Capistrano部署：在资产期间“未识别您的适配器规范”：预编译
我收到这个错误，我认为它来自multi_json gem中的这行代码，但我不够天真，不知道为什么它会被触发？！？
在开发和测试中一切正常，但deploy:assets:update_asset_mtimes任务在cap deploy:migrations失败
有关为什么会发生这种情况的任何提示？ 自上次部署以来， multi_json已经恢复，所以可能会尝试回滚到以前的版本，但想知道为什么它失败了……
血腥细节：
$ cap deploy:migrations ... * 2013-08-13 15:18:44 executing `deploy:assets:update_asset_mtimes' * executing "[ -e /path/to/rails/myapp/shared/assets/manifest* ] && cat /path/to/rails/myapp/shared/assets/manifest* || echo" servers: ["railserver"] [railserver] executing command command finished in 888ms ** Updating mtimes for ~16 assets... servers: ["railserver"] ** scp upload # -> /path/to/rails/myapp/TOUCH_ASSETS [railserver] /path/to/rails/myapp/TOUCH_ASSETS * scp upload complete * executing "cat /path/to/rails/myapp/TOUCH_ASSETS | while read asset; do touch -c -- \"$asset\"; done && rm -f -- /path/to/rails/myapp/TOUCH_ASSETS" servers: ["railserver"] [railserver] executing command command finished in 846ms * executing "cd -- /path/to/rails/myapp/releases/20130813221752 && RAILS_ENV=production RAILS_GROUPS=assets bundle exec rake assets:precompile" servers: ["railserver"] [railserver] executing command ** [out :: railserver] rake aborted! ** [out :: railserver] Did not recognize your adapter specification. ** [out :: railserver] /path/to/rails/myapp/shared/bundle/ruby/2.0.0/gems/multi_json-1.7.9/lib/multi_json.rb:106:in `rescue in load_adapter' ** [out :: railserver] /path/to/rails/myapp/shared/bundle/ruby/2.0.0/gems/multi_json-1.7.9/lib/multi_json.rb:95:in `load_adapter' ** [out :: railserver] /path/to/rails/myapp/shared/bundle/ruby/2.0.0/gems/multi_json-1.7.9/lib/multi_json.rb:99:in `load_adapter' ** [out :: railserver] /path/to/rails/myapp/shared/bundle/ruby/2.0.0/gems/multi_json-1.7.9/lib/multi_json.rb:89:in `use' ** [out :: railserver] /path/to/rails/myapp/shared/bundle/ruby/2.0.0/gems/multi_json-1.7.9/lib/multi_json.rb:71:in `adapter' ** [out :: railserver] /path/to/rails/myapp/shared/bundle/ruby/2.0.0/gems/multi_json-1.7.9/lib/multi_json.rb:129:in `current_adapter' ** [out :: railserver] /path/to/rails/myapp/shared/bundle/ruby/2.0.0/gems/multi_json-1.7.9/lib/multi_json.rb:116:in `load' ** [out :: railserver] /path/to/rails/myapp/shared/bundle/ruby/2.0.0/gems/sprockets-2.10.0/lib/sprockets/manifest.rb:229:in `json_decode' ** [out :: railserver] /path/to/rails/myapp/shared/bundle/ruby/2.0.0/gems ** [out :: railserver] /sprockets-2.10.0/lib/sprockets/manifest.rb:65:in `initialize' ** [out :: railserver] /path/to/rails/myapp/shared/bundle/ruby/2.0.0/gems/sprockets-rails-2.0.0/lib/sprockets/railtie.rb:96:in `new' ** [out :: railserver] /path/to/rails/myapp/shared/bundle/ruby/2.0.0/gems/sprockets-rails-2.0.0/lib/sprockets/railtie.rb:96:in `block (2 levels) in ' ** [out :: railserver] /path/to/rails/myapp/shared/bundle/ruby/2.0.0/gems/sprockets-rails-2.0.0/lib/sprockets/railtie.rb:78:in `instance_eval' ** [out :: railserver] /path/to/rails/myapp/shared/bundle/ruby/2.0.0/gems/sprockets-rails-2.0.0/lib/sprockets/railtie.rb:78:in `block in ' ** [out :: railserver] /path/to/rails/myapp/shared/bundle/ruby/2.0.0/gems/activesupport-4.0.0/lib/active_support/lazy_load_hooks.rb:36:in `call' ** [out :: railserver] /path/to/rails/myapp/shared/bundle/ruby/2.0.0/gems/activesupport-4.0.0/lib/active_support/lazy_load_hooks.rb:36:in `execute_hook' ** [out :: railserver] /path/to/rails/myapp/shared/bundle/ruby/2.0.0/gems/activesupport-4.0.0/lib/active_support/lazy_load_hooks.rb:45:in ** [out :: railserver] `block in run_load_hooks' ** [out :: railserver] /path/to/rails/myapp/shared/bundle/ruby/2.0.0/gems/activesupport-4.0.0/lib/active_support/lazy_load_hooks.rb:44:in `each' ** [out :: railserver] /path/to/rails/myapp/shared/bundle/ruby/2.0.0/gems/activesupport-4.0.0/lib/active_support/lazy_load_hooks.rb:44:in `run_load_hooks' ** [out :: railserver] /path/to/rails/myapp/shared/bundle/ruby/2.0.0/gems/railties-4.0.0/lib/rails/application/finisher.rb:62:in `block in ' ** [out :: railserver] /path/to/rails/myapp/shared/bundle/ruby/2.0.0/gems/railties-4.0.0/lib/rails/initializable.rb:30:in `instance_exec' ** [out :: railserver] /path/to/rails/myapp/shared/bundle/ruby/2.0.0/gems/railties-4.0.0/lib/rails/initializable.rb:30:in `run' ** [out :: railserver] /path/to/rails/myapp/shared/bundle/ruby/2.0.0/gems/railties-4.0.0/lib/rails/initializable.rb:55:in `block in run_initializers' ** [out :: railserver] /path/to/rails/myapp/shared/bundle/ruby/2.0.0/gems/railties-4.0.0/lib/rails/initializable.rb:54:in `run_initializers' ** [out :: railserver] /path/to/rails/myapp/shared/bundle/ruby/ ** [out :: railserver] 2.0.0/gems/railties-4.0.0/lib/rails/application.rb:215:in `initialize!' ** [out :: railserver] /path/to/rails/myapp/shared/bundle/ruby/2.0.0/gems/railties-4.0.0/lib/rails/railtie/configurable.rb:30:in `method_missing' ** [out :: railserver] /path/to/rails/myapp/releases/20130813221752/config/environment.rb:5:in `' ** [out :: railserver] /path/to/rails/myapp/shared/bundle/ruby/2.0.0/gems/activesupport-4.0.0/lib/active_support/dependencies.rb:228:in `require' ** [out :: railserver] /path/to/rails/myapp/shared/bundle/ruby/2.0.0/gems/activesupport-4.0.0/lib/active_support/dependencies.rb:228:in `block in require' ** [out :: railserver] /path/to/rails/myapp/shared/bundle/ruby/2.0.0/gems/activesupport-4.0.0/lib/active_support/dependencies.rb:213:in `load_dependency' ** [out :: railserver] /path/to/rails/myapp/shared/bundle/ruby/2.0.0/gems/activesupport-4.0.0/lib/active_support/dependencies.rb:228:in `require' ** [out :: railserver] /path/to/rails/myapp/shared/bundle/ruby/2.0.0/gems/railties-4.0.0/lib/rails/application.rb:189:in `require_environment!' ** [out :: railserver] /Library/WebServ ** [out :: railserver] er/rails/myapp/shared/bundle/ruby/2.0.0/gems/railties-4.0.0/lib/rails/application.rb:249:in `block in run_tasks_blocks' ** [out :: railserver] /path/to/rails/myapp/shared/bundle/ruby/2.0.0/gems/sprockets-rails-2.0.0/lib/sprockets/rails/task.rb:54:in `block (2 levels) in define' ** [out :: railserver] Tasks: TOP => environment ** [out :: railserver] (See full trace by running task with --trace) command finished in 9278ms failed: "rvm_path=/usr/local/rvm /usr/local/rvm/bin/rvm-shell 'ruby-2.0.0-p247@myapp' -c 'cd -- /path/to/rails/myapp/releases/20130813221752 && RAILS_ENV=production RAILS_GROUPS=assets bundle exec rake assets:precompile'" on railserver
您是否在Gemfile指定了合适的JSON gem，例如？
gem 'yajl-ruby', :require => "yajl"
要么
gem 'json'