--- /dev/null
+class SetterTrap < ActiveSupport::BasicObject
+ class << self
+ def rollback_sets(obj)
+ returning yield(setter_trap = new(obj)) do
+ setter_trap.rollback_sets
+ end
+ end
+ end
+
+ def initialize(obj)
+ @cache = {}
+ @obj = obj
+ end
+
+ def respond_to?(method)
+ @obj.respond_to?(method)
+ end
+
+ def method_missing(method, *args, &proc)
+ @cache[method] ||= @obj.send($`) if method.to_s =~ /=$/
+ @obj.send method, *args, &proc
+ end
+
+ def rollback_sets
+ @cache.each { |k, v| @obj.send k, v }
+ end
+end