Heroku推送错误：rake资产上的“NameError：未初始化的常量Uglifier :: VERSION”：预编译

我在尝试推向生产时收到以下错误。 这是推送的结果：

$ 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...  remote: Installing...  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. ...... 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

问题似乎是Sprockets 3.1和我使用的Uglifier压缩器版本2.1之间不兼容。 通过在我的Gemfile中放置这一行来升级Uglifier解决了这个问题：

 gem 'uglifier', '~> 2.7'