すごいErlang本の17.4のsimple_one_for_oneでterminal_childが本文と違う結果を返す件 ref: https://twitter.com/K0U_CHANG/status/645396516295733248

start_childのときにPidを受け取ってそれでterminate_childする場合

❯ erl
Erlang/OTP 17 [erts-6.4] [source] [64-bit] [smp:8:8] [async-threads:10] [hipe] [kernel-poll:false] [dtrace]

Eshell V6.4  (abort with ^G)
1> c(band_supervisor).
{ok,band_supervisor}
2> band_supervisor:start_link(jamband).
{ok,<0.39.0>}
3> {ok, Pid} = supervisor:start_child(band_supervisor, [djembe,good]).
Musician Wanda Ann, playing the djembe entered the room
{ok,<0.41.0>}
Wanda Ann produced sound!
...              
4> supervisor:terminate_child(band_supervisor, Pid).
The manager is mad and fired the whole band!Wanda Ann just got back to playing in the subway
ok
5> 

本文どおりに書いた場合

❯ erl
Erlang/OTP 17 [erts-6.4] [source] [64-bit] [smp:8:8] [async-threads:10] [hipe] [kernel-poll:false] [dtrace]

Eshell V6.4  (abort with ^G)
1> c(band_supervisor).
{ok,band_supervisor}
2> band_supervisor:start_link(jamband).
{ok,<0.39.0>}
3> supervisor:start_child(band_supervisor, [djembe,good]).
Musician Carlos Ann, playing the djembe entered the room
{ok,<0.41.0>}
Carlos Ann produced sound!
...
4> supervisor:terminate_child(band_supervisor, djembe).
{error,simple_one_for_one}
Carlos Ann produced sound!
5> 
BREAK: (a)bort (c)ontinue (p)roc info (i)nfo (l)oaded
       (v)ersion (k)ill (D)b-tables (d)istribution
^C