总是安装相同版本的 gem？

Question

我正在尝试通过以下方式创建新的ruby on rails 项目：

rails new . --no-ri --no-rdoc

但是在这个命令执行结束时我得到了：

         run  bundle install
Bundler could not find compatible versions for gem "bundler":
  In Gemfile:
    rails (= 4.2.6) was resolved to 4.2.6, which depends on
      bundler (< 2.0, >= 1.3.0)

  Current Bundler version:
    bundler (2.2.27)

Your bundle requires a different version of Bundler than the one you're running.
Install the necessary version with `gem install bundler:2.0.0.pre.3` and rerun bundler using `bundle _2.0.0.pre.3_ install`
Fetching gem metadata from https://rubygems.org/.............
Resolving dependencies...
         run  bundle exec spring binstub --all
Traceback (most recent call last):
    13: from /usr/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require'
    12: from /usr/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require'
    11: from /var/lib/gems/2.5.0/gems/bundler-2.2.27/lib/bundler/setup.rb:20:in `<top (required)>'
    10: from /var/lib/gems/2.5.0/gems/bundler-2.2.27/lib/bundler/ui/shell.rb:88:in `silence'
     9: from /var/lib/gems/2.5.0/gems/bundler-2.2.27/lib/bundler/ui/shell.rb:136:in `with_level'
     8: from /var/lib/gems/2.5.0/gems/bundler-2.2.27/lib/bundler/setup.rb:20:in `block in <top (required)>'
     7: from /var/lib/gems/2.5.0/gems/bundler-2.2.27/lib/bundler.rb:149:in `setup'
     6: from /var/lib/gems/2.5.0/gems/bundler-2.2.27/lib/bundler/runtime.rb:18:in `setup'
     5: from /var/lib/gems/2.5.0/gems/bundler-2.2.27/lib/bundler/definition.rb:234:in `specs_for'
     4: from /var/lib/gems/2.5.0/gems/bundler-2.2.27/lib/bundler/definition.rb:483:in `materialize'
     3: from /var/lib/gems/2.5.0/gems/bundler-2.2.27/lib/bundler/definition.rb:262:in `resolve'
     2: from /var/lib/gems/2.5.0/gems/bundler-2.2.27/lib/bundler/resolver.rb:23:in `resolve'
     1: from /var/lib/gems/2.5.0/gems/bundler-2.2.27/lib/bundler/resolver.rb:46:in `start'
/var/lib/gems/2.5.0/gems/bundler-2.2.27/lib/bundler/resolver.rb:59:in `rescue in start': Bundler could not find compatible versions for gem "bundler": (Bundler::VersionConflict)
  In Gemfile:
    rails (= 4.2.6) was resolved to 4.2.6, which depends on
      bundler (< 2.0, >= 1.3.0)

  Current Bundler version:
    bundler (2.2.27)

Your bundle requires a different version of Bundler than the one you're running.
Install the necessary version with `gem install bundler:1.11.2` and rerun bundler using `spring _1.11.2_ binstub --all`

之后我删除了 ruby​​，所以使用命令 ruby -v 我得到了：

bash: /home/iva/.rbenv/shims/ruby: No such file or directory

然后我再次安装了 ruby​​ 并使用 gem install bundler:1.11.2 安装了 gem。但是在安装了检查 ruby​​ 和 gem 的版本之后，我得到了：

ruby -v
ruby 2.5.1p57 (2018-03-29 revision 63029) [x86_64-linux]
gem -v
2.7.6

当我使用版本1.11.2 发出命令时，我不知道这个2.7.6 版本的gem 怎么样？ 所以它似乎是一个圈子，我不知道如何摆脱它。我正在安装 ruby​​，它需要旧版本的 gem，但是任何命令都会在我的计算机上安装最新版本的 gem。在这种情况下我该怎么办？

================================================ =============== 此命令的响应是：

rbenv versions
* 2.5.1 (set by /home/iva/.rbenv/version)
echo $PATH
/home/iva/.rbenv/shims:/home/iva/.rbenv/bin:/home/iva/.rbenv/shims:/home/iva/.rbenv/bin:/home/iva/.rbenv/shims:/home/iva/.rbenv/bin:/home/iva/.rbenv/shims:/home/iva/.rbenv/bin:/home/iva/.rbenv/shims:/home/iva/.rbenv/bin:/home/iva/.rbenv/shims:/home/iva/.rbenv/bin:/home/iva/bin:/home/iva/.local/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin:/home/iva/.rvm/bin:/home/iva/.rvm/bin:/home/iva/.rvm/bin:/home/iva/.rvm/bin:/home/iva/.rvm/bin

Answer 1

1. 您为什么要创建一个新的 Rails 项目使用 rails 版本 4.2.6？这真的是故意的吗？！ Rails 4.2.6 于 2016 年 3 月 11 日为 released。它相当老旧/过时，不再受支持。 latest version of rails 是 6.1.4.1。

2. 错误信息说你的bundler的版本和rails的版本不兼容。该错误中没有任何内容表明您需要重新安装 ruby​​，但我想它没有造成任何伤害......

3. gem 和 bundler 是不同的东西。要检查bundler 的版本，请运行：bundle -v，而不是gem -v。您应该希望看到1.11.2 如您所料。

简而言之：

• 我认为您当前的设置没有任何问题。如果你重新安装rails v4.2.6，然后运行rails new，我希望它可以工作。您的困惑似乎在于比较不同事物的版本（即ruby、gem 和bundler）。
• 如果您刚刚安装了所有内容的最新版本，就可以避免这种混淆。我不清楚你为什么要尝试用这么旧的版本创建一个新的 rails 项目。也许您有充分的理由做出该决定，这很好；但如果没有，那么就使用最新版本。