join_and_enum.rb

# frozen_string_literal: true

require "bundler/inline"

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

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

  gem "rails", '~> 6.0.0'
  gem "sqlite3"
  gem "pry"
end

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

# 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 :users, force: true do |t|
    t.string :name, null: false
  end

  create_table :shops, force: true do |t|
    t.references :user, null: false
  end

  create_table :items, force: true do |t|
    t.references :shop, null: false
    t.integer :state, null: false
  end
end

class User < ActiveRecord::Base
  has_one :shop, autosave: true
end

class Shop < ActiveRecord::Base
  belongs_to :user
  has_many :items
end

class Item < ActiveRecord::Base
  belongs_to :shop

  enum(state: %i[draft published])
end

class BugTest < Minitest::Test
  # expected nothing raised, got ActiveRecord::ReadOnlyRecord
  def test_join_and_enum
    assert_match /WHERE "items"."state" = 0/, User.joins(shop: :items).merge(Item.where(state: ['draft'])).to_sql

    # expected WHERE "items"."state" = 0, got WHERE "items"."state" = NULL
    assert_match /WHERE "items"."state" = 0/, User.joins(shop: :items).where(items: { state: ['draft'] }).to_sql
  end
end