Make sure generated sprites get into the asset manifest.

lib/compass-rails/patches/3_1.rb

@@ -1,3 +1,5 @@
+require 'compass-rails/patches/static_compiler'
+
 module Sass::Script::Functions
   def generated_image_url(path, only_path = nil)
     asset_url(path, Sass::Script::String.new("image"))
@@ -25,4 +27,4 @@ module Sass::Script::Functions
 # Wierd that this has to be re-included to pick up sub-modules. Ruby bug?
 class Sass::Script::Functions::EvaluationContext
   include Sass::Script::Functions
-end
+end

lib/compass-rails/patches/sprite_importer.rb

@@ -16,7 +16,7 @@ def find(uri, options)
           end
         end
       end
-      
+
       old
     end
 
@@ -35,4 +35,4 @@ def resolver
     end
 
   end
-end
+end

lib/compass-rails/patches/static_compiler.rb

@@ -0,0 +1,12 @@
+require 'sprockets/static_compiler'
+
+module Sprockets
+  class StaticCompiler
+    cattr_accessor :generated_sprites
+    self.generated_sprites = {}
+    def write_manifest_with_sprites(manifest)
+      write_manifest_without_sprites(manifest.merge(self.class.generated_sprites))
+    end
+    alias_method_chain :write_manifest, :sprites
+  end
+end

lib/compass-rails/railties/3_1.rb

@@ -62,12 +62,9 @@ def compass
           asset         = Rails.application.assets.find_asset(filename)
           pathname      = Pathname.new(filename)
           logical_path  = filename[(Compass.configuration.images_path.length+1)..-1]
-          # Force the asset into the cache so find_asset will find it.
-          cached_assets = Rails.application.assets.instance_variable_get("@assets")
-          cached_assets[logical_path] = cached_assets[filename] = asset
 
           target = Pathname.new(File.join(Rails.public_path, Rails.application.config.assets.prefix))
-          asset = Rails.application.assets.find_asset(logical_path)
+          Sprockets::StaticCompiler.generated_sprites[logical_path] = asset.digest_path
           filename = target.join(asset.digest_path)
           FileUtils.mkdir_p File.dirname(filename)
           asset.write_to filename