Rails控制台錯誤：nil的未定義方法`each'：NilClass（NoMethodError）

Question

任何在我的Rails應用程序的根目錄中運行rails console嘗試都會產生以下錯誤：

nil的未定義方法`each'：NilClass（NoMethodError）

完整堆棧跟蹤：

 /Users/gnerkus/.rvm/gems/ruby-2.2.3@rails-experiments/gems/railties-5.0.0.beta1.1/lib/rails/railtie.rb:245:in `each_registered_block': undefined method `each' for nil:NilClass (NoMethodError)
  from /Users/gnerkus/.rvm/gems/ruby-2.2.3@rails-experiments/gems/railties-5.0.0.beta1.1/lib/rails/railtie.rb:224:in `run_console_blocks'
  from /Users/gnerkus/.rvm/gems/ruby-2.2.3@rails-experiments/gems/railties-5.0.0.beta1.1/lib/rails/application.rb:461:in `block in run_console_blocks'
  from /Users/gnerkus/.rvm/gems/ruby-2.2.3@rails-experiments/gems/railties-5.0.0.beta1.1/lib/rails/engine/railties.rb:13:in `each'
  from /Users/gnerkus/.rvm/gems/ruby-2.2.3@rails-experiments/gems/railties-5.0.0.beta1.1/lib/rails/engine/railties.rb:13:in `each'
  from /Users/gnerkus/.rvm/gems/ruby-2.2.3@rails-experiments/gems/railties-5.0.0.beta1.1/lib/rails/application.rb:461:in `run_console_blocks'
  from /Users/gnerkus/.rvm/gems/ruby-2.2.3@rails-experiments/gems/railties-5.0.0.beta1.1/lib/rails/engine.rb:442:in `load_console'
  from /Users/gnerkus/.rvm/gems/ruby-2.2.3@rails-experiments/gems/railties-5.0.0.beta1.1/lib/rails/commands/console.rb:34:in `initialize'
  from /Users/gnerkus/.rvm/gems/ruby-2.2.3@rails-experiments/gems/railties-5.0.0.beta1.1/lib/rails/commands/console_helper.rb:9:in `new'
  from /Users/gnerkus/.rvm/gems/ruby-2.2.3@rails-experiments/gems/railties-5.0.0.beta1.1/lib/rails/commands/console_helper.rb:9:in `start'
  from /Users/gnerkus/.rvm/gems/ruby-2.2.3@rails-experiments/gems/railties-5.0.0.beta1.1/lib/rails/commands/commands_tasks.rb:78:in `console'
  from /Users/gnerkus/.rvm/gems/ruby-2.2.3@rails-experiments/gems/railties-5.0.0.beta1.1/lib/rails/commands/commands_tasks.rb:49:in `run_command!'
  from /Users/gnerkus/.rvm/gems/ruby-2.2.3@rails-experiments/gems/railties-5.0.0.beta1.1/lib/rails/command.rb:20:in `run'
  from /Users/gnerkus/.rvm/gems/ruby-2.2.3@rails-experiments/gems/railties-5.0.0.beta1.1/lib/rails/commands.rb:19:in `<top (required)>'
  from bin/rails:4:in `require'
  from bin/rails:4:in `<main>'

我已經在Rails lib的railtie.rb文件中跟蹤了這個塊的錯誤：

def each_registered_block(type, &block)
  klass = self.class
  while klass.respond_to?(type)
    # The ':console' type doesn't seem to exist
    klass.public_send(type).each(&block) 
    klass = klass.superclass
  end
end

反過來來自這個塊：

def run_console_blocks(app) #:nodoc:
  each_registered_block(:console) { |block| block.call(app) }
end

我卸載了spring gem並安裝了rubocop gem。 否則，我的Gemfile包含默認的gem。

我的Ruby版本是2.2.3 ，高於推薦用於Rails 5的2.2.2版本。

Ruby版本： 2.2.3p173 Rails版本： 5.0.0.beta1.1 RVM版本： 1.26.11

Answer 1

該錯誤是由此處引用的web-console gem引起的： 運行rails console時出錯 。 web-console的版本為3.1.0 。 執行rails console時， 3.0.0版本的web-console似乎沒有產生任何錯誤。

您需要確保您的web-console版本是3.1.1及更高版本，因為問題已在3.1.1版本中修復。

Answer 2

gem install spring為我工作。

我的問題是：

/usr/local/bin/NMONMerge.rb:209:in `block in <main>': undefined method `each' for nil:NilClass (NoMethodError)
from /usr/local/bin/NMONMerge.rb:191:in `each'
from /usr/local/bin/NMONMerge.rb:191:in `<main>'

Answer 3

你需要安裝spring gem

gem install spring  --pre