Temporary fix for the extra newline (
) Rails 3.2.3 + Haml are adding to the output of the text_area form helper.

fixing_x000a.rb

module ActionView
  module Helpers
    module FormHelper
      def text_area(object_name, method, options = {})
        html = InstanceTag.new(object_name, method, self, options.delete(:object)).to_text_area_tag(options)
        html.gsub(/>\
/, '>').html_safe
      end
    end
  end
end

FYI this will work fine for ugly mode, but in indented mode it will add spaces after the opening textarea tag.

I've opened an issue rails/rails#6236 for this.