Heroku推送錯誤：關於rake資產的「NameError：未初始化的常量Uglifier :: VERSION」：預編譯

Question

嘗試推送到生產時收到以下錯誤。這裏的推動的結果：

$ git push production master 
Counting objects: 124, done. 
Delta compression using up to 4 threads. 
Compressing objects: 100% (118/118), done. 
Writing objects: 100% (124/124), 19.73 KiB | 0 bytes/s, done. 
Total 124 (delta 66), reused 1 (delta 0) 
remote: Compressing source files... done. 
remote: Building source: 
remote: 
remote: -----> Ruby app detected 
remote: -----> Compiling Ruby/Rails 
remote: -----> Using Ruby version: ruby-2.2.2 
remote: -----> Installing dependencies using 1.9.7 
remote:  Ruby version change detected. Clearing bundler cache. 
remote:  Old: ruby 2.0.0p645 (2015-04-13 revision 50299) [x86_64-linux] 
remote:  New: ruby 2.2.2p95 (2015-04-13 revision 50295) [x86_64-linux] 
remote:  Running: bundle install --without development:test --path      vendor/bundle --binstubs vendor/bundle/bin -j4 --deployment 
remote:  Fetching gem metadata... <omitted> 
remote:  Installing... <omitted> 
remote:  Bundle complete! 33 Gemfile dependencies, 70 gems now installed. 
remote:  Gems in the groups development and test were not installed. 
remote:  Bundled gems are installed into ./vendor/bundle. 

    ...<misc post install notifications omitted>... 

