Dne 29.11.2012 09:43, Bohuslav Kabrda napsal(a):
as F19 is slowly approaching, I thought it'd be great to finalize the stuff about
JRuby/Ruby integration with Fedora. Here are the changes and additions around JRuby, that
* Global changes
- As already mentioned in , change the default operating_system.rb, the current
version is at . The question here is, whether to use versioned directories for
extensions. In my opinion we should do that, as users installing Gems under /usr/local may
want to install them for different version of JRuby (Rubinius in the future). This change
will cost us nothing and will make sure that we can utilize this in the future.
We do not support more version of MRI nor JRuby nor we support anything
else. The only exception would be if the interpreter support
compatibility modes for different Ruby versions => I am against
versioning in /usr/local unless explicitly needed.
- Add additional macros to macros.rubygems, see  (if the macros
names seem confusing, see the section about packaging gems for JRuby below).
The jruby/java suffixes are confusing. We should go only with one of
them. I am inclined to -jruby (not sure why -java was chosen by RubyGems
or as a platform)
- Two connected problems: 1) RPM generates auto provides from
shebangs, e.g. #!/usr/bin/ruby will automatically require ruby package; 2) How to run
programs with #!/usr/bin/ruby shebangs under JRuby?
-- We've discussed this situation with Vit and we came up with an interesting
proposal for solution. There will be a package (probably with just one file)
/usr/bin/ruby. This will be a bash script, that will take all given parameters and pass
them to the proper interpreter (/usr/bin/ruby-mri or /usr/bin/jruby). There will be a
default choice (MRI, I guess) and the switching will be done by passing _jruby_ (possibly
also containing version) or _mri_ as the first parameter. If e.g. /usr/bin/ruby-mri is not
found, the script will automatically try /usr/bin/jruby and if that is not present either,
it will print out that user needs to install a Ruby runtime.
Please note that RubyGems are using similar approach already. E.g. you
can run `rake _0.8.7_` to execute your rake task using explicitly
defined version of Rake. So we would just extend this idea a bit further.
-- This way, the automatically generated requires will point to the
package containing /usr/bin/ruby and not the actual ruby package, therefore leaving it up
to user which Ruby runtime he wants to install.
-- Also, every executable file with this shebang can be run with _mri_ or _jruby_
parameter: "rspec _mri_" vs. "rspec _jruby_", the same for gem, irb
and anything that has the proper shebang.
I would be interested if anybody know about any possible showstoppers.
* Changes to packaging
- Platform independent packages mustn't R: ruby, unless there is a specific reason to
- Packages with MRI binary extensions will have to R: and BR: ruby explictly, not just
ruby(abi), as that will also be provided by JRuby.
- Packages meant only for JRuby will have to R: and BR: jruby explictly (same reason).
These will use the %gem_extdir_jruby macro.
- Packages with extensions for both Ruby and JRuby (let's consider rubygem-json,
example of converted specfile is at ):
-- MRI extension will probably stay in the core package (rubygem-json).
-- There will be a subpackage with -java suffix (because the naming scheme on
gives e.g. json-1.7.5-java). The subpackage will contain it's own
.gemspec and because all the directory/file names contain the "-java" string, it
will use the %gem_*_java macros.
-- The -java subpackage will contain the JRuby extension under %gem_extdir_java and
it's platform independent part will be a symlink to platform independent part of its
MRI counterpart (e.g. /usr/share/gems/gems/json-1.7.5-java ->
-- The disadvantage of this approach is, that the core package (rubygem-json) will be a
dependency of rubygem-json-java, therefore forcing MRI to be installed.
-- The rubygem-json-java package could be independent of rubygem-json (e.g. everything
same as above, except it will actually contain the platform independent part). This would
in fact not require MRI ruby to be installed, but I'm not sure of the consequences of
-- A big question is, how to handle provides (applies to both cases). RPM cannot say
"I'm fine with rubygem-json or rubygem-json-java", so the -json package will
probably have to Provides: rubygem(json-java) and users will have to install these
manually, if they want to use JRuby.
Taking rubygem-json as an example, I'd love to see:
rubygem-json - contains platform independent code
rubygem-json-mri - subpackage containing MRI binary extension
rubygem-json-jruby - subpackage containing JRuby extension
Unfortunately, there is probably no way how to install proper
subpackages, unless we would go with comps  for example. But I opened
ticket on RPM  requesting support for this.