Ruby on rails 与rake有问题

我正在运行Rails 3.1.1，运行此命令时出现此错误。显然是Rails的新手，欢迎您提供帮助：

雷克流产了！ nil:NilClass的未定义方法“先决条件”

/Users/220040168/.rvm/gems/ruby-1.9.2-p290@rails3tutorial/gems/rspec-rails-2.6.0/lib/rspec/rails/tasks/rspec.rake:3:in `<top (required)>'
/Users/220040168/.rvm/gems/ruby-1.9.2-p290@rails3tutorial/gems/rspec-rails-2.6.0/lib/rspec-rails.rb:10:in `load'
/Users/220040168/.rvm/gems/ruby-1.9.2-p290@rails3tutorial/gems/rspec-rails-2.6.0/lib/rspec-rails.rb:10:in `block in <class:Railtie>'
/Users/220040168/.rvm/gems/ruby-1.9.2-p290@rails3tutorial/gems/railties-3.1.1/lib/rails/railtie.rb:183:in `call'
/Users/220040168/.rvm/gems/ruby-1.9.2-p290@rails3tutorial/gems/railties-3.1.1/lib/rails/railtie.rb:183:in `block in load_tasks'
/Users/220040168/.rvm/gems/ruby-1.9.2-p290@rails3tutorial/gems/railties-3.1.1/lib/rails/railtie.rb:183:in `each'
/Users/220040168/.rvm/gems/ruby-1.9.2-p290@rails3tutorial/gems/railties-3.1.1/lib/rails/railtie.rb:183:in `load_tasks'
/Users/220040168/.rvm/gems/ruby-1.9.2-p290@rails3tutorial/gems/railties-3.1.1/lib/rails/engine.rb:396:in `block in load_tasks'
/Users/220040168/.rvm/gems/ruby-1.9.2-p290@rails3tutorial/gems/railties-3.1.1/lib/rails/application/railties.rb:8:in `each'
/Users/220040168/.rvm/gems/ruby-1.9.2-p290@rails3tutorial/gems/railties-3.1.1/lib/rails/application/railties.rb:8:in `all'
/Users/220040168/.rvm/gems/ruby-1.9.2-p290@rails3tutorial/gems/railties-3.1.1/lib/rails/engine.rb:396:in `load_tasks'
/Users/220040168/.rvm/gems/ruby-1.9.2-p290@rails3tutorial/gems/railties-3.1.1/lib/rails/application.rb:103:in `load_tasks'
/Users/220040168/.rvm/gems/ruby-1.9.2-p290@rails3tutorial/gems/railties-3.1.1/lib/rails/railtie/configurable.rb:30:in `method_missing'
/Users/220040168/rails_projects/sample_app/Rakefile:7:in `<top (required)>'
/Users/220040168/.rvm/gems/ruby-1.9.2-p290@rails3tutorial/gems/rake-0.9.2.2/lib/rake/rake_module.rb:25:in `load'
/Users/220040168/.rvm/gems/ruby-1.9.2-p290@rails3tutorial/gems/rake-0.9.2.2/lib/rake/rake_module.rb:25:in `load_rakefile'
/Users/220040168/.rvm/gems/ruby-1.9.2-p290@rails3tutorial/gems/rake-0.9.2.2/lib/rake/application.rb:501:in `raw_load_rakefile'
/Users/220040168/.rvm/gems/ruby-1.9.2-p290@rails3tutorial/gems/rake-0.9.2.2/lib/rake/application.rb:82:in `block in load_rakefile'
/Users/220040168/.rvm/gems/ruby-1.9.2-p290@rails3tutorial/gems/rake-0.9.2.2/lib/rake/application.rb:133:in `standard_exception_handling'
/Users/220040168/.rvm/gems/ruby-1.9.2-p290@rails3tutorial/gems/rake-0.9.2.2/lib/rake/application.rb:81:in `load_rakefile'
/Users/220040168/.rvm/gems/ruby-1.9.2-p290@rails3tutorial/gems/rake-0.9.2.2/lib/rake/application.rb:65:in `block in run'
/Users/220040168/.rvm/gems/ruby-1.9.2-p290@rails3tutorial/gems/rake-0.9.2.2/lib/rake/application.rb:133:in `standard_exception_handling'
/Users/220040168/.rvm/gems/ruby-1.9.2-p290@rails3tutorial/gems/rake-0.9.2.2/lib/rake/application.rb:63:in `run'
/Users/220040168/.rvm/gems/ruby-1.9.2-p290@rails3tutorial/gems/rake-0.9.2.2/bin/rake:33:in `<top (required)>'
/Users/220040168/.rvm/gems/ruby-1.9.2-p290@rails3tutorial/bin/rake:19:in `load'
/Users/220040168/.rvm/gems/ruby-1.9.2-p290@rails3tutorial/bin/rake:19:in `<main>'

---

看起来与此问题相关

---

是否尝试升级到比2.6.0更新的rspec rails版本？堆栈跟踪？另外，搜索您的项目的先决条件，看看是否有调用此方法的内容。请将其全部添加到您的答案中。另外，Gemfile可能会有所帮助，因为Gem依赖关系，我也有类似的错误。将Gemfile添加到问题中，您是否可以向我们显示stacktrace（使用

--trace

），这将有希望显示出发生错误的地方。从我的头顶：有东西在对一个不存在的对象调用

先决条件

。例如，缺少配置？我们需要更多的信息来提供任何帮助。这就解决了问题…我必须重新安装并更新我的gemlock文件以获得更新。在管理我的gem版本方面有什么建议吗？谢谢你的帮助！！

source 'http://rubygems.org'

gem 'rails', '3.1.1'

# Bundle edge Rails instead:
# gem 'rails',     :git => 'git://github.com/rails/rails.git'

gem 'sqlite3'

group :development do
    gem 'rspec-rails', '2.6.0'
end

group :test do
    gem 'rspec', '2.6.0'
    gem 'webrat', '0.7.1'
    gem 'autotest', '4.3.2'
    gem 'autotest-rails-pure', '4.1.0'
    gem 'autotest-fsevent', '0.2.2'
    gem 'autotest-growl', '0.2.4'
end


# Gems used only for assets and not required
# in production environments by default.
group :assets do
  gem 'sass-rails',   '~> 3.1.4'
  gem 'coffee-rails', '~> 3.1.1'
  gem 'uglifier', '>= 1.0.3'
end

gem 'jquery-rails'

# To use ActiveModel has_secure_password
# gem 'bcrypt-ruby', '~> 3.0.0'

# Use unicorn as the web server
# gem 'unicorn'

# Deploy with Capistrano
# gem 'capistrano'

# To use debugger
# gem 'ruby-debug19', :require => 'ruby-debug'