Rails counter cache

rails_way_counter_cache.rb

# frozen_string_literal: true

# Please include only the minimum code necessary to reproduce your issue.
require "bundler/inline"

# STEP ONE: What versions are you using?
gemfile(true) do
  ruby "2.5.1"
  source "https://rubygems.org"
  gem "activerecord", "4.2.11"
  gem "minitest", "5.11.3"
  gem "sqlite3", "1.3.13"
end

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

# Please use sqlite for your bug reports, if possible.
ActiveSupport.test_order = :sorted
ActiveRecord::Base.raise_in_transactional_callbacks = true
ActiveRecord::Base.establish_connection(adapter: "sqlite3", database: ":memory:")
ActiveRecord::Base.logger = nil
ActiveRecord::Base.logger = nil
ActiveRecord::Schema.define do
  # STEP TWO: Define your tables here.
  create_table :users, force: true do |t|
    t.text :name, null: false
    t.integer :comments_count, default: 0, null: false
    t.timestamps null: false
  end

  create_table :comments, force: true do |t|
    t.integer :user_id, null: false, index: true
    t.text :body, null: false
    t.timestamps null: false
  end

  create_table :versions do |t|
    t.string :item_type, null: false
    t.integer :item_id, null: false
    t.string :event, null: false
    t.string :whodunnit
    t.text :object, limit: 1_073_741_823
    t.text :object_changes, limit: 1_073_741_823
    t.datetime :created_at
  end
  add_index :versions, %i[item_type item_id]
end
ActiveRecord::Base.logger = Logger.new(STDOUT)

# STEP FOUR: Define your AR models here.
class User < ActiveRecord::Base
  has_many :comments
end

class Comment < ActiveRecord::Base
  belongs_to :user, counter_cache: true
end

# STEP FIVE: Please write a test that demonstrates your issue.
class BugTest < ActiveSupport::TestCase
  def test_counter_cache
    # Expected to return 0
    user = User.create!(name: "Jhon")
    user.reload
    assert_equal 0, user.comments_count
    assert_equal 0, user.comments.size

    # Expected to return 1
    user.comments.create!(body: 'Nice!')
    user.reload
    assert_equal 1, user.comments_count
    assert_equal 1, user.comments.size

    # Expected to return 12345
    user = User.create!(name: "Jhon", comments_count: 12345)
    user.reload
    assert_equal 12345, user.comments_count
    assert_equal 12345, user.comments.size
  end
end

# STEP SIX: Run this script using `ruby bug_report.rb`