Raising SIGTERM SignalException returns wrong process exit code

[perlun]

(This was originally spotted in puma/puma#1558, thanks @dekellum for great help there.)

With JRuby 9.1.16.0 on Java 8 (on latest macOS), I get this:

$ jruby -e 'raise SignalException, "SIGTERM"' ; echo $?
SignalException: SIGTERM
  <main> at -e:1
1

Same with JRuby 1.7 actually:

$ rvm use jruby-1.7.27
[09:59:19] plundberg@ecvaawplun6:~/git/tmp (master)
$ jruby -e 'raise SignalException, "SIGTERM"' ; echo $?
SignalException: SIGTERM
  (root) at -e:1
1

However, with MRI 2.5.1 I get this:

$ ruby -e 'raise SignalException, "SIGTERM"' ; echo $?
Terminated: 15
143

...which is indeed the correct value for a SIGTERM-triggered exit of a process.

---

As inspired by #5049, I tried another approach also which worked slightly differently:

$ rvm use 2.5.1
Using /Users/plundberg/.rvm/gems/ruby-2.5.1
$ ruby -e "Process.kill('TERM', Process.pid)" ; echo $?
Terminated: 15
143

Here be the surprise: JRuby behaves differently, and even differently than the raise SignalException, "SIGTERM" scenario.

$ rvm use jruby
Using /Users/plundberg/.rvm/gems/jruby-9.1.16.0
$ ruby -e "Process.kill('TERM', Process.pid)" ; echo $?
0

Exit code 0 is not entirely correct, but it's at least much better than exit code 1 which indicates failure. 😄

Inspired by this Oracle article linked to from the JRuby wiki, I tested with the -Xrs parameter:

$ rvm use jruby
Using /Users/plundberg/.rvm/gems/jruby-9.1.16.0
$ export JAVA_OPTS=-Xrs
$ ruby -e "Process.kill('TERM', Process.pid)" ; echo $?
Terminated: 15
143
$ ruby -e 'raise SignalException, "SIGTERM"' ; echo $?
SignalException: SIGTERM
  <main> at -e:1
1

So that makes the Process.kill approach work just like MRI, which is good (so we have a decent enough workaround for that.) However, the raise SignalException, 'SIGTERM' still gives the seemingly incorrect exit code.

Is this by design or is it a bug?

[headius]

This is most likely a bug. I believe we are only looking for MainExitException to provide an error code, when we should also be checking for signal exceptions that get reported in return code.

[headius]

Ok, I pushed a simple fix for this to master. It should be producing the right return codes for SignalException now.

@perlun I don't think there's a spec for this. Can you add one?

[headius]

Fixed for 9.2.

[perlun]

@headius Thank you for that! In return, I added the spec that you suggested: ruby/spec#596

(It works on MRI but fails on jruby 9.1.16.0. Haven't tested with jruby master, but running rvm install jruby-head now so will check once it's done.)

[perlun]

I tested now with jruby-head. Unfortunately, there still seems to be some issues:

$ ../mspec/bin/mspec /Volumes/git/3rd-party/spec/core/process/status/exitstatus_spec.rb
$ ruby /Volumes/git/3rd-party/mspec/bin/mspec-run /Volumes/git/3rd-party/spec/core/process/status/exitstatus_spec.rb
jruby 9.2.0.0-SNAPSHOT (2.5.0) 2018-04-12 34bec6e Java HotSpot(TM) 64-Bit Server VM 25.152-b16 on 1.8.0_152-b16 +jit [darwin-x86_64]

1)
Process::Status#exitstatus for a child that raised SignalException returns nil FAILED
Expected 143
 to equal nil

/Volumes/git/3rd-party/spec/core/process/status/exitstatus_spec.rb:21:in `block in (root)'
org/jruby/RubyBasicObject.java:2596:in `instance_eval'
org/jruby/RubyEnumerable.java:1737:in `all?'
org/jruby/RubyArray.java:1778:in `each'
org/jruby/RubyArray.java:1778:in `each'
/Volumes/git/3rd-party/spec/core/process/status/exitstatus_spec.rb:3:in `<main>'
org/jruby/RubyKernel.java:990:in `load'
org/jruby/RubyBasicObject.java:2596:in `instance_eval'
org/jruby/RubyArray.java:1778:in `each'
[/ | ==================100%================== | 00:00:00]      1F      0E

Finished in 5.506023 seconds

1 file, 2 examples, 2 expectations, 1 failure, 0 errors, 0 tagged
$ ../mspec/bin/mspec /Volumes/git/3rd-party/spec/core/process/status/termsig_spec.rb
$ ruby /Volumes/git/3rd-party/mspec/bin/mspec-run /Volumes/git/3rd-party/spec/core/process/status/termsig_spec.rb
jruby 9.2.0.0-SNAPSHOT (2.5.0) 2018-04-12 34bec6e Java HotSpot(TM) 64-Bit Server VM 25.152-b16 on 1.8.0_152-b16 +jit [darwin-x86_64]

1)
Process::Status#termsig for a child that raised SignalException returns the signal FAILED
Expected nil
 to equal 15

/Volumes/git/3rd-party/spec/core/process/status/termsig_spec.rb:23:in `block in (root)'
org/jruby/RubyBasicObject.java:2596:in `instance_eval'
org/jruby/RubyEnumerable.java:1737:in `all?'
org/jruby/RubyArray.java:1778:in `each'
org/jruby/RubyArray.java:1778:in `each'
/Volumes/git/3rd-party/spec/core/process/status/termsig_spec.rb:3:in `<main>'
org/jruby/RubyKernel.java:990:in `load'
org/jruby/RubyBasicObject.java:2596:in `instance_eval'
org/jruby/RubyArray.java:1778:in `each'
[- | ==================100%================== | 00:00:00]      1F      0E

Finished in 5.705038 seconds

1 file, 3 examples, 3 expectations, 1 failure, 0 errors, 0 tagged

These issues are closely related, but they probably are in the Process::Status class. Do you want me to file another issue about it or can we reopen this one?