[erlang-bugs] Wrong EXIT status when shell startup fails

[Thomas Lange]

There is a bug that occurs when Erlang is started with shell activated
but shell cannot be launched. When this happens, erlang terminates
with exit status 0, which is incorrect behavior.

A typical example is when Erlang is started via a cron job.

How to trigger bug:

* Put both attached files in /tmp
* update crontest with path to your otp release
* compile crontest.erl
* run /tmp/crontest via cron
* cronjob should fail

Example on system running debian squeeze and otp git HEAD:
------------------------------------------
k4:/tmp$ chmod +x crontest
k4:/tmp$ /u1/otp/bin/erlc crontest.erl
k4:/tmp$ ls -l crontest*
-rwxr-xr-x 1 tle tle 681 Dec  8 14:42 crontest
-rw-r--r-- 1 tle tle 536 Dec  8 14:45 crontest.beam
-rw-r--r-- 1 tle tle  83 Dec  8 14:42 crontest.erl
k4:/tmp$ ./crontest
Erlang R15B (erts-5.9) [source] [64-bit] [smp:8:8] [async-threads:0] [hipe] [kernel-poll:false]

Eshell V5.9  (abort with ^G)
1> Erlang exit status 100. Normal result when everything is started ok.

k4:/tmp$ crontab -e
crontab: installing new crontab
k4:/tmp$ crontab -l
# m h  dom mon dow   command
47 14 * * * /tmp/crontest

Syslog:
Dec  8 14:47:02 k4 /USR/SBIN/CRON[27923]: (CRON) error (grandchild #27924 failed with exit status 1)

Cron daemon error mail contains:
----------------
Eshell V5.9  (abort with ^G)
1> *** Terminating erlang (nonode@REDACTED)
Erlang exit status 0. Should never happen!
----------------

/Thomas
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