Bogus exit code 127 from a child process

[Takashi Yano]

On Sun, 17 Mar 2024 14:10:55 +0100
Dimitry Andric wrote:
> On 17 Mar 2024, at 13:50, Dimitry Andric <dimitry@unified-streaming.com> wrote:
> > 
> > On 17 Mar 2024, at 13:35, Takashi Yano via Cygwin <cygwin@cygwin.com> wrote:
> > ...
> >> 
> >> I also test your test case:
> >> while bash -c 'true & true & wait -n || { echo 1: $?; exit 1; } && wait -n || { echo 2: $?; exit 1; }'; do echo $((i++)); done
> >> in Linux (Debian 12.5), and the issue reproduced!
> > 
> > Yeah, same here with bash 5.1.16(1)-release on Ubuntu 22.04. It errors out with 127 after ~50-200 loops.
> 
> Having built bash master (bash-5.2-27-gf3b6bd19) here, it consistently gives 127 in this area:
> 
> https://git.savannah.gnu.org/cgit/bash.git/tree/builtins/wait.def#n227
> 
>    211  #if defined (JOB_CONTROL)
>    212    if (nflag)
>    213      {
>    214        if (list)
>    215          {
>    216            opt = set_waitlist (list);
>    217            if (opt == 0)
>    218              WAIT_RETURN (127);
>    219            wflags |= JWAIT_WAITING;
>    220          }
>    221
>    222        status = wait_for_any_job (wflags, &pstat);
>    223        if (vname && status >= 0)
>    224          builtin_bind_var_to_int (vname, pstat.pid, bindflags);
>    225
>    226        if (status < 0)
> => 227          status = 127;
>    228        if (list)
>    229          unset_waitlist ();
>    230        WAIT_RETURN (status);
>    231      }
>    232  #endif
> 
> So for some reason, wait_for_any_job() returns a negative value in this particular situation.

Line 218 looks also suspicious.

-- 
Takashi Yano <takashi.yano@nifty.ne.jp>