[rubygems/rubygems] Track HEAD changes for old PR proposal

https://github.com/rubygems/rubygems/commit/e3d180620c

lib/bundler.rb

@@ -574,6 +574,7 @@ module Bundler
         raise Gem::InvalidSpecificationException, error_message
       end.flatten
       Bundler.rubygems.load_plugin_files(path_plugin_files)
+      Bundler.rubygems.load_env_plugins
       @load_plugins_ran = true
     end
 

lib/bundler/rubygems_integration.rb

@@ -156,6 +156,18 @@ module Bundler
       loaded_gem_paths.flatten
     end
 
+    def load_plugins
+      Gem.load_plugins
+    end
+
+    def load_plugin_files(plugin_files)
+      Gem.load_plugin_files(plugin_files)
+    end
+
+    def load_env_plugins
+      Gem.load_env_plugins
+    end
+
     def ui=(obj)
       Gem::DefaultUserInteraction.ui = obj
     end

spec/bundler/plugins/hook_spec.rb

@@ -200,8 +200,8 @@ RSpec.describe "hook plugins" do
       gem "rack"
     G
 
-    ruby! <<-RUBY
-      require "#{lib}/bundler"
+    ruby <<-RUBY
+      require "bundler"
       Bundler.require
     RUBY
   end