JRuby is an alternative Ruby implementation with fast growing user base due to its great performance in parallel tasks. Although JRuby 1.6.7 is already in Fedora, this feature brings in new major version and better Fedora integration.
- Name: Bohuslav Kabrda
- Email: <firstname.lastname@example.org>
- Targeted release: Fedora 19
- Last updated: 2012-12-3
- Percentage of completion: 5%
Transition to JRuby 1.7.1 will consist of 3 basic steps:
- Updating packages
- Most of the packages that JRuby depends on are in Fedora just because of JRuby, so they can be safely updated.
- Some dependencies are shared with other packages, so they will have to be discussed with their owners (see #Scope).
- Integration with Fedora
- Normally, each Ruby implementations ships with its own copy of RubyGems library. This is wrong because a) it's bundling, b) there is no reason why multiple Ruby implementations wouldn't be able to share one RubyGems library. There used to be some differencies in JRuby's copy of RubyGems, but the JRuby upstream has been very cooperative and managed to get them all merged into upstream RubyGems.
- The integration will require changing Fedora's operating_system.rb (place for distro-specific defaults for RubyGems). This change will result into all Gems with binary extensions having to be recompiled, as the binary extension placement will change. See  for current operating_system.rb look and its changes from F18.
- TODO: /usr/bin/ruby stub
- Changes in packaging
- This feature will require some additions to Ruby Packaging Guidelines, the draft can be seen at TODO: pg_draft.
- An example of RubyGem packaged with both C and Java extension can be seen at .
Benefit to Fedora
JRuby is starting to get very popular among Rubyists, mainly because of its excelent performance in tasks using concurrency (leveraging power of JVM). Because of this, JRuby is mainly used for running web (mostly Ruby on Rails) applications under great stress. Having up-to-date and sanely packaged JRuby is a must for Ruby development and deployment platform.
The changes only affect Ruby packages in Fedora. Few updated Java packages (jansi, jcodings, jline2, snakeyaml; also some jnr-* dependencies of gradle) may also affect some dependent Java packages - this will have to be discussed with their owners.
How To Test
1) There is a testing repo at http://bkabrda.fedorapeople.org/jruby/jruby.repo, which can be used to test. Do not install this on your system, due to the changes mentioned above, it would break your standard Ruby installation. This repo is meant to be tested in fedora-19-x86_64 mock chroot, where it can do no harm.
2) The repo packages do not contain all the integration features mentioned above, but provide a functional and usable JRuby installation.
JRuby will be up-to-date, usable and will be able to use Fedora's RPM-packaged RubyGems.
As mentioned, few Java packages, that are dependencies of some other packages, will have to be updated (see #Scope). Also, all the RubyGems packages with binary extensions will have to be rebuilt:
Reverting to the previous behaviour will always be doable very easily, no harm will be done.
- Discussions on Fedora's ruby-sig mailing list for last few months (http://lists.fedoraproject.org/pipermail/ruby-sig/).
- Upstream release notes at http://jruby.org/2012/10/22/jruby-1-7-0.html