Make Unauthorized Redirect patch autoloadable

app/decorators/controllers/alchemy/solidus/spree_admin_base_controller_decorator.rb

@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+module Alchemy
+  module Solidus
+    module SpreeAdminBaseControllerDecorator
+      def self.prepended(base)
+        if Alchemy.user_class_name == "::Alchemy::User"
+          base.unauthorized_redirect = -> do
+            if spree_current_user
+              flash[:error] = I18n.t('spree.authorization_failure')
+              redirect_to spree.root_path
+            else
+              store_location
+              redirect_to Alchemy.login_path
+            end
+          end
+        end
+      end
+
+      if defined?(::Spree::Admin::BaseController)
+        ::Spree::Admin::BaseController.prepend self
+      end
+    end
+  end
+end

lib/alchemy/solidus/engine.rb

@@ -25,10 +25,6 @@ class Engine < ::Rails::Engine
         Alchemy.register_ability ::Spree::Ability
         ::Spree::Ability.register_ability ::Alchemy::Permissions
 
-        if Alchemy.user_class_name == "::Alchemy::User"
-          require "alchemy/solidus/spree_admin_unauthorized_redirect"
-        end
-
         if SolidusSupport.frontend_available?
           # Allows to render Alchemy content within Solidus' controller views