ruby-on-rails – 为什么我的Rails资源预编译两次？

~/projects/rewportal(mapwidget ?) rake assets:precompile
/home/ruy/.rvm/rubies/ruby-1.9.3-p194/bin/ruby /home/ruy/.rvm/gems/ruby-1.9.3-p194@rewportal/bin/rake assets:precompile:all RAILS_ENV=production RAILS_GROUPS=assets
AssetSync: using /home/ruy/projects/rewportal/config/initializers/asset_sync.rb
AssetSync: using /home/ruy/projects/rewportal/config/initializers/asset_sync.rb
AssetSync: Syncing.
Using: Directory Search of /home/ruy/projects/rewportal/public/assets
Uploading: assets/application-5170f52c1dd49cb382d5135bee01d75e.js
[...]
Fetching files to flag for delete
Flagging 8 file(s) for deletion
Deleting: assets/active_admin-4ce46d089d4b0080e87c9abcb6fa6c97.css
[...]
AssetSync: Done.

这是正常吗？

当我预编译到其他环境(非生产)时,我可以看到每个资产的详细编译两次：

~/projects/rewportal(mapwidget ?) rake RAILS_ENV=qa assets:precompile --trace
** Invoke assets:precompile (first_time)
** Execute assets:precompile
/home/ruy/.rvm/rubies/ruby-1.9.3-p194/bin/ruby /home/ruy/.rvm/gems/ruby-1.9.3-p194@rewportal/bin/rake assets:precompile:all RAILS_ENV=qa RAILS_GROUPS=assets --trace
** Invoke assets:precompile:all (first_time)
** Execute assets:precompile:all
** Invoke assets:precompile:primary (first_time)
** Invoke assets:environment (first_time)
** Execute assets:environment
AssetSync: using /home/ruy/projects/rewportal/config/initializers/asset_sync.rb
** Invoke tmp:cache:clear (first_time)
** Execute tmp:cache:clear
** Execute assets:precompile:primary
Compiled gmaps4rails/gmaps4rails.base.js  (141ms)  (pid 8480)
Compiled gmaps4rails/gmaps4rails.googlemaps.js  (148ms)  (pid 8480)
[...]
Compiled active_admin.css  (1299ms)  (pid 8480)
Compiled active_admin/print.css  (113ms)  (pid 8480)
** Invoke assets:precompile:nondigest (first_time)
** Invoke assets:environment (first_time)
** Execute assets:environment
AssetSync: using /home/ruy/projects/rewportal/config/initializers/asset_sync.rb
** Invoke tmp:cache:clear (first_time)
** Execute tmp:cache:clear
** Execute assets:precompile:nondigest
Compiled gmaps4rails/gmaps4rails.base.js  (133ms)  (pid 8480)
Compiled gmaps4rails/gmaps4rails.googlemaps.js  (133ms)  (pid 8480)
[...]
Compiled active_admin.css  (1290ms)  (pid 8480)
Compiled active_admin/print.css  (116ms)  (pid 8480)
AssetSync: Syncing.
Using: Directory Search of /home/ruy/projects/rewportal/public/assets
Uploading: assets/active_admin-d05b61ab8366b74eabc9074d3e60fe82.css.gz
[...]
Fetching files to flag for delete
Flagging 6 file(s) for deletion
Deleting: assets/active_admin-ec90e7d9a9f45f14d1387f58fa1452b4.css
[...]
AssetSync: Done.

我的application.rb具有以下内容：

config.assets.precompile += %w( active_admin/print.css active_admin.css active_admin.js admin.js admin.css html5shiv.js )

想法？