPid, SubOpts) ->
-    true = ets:insert(?SUBSCRIPTION, {SubPid, Topic}),
-    do_subscribe2(Topic, SubPid, SubOpts).
-
-do_subscribe2(Topic, SubPid, SubOpts) when is_binary(Topic) ->
+do_subscribe(Topic, SubPid, SubOpts) when is_binary(Topic) ->
     %% FIXME: subscribe shard bug
     %% https://emqx.atlassian.net/browse/EMQX-10214
     case emqx_broker_helper:get_sub_shard(SubPid, Topic) of
@@ -170,7 +167,7 @@ do_subscribe2(Topic, SubPid, SubOpts) when is_binary(Topic) ->
             true = ets:insert(?SUBOPTION, {{Topic, SubPid}, maps:put(shard, I, SubOpts)}),
             call(pick({Topic, I}), {subscribe, Topic, I})
     end;
-do_subscribe2(Topic = #share{group = Group, topic = RealTopic}, SubPid, SubOpts) when
+do_subscribe(Topic = #share{group = Group, topic = RealTopic}, SubPid, SubOpts) when
     is_binary(RealTopic)
 ->
     true = ets:insert(?SUBOPTION, {{Topic, SubPid}, SubOpts}),