module ActiveSupport::Deprecation::Reporting

def warn(message = nil, callstack = nil)

# => "DEPRECATION WARNING: something broke! (called from your_code.rb:1)"
ActiveSupport::Deprecation.warn('something broke!')

ActiveSupport::Deprecation.behavior.
Outputs a deprecation warning to the output configured by 
def warn(message = nil, callstack = nil)
  return if silenced
  callstack ||= caller_locations(2)
  deprecation_message(callstack, message).tap do |m|
    if deprecation_disallowed?(message)
      disallowed_behavior.each { |b| b.call(m, callstack, deprecation_horizon, gem_name) }
    else
      behavior.each { |b| b.call(m, callstack, deprecation_horizon, gem_name) }
    end
  end
end