rails issue #15468

gistfile1.rb

unless File.exist?('Gemfile')
  File.write('Gemfile', <<-GEMFILE)
    source 'https://rubygems.org'
    gem 'rails', github: 'rails/rails'
    gem 'arel', github: 'rails/arel'
    gem 'sqlite3'
    gem 'pry-byebug'
  GEMFILE
 
  system 'bundle'
end
 
require 'bundler'
Bundler.setup(:default)
 
require 'active_record'
require 'minitest/autorun'
require 'logger'
require 'pry-byebug'
 
# 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 :foos do |t|
  end
 
  create_table :quxes do |t|
    t.references :foo, index: true
    t.references :ba, polymorphic: true, index: true
  end
 
  create_table :bars do |t|
  end
 
  create_table :bazs do |t|
  end
end
 
class Foo < ActiveRecord::Base
  has_one :qux, dependent: :destroy, inverse_of: :foo
  has_one :bar, through: :qux, source: :ba,
                             source_type: 'Bar', inverse_of: :foo
  has_one :baz, through: :qux, source: :ba,
                            source_type: 'Baz', inverse_of: :foo
  validates :qux, presence: true
  validates_associated :qux
end
 
class Qux < ActiveRecord::Base
  belongs_to :foo, inverse_of: :qux
  belongs_to :ba, polymorphic: true, inverse_of: :qux, dependent: :destroy
  validates :foo, :ba, presence: true
  validates_associated :ba
end
 
class Bar < ActiveRecord::Base
  has_one :qux, as: :ba, inverse_of: :ba
  has_one :foo, through: :qux, inverse_of: :bar
  validates :qux, :foo, presence: true
end
 
class Baz < ActiveRecord::Base
  has_one :qux, as: :ba, inverse_of: :ba
  has_one :foo, through: :qux, inverse_of: :baz
  validates :qux, :foo, presence: true
end
 
class BugTest < Minitest::Test
  def test_association_stuff
    foo = Foo.new
    foo.build_qux(ba: Bar.new(foo: foo), foo: foo)
    foo.save!

    foo.destroy!
    
    assert Bar.all.empty?
    assert Foo.all.empty?
  end
end