Why does my supervisor fail on init with badarg? - erlang

Question

I am trying to start a supervisor of type one_for_one with one child and am getting this error:
A = pl:start().
{error,{badarg,[{erlang,apply,[{state,[0|1]},init,[[]]],[]},
{supervisor,init,1,[{file,"supervisor.erl"},{line,295}]},
{gen_server,init_it,2,[{file,"gen_server.erl"},{line,374}]},
{gen_server,init_it,6,[{file,"gen_server.erl"},{line,342}]},
{proc_lib,init_p_do_apply,3,
[{file,"proc_lib.erl"},{line,249}]}]}}
=CRASH REPORT==== 1-Mar-2020::15:28:41.090000 ===
crasher:
pid: <0.215.0>
registered_name: []
exception error: bad argument
in function apply/3
called as apply({state,[0|1]},init,[[]])
in call from supervisor:init/1 (supervisor.erl, line 295)
in call from gen_server:init_it/2 (gen_server.erl, line 374)
in call from gen_server:init_it/6 (gen_server.erl, line 342)
ancestors: [<0.209.0>]
message_queue_len: 0
messages: []
links: [<0.209.0>]
dictionary: []
trap_exit: true
status: running
heap_size: 376
stack_size: 25
reductions: 192
neighbours:
neighbour:
pid: <0.209.0>
registered_name: []
initial_call: {erlang,apply,2}
current_function: {io,execute_request,2}
ancestors: []
message_queue_len: 0
links: [<0.63.0>,<0.215.0>]
trap_exit: false
status: waiting
heap_size: 1598
stack_size: 25
reductions: 5867
current_stacktrace: [{io,execute_request,2,[{file,"io.erl"},{line,579}]},
{shell,exprs,7,[{file,"shell.erl"},{line,693}]},
{shell,eval_exprs,7,[{file,"shell.erl"},{line,642}]},
{shell,eval_loop,3,[{file,"shell.erl"},{line,627}]}]
** exception exit: badarg
in function apply/3
called as apply({state,[0|1]},init,[[]])
in call from supervisor:init/1 (supervisor.erl, line 295)
in call from gen_server:init_it/2 (gen_server.erl, line 374)
in call from gen_server:init_it/6 (gen_server.erl, line 342)
in call from proc_lib:init_p_do_apply/3 (proc_lib.erl, line 249)
Supervisor:
-module(pl).
-behaviour(supervisor).
-export([start/0,init/1]).
-record(state,{
data=[]
}).
%% {ChildId, StartFunc, Restart, Shutdown, Type, Modules}
start()->
supervisor:start_link({local,?MODULE},#state{data=[0|1]},[]).
init(State=#state{data=D})->
InitialChild={fchild,{serv,start_link,[-1]},temporary,3000,brutal_kill,worker},
MaxRestart=2,
MaxTime=600,
Strategy={one_for_one,MaxRestart,MaxTime},
{ok,{Strategy,[
InitialChild
]}}.
Worker:
-module(serv).
-behaviour(gen_server).
-compile(export_all).
-define(A,300).
-record(state,{
values=[],
id
}).
call(Pid,Message)->
gen_server:call(Pid,Message).
cast(Pid,Message)->
gen_server:cast(Pid,Message).
start_link(Id)->
{ok,Pid}=gen_server:start_link({local,xx},?MODULE,[Id],[]),
Pid.
stop(Ref)->
gen_server:stop(Ref).
init(Id)->
{ok,#state{values=[],id=Id}}.
handle_call(state,From,State=#state{values=V})->
Reply={reply,State,State},
Reply;
I am just trying to start a supervisor with only one child that gets a parameter in its init method. What is wrong in this code?

Answer 1

The second argument of start_link with 3 arguments is supposed to be the module name; it should be
start()->
supervisor:start_link({local,?MODULE}, ?MODULE, [#state{data=[0|1]}]).