extra_select.rb

# frozen_string_literal: true

begin
  require "bundler/inline"
rescue LoadError => e
  $stderr.puts "Bundler version 1.10 or later is required. Please update your Bundler"
  raise e
end

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 'rails', :git => 'https://github.com/rails/rails.git', :ref => '8df7ed3b88fc9f19446d7207a745a331893b81cd' # tip of master atm
  gem "sqlite3"
end

require "active_record"
require "minitest/autorun"
require "logger"

# Ensure backward compatibility with minitest 4.
Minitest::Test = MiniTest::Unit::TestCase unless defined?(Minitest::Test)

# 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 :posts, force: true do |t|
  end

  create_table :comments, force: true do |t|
    t.integer :post_id
  end
end

class Post < ActiveRecord::Base
  has_many :comments, inverse_of: :post
end

class Comment < ActiveRecord::Base
  belongs_to :post, inverse_of: :comments

 # not strictly necessary since validation fetches all the attributes; this is for being explicit
  before_validation do
    self.post
  end
end

class BugTest < Minitest::Test
  def test_saving_parent_and_child_by_using_child
    post = Post.new
    comment = post.comments.new
    comment.post = post # this assign rids comment.association(:post) of inversed status.
                        # It thinks the parent is stale after post finishes saving.

    # there should only be two inserts, but there an extra select
    comment.save!
    # it also allocates a new instance of the model. This fails.
    assert comment.post.equal?(post)
  end
end