possible fix for https://github.com/rubygems/rubygems/issues/1420

bundler-unload.patch

diff --git a/lib/bundler-unload.rb b/lib/bundler-unload.rb
index ff86037..c433c7b 100644
--- a/lib/bundler-unload.rb
+++ b/lib/bundler-unload.rb
@@ -28,6 +28,15 @@ module Bundler
         Gem::Specification.all = specs
       end
     end
+
+    class MoreFuture
+      def plain_specs
+        Gem::Specification.stubs
+      end
+      def plain_specs=(specs)
+        Gem::Specification.all = specs
+      end
+    end
   end

   class << self