Failed ImportProcessor

hacks.rb

module Less  
  module Rails    
    class ImportProcessor < Tilt::Template
      
      IMPORT_SCANNER = /@import\s*['"]([^'"]+)['"]\s*;/.freeze
      
      def prepare
      end
      
      def evaluate(context, locals, &block)
        import_paths = data.scan(IMPORT_SCANNER).flatten.compact.uniq
        import_paths.each do |path|
          context.depend_on(path)
        end
        data
      end
      
    end
  end
end

it 'must register our import processor' do
  dummy_assets.bundle_processors['text/css'].must_include Less::Rails::ImportProcessor
end

initializer 'less-rails.before.load_config_initializers', :before => 'load_config_initializers', :group => :all do |app|
  raise 'The less-rails plugin requires the asset pipeline to be enabled.' unless app.config.assets.enabled
  app.assets.register_bundle_processor 'text/css', ImportProcessor
end

OK, a pre-processor does it

module Less  
  module Rails    
    class ImportProcessor < Tilt::Template

      IMPORT_SCANNER = /@import\s*['"]([^'"]+)['"]\s*;/.freeze

      def prepare
      end

      def evaluate(context, locals, &block)
        import_paths = data.scan(IMPORT_SCANNER).flatten.compact.uniq
        import_paths.each do |path|
          asset = context.environment[path]
          if asset && asset.pathname.to_s.ends_with?('.less')
            context.depend_on(asset.pathname)
          end
        end
        data
      end

    end
  end
end