has_many :dependent => :destroy and association callbacks

Robert_Pankowecki · December 28, 2010, 4:27pm

Today I noticed that calling object.collection.destroy_all leads to calling association callbacks like ex. :before_remove but object.destroy does not call those callbacks when configured with :dependent => :destroy option.

You can find that hbtm uses collection.clear which under the hoods calls collection.destroy_all however has_many uses the metod configure_dependency_for_has_many to setup the hooks (

github.com

rails/rails/blob/main/activerecord/lib/active_record/associations.rb#L1000


      
          # returning all the associated objects:
          #
          #   class Picture < ActiveRecord::Base
          #     has_many :most_recent_comments, -> { order('id DESC').limit(10) }, class_name: 'Comment'
          #   end
          #
          #   Picture.includes(:most_recent_comments).first.most_recent_comments # => returns all associated comments.
          #
          # Eager loading is supported with polymorphic associations.
          #
          #   class Address < ActiveRecord::Base
          #     belongs_to :addressable, polymorphic: true
          #   end
          #
          # A call that tries to eager load the addressable model
          #
          #   Address.includes(:addressable)
          #
          # This will execute one query to load the addresses and load the addressables with one
          # query per addressable type.
          # For example, if all the addressables are either of class Person or Company, then a total

) which iterates over the collection and sends destroy() to every object (rails/activerecord/lib at main · rails/rails · GitHub active_record/associations.rb#L1625)

I think it could be a good thing to make has_many behave more like hbtm and just use collection.destroy_all . This way also the association callbacks would get called. Also probably the optimization fix with counter_method could probably be move to the call in destroy_all.

Jon_Leighton · December 30, 2010, 11:42am

Hiya,

I am working on refactoring this section of the code at the moment actually, and this problem will be fixed when I'm done.

Cheers

Robert_Pankowecki · December 30, 2010, 11:56am

I'm glad to hear it.

Robert Pankowecki

Topic		Replies	Views
Improve(?) has_many :dependent => :destroy before destroy callback rubyonrails-talk	0	171	February 3, 2009
Why doesn't collection=objects on has_many :through trigger destroy callbacks on the join model? rubyonrails-talk	5	433	December 18, 2015
:dependent => :delete_all not working rubyonrails-talk	3	113	April 18, 2007
relationships and delete rubyonrails-talk	0	86	October 3, 2006
Remove instance of model and its associations rubyonrails-talk	5	145	July 5, 2008

has_many :dependent => :destroy and association callbacks

Related topics

More Resources