has_one，reject_if和accept_nested_attributes_for仍会触发验证

Question

I'm trying to provide a place to set a single service login for an account, yet not require that the account owner enter the service login credentials every time the rest of the record is updated.

My understanding is that the :reject_if option on accepts_nested_attributes_for is the way to have the nested hash values ignored. Yet, in Rails 4.1, I'm getting a "password can't be blank".

I've traced through the nested_attributes code and it seems to properly ignore the values, yet nothing I do to avoid the update works. I've even deleted the web_service_user_attributes hash from the params passed to update , so I'm wondering if there is something else going on.

Am I understanding :reject_if correctly for a has_one association?

Parent model code:

class Account
  has_one :web_service_user

  accepts_nested_attributes_for :web_service_user, :allow_destroy => true, :reject_if => :password_not_specified, :update_only => true

  def password_not_specified(attributes)
    attributes[:password].blank?
  end
end

Child model code:

class WebServiceUser
  devise :database_authenticatable

  belongs_to :account

  validates_uniqueness_of :username
  validates_presence_of :password, if: Proc.new{|wsu| !username.blank? }
end

Controller code:

def update
  respond_to do |format|
    if @licensee.update(account_params)
  #etc...
end

private
def account_params
  params.require(:account).permit(:name, :area_of_business, :address1, :address2, :city, :state_code, :zip, :website_url, :web_service_user_attributes => [:id, :username, :password, :_destroy])
end

Answer 1

Ok, it appears that my primary goof was trying to validate the presence of :password . I really wanted to validate the length of the password if it existed.

class WebServiceUser
  devise :database_authenticatable

  belongs_to :account

  validates_uniqueness_of :username
  validates_length_of :password, :minimum => 14, if: Proc.new { |u| !u.password.nil? }
end