fix: the exclusive topics aren't removed when the session has already been cleaned

src/emqx_broker.erl

@@ -183,8 +183,7 @@ do_unsubscribe(Topic, SubPid, SubOpts) ->
     true = ets:delete(?SUBOPTION, {SubPid, Topic}),
     true = ets:delete_object(?SUBSCRIPTION, {SubPid, Topic}),
     Group = maps:get(share, SubOpts, undefined),
-    do_unsubscribe(Group, Topic, SubPid, SubOpts),
-    emqx_exclusive_subscription:unsubscribe(Topic, SubOpts).
+    do_unsubscribe(Group, Topic, SubPid, SubOpts).
 
 do_unsubscribe(undefined, Topic, SubPid, SubOpts) ->
     clean_subscribe(SubOpts, Topic, SubPid);
@@ -344,9 +343,12 @@ subscriber_down(SubPid) ->
 
 clean_subscribe(SubOpts, Topic, SubPid) ->
     case maps:get(shard, SubOpts, 0) of
-        0 -> true = ets:delete_object(?SUBSCRIBER, {Topic, SubPid}),
+        0 ->
+            true = ets:delete_object(?SUBSCRIBER, {Topic, SubPid}),
+            ok = emqx_exclusive_subscription:unsubscribe(Topic, SubOpts),
             ok = cast(pick(Topic), {unsubscribed, Topic});
-        I -> true = ets:delete_object(?SUBSCRIBER, {{shard, Topic, I}, SubPid}),
+        I ->
+            true = ets:delete_object(?SUBSCRIBER, {{shard, Topic, I}, SubPid}),
             ok = cast(pick({Topic, I}), {unsubscribed, Topic, I})
     end.
 

