Handle strange crash report from gen_statem

src/error_logger_lager_h.erl

@@ -207,6 +207,9 @@ log_event(Event, #state{sink=Sink} = State) ->
                         [TName, _Msg, TStateName, _StateData, TReason] ->
                             {gen_fsm, TName, TStateName, TReason};
                         [TName, _Msg, {TStateName, _StateData}, _ExitType, TReason, _FsmType, Stacktrace] ->
+                            {gen_statem, TName, TStateName, {TReason, Stacktrace}};
+                        [TName, _Msg, [{TStateName, _StateData}], _ExitType, TReason, _FsmType, Stacktrace] ->
+                            %% sometimes gen_statem wraps its statename/data in a list for some reason???
                             {gen_statem, TName, TStateName, {TReason, Stacktrace}}
                     end,
                     {Md, Formatted} = format_reason_md(Reason),

test/crash_statem.erl

@@ -6,6 +6,8 @@
 -export([
          start/0,
          crash/0,
+         stop/1,
+         timeout/0,
          handle_event/4
 ]).
 
@@ -17,6 +19,12 @@ start() ->
 crash() ->
     gen_statem:call(?MODULE, boom).
 
+stop(Reason) ->
+    gen_statem:call(?MODULE, {stop, Reason}).
+
+timeout() ->
+    gen_statem:call(?MODULE, timeout).
+
 %% Mandatory callback functions
 terminate(_Reason, _State, _Data) -> ok.
 code_change(_Vsn, State, Data, _Extra) -> {ok,State,Data}.
@@ -26,12 +34,17 @@ init([]) ->
         "8.0" -> {callback_mode(),state1,undefined};
         _ -> {ok, state1, undefined}
     end.
+
 callback_mode() -> handle_event_function.
 
 %%% state callback(s)
 
-handle_event({call, _From}, state1, _Arg, Data) ->
-    {next_state, state1, Data}.
+handle_event(state_timeout, timeout, state1, _) ->
+    {stop, timeout};
+handle_event({call, _From}, timeout, _Arg, Data) ->
+    {keep_state_and_data, [{state_timeout, 0, timeout}]};
+handle_event({call, _From}, {stop, Reason}, state1, Data) ->
+    {stop, Reason}.
 
 -else.
 -export([start/0, crash/0]).

test/lager_test_backend.erl

@@ -996,14 +996,14 @@ kill_crasher(RegName) ->
         Pid -> exit(Pid, kill)
     end.
 
-spawn_fsm_crash(Module) ->
-    spawn(fun() -> Module:crash() end),
+spawn_fsm_crash(Module, Function, Args) ->
+    spawn(fun() -> erlang:apply(Module, Function, Args) end),
     timer:sleep(100),
     _ = gen_event:which_handlers(error_logger),
     ok.
 
 crash_fsm_test_() ->
-    TestBody = fun(Name, FsmModule, Expected) ->
+    TestBody = fun(Name, FsmModule, FSMFunc, FSMArgs, Expected) ->
                    fun(Sink) ->
                       {Name,
                        fun() ->
@@ -1011,7 +1011,7 @@ crash_fsm_test_() ->
                                 {true, true} -> ok;
                                 _ ->
                                     Pid = whereis(FsmModule),
-                                    spawn_fsm_crash(FsmModule),
+                                    spawn_fsm_crash(FsmModule, FSMFunc, FSMArgs),
                                     {Level, _, Msg, Metadata} = pop(Sink),
                                     test_body(Expected, lists:flatten(Msg)),
                                     ?assertEqual(Pid, proplists:get_value(pid, Metadata)),
@@ -1031,8 +1031,10 @@ crash_fsm_test_() ->
             }
         end,
 
-        TestBody("gen_fsm crash", crash_fsm, "gen_fsm crash_fsm in state state1 terminated with reason: call to undefined function crash_fsm:state1/3 from gen_fsm:handle_msg/"),
-        TestBody("gen_statem crash", crash_statem, "gen_statem crash_statem in state state1 terminated with reason: no function clause matching crash_statem:handle")
+        TestBody("gen_fsm crash", crash_fsm, crash, [], "gen_fsm crash_fsm in state state1 terminated with reason: call to undefined function crash_fsm:state1/3 from gen_fsm:handle_msg/"),
+        TestBody("gen_statem crash", crash_statem, crash, [], "gen_statem crash_statem in state state1 terminated with reason: no function clause matching crash_statem:handle"),
+        TestBody("gen_statem stop", crash_statem, stop, [explode], "gen_statem crash_statem in state state1 terminated with reason: explode"),
+        TestBody("gen_statem timeout", crash_statem, timeout, [], "gen_statem crash_statem in state state1 terminated with reason: timeout")
     ],
 
     {"FSM crash output tests", [