class ActiveRecord::StaleObjectError

documentation.
Read more about optimistic locking in ActiveRecord::Locking module
the page before the other.
instantiation, for example, when two users edit the same wiki page and one starts editing and saves
Raised on attempt to save stale record. Record is stale when it’s being saved in another query after

def initialize(record = nil, attempted_action = nil) 

def initialize(record = nil, attempted_action = nil)
  if record && attempted_action
    @record = record
    @attempted_action = attempted_action
    super("Attempted to #{attempted_action} a stale object: #{record.class.name}.")
  else
    super("Stale object error.")
  end
end