我的问题几乎在标题中.
例如在使用Rails 3.1应用程序创建的默认Gemfile中;
gem 'sass-rails','~> 3.1.5'
似乎我应该知道这一点,但是我在Bundler网站上找不到任何参考.
解决方法
从bundler网站：
The specifier ~> has a special meaning,best shown by example. ~> 2.0.3 is identical to >= 2.0.3 and < 2.1. ~> 2.1 is identical to >= 2.1 and < 3.0. ~> 2.2.beta will match prerelease versions like 2.2.beta.12.
见http://gembundler.com/gemfile.html和http://guides.rubygems.org/patterns/#pessimistic-version-constraint