Reuse RubyGems' compact index client in Bundler

Manifest.txt

@@ -53,11 +53,6 @@ lib/bundler/cli/pristine.rb
 lib/bundler/cli/remove.rb
 lib/bundler/cli/show.rb
 lib/bundler/cli/update.rb
-lib/bundler/compact_index_client.rb
-lib/bundler/compact_index_client/cache.rb
-lib/bundler/compact_index_client/cache_file.rb
-lib/bundler/compact_index_client/parser.rb
-lib/bundler/compact_index_client/updater.rb
 lib/bundler/constants.rb
 lib/bundler/current_ruby.rb
 lib/bundler/definition.rb

bundler.gemspec

@@ -36,13 +36,15 @@ Gem::Specification.new do |s|
 
   s.files = Dir.glob("lib/bundler{.rb,/**/*}", File::FNM_DOTMATCH).reject {|f| File.directory?(f) }
 
-  # Bundler reuses RubyGems' vendored URI, SecureRandom and PubGrub and its
-  # pure-Ruby YAML serializer. Ship a copy under lib/rubygems so Bundler stays
-  # self-contained on RubyGems versions that predate them.
+  # Bundler reuses RubyGems' vendored URI, SecureRandom and PubGrub, its
+  # pure-Ruby YAML serializer and its compact index client. Ship a copy under
+  # lib/rubygems so Bundler stays self-contained on RubyGems versions that
+  # predate them.
   s.files += Dir.glob("lib/rubygems/vendor/uri/**/*", File::FNM_DOTMATCH).reject {|f| File.directory?(f) }
   s.files += Dir.glob("lib/rubygems/vendor/securerandom/**/*", File::FNM_DOTMATCH).reject {|f| File.directory?(f) }
   s.files += Dir.glob("lib/rubygems/vendor/pub_grub/**/*", File::FNM_DOTMATCH).reject {|f| File.directory?(f) }
   s.files += Dir.glob("lib/rubygems/yaml_serializer.rb")
+  s.files += Dir.glob("lib/rubygems/compact_index_client{.rb,/**/*}", File::FNM_DOTMATCH).reject {|f| File.directory?(f) }
 
   # include the gemspec itself because warbler breaks w/o it
   s.files += %w[bundler.gemspec]

lib/bundler.rb

@@ -41,7 +41,6 @@ module Bundler
   autoload :Checksum,               File.expand_path("bundler/checksum", __dir__)
   autoload :CLI,                    File.expand_path("bundler/cli", __dir__)
   autoload :CIDetector,             File.expand_path("bundler/ci_detector", __dir__)
-  autoload :CompactIndexClient,     File.expand_path("bundler/compact_index_client", __dir__)
   autoload :Definition,             File.expand_path("bundler/definition", __dir__)
   autoload :Dependency,             File.expand_path("bundler/dependency", __dir__)
   autoload :Deprecate,              File.expand_path("bundler/deprecate", __dir__)

lib/bundler/cli.rb

@@ -785,9 +785,13 @@ def warn_on_outdated_bundler
       return unless SharedHelpers.md5_available?
 
       require_relative "vendored_uri"
+      require "rubygems/compact_index_client"
+      if Gem::CompactIndexClient.respond_to?(:filesystem_access=)
+        Gem::CompactIndexClient.filesystem_access = SharedHelpers.method(:filesystem_access)
+      end
       remote = Source::Rubygems::Remote.new(Gem::URI("https://rubygems.org"))
       cache_path = Bundler.user_cache.join("compact_index", remote.cache_slug)
-      latest = Bundler::CompactIndexClient.new(cache_path).latest_version("bundler")
+      latest = Gem::CompactIndexClient.new(cache_path).latest_version("bundler")
       return unless latest
 
       current = Gem::Version.new(VERSION)