test/emqx_exclusive_sub_SUITE.erl

@@ -0,0 +1,170 @@
+%%--------------------------------------------------------------------
+%% Copyright (c) 2018-2023 EMQ Technologies Co., Ltd. All Rights Reserved.
+%%
+%% Licensed under the Apache License, Version 2.0 (the "License");
+%% you may not use this file except in compliance with the License.
+%% You may obtain a copy of the License at
+%%
+%%     http://www.apache.org/licenses/LICENSE-2.0
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+%% See the License for the specific language governing permissions and
+%% limitations under the License.
+%%--------------------------------------------------------------------
+
+-module(emqx_exclusive_sub_SUITE).
+
+-compile(export_all).
+-compile(nowarn_export_all).
+
+-include_lib("emqx/include/emqx.hrl").
+-include_lib("emqx/include/emqx_mqtt.hrl").
+-include_lib("eunit/include/eunit.hrl").
+
+-define(TAB, emqx_exclusive_subscription).
+-define(EXCLUSIVE_TOPIC, <<"$exclusive/t/1">>).
+-define(NORMAL_TOPIC, <<"t/1">>).
+
+-define(CHECK_SUB(Client, Code), ?CHECK_SUB(Client, ?EXCLUSIVE_TOPIC, Code)).
+-define(CHECK_SUB(Client, Topic, Code),
+    {ok, _, [Code]} = emqtt:subscribe(Client, Topic, [])
+).
+
+all() -> emqx_ct:all(?MODULE).
+
+init_per_suite(Config) ->
+    emqx_ct_helpers:start_apps([]),
+    enable_exclusive_sub(true),
+    Config.
+
+end_per_suite(_Config) ->
+    reset_zone_env(),
+    emqx_ct_helpers:stop_apps([]).
+
+end_per_testcase(_TestCase, _Config) ->
+    mnesia:clear_table(?TAB).
+
+%% test that this feature is working during the whole session life cycle
+t_exclusive_sub(_) ->
+    {ok, C1} = emqtt:start_link([
+        {clientid, <<"client1">>},
+        {clean_start, false},
+        {proto_ver, v5},
+        {properties, #{'Session-Expiry-Interval' => 100}}
+    ]),
+    {ok, _} = emqtt:connect(C1),
+    ?CHECK_SUB(C1, 0),
+
+    {ok, C2} = emqtt:start_link([
+        {clientid, <<"client2">>},
+        {clean_start, false},
+        {proto_ver, v5}
+    ]),
+    {ok, _} = emqtt:connect(C2),
+    ?CHECK_SUB(C2, ?RC_QUOTA_EXCEEDED),
+
+    %% keep exclusive even disconnected
+    ok = emqtt:disconnect(C1),
+    timer:sleep(1000),
+
+    ?CHECK_SUB(C2, ?RC_QUOTA_EXCEEDED),
+
+    ok = emqtt:disconnect(C2).
+
+%% test this feature does not interfere with normal subs
+t_allow_normal_sub(_) ->
+    {ok, C1} = emqtt:start_link([
+        {clientid, <<"client1">>},
+        {proto_ver, v5}
+    ]),
+    {ok, _} = emqtt:connect(C1),
+    ?CHECK_SUB(C1, 0),
+
+    {ok, C2} = emqtt:start_link([
+        {clientid, <<"client2">>},
+        {proto_ver, v5}
+    ]),
+    {ok, _} = emqtt:connect(C2),
+    ?CHECK_SUB(C2, ?NORMAL_TOPIC, 0),
+
+    ok = emqtt:disconnect(C1),
+    ok = emqtt:disconnect(C2).
+
+%% test the exclusive topics can be released correctly
+t_unsub(_) ->
+    {ok, C1} = emqtt:start_link([
+        {clientid, <<"client1">>},
+        {proto_ver, v5}
+    ]),
+    {ok, _} = emqtt:connect(C1),
+    ?CHECK_SUB(C1, 0),
+
+    {ok, C2} = emqtt:start_link([
+        {clientid, <<"client2">>},
+        {proto_ver, v5}
+    ]),
+    {ok, _} = emqtt:connect(C2),
+    ?CHECK_SUB(C2, ?RC_QUOTA_EXCEEDED),
+
+    {ok, #{}, [0]} = emqtt:unsubscribe(C1, ?EXCLUSIVE_TOPIC),
+
+    ?CHECK_SUB(C2, 0),
+
+    ok = emqtt:disconnect(C1),
+    ok = emqtt:disconnect(C2).
+
+%% test whether the exclusive topics would auto-clean after the session was cleaned
+t_clean_session(_) ->
+    erlang:process_flag(trap_exit, true),
+    {ok, C1} = emqtt:start_link([
+        {clientid, <<"client1">>},
+        {clean_start, true},
+        {proto_ver, v5},
+        {properties, #{'Session-Expiry-Interval' => 0}}
+    ]),
+    {ok, _} = emqtt:connect(C1),
+    ?CHECK_SUB(C1, 0),
+
+    {ok, C2} = emqtt:start_link([
+        {clientid, <<"client2">>},
+        {proto_ver, v5}
+    ]),
+    {ok, _} = emqtt:connect(C2),
+    ?CHECK_SUB(C2, ?RC_QUOTA_EXCEEDED),
+
+    %% auto clean when session was cleand
+    ok = emqtt:disconnect(C1),
+
+    timer:sleep(1000),
+
+    ?CHECK_SUB(C2, 0),
+
+    ok = emqtt:disconnect(C2).
+
+%% test the feature switch
+t_feat_disabled(_) ->
+    enable_exclusive_sub(false),
+
+    {ok, C1} = emqtt:start_link([
+        {clientid, <<"client1">>},
+        {proto_ver, v5}
+    ]),
+    {ok, _} = emqtt:connect(C1),
+    ?CHECK_SUB(C1, ?RC_TOPIC_FILTER_INVALID),
+    ok = emqtt:disconnect(C1),
+
+    enable_exclusive_sub(true).
+
+enable_exclusive_sub(Enable) ->
+    emqx_zone:set_env(
+        external,
+        '$mqtt_sub_caps',
+        #{exclusive_subscription => Enable}
+    ),
+    timer:sleep(50).
+
+reset_zone_env() ->
+    emqx_zone:unset_env(external, '$mqtt_sub_caps'),
+    timer:sleep(50).