chore(topic_index): add topic validation

apps/emqx/src/emqx_trie_search.erl

@@ -113,7 +113,7 @@
 %% @doc Make a search-key for the given topic.
 -spec make_key(emqx_types:topic(), ID) -> key(ID).
 make_key(Topic, ID) when is_binary(Topic) ->
-    Words = words(Topic),
+    Words = filter_words(Topic),
     case emqx_topic:wildcard(Words) of
         true ->
             %% it's a wildcard
@@ -171,7 +171,7 @@ matches(Topic, NextF, Opts) ->
 
 %% @doc Entrypoint of the search for a given topic.
 search(Topic, NextF, Opts) ->
-    Words = words(Topic),
+    Words = topic_words(Topic),
     Base = base_init(Words),
     ORetFirst = proplists:get_bool(return_first, Opts),
     OUnique = proplists:get_bool(unique, Opts),
@@ -320,18 +320,22 @@ match_add(K, Acc) when is_list(Acc) ->
 match_add(K, first) ->
     throw({first, K}).
 
--spec words(emqx_types:topic()) -> [word()].
-words(Topic) when is_binary(Topic) ->
+-spec filter_words(emqx_types:topic()) -> [word()].
+filter_words(Topic) when is_binary(Topic) ->
     % NOTE
     % This is almost identical to `emqx_topic:words/1`, but it doesn't convert empty
     % tokens to ''. This is needed to keep ordering of words consistent with what
     % `match_filter/3` expects.
-    [word(W) || W <- emqx_topic:tokens(Topic)].
+    [word(W, filter) || W <- emqx_topic:tokens(Topic)].
 
--spec word(binary()) -> word().
-word(<<"+">>) -> '+';
-word(<<"#">>) -> '#';
-word(Bin) -> Bin.
+topic_words(Topic) when is_binary(Topic) ->
+    [word(W, topic) || W <- emqx_topic:tokens(Topic)].
+
+word(<<"+">>, topic) -> error(badarg);
+word(<<"#">>, topic) -> error(badarg);
+word(<<"+">>, filter) -> '+';
+word(<<"#">>, filter) -> '#';
+word(Bin, _) -> Bin.
 
 %% match non-wildcard topics
 match_topics(Topic, {Topic, _} = Key, NextF, Acc) ->

apps/emqx/test/emqx_trie_search_tests.erl

@@ -0,0 +1,32 @@
+%%--------------------------------------------------------------------
+%% Copyright (c) 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_trie_search_tests).
+
+-include_lib("eunit/include/eunit.hrl").
+
+topic_validation_test() ->
+    NextF = fun(_) -> '$end_of_table' end,
+    Call = fun(Topic) ->
+        emqx_trie_search:match(Topic, NextF)
+    end,
+    ?assertError(badarg, Call(<<"+">>)),
+    ?assertError(badarg, Call(<<"#">>)),
+    ?assertError(badarg, Call(<<"a/+/b">>)),
+    ?assertError(badarg, Call(<<"a/b/#">>)),
+    ?assertEqual(false, Call(<<"a/b/b+">>)),
+    ?assertEqual(false, Call(<<"a/b/c#">>)),
+    ok.