Require order appears to impact JRuby extensions [9k] #2521
Description
It appears something in our load logic is causing extensions to have some sort of load-order dependency.
Gem install the PageRankr gem, and you can have this sort of fun too:
~/projects/jruby $ jruby -e "require 'page_rankr'"
NameError: uninitialized constant Nokogiri::XERCES_VERSION
const_missing at org/jruby/RubyModule.java:2935
to_hash at /Users/headius/projects/jruby/lib/ruby/gems/shared/gems/nokogiri-1.6.6.2-java/lib/nokogiri/version.rb:73
(root) at /Users/headius/projects/jruby/lib/ruby/gems/shared/gems/nokogiri-1.6.6.2-java/lib/nokogiri/version.rb:99
(root) at /Users/headius/projects/jruby/lib/ruby/stdlib/rubygems/core_ext/kernel_require.rb:1
require at org/jruby/RubyKernel.java:954
require at /Users/headius/projects/jruby/lib/ruby/stdlib/rubygems/core_ext/kernel_require.rb:69
(root) at /Users/headius/projects/jruby/lib/ruby/gems/shared/gems/nokogiri-1.6.6.2-java/lib/nokogiri.rb:31
require at org/jruby/RubyKernel.java:954
(root) at /Users/headius/projects/jruby/lib/ruby/stdlib/rubygems/core_ext/kernel_require.rb:1
require at /Users/headius/projects/jruby/lib/ruby/stdlib/rubygems/core_ext/kernel_require.rb:121
require at org/jruby/RubyKernel.java:954
(root) at /Users/headius/projects/jruby/lib/ruby/gems/shared/gems/PageRankr-4.4.0/lib/page_rankr/tracker.rb:1
(root) at /Users/headius/projects/jruby/lib/ruby/stdlib/rubygems/core_ext/kernel_require.rb:1
require at org/jruby/RubyKernel.java:954
require at /Users/headius/projects/jruby/lib/ruby/stdlib/rubygems/core_ext/kernel_require.rb:121
(root) at /Users/headius/projects/jruby/lib/ruby/gems/shared/gems/PageRankr-4.4.0/lib/page_rankr/backlink.rb:1
require at org/jruby/RubyKernel.java:954
(root) at /Users/headius/projects/jruby/lib/ruby/stdlib/rubygems/core_ext/kernel_require.rb:1
require at /Users/headius/projects/jruby/lib/ruby/stdlib/rubygems/core_ext/kernel_require.rb:121
require at org/jruby/RubyKernel.java:954
(root) at /Users/headius/projects/jruby/lib/ruby/gems/shared/gems/PageRankr-4.4.0/lib/page_rankr/backlinks/alexa.rb:1
(root) at /Users/headius/projects/jruby/lib/ruby/stdlib/rubygems/core_ext/kernel_require.rb:1
require at org/jruby/RubyKernel.java:954
require at /Users/headius/projects/jruby/lib/ruby/stdlib/rubygems/core_ext/kernel_require.rb:121
(root) at /Users/headius/projects/jruby/lib/ruby/gems/shared/gems/PageRankr-4.4.0/lib/page_rankr/backlinks.rb:2
However, if you require nokogiri before page_rankr, it succeeds.
It could be related to load path/loaded features/extension service changes (e.g. dependency loading in RubyGems might be causing the Nokogiri ext to not load).