[erlang-questions] gen_statem 20.3 init/1 - {next_event, internal, initial_event}

[Peter Morgan]

Thanks very much for the diff!
Regards
Peter 

> On 15 Mar 2018, at 14:51, Raimo Niskanen <raimo+erlang-questions@REDACTED> wrote:
> 
> I am sorry i fubmled when optimizing gen_statem.  That typo is mine,
> besides the erroneous actions list handling from init/1.
> 
> This diff should fix the problems:
> 
> diff --git a/lib/stdlib/src/gen_statem.erl b/lib/stdlib/src/gen_statem.erl
> index b1d99e2..eb0d6bd 100644
> --- a/lib/stdlib/src/gen_statem.erl
> +++ b/lib/stdlib/src/gen_statem.erl
> @@ -677,9 +677,9 @@ enter(Module, Opts, State, Data, Server, Actions,
> Parent) ->
>     NewDebug = ?sys_debug(Debug, {Name,State}, {enter,Event,State}),
>     case call_callback_mode(S) of
>        #state{} = NewS ->
> -           loop_event_actions(
> +           loop_event_actions_list(
>              Parent, NewDebug, NewS,
> -             Events, Event, State, Data, #trans_opts{},
> +             Events, Event, State, Data, false,
>               NewActions, CallEnter);
>        [Class,Reason,Stacktrace] ->
>            terminate(
> @@ -1295,7 +1295,7 @@ parse_actions_next_event(
>                 next_events_r = [{Type,Content}|NextEventsR]});
>         _ ->
>             [error,
> -             {bad_action_from_state_function,{next_events,Type,Content}},
> +             {bad_action_from_state_function,{next_event,Type,Content}},
>              ?STACKTRACE(),
>              ?not_sys_debug]
>     end;
> @@ -1312,7 +1312,7 @@ parse_actions_next_event(
>                 next_events_r = [{Type,Content}|NextEventsR]});
>         _ ->
>             [error,
> -             {bad_action_from_state_function,{next_events,Type,Content}},
> +             {bad_action_from_state_function,{next_event,Type,Content}},
>              ?STACKTRACE(),
>              Debug]
>     end.
> 
> 
> 
> That, running it through our daily builds, and apparently writing a
> writing a missing test case. ;-)
> 
> I am at the San Francisco Code Beam event right now so a patch will have to
> wait to next week..
> 
> Sorry about this!
> / Raimo Niskanen
> 
> 
> 
>> On Thu, Mar 15, 2018 at 12:32:04PM +0000, Guilherme Andrade wrote:
>> Crash log mentions 'next_events' (rather than 'next_event'.) Perhaps you
>> have a typo somewhere? But if that's the case, then it's weird that 20.2.x
>> doesn't complaint about it as well.
>> 
>> On 15 March 2018 at 11:23, Peter Morgan <peter.james.morgan@REDACTED>
>> wrote:
>> 
>>> Hello -
>>> 
>>> I am sure I am doing something daft. I picked up 20.3 this morning and
>>> have some gen_statem code that previously worked in 20.2.4:
>>> 
>>> -module(ex1).
>>> 
>>> -export([callback_mode/0]).
>>> -export([handle_event/4]).
>>> -export([init/1]).
>>> -export([start/0]).
>>> 
>>> start() ->
>>>    gen_statem:start({local, ?MODULE}, ?MODULE, [], []).
>>> 
>>> init([]) ->
>>>    {ok,
>>>     initial_state,
>>>     initial_data,
>>>     {next_event, internal, initial_event}}.
>>> 
>>> callback_mode() ->
>>>    handle_event_function.
>>> 
>>> handle_event(Type, Event, State, Data) ->
>>>    error_logger:info_report([{type, Type},
>>>                              {event, Event},
>>>                              {state, State},
>>>                              {data, Data}]),
>>>    keep_state_and_data.
>>> 
>>> 
>>> 
>>> 
>>> brew switch erlang 20.2.4
>>> 
>>> Erlang/OTP 20 [erts-9.2.1] [source] [64-bit] [smp:4:4] [ds:4:4:10]
>>> [async-threads:10] [hipe] [kernel-poll:false] [dtrace]
>>> 
>>> Eshell V9.2.1  (abort with ^G)
>>> 1> ex1:start().
>>> {ok,<0.62.0>}
>>> 
>>> =INFO REPORT==== 15-Mar-2018::12:13:29 ===
>>>    type: internal
>>>    event: initial_event
>>>    state: initial_state
>>>    data: initial_data
>>> 
>>> 
>>> 
>>> brew switch erlang 20.3
>>> Erlang/OTP 20 [erts-9.3] [source] [64-bit] [smp:4:4] [ds:4:4:10]
>>> [async-threads:10] [hipe] [kernel-poll:false] [dtrace]
>>> 
>>> Eshell V9.3  (abort with ^G)
>>> 1> c(ex1).
>>> {ok,ex1}
>>> 2> ex1:start().
>>> {ok,<0.67.0>}
>>> 3>
>>> =ERROR REPORT==== 15-Mar-2018::12:15:02 ===
>>> ** State machine ex1 terminating
>>> ** Last event = {internal,init_state}
>>> ** When server state  = {initial_state,initial_data}
>>> ** Reason for termination = error:{bad_action_from_state_function,
>>>                                      {next_events,internal,
>>> initial_event}}
>>> ** Callback mode = handle_event_function
>>> ** Stacktrace =
>>> **  [{gen_statem,parse_actions_next_event,7,
>>>                 [{file,"gen_statem.erl"},{line,1299}]},
>>>     {gen_statem,loop_event_actions_list,10,
>>>                 [{file,"gen_statem.erl"},{line,1194}]},
>>>     {proc_lib,init_p_do_apply,3,[{file,"proc_lib.erl"},{line,247}]}]
>>> 
>>> 
>>> The docs seem to indicate that next_event remains valid on init/1 -
>>> http://erlang.org/doc/man/gen_statem.html#type-init_result.
>>> 
>>> Thanks
>>> Peter.
>>> 
>>> 
>>> _______________________________________________
>>> erlang-questions mailing list
>>> erlang-questions@REDACTED
>>> http://erlang.org/mailman/listinfo/erlang-questions
>>> 
>>> 
>> 
>> 
>> -- 
>> Guilherme
> 
>> _______________________________________________
>> erlang-questions mailing list
>> erlang-questions@REDACTED
>> http://erlang.org/mailman/listinfo/erlang-questions
> 
> 
> -- 
> 
> / Raimo Niskanen, Erlang/OTP, Ericsson AB
> _______________________________________________
> erlang-questions mailing list
> erlang-questions@REDACTED
> http://erlang.org/mailman/listinfo/erlang-questions