lib/rails/generators/mongoid/config/config_generator.rb in mongoid-7.0.12 vs lib/rails/generators/mongoid/config/config_generator.rb in mongoid-7.0.13

@@ -11,10 +11,17 @@
       def self.source_root
         @_mongoid_source_root ||= File.expand_path("../templates", __FILE__)
       end
 
       def app_name
-        Rails::Application.subclasses.first.parent.to_s.underscore
+        app_cls = Rails.application.class
+        parent = begin
+          # Rails 6.1+
+          app_cls.module_parent_name
+        rescue NoMethodError
+          app_cls.parent.to_s
+        end
+        parent.underscore
       end
 
       def create_config_file
         template 'mongoid.yml', File.join('config', "mongoid.yml")
       end