Fix compatible_language_from in the http_accept_language plugin to

correctly follow the RFC 2616 language selection algorithm and then
revert to the previous way of selecting languages.

app/controllers/application_controller.rb

@@ -110,9 +110,8 @@ class ApplicationController < ActionController::Base
       end
     end
 
-    I18n.locale = request.preferred_language_from(I18n.available_locales) ||
-                  request.compatible_language_from(I18n.available_locales)
-    logger.info("Select #{I18n.locale} matching #{request.user_preferred_languages.join(',')} against #{I18n.available_locales.join(',')}")
+    I18n.locale = request.compatible_language_from(I18n.available_locales)
+
     response.headers['Content-Language'] = I18n.locale.to_s
   end
 

vendor/plugins/http_accept_language/lib/http_accept_language.rb

@@ -48,9 +48,8 @@ module HttpAcceptLanguage
   #
   def compatible_language_from(array)
     user_preferred_languages.map do |x|
-      x = x.to_s.split("-")[0]
       array.find do |y|
-        y.to_s.split("-")[0] == x
+        y.to_s =~ /^#{x.to_s}(-|$)/
       end
     end.compact.first
   end