consistently return {ok, Pid} from start_{link} functionsbug23032

6 files changed, 32 insertions, 36 deletions

diff --git a/src/rabbit_channel.erl b/src/rabbit_channel.erl
index dafc3075..dd639dd0 100644
--- a/src/rabbit_channel.erl
+++ b/src/rabbit_channel.erl
@@ -78,7 +78,7 @@
 
 -spec(start_link/6 ::
       (channel_number(), pid(), pid(), rabbit_access_control:username(),
-       rabbit_types:vhost(), pid()) -> pid()).
+       rabbit_types:vhost(), pid()) -> rabbit_types:ok(pid())).
 -spec(do/2 :: (pid(), rabbit_framing:amqp_method_record()) -> 'ok').
 -spec(do/3 :: (pid(), rabbit_framing:amqp_method_record(),
                rabbit_types:maybe(rabbit_types:content())) -> 'ok').
@@ -102,10 +102,8 @@
 %%----------------------------------------------------------------------------
 
 start_link(Channel, ReaderPid, WriterPid, Username, VHost, CollectorPid) ->
-    {ok, Pid} = gen_server2:start_link(
-                  ?MODULE, [Channel, ReaderPid, WriterPid,
-                            Username, VHost, CollectorPid], []),
-    Pid.
+    gen_server2:start_link(?MODULE, [Channel, ReaderPid, WriterPid,
+                                     Username, VHost, CollectorPid], []).
 
 do(Pid, Method) ->
     do(Pid, Method, none).
@@ -1031,7 +1029,7 @@ fold_per_queue(F, Acc0, UAQ) ->
               Acc0, D).
 
 start_limiter(State = #ch{unacked_message_q = UAMQ}) ->
-    LPid = rabbit_limiter:start_link(self(), queue:len(UAMQ)),
+    {ok, LPid} = rabbit_limiter:start_link(self(), queue:len(UAMQ)),
     ok = limit_queues(LPid, State),
     LPid.
 
diff --git a/src/rabbit_framing_channel.erl b/src/rabbit_framing_channel.erl
index bc1a2a08..31be1cf7 100644
--- a/src/rabbit_framing_channel.erl
+++ b/src/rabbit_framing_channel.erl
@@ -40,13 +40,14 @@
 %%--------------------------------------------------------------------
 
 start_link(StartFun, StartArgs) ->
-    spawn_link(
-      fun () ->
-              %% we trap exits so that a normal termination of the
-              %% channel or reader process terminates us too.
-              process_flag(trap_exit, true),
-              mainloop(apply(StartFun, StartArgs))
-      end).
+    {ok, spawn_link(
+           fun () ->
+                   %% we trap exits so that a normal termination of
+                   %% the channel or reader process terminates us too.
+                   process_flag(trap_exit, true),
+                   {ok, ChannelPid} = apply(StartFun, StartArgs),
+                   mainloop(ChannelPid)
+           end)}.
 
 process(Pid, Frame) ->
     Pid ! {frame, Frame},
diff --git a/src/rabbit_limiter.erl b/src/rabbit_limiter.erl
index 878af029..491ae7d6 100644
--- a/src/rabbit_limiter.erl
+++ b/src/rabbit_limiter.erl
@@ -45,7 +45,7 @@
 
 -type(maybe_pid() :: pid() | 'undefined').
 
--spec(start_link/2 :: (pid(), non_neg_integer()) -> pid()).
+-spec(start_link/2 :: (pid(), non_neg_integer()) -> {'ok', pid()}).
 -spec(shutdown/1 :: (maybe_pid()) -> 'ok').
 -spec(limit/2 :: (maybe_pid(), non_neg_integer()) -> 'ok' | 'stopped').
 -spec(can_send/3 :: (maybe_pid(), pid(), boolean()) -> boolean()).
@@ -74,8 +74,7 @@
 %%----------------------------------------------------------------------------
 
 start_link(ChPid, UnackedMsgCount) ->
-    {ok, Pid} = gen_server2:start_link(?MODULE, [ChPid, UnackedMsgCount], []),
-    Pid.
+    gen_server2:start_link(?MODULE, [ChPid, UnackedMsgCount], []).
 
