Rails console error: undefined method `each' for nil:NilClass (NoMethodError)

Question

在我的 Rails 应用程序的根目录中对运行 rails console 的任何尝试都会产生以下错误：

undefined method `each' for nil:NilClass (NoMethodError)

完整堆栈跟踪：

 /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>'

我已将错误追踪到 Rails 库中的 railtie.rb 文件中的这个块：

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

这又来自这个区块：

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

我卸载了 spring gem 并安装了 rubocop gem。否则，我的 Gemfile 包含默认的 gems.

我的 Ruby 版本是 2.2.3，高于为 Rails 5.

推荐的 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

错误是由此处引用的 web-console gem 引起的：Error when running rails console。报告时 web-console 的版本为 3.1.0。 3.0.0 版本的 web-console 似乎在执行 rails console 时没有产生任何错误。

您需要确保您的 web-console 版本为 3.1.1 或更高版本，因为此问题已在 3.1.1 版本中修复。

Answer 2

您需要安装springgem

gem install spring  --pre

Answer 3

gem install spring 为我工作。

我的问题是：

/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>'

Rails console error: undefined method `each' for nil:NilClass (NoMethodError)

Rails console error: undefined method `each' for nil:NilClass (NoMethodError)

ruby

ruby-on-rails

ruby-on-rails-5