1 files changed, 71 insertions, 0 deletions
diff --git a/activesupport/lib/active_support/dependencies/zeitwerk_integration.rb b/activesupport/lib/active_support/dependencies/zeitwerk_integration.rb
new file mode 100644
index 0000000000..8b2e1b5391
--- /dev/null
+++ b/activesupport/lib/active_support/dependencies/zeitwerk_integration.rb
@@ -0,0 +1,71 @@
+module ActiveSupport
+  module Dependencies
+    module ZeitwerkIntegration # :nodoc: all
+      module Decorations
+        def clear
+          Dependencies.unload_interlock do
+            Rails.autoloader.reload
+          end
+        end
+
+        def constantize(cpath)
+          Inflector.constantize(cpath)
+        end
+
+        def safe_constantize(cpath)
+          Inflector.safe_constantize(cpath)
+        end
+
+        def autoloaded_constants
+          Rails.autoloaders.flat_map do |autoloader|
+            autoloader.loaded.to_a
+          end
+        end
+
+        def autoloaded?(object)
+          cpath = object.is_a?(Module) ? object.name : object.to_s
+          Rails.autoloaders.any? { |autoloader| autoloader.loaded?(cpath) }
+        end
+      end
+
+      class << self
+        def take_over
+          setup_autoloaders
+          freeze_autoload_paths
+          decorate_dependencies
+        end
+
+        private
+
+          def setup_autoloaders
+            Dependencies.autoload_paths.each do |autoload_path|
+              if File.directory?(autoload_path)
+                if autoload_once?(autoload_path)
+                  Rails.once_autoloader.push_dir(autoload_path)
+                else
+                  Rails.autoloader.push_dir(autoload_path)
+                end
+              end
+            end
+
+            Rails.autoloaders.each(&:setup)
+          end
+
+          def autoload_once?(autoload_path)
+            Dependencies.autoload_once_paths.include?(autoload_path) ||
+            Gem.path.any? { |gem_path| autoload_path.to_s.start_with?(gem_path) }
+          end
+
+          def freeze_autoload_paths
+            Dependencies.autoload_paths.freeze
+            Dependencies.autoload_once_paths.freeze
+          end
+
+          def decorate_dependencies
+            Dependencies.singleton_class.prepend(Decorations)
+            Object.class_eval { alias_method :require_dependency, :require }
+          end
+      end
+    end
+  end
+end