Delete all on has many relationship

[maletor]

My assumption is that I should be able to delete all ThreadSubscriptions when I delete an Alert, but instead an exception is raised "ActiveRecord::HasManyThroughCantAssociateThroughHasOneOrManyReflection: Cannot modify association 'Alert#thread_subscriptions' because the source reflection class 'ThreadSubscription' is associated to 'Notification' via :has_many."

If I am able to SELECT from the association what exactly is preventing me to DELETE from them?

https://gist.github.com/maletor/5259494#file-alert-rb-L23

# == Schema Information
# Schema version: 20130325215115
#
# Table name: alerts
#
#  id          :integer          not null, primary key
#  campaign_id :integer          not null
#  headline    :string(255)      not null
#  sponsor     :string(255)      not null
#  body        :text             not null
#  pi          :text             not null
#  created_at  :datetime
#  updated_at  :datetime
#
# Indexes
#
#  index_alerts_on_campaign_id  (campaign_id)
#

class Alert < ActiveRecord::Base
  include Subscribable
  has_many :notifications, as: :subject, dependent: :delete_all
  has_many :thread_subscriptions, through: :notifications, dependent: :delete_all
  validates :campaign_id, :headline, :sponsor, :body, :pi,
    presence: true

  belongs_to :campaign

  def priority
    3
  end

  def expires_at
    2.weeks.from_now
  end
end

# == Schema Information
# Schema version: 20130325215115
#
# Table name: notifications
#
#  id               :integer          not null, primary key
#  user_id :integer          not null
#  campaign_id      :integer          not null
#  subject_id       :integer          not null
#  subject_type     :string(255)      not null
#  priority         :integer          not null
#  expires_at       :datetime         not null
#  reason           :string(255)      not null
#  last_read_at     :datetime
#  unread           :boolean          default(TRUE), not null
#  created_at       :datetime
#  updated_at       :datetime
#
# Indexes
#
#  index_notifications_on_campaign_id                  (campaign_id)
#  index_notifications_on_user_id             (user_id)
#  index_notifications_on_subject_id_and_subject_type  (subject_id,subject_type)
#

class Notification < ActiveRecord::Base
  belongs_to :subject, polymorphic: true
  belongs_to :campaign
  belongs_to :user
  has_many :thread_subscriptions

  validates :user_id, :campaign_id, :subject_id,
    :subject_type, :priority, :expires_at, :reason, presence: true
end

# == Schema Information
# Schema version: 20130325215115
#
# Table name: thread_subscriptions
#
#  id               :integer          not null, primary key
#  notification_id  :integer          not null
#  user_id :integer          not null
#  subscribed       :boolean          default(TRUE), not null
#  ignored          :boolean          default(FALSE), not null
#  reason           :string(255)
#  created_at       :datetime
#  updated_at       :datetime
#
# Indexes
#
#  index_thread_subscriptions_on_user_id  (user_id)
#  index_thread_subscriptions_on_notification_id   (notification_id)
#

class ThreadSubscription < ActiveRecord::Base
  belongs_to :user
  belongs_to :notification
  validates :user_id, :notification_id, presence: true
  validates :subscribed, :ignored, inclusion: { in: [true, false] }
  validates :subscribed, inclusion: { in: [true] }, unless: :ignored?
  validates :subscribed, inclusion: { in: [false] }, if: :ignored?
  validates :user_id, uniqueness: { scope: :notification_id }
end

[divoxx]

+1

[neerajsingh0101]

@maletor Please create a gist with failing test as mentioned in section 1.2 http://edgeguides.rubyonrails.org/contributing_to_ruby_on_rails.html#create-a-self-contained-gist-for-active-record-issues

[Crunch09]

i think you have a nested association there

has_many :notifications, as: :subject, dependent: :delete_all
has_many :thread_subscriptions, through: :notifications, dependent: :delete_all

according to the docs:

When using nested association, you will not be able to modify the association because there is not enough information to know what modification to make.

[senny]

@maletor what is the state of this issue? Can you please provide an executable test-case as @neerajdotname suggested. This will help us to debug the problem.

[nishantmodak]

Not an issue. Should be closed

https://gist.github.com/nishantmodak/8147200 - Gist Test Case for the issue. / @neerajdotname

@maletor If one ends up using delete instead of destroy then its not going to work, as 'delete' would not look at the associations.

[senny]

It's been several months with no feedback. I'm giving this a close.

Thanks @nishantmodak for the notification. 💛