RubyGems can't find JRuby's Java extensions defined in default_ext_dir_for paths

[strzibny]

Current gems with Java extensions adds compiled .jar in /lib, but on Fedora we implement our own operating_system.rb to tell RubyGems that the path for Java extensions should be in /usr/share/gems/jruby/.

Gem.default_ext_dir_for returns correct paths, but the paths are never added since RubyGems only checks for gemspec.extensions in

rubygems/lib/rubygems/basic_specification.rb

Line 241 in 540d1d9

return raw_require_paths if @extensions.nil? || @extensions.empty?

. This is unfortunately undefined only for Java extensions as there is no extconf.rb file, since JARs are included in .gem files. There are gems like thread_safe that provide only Java extension and therefore lack any gemspec.extensions entry in gemspec file and RubyGems treat such gems as a gems without extension.

IMHO RubyGems should have a way of detecting if Java extension is present and should try to add it to require paths.

[mkristian]

jruby can tread any ".class" or ".jar" as resource and can require them as any other ".rb" files. in case of a jar there is some "introspection" going on to find some BasicLibraryExtension.class which will be loaded.

but there are plenty of gems which just pack some jar dependencies inside the gem and requires them when needed. examples are: xerces, xalan, jackson, bouncy-castle, jline, snakeyaml, etc

the ruby code expect those jar where they are or on the $LOAD_PATH

so what makes a jruby only gem one with an extension ? how do you distinguish vendored jars from "extension" jars ?

what is the benefit of copying some jars from under lib/ to another directory ?

what do you do if the ruby code does something like

Dir[ File.expand_path( "../*.jar, __FILE__ )].each { |jar| require jar }

?

[copiousfreetime]

There has been no more traction on this ticket, going to close for now. If this is still an issue for folks, please reopen.