Don't work when we assign parent model to children.

[rjurado01]

Hi, I have the next problem:

class Library
  include Mongoid::Document

  field :name
  field :city
  field :book_count
  has_many :books
end

class Book
  include Mongoid::Document
  include Mongoid::MagicCounterCache

  field :first
  field :last

  belongs_to    :library
  counter_cache :library
end

> library = Library.create
 => #<Library _id: 53271d5a7cf9782c8b000005, name: nil, city: nil, book_count: nil> 
> book = Book.create
 => #<Book _id: 53271d6d7cf9782c8b000006, first: nil, last: nil, library_id: nil>

> book.library = library
 => #<Library _id: 53271d5a7cf9782c8b000005, name: nil, city: nil, book_count: nil>
> book.save
 => true
> library.reload.book_count
 => nil

How you can see, the library book_count don't be updated when we assign the library to book. This is a bug ?

Thanks.

[jah2488]

Have you tried creating the book with this syntax?

library = Library.create
library.books.create
library.book_count
#=> 1

The gem updates the counter when associated objects are created or destroyed, but not when they are associated. So this isn't entirely a bug, but I can see why this would be unexpected.

In the end. Its not a running count that is dynamically maintained, but instead a static number that is updated in the create lifecycle.

[rjurado01]

Ok, thanks for the clarification, but I need that it works with associations.

[jah2488]

@drinor I'm glad that helped and thanks for opening this issue. It showed me that the readme isn't as helpful as it could be.