method

attribute_will_change!

v4.1.8 - Show latest stable - 1 note - Class: ActiveModel::Dirty

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What's this?

attribute_will_change!(attr) private

Handle *_will_change! for method_missing.

# File activemodel/lib/active_model/dirty.rb, line 185 def attribute_will_change!(attr) return if attribute_changed?(attr) begin value = __send__(attr) value = value.duplicable? ? value.clone : value rescue TypeError, NoMethodError end changed_attributes[attr] = value end

January 26, 2011 - (>= v3.0.0)

2 thanks

Use this for validatating nested forms

When you create a nested form, and want the main object to validate all nested models, you should make all the nested models dirty or validations will not run upon them.

class Order < ActiveRecord::Base has_many :order_lines accepts_nested_attributes_for :order_lines before_validation :mark_order_lines_as_changed private def mark_order_lines_as_changed order_lines.each(&:updated_at_will_change!) end end

attribute_will_change!

Related methods

Use this for validatating nested forms