Load rubygems plugins from RUBYLIB during bundle install and bundle update

bundler/lib/bundler/installer.rb

@@ -244,6 +244,7 @@ def load_plugins
         end
       end.flatten
       Bundler.rubygems.load_plugin_files(path_plugin_files)
+      Bundler.rubygems.load_env_plugins
     end
 
     def ensure_specs_are_compatible!

bundler/lib/bundler/rubygems_integration.rb

@@ -227,6 +227,10 @@ def load_plugin_files(files)
       Gem.load_plugin_files(files) if Gem.respond_to?(:load_plugin_files)
     end
 
+    def load_env_plugins
+      Gem.load_env_plugins if Gem.respond_to?(:load_env_plugins)
+    end
+
     def ui=(obj)
       Gem::DefaultUserInteraction.ui = obj
     end

bundler/spec/commands/install_spec.rb

@@ -222,6 +222,18 @@
       expect(the_bundle).to include_gems "rack 1.0.0", "activesupport 2.3.5"
     end
 
+    it "loads env plugins" do
+      plugin_msg = "hello from an env plugin!"
+      create_file "plugins/rubygems_plugin.rb", "puts '#{plugin_msg}'"
+      rubylib = ENV["RUBYLIB"].to_s.split(File::PATH_SEPARATOR).unshift(bundled_app("plugins").to_s).join(File::PATH_SEPARATOR)
+      install_gemfile <<-G, :env => { "RUBYLIB" => rubylib }
+        source "#{file_uri_for(gem_repo1)}"
+        gem "rack"
+      G
+
+      expect(last_command.stdboth).to include(plugin_msg)
+    end
+
     describe "with a gem that installs multiple platforms" do
       it "installs gems for the local platform as first choice" do
         skip "version is 1.0, not 1.0.0" if Gem.win_platform?