Ruby 2.4 和 Rails 4 堆栈级别太深 (SystemStackError)

Question

我正在尝试在 Rails 4.0.8 中运行新创建的项目，但收到错误消息：

    rails s
=> Booting WEBrick
=> Rails 4.0.8 application starting in development on http://0.0.0.0:3000
=> Run `rails server -h` for more startup options
=> Ctrl-C to shutdown server
/usr/local/lib/ruby/gems/2.4.0/gems/activesupport-4.0.8/lib/active_support/core_ext/numeric/conversions.rb:121: warning: constant ::Fixnum is deprecated
/usr/local/lib/ruby/gems/2.4.0/gems/activesupport-4.0.8/lib/active_support/core_ext/numeric/conversions.rb:121: warning: constant ::Bignum is deprecated
Exiting
/usr/local/lib/ruby/gems/2.4.0/gems/activesupport-4.0.8/lib/active_support/core_ext/numeric/conversions.rb:124:in `block (2 levels) in <class:Numeric>': stack level too deep (SystemStackError)
    from /usr/local/lib/ruby/gems/2.4.0/gems/activesupport-4.0.8/lib/active_support/core_ext/numeric/conversions.rb:131:in `block (2 levels) in <class:Numeric>'
    from /usr/local/lib/ruby/gems/2.4.0/gems/activesupport-4.0.8/lib/active_support/core_ext/numeric/conversions.rb:131:in `block (2 levels) in <class:Numeric>'
    from /usr/local/lib/ruby/gems/2.4.0/gems/activesupport-4.0.8/lib/active_support/core_ext/numeric/conversions.rb:131:in `block (2 levels) in <class:Numeric>'
    from /usr/local/lib/ruby/gems/2.4.0/gems/activesupport-4.0.8/lib/active_support/core_ext/numeric/conversions.rb:131:in `block (2 levels) in <class:Numeric>'
    from /usr/local/lib/ruby/gems/2.4.0/gems/activesupport-4.0.8/lib/active_support/core_ext/numeric/conversions.rb:131:in `block (2 levels) in <class:Numeric>'
    from /usr/local/lib/ruby/gems/2.4.0/gems/activesupport-4.0.8/lib/active_support/core_ext/numeric/conversions.rb:131:in `block (2 levels) in <class:Numeric>'
    from /usr/local/lib/ruby/gems/2.4.0/gems/activesupport-4.0.8/lib/active_support/core_ext/numeric/conversions.rb:131:in `block (2 levels) in <class:Numeric>'
    from /usr/local/lib/ruby/gems/2.4.0/gems/activesupport-4.0.8/lib/active_support/core_ext/numeric/conversions.rb:131:in `block (2 levels) in <class:Numeric>'
     ... 5532 levels...
    from /usr/local/lib/ruby/gems/2.4.0/gems/railties-4.0.8/lib/rails/commands.rb:71:in `tap'
    from /usr/local/lib/ruby/gems/2.4.0/gems/railties-4.0.8/lib/rails/commands.rb:71:in `<top (required)>'
    from bin/rails:4:in `require'
    from bin/rails:4:in `<main>'

Ruby 版本：

Rails 4.0.8

我的 Gemefile：

source 'https://rubygems.org'

# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
gem 'rails', '4.0.8'

# Use sqlite3 as the database for Active Record
gem 'sqlite3'

# Use SCSS for stylesheets
gem 'sass-rails', '~> 4.0.2'

# Use Uglifier as compressor for JavaScript assets
gem 'uglifier', '>= 1.3.0'

# Use CoffeeScript for .js.coffee assets and views
gem 'coffee-rails', '~> 4.0.0'

# See https://github.com/sstephenson/execjs#readme for more supported runtimes
# gem 'therubyracer', platforms: :ruby

# Use jquery as the JavaScript library
gem 'jquery-rails'

# Turbolinks makes following links in your web application faster. Read more: https://github.com/rails/turbolinks
gem 'turbolinks'

# Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
gem 'jbuilder', '~> 1.2'
gem 'json', github: 'flori/json', branch: 'v1.8'
group :doc do
  # bundle exec rake doc:rails generates the API under doc/api.
  gem 'sdoc', require: false
end

我尝试重新安装 Rails，因为在我的机器上安装了 5.0 Rails 之前。

本地宝石：

*** LOCAL GEMS ***

autoprefixer-rails (6.6.0)
coffee-rails (4.2.1, 4.0.1)
font-awesome-rails (4.7.0.1)
jquery-atwho-rails (1.3.2)
jquery-rails (4.2.2, 3.1.4)
rails (4.0.8, 4.0.0)
rails-dom-testing (2.0.2)
rails-html-sanitizer (1.0.3)
rails_12factor (0.0.3)
rails_serve_static_assets (0.0.5)
rails_stdout_logging (0.0.5)
sass-rails (5.0.6, 4.0.5)
sprockets-rails (3.2.0, 2.3.3, 2.0.1)

Meybe unistall：ruby 和 rails 会解决这个问题，但我不想这样做。 Beasically 我想安装两个版本的导轨，例如：导轨 4 和导轨 5。这种配置可行吗？

Answer 1

在 Ruby 2.4 中，统一了整数类型（即 Fixnum 和 Bignum 现在是相同的东西：Integer）。这导致与依赖于类的区别的现有 gem 存在相当多的不兼容。

旧版本的 ActiveSupport 不喜欢这种统一，并且在尝试序列化数据时会反对它。因此，您有以下两种选择之一：

• 您可以将 Ruby 降级到 2.4 之前的版本，例如Ruby 2.3.x。
• 或者您可以将 Rails 升级到更新的版本。最好是 Rails 5.x。 4.2-stable 分支中还有一个补丁，它与Rails 4.2.8 一起发布，使其成为Rails 4.2 系列的第一个正式支持Ruby 2.4 的版本。早期的 Rails 版本与 Ruby 2.4 不兼容。

Answer 2

关于错误，您运行的是刚刚发布的 Ruby 2.4，Rails 和 ActiveSupport（尤其是旧版本）很可能还不支持。

This Rails 指南指出您的 Rails 版本 (4.0.8) 更喜欢 Ruby 2.0。

您可以通过升级 Rails 安装 (gem 'rails', '5.0') 或使用版本管理器（例如 $ rvm install 2.3.0; rvm use 2.3.0）降级到旧版 Ruby 来修复错误。

Answer 3

我有同样的错误，但我不想升级到 5.0，我的应用程序很大，升级需要太多时间。我正在将Rails 4.1.7 升级到Rails to 4.2.8 第一个带有Ruby 2.4 支持的Rails 版本：

在 Gemfile 中：

gem 'rails', '4.2.8'

然后：

bundle update rails