Define our own template instead of monkey patching sprockets

Author: Rafael Mendonça França

lib/sass/rails/railtie.rb

@@ -56,6 +56,9 @@ module SassContext
       end
 
       if app.assets
+        app.assets.register_engine '.sass', Sass::Rails::SassTemplate
+        app.assets.register_engine '.scss', Sass::Rails::ScssTemplate
+
         app.assets.context_class.extend(SassContext)
         app.assets.context_class.sass_config = app.config.sass
       end

lib/sass/rails/template.rb

@@ -1,28 +1,47 @@
 require "sprockets/sass_template"
 
-module Sprockets
-  class SassTemplate
-    def evaluate(context, locals, &block)
-      cache_store = SassCacheStore.new(context.environment)
-
-      options = {
-        :filename => eval_file,
-        :line => line,
-        :syntax => syntax,
-        :cache_store => cache_store,
-        :importer => SassImporter.new(context, context.pathname),
-        :load_paths => context.environment.paths.map { |path| SassImporter.new(context, path) },
-        :sprockets => {
-          :context => context,
-          :environment => context.environment
+module Sass
+  module Rails
+    class SassTemplate < Sprockets::SassTemplate
+
+      def evaluate(context, locals, &block)
+        cache_store = Sprockets::SassCacheStore.new(context.environment)
+
+        options = {
+          :filename => eval_file,
+          :line => line,
+          :syntax => syntax,
+          :cache_store => cache_store,
+          :importer => Sprockets::SassImporter.new(context.pathname.to_s),
+          :load_paths => context.environment.paths.map { |path| Sprockets::SassImporter.new(path.to_s) },
+          :sprockets => {
+            :context => context,
+            :environment => context.environment
+          }
         }
-      }
 
-      sass_config = context.environment.context_class.sass_config.merge(options)
-      ::Sass::Engine.new(data, sass_config).render
-    rescue ::Sass::SyntaxError => e
-      context.__LINE__ = e.sass_backtrace.first[:line]
-      raise e
+        sass_config = context.environment.context_class.sass_config.merge(options)
+
+        result = ::Sass::Engine.new(data, sass_config).render
+
+        filenames = ([options[:importer].imported_filenames] + options[:load_path].map(&:imported_filenames)).flatten.uniq
+        filenames.each { |filename| context.depend_on(filename) }
+
+        result
+      rescue ::Sass::SyntaxError => e
+        context.__LINE__ = e.sass_backtrace.first[:line]
+        raise e
+      end
+    end
+
+    class ScssTemplate < SassTemplate
+      def self.default_mime_type
+        'text/css'
+      end
+
+      def syntax
+        :scss
+      end
     end
   end
 end