Rails 4 by default wants to upgrade all cookies, which makes rails 3 unable to read them. But we want that to work since we let rails 3 and 4 run in parallel to test performance (which is terrible on rails 4 … )

# While we run servers with rails 3 and rails 4 we don't want to encrypt our cookie
# once everything is on rails 4 we can by using the upgrade signed to encrypted strategy
# tested via test/integration/rails_compatibility_test.rb
if RAILS4
  ActionDispatch::Cookies::ChainedCookieJars.class_eval do
    def signed_or_encrypted
      signed
    end
  end

  # do not update ... compare to action_dispatch/middleware/cookies.rb:184
  ActionDispatch::Cookies::UpgradeLegacySignedCookieJar.class_eval do
    def initialize(*args)
      super
      @verifier = @legacy_verifier
    end

    def verify_and_upgrade_legacy_signed_message(name, signed_message)
      deserialize(name, @legacy_verifier.verify(signed_message))
    rescue ActiveSupport::MessageVerifier::InvalidSignature
      nil
    end
  end
end