Rails 4.1 ActiveRecord::relation is no more like Array

Question

in Rails 4.0.4 this code work:

mailboxes = Mailbox.order(:mailbox)
mailboxes.keep_if do |mailbox|
  # test
end

in Rails 4.1.0 it break with

Answer 1

Its in release notes for rails 4.1

Relation no longer has mutator methods like #map! and #delete_if. Convert to an Array by calling #to_a before using these methods. (Pull Request)

Since keep_if is a mutator method, its removed from Relation