JRuby 1.7.8 (1.9) Open3 `capture3` bug

[slippycheeze]

The newest version of JRuby fixes the old issue where popen3 would not pass a status object to the block, which is awesome. Unfortunately, while this makes capture3 run, it is not quite correct:

jruby-1.7.8 :001 > require 'open3'
 => true
jruby-1.7.8 :002 > Open3.capture3('echo')
 => ["{}\n", "", #]
jruby-1.7.8 :003 > Open3.capture3('echo', :foo => :bar)
 => ["{:foo=>:bar}\n", "", #]

As you will observe, the output includes a stringified hash, which is the "options" part of handling the thing. It seems like your IO::popen3 implementation should either handle those appropriately, or you should move the "RUBY_ENGINE" part down below the "if Hash === cmd.last" part to handle (by ignoring) the options passed. :)

Another option, perhaps better, might be to go down and implement popen_run instead of popen3, which is invoked by the rest of the methods to handle the actual I/O process.

[randycoulman]

+1. I just ran into this with a gem I'm working on. In my case, I can handle the extra argument to work around it, but if I was trying to run a program that couldn't handle it, I'm not sure what I'd do.

[gucki]

+1 Just hit this bug, which just makes this method completely useless. Please fix asap. Thank you.

[flavorjones]

This bug makes capture3 and popen3 useless for most conventional use cases.

Additional example, if one is needed:

#!/usr/bin/env ruby

require 'open3'

def run_test *args
  puts "------\n- args: `#{args.inspect}`"
  begin
    o, e, s = Open3.capture3(*args)
    puts "- stdout:"
    puts o
    puts "- stderr:"
    puts e
    puts "- status: #{s.exitstatus}"
  rescue Exception => e
    puts e.inspect
  end
end

puts ::RUBY_DESCRIPTION

# from the test/mri/test_open3.rb, which passes
run_test "ruby", '-e', 'i=STDIN.read; print i+"o"; STDOUT.flush; STDERR.print i+"e"', :stdin_data=>"i"

# but you can see that additional args are being included in the executed command ...
run_test "cat", "-n", :stdin_data => "asdf\nqwer\nzxcv\n"

On MRI outputs:

ruby 2.1.2p95 (2014-05-08 revision 45877) [x86_64-linux]
------
- args: `["ruby", "-e", "i=STDIN.read; print i+\"o\"; STDOUT.flush; STDERR.print i+\"e\"", {:stdin_data=>"i"}]`
- stdout:
io
- stderr:
ie
- status: 0
------
- args: `["cat", "-n", {:stdin_data=>"asdf\nqwer\nzxcv\n"}]`
- stdout:
     1  asdf
     2  qwer
     3  zxcv
- stderr:

- status: 0

On JRuby outputs:

jruby 1.7.15 (1.9.3p392) 2014-09-03 82b5cc3 on OpenJDK 64-Bit Server VM 1.7.0_65-b32 +jit [linux-amd64]
------
- args: `["ruby", "-e", "i=STDIN.read; print i+\"o\"; STDOUT.flush; STDERR.print i+\"e\"", {:stdin_data=>"i"}]`
- stdout:
io
- stderr:
ie
- status: 0
------
- args: `["cat", "-n", {:stdin_data=>"asdf\nqwer\nzxcv\n"}]`
- stdout:

- stderr:
cat: {}: No such file or directory
- status: 1

(you'll notice that there is an additional argument of {} being passed to cat on the command line).

[nadavshatz]

+1

[mgomes]

+1 for this. This bug makes JRuby unable to run the latest mini_magick (minimagick/minimagick#254).

[retoo]

+1, painful

[headius]

Fixed for 1.7.17. I will add a test to MRI, since open3 is no longer part of RubySpec proper and we don't run the rubysl specs.

[flavorjones]

Thanks so much, @headius.

[nadavshatz]

Yay @headius !