overriding constants

Actually, you can override it with the right statements.

The constant is defined as:
http://caboo.se/doc/classes/ActionView/Helpers/InstanceTag.html
http://caboo.se/doc/classes/ActionView/Helpers/InstanceTag.html
DEFAULT_TEXT_AREA_OPTIONS = { "cols" => 40, "rows" => 20 }.freeze unless
const_defined?(:DEFAULT_TEXT_AREA_OPTIONS)

The key is the "unless const_defined?(...)".
It says that the constant should be defined and frozen, UNLESS it is aready
defined.

How do you define it before ActionView::Helpers::InstanceTag is defined?.
Well, just define it at the beginning of environment.rb, however, since
neither ActionView, Helpers or InstanceTag is defined yet, we must define
them fully with Module/Class...End blocks like this:

module ActionView
  module Helpers
    class InstanceTag
      DEFAULT_TEXT_AREA_OPTIONS = { :cols => 60, :rows => 10 }
    end
  end
end

So, just add the code above at the top of your config/environment.rb, and
you should be all set and warning-free. I hope this helps someone.

Gabriel Medina.
http://www.dottut.com/