repro.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 "activerecord", ENV.fetch('AR_VERSION', '5.2.4')
  gem "sqlite3", "~> 1.3.6"
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 :users, force: true do |t|
  end

  create_table :settings, force: :true do |t|
    t.bigint :user_id
    t.integer :count, null: false
  end
end

class User < ActiveRecord::Base
  has_one :setting, required: true
  accepts_nested_attributes_for :setting
end

class Setting < ActiveRecord::Base
  belongs_to :user

  validate do
    if count < 0
      errors.add(:count, 'error')
    end
  end
end


class T < Minitest::Test
  def test_case
    setting = Setting.create!(count: 0)
    user = User.create!(setting: setting)

    setting.count = -1
    setting.save!(validate: false) # we do have invalid records in our production db

    user = User.find(user.id)

    # We don't want to allow to use invalid setting. End users must update their setting.
    # `user.valid?` should return false when the user's setting is invalid.
    assert_equal false, user.valid?
  end
end