Question

I have two methods which are used to determine whether to apply a class to the page to show that something is overdue and needs attention.

I’m getting an error when a brand new user registers:

undefined method `last_contact_done_date=' for #<User:0x6183708>

The line that it’s referencing the error to is this:

2:   <div class="span3 <%= "overdue" if (signed_in? && contact_overdue?(current_user.id)) %>">

The contact_overdue? method is this (in a home page helper)

def contact_overdue?(user_id)
  @user = User.find_by_id(user_id)
  return true if (Date.today - (@user.last_contact_done_date ||= Date.tomorrow)) > 6
end

and the last_contact_done_date method is this in the User model

  def last_contact_done_date
      self.contacts.order('date_done DESC').first.try(:date_done)
  end

I thought that if I was using the ||= operator in the contact_overdue? method, then I would return -1 if the last_contact_done_date is nil. But it appears that’s not working. What operator should I be using in last_contact_done_date or how should I change the contact_overdue? method so that if there are no contacts, then false is returned from the contact_overdue? method?

Answer 1

To return the default value of -1 when there is no last contact done date, use

@user.last_contact_done_date || -1

(it is unreasonable to expect Date.tomorrow to return -1 😉 )

||= is an assignment operator; a ||= b is equivalent to a = a || b; and if a is an attribute (i.e. is prefixed with a dot and an instance, c.a), assignment to it will call the method a=. Thus, your code necessitates that you have a method named last_contact_done_date= to handle the assignment, which you don’t.