distinct and include

example.rb

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"
  gem "rails", '6.0.0.beta1'
  # gem "rails", '5.2.1.1'
  gem 'pg'
end

require 'pg'
require "active_record"
require 'active_support'
require "minitest/autorun"
require "logger"

ActiveRecord::Base.establish_connection(adapter: "postgresql", database: "penseo_test2")
ActiveRecord::Base.logger = Logger.new(STDOUT)

ActiveRecord::Schema.define do
  create_table :posts, force: true do |t|
    t.timestamps(null: false)
  end

  create_table :comments, force: true do |t|
    t.integer :post_id
    t.timestamps(null: false)
  end
end

class Post < ActiveRecord::Base
  has_many :comments
end

class Comment < ActiveRecord::Base
  belongs_to :post
end

class BugTest < Minitest::Test
  def test_fails_with_distinct_size
    post = Post.create!
    post.comments << Comment.create!

    assert Comment.where('posts.created_at > ?', 4.days.ago).includes(:post).distinct.order('posts.created_at').to_a
    assert Comment.where('posts.created_at > ?', 4.days.ago).references(:post).distinct.order('posts.created_at').to_a
    assert Comment.where('posts.created_at > ?', 4.days.ago).joins(:post).includes(:post).distinct.order('posts.created_at').to_a

  end
end