Use cache/assets instead.

railties/lib/rails/application/configuration.rb

@@ -38,7 +38,7 @@ module Rails
         @assets.precompile = [ /\w+\.(?!js|css).+/, /application.(css|js)$/ ]
         @assets.prefix     = "/assets"
 
-        @assets.cache_store    = [ :file_store, "#{root}/tmp/assets_cache/" ]
+        @assets.cache_store    = [ :file_store, "#{root}/tmp/cache/assets/" ]
         @assets.js_compressor  = nil
         @assets.css_compressor = nil
       end

railties/lib/rails/generators/rails/app/app_generator.rb

@@ -118,7 +118,7 @@ module Rails
 
     def tmp
       empty_directory "tmp/cache"
-      empty_directory "tmp/assets_cache"
+      empty_directory "tmp/cache/assets"
     end
 
     def vendor

railties/lib/rails/tasks/tmp.rake

@@ -4,7 +4,7 @@ namespace :tmp do
 
   desc "Creates tmp directories for sessions, cache, sockets, and pids"
   task :create do
-    FileUtils.mkdir_p(%w( tmp/sessions tmp/cache tmp/sockets tmp/pids tmp/assets_cache ))
+    FileUtils.mkdir_p(%w( tmp/sessions tmp/cache tmp/sockets tmp/pids tmp/cache/assets ))
   end
 
   namespace :sessions do
@@ -18,7 +18,6 @@ namespace :tmp do
     # desc "Clears all files and directories in tmp/cache"
     task :clear do
       FileUtils.rm_rf(Dir['tmp/cache/[^.]*'])
-      FileUtils.rm_rf(Dir['tmp/assets_cache/[^.]*'])
     end
   end
 

railties/test/generators/app_generator_test.rb

@@ -34,8 +34,8 @@ DEFAULT_APP_FILES = %w(
   vendor
   vendor/assets
   vendor/plugins
-  tmp/assets_cache
   tmp/cache
+  tmp/cache/assets
 )
 
 class AppGeneratorTest < Rails::Generators::TestCase