Add deprecator to the application's deprecators

lib/devise/rails.rb

@@ -17,6 +17,10 @@ class Engine < ::Rails::Engine
       app.reload_routes! if Devise.reload_routes
     end
 
+    initializer "devise.deprecator" do |app|
+      app.deprecators[:devise] = Devise.deprecator if app.respond_to?(:deprecators)
+    end
+
     initializer "devise.url_helpers" do
       Devise.include_helpers(Devise::Controllers)
     end

test/rails_test.rb

@@ -8,4 +8,10 @@ class RailsTest < ActiveSupport::TestCase
     assert_equal :load_config_initializers, initializer.after
     assert_equal :build_middleware_stack, initializer.before
   end
+
+  if Rails.gem_version > Gem::Version.new("7.1")
+    test 'deprecator is added to application deprecators' do
+      assert_not_nil Rails.application.deprecators[:devise]
+    end
+  end
 end