ruby 升级后启动 Rails Server 时出错

Question

我使用的是 Ruby 2.2 和 Rails 4.2.0，一切正常但是自从将 Ruby 升级到 2.4.0 后，我收到以下错误消息。 我也试过 Ruby 2.6.5。 一样。 请帮忙！

rails s
/Users/varunaggarwal/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/roxml-3.3.1/lib/roxml/definition.rb:156: warning: constant ::Fixnum is deprecated
/Users/varunaggarwal/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/activesupport-4.2.0/lib/active_support/core_ext/numeric/conversions.rb:121: warning: constant ::Fixnum is deprecated
/Users/varunaggarwal/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/activesupport-4.2.0/lib/active_support/core_ext/numeric/conversions.rb:121: warning: constant ::Bignum is deprecated
/Users/varunaggarwal/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/activesupport-4.2.0/lib/active_support/core_ext/numeric/conversions.rb:131:in `block (2 levels) in <class:Numeric>': stack level too deep (SystemStackError)
  from /Users/varunaggarwal/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/activesupport-4.2.0/lib/active_support/core_ext/numeric/conversions.rb:131:in `block (2 levels) in <class:Numeric>'
  from /Users/varunaggarwal/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/activesupport-4.2.0/lib/active_support/core_ext/numeric/conversions.rb:131:in `block (2 levels) in <class:Numeric>'
  from /Users/varunaggarwal/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/activesupport-4.2.0/lib/active_support/core_ext/numeric/conversions.rb:131:in `block (2 levels) in <class:Numeric>'
  from /Users/varunaggarwal/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/activesupport-4.2.0/lib/active_support/core_ext/numeric/conversions.rb:131:in `block (2 levels) in <class:Numeric>'
  from /Users/varunaggarwal/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/activesupport-4.2.0/lib/active_support/core_ext/numeric/conversions.rb:131:in `block (2 levels) in <class:Numeric>'
  from /Users/varunaggarwal/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/activesupport-4.2.0/lib/active_support/core_ext/numeric/conversions.rb:131:in `block (2 levels) in <class:Numeric>'
  from /Users/varunaggarwal/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/activesupport-4.2.0/lib/active_support/core_ext/numeric/conversions.rb:131:in `block (2 levels) in <class:Numeric>'
  from /Users/varunaggarwal/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/activesupport-4.2.0/lib/active_support/core_ext/numeric/conversions.rb:131:in `block (2 levels) in <class:Numeric>'
   ... 4818 levels...
  from /Users/varunaggarwal/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/railties-4.2.0/lib/rails/commands/commands_tasks.rb:39:in `run_command!'
  from /Users/varunaggarwal/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/railties-4.2.0/lib/rails/commands.rb:17:in `<top (required)>'
  from bin/rails:8:in `require'
  from bin/rails:8:in `<main>'

Answer 1

我在这里（ https://github.com/rails/rails/issues/27670 ）读到 Ruby 2.4 需要 Rails 4.2.8 或更高版本。 将 rails 从 4.2.0 升级到 4.2.8 解决了这个问题。

在 gemfile 中，我将 gem 'rails', '4.2.0' 更改为 gem 'rails', '4.2.8'