I responded on stackoverflow, but I'll do here as well so that it is covered everywhere on the internet.
In my case I was doing something similar to what you were doing and was running into the same issue with the join table being deleted instead of destroyed. I started looking through the code and I believe the documentation is just out of date. [has_many_through_association](https://github.com/rails/rails/blob/master/activerecord/lib/active_record/associations/has_many_through_association.rb#L131) All you need to do is add the dependent: :destroy to the has_many :through relationship. class User has_many :partnerships, dependent: :destroy has_many :partners, through: :partnerships, dependent: :destroy end The pain I was dealing with was: user.partner_ids = [1,2,3] #creates the relationships user.partner_ids = [] #was deleting the records from partnerships without callbacks. The dependent: :destroy on the partners relationship fixed that. Callbacks are now being run and things are good again. Eric On Monday, December 14, 2015 at 5:43:57 PM UTC-7, spike22 wrote: > > I've asked this on on Stack Overflow but didn't receive much of a response: > > The Rails 4 documentation says this regarding destroy callbacks on the > join model for a has_many :through relationship: > > collection=objects Replaces the collections content by deleting and > adding objects as appropriate. If the :through option is true callbacks in > the join models are triggered except destroy callbacks, since deletion is > direct. > > Thankfully it's documented at least, but I want to know why on earth this > is the case? It makes more sense to trigger destroy callbacks (or have the > option to) on a :through since these types of models can have destroy > callbacks and other associations. > > In my case I had a has_and_belongs_to_many relationship on the join > tables model off to another model. The records on that second join table > would never be deleted when the associated records on the first join table > were deleted. I resorted to this which feels hacky, and I have to repeat > myself on each side of the :through relationship: > > class SchoolsTemplate < ActiveRecord::Base > > belongs_to :school > belongs_to :template > > has_and_belongs_to_many :groups > > end > > > class School < ActiveRecord::Base > > has_many :schools_templates, dependent: :destroy > has_many :templates, through: :schools_templates, before_remove: > :remove_groups_school_templates > > private > def remove_groups_school_templates(template) > schools_templates.where(template: template).first.groups.clear end > > end > > There's a validation to 'ensure' uniqueness on the join tables records > between the two foreign keys, so that's why I can call first in the > callback. > -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscr...@googlegroups.com. To post to this group, send email to rubyonrails-talk@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/rubyonrails-talk/36dc4015-38a9-47de-bc37-99c4b3eca150%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
