Splatted arguments sometimes aren't passed to methods properly.

[chanks]

This is a weird one. The JIT, maybe?

# test.rb
$index = 0

def m(input = 5)
  if input == 5
    puts $index += 1
  else
    raise "Input: #{input.inspect}"
  end
end

value = nil

loop do
  m(*value)
end

Then:

ruby test.rb
...
43304
43305
43306
43307
43308
43309
An exception occurred running test.rb:

    Input: nil (RuntimeError)

Backtrace:

                          Object#m at test.rb:7
          { } in Object#__script__ at test.rb:14
               Kernel(Object)#loop at kernel/common/kernel.rb:460
                 Object#__script__ at test.rb:13
  Rubinius::CodeLoader#load_script at kernel/delta/code_loader.rb:66
  Rubinius::CodeLoader.load_script at kernel/delta/code_loader.rb:201
           Rubinius::Loader#script at kernel/loader.rb:649
             Rubinius::Loader#main at kernel/loader.rb:831

ruby -v
rubinius 2.2.3 (2.1.0 4792e746 2013-12-29 JI) [x86_64-linux-gnu]

[chanks]

Just upgraded to 2.2.4, same thing happens.

[yorickpeterse]

This indeed seems to be the JIT. Running the script with the JIT disabled (rbx -Xint script.rb) does not seem to produce the same error.

[dbussink]

Further simplification:

loop do
  value = nil
  ary = *value
  if ary == [nil]
    raise "error"
  end
end

[dbussink]

So I've found the issue and it's fairly straightforward. I'd like to offer up pairing on this with someone if they're interested in finding out more about how some of the bits in the JIT work and how this case can be fixed.

[yorickpeterse]

I'd be up for that, and I'm pretty sure others might be too (e.g. @razielgn might be interested as well).

[ileitch]

Maybe record a short video like you did once before? I enjoyed watching.

[dbussink]

@ileitch One thing I thought about is doing a hangout and recording that for posterity so people can view that.

[razielgn]

An hangout sounds very good to me. We could join live to ask questions if we manage to find a common time/date. :)

[dbussink]

I can do a hangout Tuesday evening CET timezone, how does that sound?

[yorickpeterse]

Fine by me!

[razielgn]

I can make it from 6pm to 8pm.

[dbussink]

How about Tuesday 19:00 CET then? We should get through it pretty quick I think.

[razielgn]

Yeah, sounds good. Thank you. :)

[yorickpeterse]

19:00 is a bit too early for me as that's around the time I hop in a train. I'm perfectly fine with watching the recording though.