Question

我正在写一个宝石。我依赖的一个宝石是停止执行需要它的文件。这是一个例子：

# main.rb
require 'bundler'
Bundler.require
puts 'Going to do something now...'
Mygem::Nested::Thing.do_something

# Gemfile
source 'https://rubygems.org'
gem 'mygem', path: './mygem'

# mygem.gemspec
...
spec.add_dependency 'mygem-dependency'
...

# mygem.rb
puts 'Loading mygem.rb'
require_relative 'mygem/nested/thing'
puts 'Finished loading my gem.rb'

# mygem/nested/thing.rb
puts 'Loading mygem/nested/thing.rb'
require 'mygem-dependency'
module Mygem
  module Nested
    class Thing
      def self.do_something
        MygemDependency.do_something
      end
    end
  end
end
puts 'Finished loading mygem/nested/thing.rb'

当我运行脚本时，当我尝试加载依赖gem时加载停止：

$ bundle exec ruby main.rb
Loading mygem.rb
Loading mygem/nested/thing.rb
Going to do something now...
main.rb:4:in `<main>': uninitialized constant Mygem::Nested (NameError)

它永远不会完成加载我宝石的其余部分。但是，似乎在Bundler.require之后继续执行所有操作。如果我注释掉需要依赖gem的行，除了依赖于其他gem的行之外，一切都按预期工作。

$ bundle exec ruby main.rb
Loading mygem.rb
Loading mygem/nested/thing.rb
Finished loading mygem/nested/thing.rb
Finished loading my gem.rb
Going to do something now...
mygem/nested/thing.rb:7:in `<main>': uninitialized constant Mygem::Nested::Thing::MygemDependency (NameError)

如果我将require语句移动到方法体中，我会收到一个加载错误：

module Mygem
  module Nested
    class Thing
      def self.do_something
        require 'mygem-dependency'
        MygemDependency.do_something
      end
    end
  end
end

$ bundle exec ruby main.rb
Loading mygem.rb
Loading mygem/nested/thing.rb
Finished loading mygem/nested/thing.rb
Finished loading my gem.rb
Going to do something now...
mygem/nested/thing.rb:7:in `require': cannot load such file -- mygem-dependency (LoadError)

宝石没有问题因为我可以直接使用它。出于某种原因，我在尝试在我的宝石中使用它时遇到了问题。我怎样才能找出问题并解决它？

Answer 1

如何在需要特定Ruby gem时调试正在停止执行

选择任何错误，并尝试解决问题。重复，直到您不再收到任何错误。获得的经验越多，您就越能够知道从哪里开始。当你收到这样的错误时：

main.rb:4:in `<main>': uninitialized constant Mygem::Nested (NameError)

我会检查：

您是否确实定义了以Mygem::Nested开头的内容？
您是否在一份要求声明中拼错了名字？它应该是MyGem::Nested吗？
您的require语句是否使用正确的语法？换句话说，您是否需要使用完整路径，相对路径或文件名？

您的代码实际上适合我：

$ tree .
.
├── Gemfile
├── Gemfile.lock
├── main.rb
├── mygem
│   ├── lib
│   │   ├── mygem
│   │   │   └── nested
│   │   │       └── thing.rb
│   │   └── mygem.rb
│   └── mygem.gemspec
└── your_main.rb

main.rb的：

require 'bundler'
Bundler.require

#Bundler.setup(:default)
#require 'mygem'

Mygem::Nested::Thing.do_something

mygem.gemspec：

Gem::Specification.new do |s|
  s.name        = 'mygem'
  s.version     = '0.0.0'
  s.date        = '2015-02-12'
  s.summary     = "A new internet!"
  s.description = "Creates a new internet that is completely secure."
  s.authors     = ["7stud"]
  s.email       = '7@new.i.com'
  s.files       = [
    "lib/mygem.rb",
    "lib/mygem/nested/thing.rb",
  ]
  s.homepage    = 'http://rubygems.org/gems/mygem'
  s.license     = 'GNU Public'

  s.add_dependency 'nokogiri' 
end

LIB / mygem.rb：

puts 'Loading mygem.rb'
require_relative 'mygem/nested/thing'
puts 'Finished loading my gem.rb'

LIB / mygem /嵌套/ thing.rb：

puts 'Loading mygem/nested/thing.rb'

require 'nokogiri'  #Your gem's dependency, which is added to .gemspec file

module Mygem
  module Nested
    class Thing
      def self.do_something
        doc = Nokogiri::HTML('<div>hello</div>')
        puts doc.at_xpath('//div/text()')
      end
    end
  end
end

puts 'Finished loading mygem/nested/thing.rb'

的Gemfile：

source 'https://rubygems.org'

gem 'mygem', path: './mygem'

结果：

$ ruby --version
ruby 2.1.2p95 (2014-05-08 revision 45877) [x86_64-darwin10.0]

$ ruby main.rb 
Loading mygem.rb
Loading mygem/nested/thing.rb
Finished loading mygem/nested/thing.rb
Finished loading my gem.rb
hello

Answer 2

问题证明是＆＃34;扩展＆＃34;我正在使用的gem（mygem-dependency）未在其mygem-dependency.rb目录中提供名为lib的文件。因此，我不需要mygem-dependency，而是需要mygem/dependency。

另一个问题是Bundler正在为Gemfile中指定的gem中的依赖关系加载错误。 https://github.com/bundler/bundler/blob/master/lib/bundler/runtime.rb#L49

当需要特定的Ruby gem时如何调试停止执行？

2 个答案: