Rails 4.1.0.rc1 has_and_belongs_to_many vaidation ignoring error.

habtm_validation_bug.rb

# gem 'activerecord', '4.0.3'
gem 'activerecord', '4.1.0.rc1'
# gem 'rails', github: 'rails/rails', branch: '4-1-stable'
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 :events do |t|
  end

  create_table :languages do |t|
    t.string :info
  end

  create_table :events_languages, id: false do |t|
    t.integer :event_id
    t.integer :language_id
  end
end

class Language < ActiveRecord::Base
  before_validation :run_before_create, on: :create
  before_validation :run_before_validation

  private

  def run_before_create
    write_attribute(:info, info.to_s + 'run_before_create')
  end

  def run_before_validation
    write_attribute(:info, info.to_s + 'run_before_validation')
  end
end

class Event < ActiveRecord::Base
  has_and_belongs_to_many :languages, validate: false
end


class BugTest < Minitest::Test
  def setup
    language = Language.create!
    language.update_column(:info, '')
  end

  def test_association_stuff
    event = Event.new
    language = Language.first
    event.languages << language
    event.valid?

    assert_equal 1, event.languages.size
    # Should not run associated language validation when :validate => false
    assert_equal language.info, ''
  end
end