simpler_bug.rb

# frozen_string_literal: true

require "bundler/inline"

gemfile(true) do
  source "https://rubygems.org"

  git_source(:github) { |repo| "https://github.com/#{repo}.git" }

  # Activate the gem you are reporting the issue against.
  gem "activerecord", "6.1.0"
  gem "activesupport", "6.1.0"
  gem "sqlite3"
end

require "active_record"
require "minitest/autorun"
require "logger"
require 'active_support/testing/assertions'

ActiveRecord::Base.has_many_inversing = true

# This connection will do for database-independent bug reports.
ActiveRecord::Base.establish_connection(adapter: "sqlite3", database: ":memory:")
ActiveRecord::Base.logger = Logger.new(STDOUT)

ActiveRecord::Schema.define do  
  create_table :pages, force: true do |t|
      t.string :name
      t.bigint :parent_id, foreign_key: true

      t.timestamps
  end

  create_table :page_comments do |t|
    t.string :name
    t.references :page, null: false, foreign_key: true
  end

end

class Page < ActiveRecord::Base
  belongs_to :parent, class_name: 'Page', foreign_key: 'parent_id', optional: true, touch: true, inverse_of: :children

  has_many :children, class_name: 'Page', foreign_key: 'parent_id', inverse_of: :parent
  has_many :comments, class_name: 'PageComment', inverse_of: :page
end

class PageComment < ActiveRecord::Base
  belongs_to :page, touch: true, inverse_of: :comments
end

class BugTest < Minitest::Test
  include ActiveSupport::Testing::Assertions

  def test_association_stuff
    root= Page.create!(name: 'parent')
    child= root.children.create!(name: 'child')
    child.reload
    
    assert_difference 'Page.count', -1 do
      child.destroy
    end

  end

  def test_association_stuff2
    root= Page.create!(name: 'parent')
    child= root.comments.create!(name: 'child')
    child.reload
    
    assert_difference 'PageComment.count', -1 do
      child.destroy
    end

  end
  
end