rails version checking logic wrong in rails.rb

[betelgeuse]

In lib/sass/plugin/rails.rb we have the following code

  # Rails 3.1 loads and handles Sass all on its own
  if defined?(ActionController::Metal)
    #3.1 > Rails >= 3.0
    require 'sass/plugin/rack'
    Rails.configuration.middleware.use(Sass::Plugin::Rack)
  elsif defined?(ActionController::Dispatcher) &&
      defined?(ActionController::Dispatcher.middleware)
    # Rails >= 2.3
    require 'sass/plugin/rack'
    ActionController::Dispatcher.middleware.use(Sass::Plugin::Rack)
  else
    module ActionController
      class Base
        alias_method :sass_old_process, :process
        def process(*args)
          Sass::Plugin.check_for_updates
          sass_old_process(*args)
        end
      end
    end
  end

In rails console for 3.1:

1.9.3p125 :002 > defined?(ActionController::Metal)
 => "constant"

This means that sass will run code where the comments claim to be for 3.0.x also on 3.1. Can someone knowing the history explain what the goal here is? I am thinking that if asset pipeline is enabled we don't want to load the plugin.

[nex3]

sass/plugin is typically not required at all in a Rails 3.1+ project, I believe.

[chriseppstein]

@nex3 it's possible to disable the asset pipeline and use the Sass::Plugin instead. Sass::Plugin can check whether the asset pipeline is enabled. In compass-rails we use this to check:

(cfg = Rails.application.config) && cfg.respond_to?(:assets) && cfg.assets.try(:enabled)

[nex3]

But why would sass/plugin be loaded in the first place if the user wants to use the asset pipeline?

[chriseppstein]

@nex3 Isn't it the default behavior?

[nex3]

No, I believe sass/plugin is not loaded at all in Rails >= 3.1.