Rails Model - after_destroy never called

Question

I have some trouble to use after_destroy in model

Here is this one:

class Transaction < ActiveRecord::Base
  belongs_to :user
  delegate :first_name, :last_name, :email, to: :user, prefix: true

  belongs_to :project
  delegate :name, :thanking_msg, to: :project, prefix: true

  validates_presence_of :project_id

  after_save :update_collected_amount_in_project
  after_update :update_collected_amount_if_disclaimer
  after_destroy :update_collected_amount_after_destroy

  def currency_symbol
    currency = Rails.application.config.supported_currencies.fetch(self.currency)
    currency[:symbol]
  end

  private

  def update_collected_amount
    new_collected_amount = project.transactions.where(success: true, transaction_type: 'invest').sum(:amount)
    project.update_attributes(collected_amount: (new_collected_amount / 100).to_f) # Stored in € not cents inside projects table
  end

  def update_collected_amount_in_project
    update_collected_amount if transaction_type == 'invest' && success == true
  end

  def update_collected_amount_if_disclaimer
    update_collected_amount if transaction_type == 'invest' && self.changes.keys.include?('success') && self.changes.fetch('success', []).fetch(1) == false
  end

  def update_collected_amount_after_destroy
    update_collected_amount
  end
end

When I use something like:

Transaction.last.delete

It never go inside my after_destroy, I tried to include some outputs but nothing. I don't know if I'm wrong on how I use this after_destroy, I also tried before_destroy and I have the same problem. after_save and after_update work perfectly.

Answer 1

The after_destroy callbacks aren't called on delete. They are only called if you call destroy, like so:

Transaction.last.destroy

That's actually the only difference between the two methods. Delete bypasses the callbacks.

Delete also won't execute any :dependent association options.

The reason for this is that it never instantiates any of the active record objects that you are deleting, it simply executes an SQL delete statement against the database.