Rails：为什么调用parent的before_save？

Question

Job has many invoices:

class Job < ActiveRecord::Base
  has_many :invoices, :autosave => true
  before_save :set_outstanding_payments
end

class Invoice < ActiveRecord::Base
  belongs_to :job
end

When invoice is updated ( @invoice.update(...) ), job's set_outstanding_payments is called.

Why?

Answer 1

I'm really astonished with this behavior since, as documentations said, autosaving is only triggered when the parent is saved.

The cause could be because having the :autosave => true declaration in your Job association with Invoice causes the child update to call save on the parent.

When the save is called on the parent, all save hooks are called. Even though, make sure you don't have any before or after update hooks in the Invoice model which messes with the parent.

For more information about the Autosave Association feature, please refer to this link:

http://api.rubyonrails.org/classes/ActiveRecord/AutosaveAssociation.html

I hope it helps somehow.