Rails accepts_nested_attributes_for child doesn't have parent set when validating

Question

I\'m trying to access my parent model in my child model when validating. I found something about an inverse property on the has_one, but my Rails 2.3.5 doesn\'t recognize it, s

Answer 1

I had basically the same problem with Rails 3.2. As suggested in the question, adding the inverse_of option to the parent's association fixed it for me.

Applied to your example:

class Parent < AR
  has_one :child, inverse_of: :parent
  accepts_nested_attributes_for :child
end

class Child < AR
  belongs_to :parent, inverse_of: :child
  validates_presence_of :name, :if => :some_method

  def some_method
    return self.parent.some_condition   # => undefined method `some_condition' for nil:NilClass
  end
end