ar_group_cast_type.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" }

  gem "rails", github: "rails/rails"
  gem "arel", github: "rails/arel"
  gem "sqlite3"
end

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 :posts, force: true do |t|
    t.string :body
  end

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

class Post < ActiveRecord::Base
  has_many :comments
end

class Comment < ActiveRecord::Base
  belongs_to :post
end

class BugTest < Minitest::Test
  def test_group_key_type
    post = Post.create!(body: "text")
    post.comments << Comment.create!(body: 42)
    
    assert_equal { 42 => 1 }, Comment.group(:body).count
    assert_equal { 42 => 1 }, Post.joins(:comments).group("comments.body").count
  end
end