 shutdown(undefined) ->
     ok;
diff --git a/src/rabbit_reader.erl b/src/rabbit_reader.erl
index b5514c82..83bc7e68 100644
--- a/src/rabbit_reader.erl
+++ b/src/rabbit_reader.erl
@@ -771,10 +771,10 @@ send_to_new_channel(Channel, AnalyzedFrame,
                        frame_max = FrameMax,
                        user = #user{username = Username},
                        vhost = VHost}} = State,
-    WriterPid = rabbit_writer:start(Sock, Channel, FrameMax),
-    ChPid = rabbit_framing_channel:start_link(
-              fun rabbit_channel:start_link/6,
-              [Channel, self(), WriterPid, Username, VHost, Collector]),
+    {ok, WriterPid} = rabbit_writer:start(Sock, Channel, FrameMax),
+    {ok, ChPid} = rabbit_framing_channel:start_link(
+                    fun rabbit_channel:start_link/6,
+                    [Channel, self(), WriterPid, Username, VHost, Collector]),
     put({channel, Channel}, {chpid, ChPid}),
     put({chpid, ChPid}, {channel, Channel}),
     ok = rabbit_framing_channel:process(ChPid, AnalyzedFrame).
diff --git a/src/rabbit_tests.erl b/src/rabbit_tests.erl
index 090c714b..dc77dbbf 100644
--- a/src/rabbit_tests.erl
+++ b/src/rabbit_tests.erl
@@ -938,8 +938,8 @@ test_user_management() ->
 test_server_status() ->
     %% create a few things so there is some useful information to list
     Writer = spawn(fun () -> receive shutdown -> ok end end),
-    Ch = rabbit_channel:start_link(1, self(), Writer, <<"user">>, <<"/">>,
-                                   self()),
+    {ok, Ch} = rabbit_channel:start_link(1, self(), Writer,
+                                         <<"user">>, <<"/">>, self()),
     [Q, Q2] = [Queue || Name <- [<<"foo">>, <<"bar">>],
                         {new, Queue = #amqqueue{}} <-
                             [rabbit_amqqueue:declare(
@@ -1068,8 +1068,8 @@ test_memory_pressure_sync(Ch, Writer) ->
 test_memory_pressure_spawn() ->
     Me = self(),
     Writer = spawn(fun () -> test_memory_pressure_receiver(Me) end),
-    Ch = rabbit_channel:start_link(1, self(), Writer, <<"user">>, <<"/">>,
-                                   self()),
+    {ok, Ch} = rabbit_channel:start_link(1, self(), Writer,
+                                         <<"user">>, <<"/">>, self()),
     ok = rabbit_channel:do(Ch, #'channel.open'{}),
     MRef = erlang:monitor(process, Ch),
     receive #'channel.open_ok'{} -> ok
@@ -1142,8 +1142,8 @@ test_memory_pressure() ->
     alarm_handler:set_alarm({vm_memory_high_watermark, []}),
     Me = self(),
     Writer4 = spawn(fun () -> test_memory_pressure_receiver(Me) end),
-    Ch4 = rabbit_channel:start_link(1, self(), Writer4, <<"user">>, <<"/">>,
-                                    self()),
+    {ok, Ch4} = rabbit_channel:start_link(1, self(), Writer4,
+                                          <<"user">>, <<"/">>, self()),
     ok = rabbit_channel:do(Ch4, #'channel.open'{}),
     MRef4 = erlang:monitor(process, Ch4),
     Writer4 ! sync,
diff --git a/src/rabbit_writer.erl b/src/rabbit_writer.erl
index 80602038..8857784b 100644
--- a/src/rabbit_writer.erl
+++ b/src/rabbit_writer.erl
@@ -50,12 +50,10 @@
 
 -spec(start/3 ::
         (rabbit_net:socket(), rabbit_channel:channel_number(),
-         non_neg_integer())
-        -> pid()).
+         non_neg_integer()) -> rabbit_types:ok(pid())).
 -spec(start_link/3 ::
         (rabbit_net:socket(), rabbit_channel:channel_number(),
-         non_neg_integer())
-        -> pid()).
+         non_neg_integer()) -> rabbit_types:ok(pid())).
 -spec(send_command/2 ::
         (pid(), rabbit_framing:amqp_method_record()) -> 'ok').
 -spec(send_command/3 ::
@@ -85,14 +83,14 @@
 %%----------------------------------------------------------------------------
 
 start(Sock, Channel, FrameMax) ->
-    spawn(?MODULE, mainloop, [#wstate{sock = Sock,
-                                      channel = Channel,
-                                      frame_max = FrameMax}]).
+    {ok, spawn(?MODULE, mainloop, [#wstate{sock = Sock,
+                                           channel = Channel,
+                                           frame_max = FrameMax}])}.
 
 start_link(Sock, Channel, FrameMax) ->
-    spawn_link(?MODULE, mainloop, [#wstate{sock = Sock,
-                                           channel = Channel,
-                                           frame_max = FrameMax}]).
+    {ok, spawn_link(?MODULE, mainloop, [#wstate{sock = Sock,
+                                                channel = Channel,
+                                                frame_max = FrameMax}])}.
 
 mainloop(State) ->
     receive