Question

Short copy from here:

exit(Pid, Reason) -> true

Types:

Pid = pid()
Reason = term()

Sends an exit signal with exit reason Reason to the process Pid.

The following behavior apply if Reason is any term except normal or kill:

If Pid is not trapping exits, Pid itself will exit with exit reason Reason. If Pid is trapping exits, the exit signal is transformed into a message {'EXIT', From, Reason} and delivered to the message queue of Pid. From is the pid of the process which sent the exit signal. See also process_flag/2.

If Reason is the atom normal, Pid will not exit. If it is trapping exits, the exit signal is transformed into a message {'EXIT', From, normal} and delivered to its message queue.

If Reason is the atom kill, that is if exit(Pid, kill) is called, an untrappable exit signal is sent to Pid which will unconditionally exit with exit reason killed.

I am playing around with the exit/2 function and its behavior when self() is used as a Pid and normal as a Reason.

Erlang R15B03 (erts-5.9.3) [source] [64-bit] [smp:8:8] [async-threads:0] [hipe] [kernel-poll:false]

Eshell V5.9.3  (abort with ^G)
1> self().
<0.32.0>
2> exit(self(), normal).
** exception exit: normal
3> self().
<0.35.0>

Shouldn’t it be the case that only a ‘normal’ exit message is sent to the shell process, so there is no reason to exit?

Similarly:

4> spawn(fun() -> receive Pid -> Pid ! ok end end). 
<0.38.0>
5> exit(v(4), normal).
true
6> v(4) ! self().
<0.35.0>
7> flush().
Shell got ok
ok

But:

8> spawn(fun() -> exit(self(), normal), receive _ -> ok end end).         
<0.43.0>
9> is_process_alive(v(8)).
false

Answer 1

As your third example shows if any process does an exit(self(), normal) then it crashes while doing exit(AnotherPid, normal) does not crash the other process. I have verified it on an R15B. I personally think that this is a bug as sending exit signal normal to any process should not result in its crashing.