From 760ef9210a76de98efb21980616168ad7ba4fdf3 Mon Sep 17 00:00:00 2001
From: Zaiming Shi <zmstone@gmail.com>
Date: Wed, 4 Nov 2020 13:07:42 +0100
Subject: [PATCH] fix(stomp): Fix dialyzer warnings

---
 apps/emqx_stomp/include/emqx_stomp.hrl      |  2 +-
 apps/emqx_stomp/src/emqx_stomp_frame.erl    |  6 +++++-
 apps/emqx_stomp/src/emqx_stomp_protocol.erl | 19 +++++++++----------
 3 files changed, 15 insertions(+), 12 deletions(-)

diff --git a/apps/emqx_stomp/include/emqx_stomp.hrl b/apps/emqx_stomp/include/emqx_stomp.hrl
index 504191110..e2eeee7d8 100644
--- a/apps/emqx_stomp/include/emqx_stomp.hrl
+++ b/apps/emqx_stomp/include/emqx_stomp.hrl
@@ -24,7 +24,7 @@
 %% STOMP Frame
 %%--------------------------------------------------------------------
 
--record(stomp_frame, {command, headers = [], body = <<>> :: iolist()}).
+-record(stomp_frame, {command, headers = [], body = <<>> :: iodata()}).
 
 -type(stomp_frame() :: #stomp_frame{}).
 
diff --git a/apps/emqx_stomp/src/emqx_stomp_frame.erl b/apps/emqx_stomp/src/emqx_stomp_frame.erl
index e5795335a..20bbf513d 100644
--- a/apps/emqx_stomp/src/emqx_stomp_frame.erl
+++ b/apps/emqx_stomp/src/emqx_stomp_frame.erl
@@ -87,7 +87,11 @@
 
 -define(IS_ESC(Ch), Ch == ?CR; Ch == ?LF; Ch == ?BSL; Ch == ?COLON).
 
--record(parser_state, {cmd, headers = [], hdname, acc = <<>>, limit}).
+-record(parser_state, {cmd,
+                       headers = [],
+                       hdname,
+                       acc = <<>> :: binary(),
+                       limit}).
 
 -record(frame_limit, {max_header_num, max_header_length, max_body_length}).
 
diff --git a/apps/emqx_stomp/src/emqx_stomp_protocol.erl b/apps/emqx_stomp/src/emqx_stomp_protocol.erl
index fa75f08e3..ff49cd381 100644
--- a/apps/emqx_stomp/src/emqx_stomp_protocol.erl
+++ b/apps/emqx_stomp/src/emqx_stomp_protocol.erl
@@ -99,12 +99,12 @@ received(#stomp_frame{command = <<"CONNECT">>, headers = Headers},
                     send(connected_frame([{<<"version">>, Version},
                                           {<<"heart-beat">>, reverse_heartbeats(Heartbeats)}]), NewState);
                 false ->
-                    send(error_frame(undefined, <<"Login or passcode error!">>), State),
+                    _ = send(error_frame(undefined, <<"Login or passcode error!">>), State),
                     {error, login_or_passcode_error, State}
              end;
         {error, Msg} ->
-            send(error_frame([{<<"version">>, <<"1.0,1.1,1.2">>},
-                              {<<"content-type">>, <<"text/plain">>}], undefined, Msg), State),
+            _ = send(error_frame([{<<"version">>, <<"1.0,1.1,1.2">>},
+                                  {<<"content-type">>, <<"text/plain">>}], undefined, Msg), State),
             {error, unsupported_version, State}
     end;
 
@@ -114,10 +114,9 @@ received(#stomp_frame{command = <<"CONNECT">>}, State = #stomp_proto{connected =
 received(#stomp_frame{command = <<"SEND">>, headers = Headers, body = Body}, State) ->
     Topic = header(<<"destination">>, Headers),
     Action = fun(State0) ->
-                 maybe_send_receipt(receipt_id(Headers), State0),
-                 emqx_broker:publish(
-                     make_mqtt_message(Topic, Headers, iolist_to_binary(Body))
-                 ),
+                 _ = maybe_send_receipt(receipt_id(Headers), State0),
+                 _ = emqx_broker:publish(
+                       make_mqtt_message(Topic, Headers, iolist_to_binary(Body))),
                  State0
              end,
     case header(<<"transaction">>, Headers) of
@@ -160,7 +159,7 @@ received(#stomp_frame{command = <<"UNSUBSCRIBE">>, headers = Headers},
 received(#stomp_frame{command = <<"ACK">>, headers = Headers}, State) ->
     Id = header(<<"id">>, Headers),
     Action = fun(State0) -> 
-                 maybe_send_receipt(receipt_id(Headers), State0),
+                 _ = maybe_send_receipt(receipt_id(Headers), State0),
                  ack(Id, State0) 
              end,
     case header(<<"transaction">>, Headers) of
@@ -176,7 +175,7 @@ received(#stomp_frame{command = <<"ACK">>, headers = Headers}, State) ->
 received(#stomp_frame{command = <<"NACK">>, headers = Headers}, State) ->
     Id = header(<<"id">>, Headers),
     Action = fun(State0) -> 
-                 maybe_send_receipt(receipt_id(Headers), State0),
+                 _ = maybe_send_receipt(receipt_id(Headers), State0),
                  nack(Id, State0) 
              end,
     case header(<<"transaction">>, Headers) of
@@ -226,7 +225,7 @@ received(#stomp_frame{command = <<"ABORT">>, headers = Headers}, State) ->
     end;
 
 received(#stomp_frame{command = <<"DISCONNECT">>, headers = Headers}, State) ->
-    maybe_send_receipt(receipt_id(Headers), State),
+    _ = maybe_send_receipt(receipt_id(Headers), State),
     {stop, normal, State}.
 
 send(Msg = #message{topic = Topic, headers = Headers, payload = Payload},