Я настраиваю почтовые программы Devise по умолчанию, наследуя их в UserMailer, но это вызвало предупреждение об устаревании. Я не очень понимаю, что это говорит мне.
DEPRECATION WARNING: Initialization autoloaded the constants Devise::Mailer, ApplicationHelper, and UserMailer.
Being able to do this is deprecated. Autoloading during initialization is going
to be an error condition in future versions of Rails.
Reloading does not reboot the application, and therefore code executed during
initialization does not run again. So, if you reload Devise::Mailer, for example,
the expected changes won't be reflected in that stale Class object.
These autoloaded constants have been unloaded.
# devise.rb
...
config.mailer = UserMailer
config.parent_mailer = 'ApplicationMailer'
...
# user_mailer.rb
class UserMailer < Devise::Mailer
helper :application
include Devise::Controllers::UrlHelpers
...
end