ruby-on-rails-3 - 橡胶::Util.has_asset_pipeline？方法缺失

Question

我想我们几天前将 Rubber 更新回 1.15.0，这个问题现在出现在 deploy.rb 中。这是块：

if Rubber::Util.has_asset_pipeline?
 # load asset pipeline tasks, and reorder them to run after
 # rubber:config so that database.yml/etc has been generated
 load 'deploy/assets'
 callbacks[:after].delete_if {|c| c.source == "deploy:assets:precompile"}
 callbacks[:before].delete_if {|c| c.source == "deploy:assets:symlink"}
 before "deploy:assets:precompile", "deploy:assets:symlink"
 after "rubber:config", "deploy:assets:precompile"
end

问题是当我将其注释掉时，部署失败说：

* executing "sudo -p 'sudo password: '  bash -l -c 'cd /mnt/foo-production/current &&  RUBBER_ENV=\"production\" RAILS_ENV=\"production\" bundle exec rake rubber:config'"
servers: ["app01.foo.com"]
[app01.foo.com] executing command
** [out :: app01.foo.com] rake aborted!
** [out :: app01.foo.com] Don't know how to build task 'rubber:config'
** [out :: app01.foo.com] 
** [out :: app01.foo.com] (See full trace by running task with --trace)
command finished in 17128ms
failed: "/bin/bash -l -c 'sudo -p '\\''sudo password: '\\''  bash -l -c '\\''cd /mnt/foo-production/current &&  RUBBER_ENV=\"production\" RAILS_ENV=\"production\" bundle exec rake rubber:config'\\'''" on app01.foo.com

知道为什么吗？谢谢！