Rails: Simple-Form & Devise: mark email field of user model as required in forms automatically?

Question

I wonder why the field email is not marked as a required field in Simple-Form, as when submitting it empty there is a validation error "can't be blank".

It seems that the validation rules for the email field come from Devise, so they are available to the validation mechanism, but not to Simple-Form. Why's that?

I could simply add another validates :email, presence: true to my User model, but this seems overkill. Or I could add a required: true to the f.input :email method of Simple-Form, but this seems like overkill, too.

Here's the relevant part of my User model:

class User < ActiveRecord::Base
  # Include default devise modules. Others available are:
  # :timeoutable and :omniauthable
  devise :database_authenticatable, :registerable,
         :recoverable, :rememberable, :trackable, :validatable,
         :confirmable, :lockable, authentication_keys: [:login]

  validates :name, presence: true

Do I have something configured incorrect/incomplete?

Answer 1

From Simple Form's README:

For performance reasons, this detection is skipped on validations that make use of conditional options, such as :if and :unless.

And you can see that Devise will add validation with an :if in https://github.com/plataformatec/devise/blob/master/lib/devise/models/validatable.rb

    base.class_eval do
      validates_presence_of   :email, if: :email_required?
      validates_uniqueness_of :email, allow_blank: true, if: :email_changed?
      validates_format_of     :email, with: email_regexp, allow_blank: true, if: :email_changed?

      validates_presence_of     :password, if: :password_required?
      validates_confirmation_of :password, if: :password_required?
      validates_length_of       :password, within: password_length, allow_blank: true
    end

So you have to mark the field as required in your views.