remote:  Bundle completed (93.05s) 
remote:  Cleaning up the bundler cache. 
remote: -----> Preparing app for Rails asset pipeline 
remote:  Running: rake assets:precompile 
remote:  rake aborted! 
remote:  NameError: uninitialized constant Uglifier::VERSION 
remote:  /tmp/build_1185918c8fd4fbf904b3d7c2f09505d5/vendor/bundle/ruby/2.2.0/gems/sprockets-3.1.0/lib/sprockets/uglifier_compressor.rb:48:in `initialize' 
remote:  /tmp/build_1185918c8fd4fbf904b3d7c2f09505d5/vendor/bundle/ruby/2.2.0/gems/sprockets-3.1.0/lib/sprockets/uglifier_compressor.rb:24:in `new' 
remote:  /tmp/build_1185918c8fd4fbf904b3d7c2f09505d5/vendor/bundle/ruby/2.2.0/gems/sprockets-3.1.0/lib/sprockets/uglifier_compressor.rb:24:in `instance' 
remote:  /tmp/build_1185918c8fd4fbf904b3d7c2f09505d5/vendor/bundle/ruby/2.2.0/gems/sprockets-3.1.0/lib/sprockets/uglifier_compressor.rb:28:in `call' 
remote:  /tmp/build_1185918c8fd4fbf904b3d7c2f09505d5/vendor/bundle/ruby/2.2.0/gems/sprockets-3.1.0/lib/sprockets/processor_utils.rb:75:in `call_processor' 
remote:  /tmp/build_1185918c8fd4fbf904b3d7c2f09505d5/vendor/bundle/ruby/2.2.0/gems/sprockets-3.1.0/lib/sprockets/processor_utils.rb:57:in `block in call_processors' 
remote:  /tmp/build_1185918c8fd4fbf904b3d7c2f09505d5/vendor/bundle/ruby/2.2.0/gems/sprockets-3.1.0/lib/sprockets/processor_utils.rb:56:in `reverse_each' 
remote:  /tmp/build_1185918c8fd4fbf904b3d7c2f09505d5/vendor/bundle/ruby/2.2.0/gems/sprockets-3.1.0/lib/sprockets/processor_utils.rb:56:in `call_processors' 
remote:  /tmp/build_1185918c8fd4fbf904b3d7c2f09505d5/vendor/bundle/ruby/2.2.0/gems/sprockets-3.1.0/lib/sprockets/loader.rb:86:in `load_asset_by_uri' 
remote:  /tmp/build_1185918c8fd4fbf904b3d7c2f09505d5/vendor/bundle/ruby/2.2.0/gems/sprockets-3.1.0/lib/sprockets/loader.rb:45:in `block in load' 
remote:  /tmp/build_1185918c8fd4fbf904b3d7c2f09505d5/vendor/bundle/ruby/2.2.0/gems/sprockets-3.1.0/lib/sprockets/loader.rb:156:in `fetch_asset_from_dependency_cache' 
remote:  /tmp/build_1185918c8fd4fbf904b3d7c2f09505d5/vendor/bundle/ruby/2.2.0/gems/sprockets-3.1.0/lib/sprockets/loader.rb:38:in `load' 
remote:  /tmp/build_1185918c8fd4fbf904b3d7c2f09505d5/vendor/bundle/ruby/2.2.0/gems/sprockets-3.1.0/lib/sprockets/cached_environment.rb:20:in `block in initialize' 
remote:  /tmp/build_1185918c8fd4fbf904b3d7c2f09505d5/vendor/bundle/ruby/2.2.0/gems/sprockets-3.1.0/lib/sprockets/cached_environment.rb:47:in `yield' 
remote:  /tmp/build_1185918c8fd4fbf904b3d7c2f09505d5/vendor/bundle/ruby/2.2.0/gems/sprockets-3.1.0/lib/sprockets/cached_environment.rb:47:in `load' 
remote:  /tmp/build_1185918c8fd4fbf904b3d7c2f09505d5/vendor/bundle/ruby/2.2.0/gems/sprockets-3.1.0/lib/sprockets/base.rb:63:in `find_asset' 
remote:  /tmp/build_1185918c8fd4fbf904b3d7c2f09505d5/vendor/bundle/ruby/2.2.0/gems/sprockets-3.1.0/lib/sprockets/base.rb:70:in `find_all_linked_assets' 
remote:  /tmp/build_1185918c8fd4fbf904b3d7c2f09505d5/vendor/bundle/ruby/2.2.0/gems/sprockets-3.1.0/lib/sprockets/manifest.rb:138:in `block in find' 
remote:  /tmp/build_1185918c8fd4fbf904b3d7c2f09505d5/vendor/bundle/ruby/2.2.0/gems/sprockets-3.1.0/lib/sprockets/legacy.rb:114:in `block (2 levels) in logical_paths' 
remote:  /tmp/build_1185918c8fd4fbf904b3d7c2f09505d5/vendor/bundle/ruby/2.2.0/gems/sprockets-3.1.0/lib/sprockets/path_utils.rb:223:in `block in stat_tree' 
remote:  /tmp/build_1185918c8fd4fbf904b3d7c2f09505d5/vendor/bundle/ruby/2.2.0/gems/sprockets-3.1.0/lib/sprockets/path_utils.rb:207:in `block in stat_directory' 
remote:  /tmp/build_1185918c8fd4fbf904b3d7c2f09505d5/vendor/bundle/ruby/2.2.0/gems/sprockets-3.1.0/lib/sprockets/path_utils.rb:204:in `each' 
remote:  /tmp/build_1185918c8fd4fbf904b3d7c2f09505d5/vendor/bundle/ruby/2.2.0/gems/sprockets-3.1.0/lib/sprockets/path_utils.rb:204:in `stat_directory' 
remote:  /tmp/build_1185918c8fd4fbf904b3d7c2f09505d5/vendor/bundle/ruby/2.2.0/gems/sprockets-3.1.0/lib/sprockets/path_utils.rb:222:in `stat_tree' 
remote:  /tmp/build_1185918c8fd4fbf904b3d7c2f09505d5/vendor/bundle/ruby/2.2.0/gems/sprockets-3.1.0/lib/sprockets/legacy.rb:105:in `each' 
remote:  /tmp/build_1185918c8fd4fbf904b3d7c2f09505d5/vendor/bundle/ruby/2.2.0/gems/sprockets-3.1.0/lib/sprockets/legacy.rb:105:in `block in logical_paths' 
remote:  /tmp/build_1185918c8fd4fbf904b3d7c2f09505d5/vendor/bundle/ruby/2.2.0/gems/sprockets-3.1.0/lib/sprockets/legacy.rb:104:in `each' 
remote:  /tmp/build_1185918c8fd4fbf904b3d7c2f09505d5/vendor/bundle/ruby/2.2.0/gems/sprockets-3.1.0/lib/sprockets/legacy.rb:104:in `logical_paths' 
remote:  /tmp/build_1185918c8fd4fbf904b3d7c2f09505d5/vendor/bundle/ruby/2.2.0/gems/sprockets-3.1.0/lib/sprockets/manifest.rb:136:in `find' 
remote:  /tmp/build_1185918c8fd4fbf904b3d7c2f09505d5/vendor/bundle/ruby/2.2.0/gems/sprockets-3.1.0/lib/sprockets/manifest.rb:162:in `compile' 
remote:  /tmp/build_1185918c8fd4fbf904b3d7c2f09505d5/vendor/bundle/ruby/2.2.0/gems/sprockets-rails-2.3.1/lib/sprockets/rails/task.rb:70:in `block (3 levels) in define' 
remote:  /tmp/build_1185918c8fd4fbf904b3d7c2f09505d5/vendor/bundle/ruby/2.2.0/gems/sprockets-3.1.0/lib/rake/sprocketstask.rb:147:in `with_logger' 
remote:  /tmp/build_1185918c8fd4fbf904b3d7c2f09505d5/vendor/bundle/ruby/2.2.0/gems/sprockets-rails-2.3.1/lib/sprockets/rails/task.rb:69:in `block (2 levels) in define' 
remote:  Tasks: TOP => assets:precompile 
remote:  (See full trace by running task with --trace) 
remote: ! 
remote: !  Precompiling assets failed. 
remote: ! 
remote: 
remote: !  Push rejected, failed to compile Ruby app 

Answer 1

的問題似乎是鏈輪3.1和我所用，2.1 Uglifier壓縮機版本之間的不兼容。升級Uglifier通過把這條線放在我的Gemfile中解決了問題：

gem 'uglifier', '~> 2.7'