From a47d47ac92d080c6f8e4fcba1dd8b8575c5a3f96 Mon Sep 17 00:00:00 2001
From: Raimo Niskanen <raimo@erlang.org>
Date: Wed, 17 Aug 2016 10:42:58 +0200
Subject: Clarify error values

---
 lib/stdlib/src/gen_statem.erl        | 38 +++++++++++++++++++++++++-----------
 lib/stdlib/test/gen_statem_SUITE.erl |  8 ++++----
 2 files changed, 31 insertions(+), 15 deletions(-)

(limited to 'lib/stdlib')

diff --git a/lib/stdlib/src/gen_statem.erl b/lib/stdlib/src/gen_statem.erl
index a39503cb6b..7e4fab5365 100644
--- a/lib/stdlib/src/gen_statem.erl
+++ b/lib/stdlib/src/gen_statem.erl
@@ -582,7 +582,7 @@ init_result(Starter, Parent, ServerRef, Module, Result, Opts) ->
 	    proc_lib:init_ack(Starter, ignore),
 	    exit(normal);
 	_ ->
-	    Error = {bad_return_value,Result},
+	    Error = {bad_return_from_init,Result},
 	    proc_lib:init_ack(Starter, {error,Error}),
 	    exit(Error)
     end.
@@ -656,11 +656,11 @@ format_status(
 
 print_event(Dev, {in,Event}, {Name,_}) ->
     io:format(
-      Dev, "*DBG* ~p received ~s~n",
+      Dev, "*DBG* ~p receive ~s~n",
       [Name,event_string(Event)]);
 print_event(Dev, {out,Reply,{To,_Tag}}, {Name,_}) ->
     io:format(
-      Dev, "*DBG* ~p sent ~p to ~p~n",
+      Dev, "*DBG* ~p send ~p to ~p~n",
       [Name,Reply,To]);
 print_event(Dev, {Tag,Event,NextState}, {Name,State}) ->
     StateString =
@@ -992,7 +992,9 @@ loop_event_result(
 	      State, Data, P, Event, State, Actions);
 	_ ->
 	    terminate(
-	      error, {bad_return_value,Result}, ?STACKTRACE(),
+	      error,
+	      {bad_return_from_state_function,Result},
+	      ?STACKTRACE(),
 	      Debug, S, [Event|Events], State, Data, P)
     end.
 
@@ -1029,7 +1031,9 @@ loop_event_actions(
 		      Postpone, Hibernate, Timeout, NextEvents);
 		false ->
 		    terminate(
-		      error, {bad_action,Action}, ?STACKTRACE(),
+		      error,
+		      {bad_action_from_state_function,Action},
+		      ?STACKTRACE(),
 		      Debug, S, [Event|Events], State, NewData, P)
 	    end;
 	{next_event,Type,Content} ->
@@ -1042,7 +1046,9 @@ loop_event_actions(
 		      [{Type,Content}|NextEvents]);
 		false ->
 		    terminate(
-		      error, {bad_action,Action}, ?STACKTRACE(),
+		      error,
+		      {bad_action_from_state_function,Action},
+		      ?STACKTRACE(),
 		      Debug, S, [Event|Events], State, NewData, P)
 	    end;
 	%% Actions that set options
@@ -1053,7 +1059,9 @@ loop_event_actions(
 	      NewPostpone, Hibernate, Timeout, NextEvents);
 	{postpone,_} ->
 	    terminate(
-	      error, {bad_action,Action}, ?STACKTRACE(),
+	      error,
+	      {bad_action_from_state_function,Action},
+	      ?STACKTRACE(),
 	      Debug, S, [Event|Events], State, NewData, P);
 	postpone ->
 	    loop_event_actions(
@@ -1067,7 +1075,9 @@ loop_event_actions(
 	      Postpone, NewHibernate, Timeout, NextEvents);
 	{hibernate,_} ->
 	    terminate(
-	      error, {bad_action,Action}, ?STACKTRACE(),
+	      error,
+	      {bad_action_from_state_function,Action},
+	      ?STACKTRACE(),
 	      Debug, S, [Event|Events], State, NewData, P);
 	hibernate ->
 	    loop_event_actions(
@@ -1086,7 +1096,9 @@ loop_event_actions(
 	      Postpone, Hibernate, NewTimeout, NextEvents);
 	{timeout,_,_} ->
 	    terminate(
-	      error, {bad_action,Action}, ?STACKTRACE(),
+	      error,
+	      {bad_action_from_state_function,Action},
+	      ?STACKTRACE(),
 	      Debug, S, [Event|Events], State, NewData, P);
 	infinity -> % Clear timer - it will never trigger
 	    loop_event_actions(
@@ -1101,7 +1113,9 @@ loop_event_actions(
 	      Postpone, Hibernate, NewTimeout, NextEvents);
 	_ ->
 	    terminate(
-	      error, {bad_action,Action}, ?STACKTRACE(),
+	      error,
+	      {bad_action_from_state_function,Action},
+	      ?STACKTRACE(),
 	      Debug, S, [Event|Events], State, NewData, P)
     end;
 %%
@@ -1173,7 +1187,9 @@ do_reply_then_terminate(
 	      NewDebug, S, Q, State, Data, P, Rs);
 	_ ->
 	    terminate(
-	      error, {bad_action,R}, ?STACKTRACE(),
+	      error,
+	      {bad_reply_action_from_state_function,R},
+	      ?STACKTRACE(),
 	      Debug, S, Q, State, Data, P)
     end.
 
diff --git a/lib/stdlib/test/gen_statem_SUITE.erl b/lib/stdlib/test/gen_statem_SUITE.erl
index d90119de54..1d1417c2e6 100644
--- a/lib/stdlib/test/gen_statem_SUITE.erl
+++ b/lib/stdlib/test/gen_statem_SUITE.erl
@@ -460,10 +460,10 @@ abnormal2(Config) ->
     {ok,Pid} = gen_statem:start_link(?MODULE, start_arg(Config, []), []),
 
     %% bad return value in the gen_statem loop
-    {{bad_return_value,badreturn},_} =
+    {{bad_return_from_state_function,badreturn},_} =
 	?EXPECT_FAILURE(gen_statem:call(Pid, badreturn), Reason),
     receive
-	{'EXIT',Pid,{bad_return_value,badreturn}} -> ok
+	{'EXIT',Pid,{bad_return_from_state_function,badreturn}} -> ok
     after 5000 ->
 	    ct:fail(gen_statem_did_not_die)
     end,
@@ -709,7 +709,7 @@ error_format_status(Config) ->
 	gen_statem:start(
 	  ?MODULE, start_arg(Config, {data,Data}), []),
     %% bad return value in the gen_statem loop
-    {{bad_return_value,badreturn},_} =
+    {{bad_return_from_state_function,badreturn},_} =
 	?EXPECT_FAILURE(gen_statem:call(Pid, badreturn), Reason),
     receive
 	{error,_,
@@ -717,7 +717,7 @@ error_format_status(Config) ->
 	  "** State machine"++_,
 	  [Pid,{{call,_},badreturn},
 	   {formatted,idle,Data},
-	   error,{bad_return_value,badreturn}|_]}} ->
+	   error,{bad_return_from_state_function,badreturn}|_]}} ->
 	    ok;
 	Other when is_tuple(Other), element(1, Other) =:= error ->
 	    error_logger_forwarder:unregister(),
-- 
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