rake错误:"警告:已初始化常量FileUtils :: OPT_TABLE"

Question

我已经看到有关此错误的类似问题,但所有这些都与rails有关.我没有使用铁轨; 我正在研究一个从yaml文件读取的本地rake任务,然后处理数据.我宁愿不为此安装bundler(类似rails问题的解决方案建议在前面加上bundle exec),因为这个脚本很简单,因此不需要它.

这是简化的代码(它得到与我正在处理的代码相同的错误):

require 'FileUtils'
require 'yaml'

SOME_FILE = "#{Dir.pwd}/some_file.yaml"

task default: :foo

task :foo do
  bar = File.open(SOME_FILE) { |yf| YAML::load( yf ) }
  bar.each {|k,v| puts k}
end

这是错误列表:

/Users/jpalmieri/.rbenv/versions/2.0.0-p353/lib/ruby/2.0.0/FileUtils.rb:93: warning: already initialized constant FileUtils::OPT_TABLE
/Users/jpalmieri/.rbenv/versions/2.0.0-p353/lib/ruby/2.0.0/fileutils.rb:93: warning: previous definition of OPT_TABLE was here
/Users/jpalmieri/.rbenv/versions/2.0.0-p353/lib/ruby/2.0.0/FileUtils.rb:1272: warning: already initialized constant FileUtils::Entry_::S_IF_DOOR
/Users/jpalmieri/.rbenv/versions/2.0.0-p353/lib/ruby/2.0.0/fileutils.rb:1272: warning: previous definition of S_IF_DOOR was here
/Users/jpalmieri/.rbenv/versions/2.0.0-p353/lib/ruby/2.0.0/FileUtils.rb:1535: warning: already initialized constant FileUtils::Entry_::DIRECTORY_TERM
/Users/jpalmieri/.rbenv/versions/2.0.0-p353/lib/ruby/2.0.0/fileutils.rb:1535: warning: previous definition of DIRECTORY_TERM was here
/Users/jpalmieri/.rbenv/versions/2.0.0-p353/lib/ruby/2.0.0/FileUtils.rb:1537: warning: already initialized constant FileUtils::Entry_::SYSCASE
/Users/jpalmieri/.rbenv/versions/2.0.0-p353/lib/ruby/2.0.0/fileutils.rb:1537: warning: previous definition of SYSCASE was here
/Users/jpalmieri/.rbenv/versions/2.0.0-p353/lib/ruby/2.0.0/FileUtils.rb:1656: warning: already initialized constant FileUtils::LOW_METHODS
/Users/jpalmieri/.rbenv/versions/2.0.0-p353/lib/ruby/2.0.0/fileutils.rb:1656: warning: previous definition of LOW_METHODS was here
/Users/jpalmieri/.rbenv/versions/2.0.0-p353/lib/ruby/2.0.0/FileUtils.rb:1662: warning: already initialized constant FileUtils::METHODS
/Users/jpalmieri/.rbenv/versions/2.0.0-p353/lib/ruby/2.0.0/fileutils.rb:1662: warning: previous definition of METHODS was here

尽管有警告,脚本仍然运行良好; 在puts警告之后,上面的代码会按预期方式按键.

Answer 1

我写的时候会出现这个警告require 'FileUtils'.如果我写require 'fileutils'(全部小写)警告消失.

此链接可能有助于解释行为.我认为本质上ruby认为FileUtils并且fileutils是不同的模块,因此导入它两次.然后,常量的重新声明会发出警告信息.