耙子中止；运行 bundle exec rake db:migrate 时出现 SystemStackError、NoMethodError答案

【问题标题】：rake aborted; SystemStackError, NoMethodError while running bundle exec rake db:migrate耙子中止；运行 bundle exec rake db:migrate 时出现 SystemStackError、NoMethodError
【发布时间】：2020-11-18 23:31:30
【问题描述】：

我正在处理一个在 2014 年左右制作的现有项目。运行 bundle exec rake db:migrate 时出现以下错误：

bundle exec rake db:migrate
D:/Ruby/Ruby26-x64/lib/ruby/gems/2.6.0/gems/activesupport-4.0.0/lib/active_support/core_ext/object/duplicable.rb:82: warning: BigDecimal.new is deprecated; use BigDecimal() method instead.
D:/Ruby/Ruby26-x64/lib/ruby/gems/2.6.0/gems/activesupport-4.0.0/lib/active_support/values/time_zone.rb:282: warning: circular argument reference - now
D:/Ruby/Ruby26-x64/lib/ruby/gems/2.6.0/gems/activesupport-4.0.0/lib/active_support/core_ext/numeric/conversions.rb:121: warning: constant ::Fixnum is deprecated
D:/Ruby/Ruby26-x64/lib/ruby/gems/2.6.0/gems/activesupport-4.0.0/lib/active_support/core_ext/numeric/conversions.rb:121: warning: constant ::Bignum is deprecated
rake aborted!
SystemStackError: stack level too deep
rake aborted!
NoMethodError: undefined method `reject' for nil:NilClass
Traceback (most recent call last):
D:/Ruby/Ruby26-x64/bin/rake: stack level too deep (SystemStackError)
D:/Ruby/Ruby26-x64/bin/rake: undefined method `reject' for nil:NilClass (NoMethodError)
        9: from D:/Ruby/Ruby26-x64/bin/rake:23:in `<main>'
        8: from D:/Ruby/Ruby26-x64/bin/rake:23:in `load'
        7: from D:/Ruby/Ruby26-x64/lib/ruby/gems/2.6.0/gems/rake-13.0.1/exe/rake:27:in `<top (required)>'
        6: from D:/Ruby/Ruby26-x64/lib/ruby/gems/2.6.0/gems/rake-13.0.1/lib/rake/application.rb:80:in `run'
        5: from D:/Ruby/Ruby26-x64/lib/ruby/gems/2.6.0/gems/rake-13.0.1/lib/rake/application.rb:185:in `standard_exception_handling'
        4: from D:/Ruby/Ruby26-x64/lib/ruby/gems/2.6.0/gems/rake-13.0.1/lib/rake/application.rb:195:in `rescue in standard_exception_handling'
        3: from D:/Ruby/Ruby26-x64/lib/ruby/gems/2.6.0/gems/rake-13.0.1/lib/rake/application.rb:208:in `display_error_message'
        2: from D:/Ruby/Ruby26-x64/lib/ruby/gems/2.6.0/gems/rake-13.0.1/lib/rake/application.rb:218:in `display_exception_details'
        1: from D:/Ruby/Ruby26-x64/lib/ruby/gems/2.6.0/gems/rake-13.0.1/lib/rake/application.rb:249:in `display_exception_backtrace'
D:/Ruby/Ruby26-x64/lib/ruby/gems/2.6.0/gems/rake-13.0.1/lib/rake/backtrace.rb:21:in `collapse': undefined method `reject' for nil:NilClass (NoMethodError)

我的 Ruby 版本是 2.6.6p146，Rails 4.0.0（根据 gemfile 的要求）

我也读过类似的问题并尝试过gem update --system，但同样的问题仍然存在。

【问题讨论】：

标签： ruby-on-rails ruby rake

【解决方案1】：

我真的不能说 Rails 4 不能在 Ruby 2.6 上运行。但总有可能遇到微妙的问题，具体取决于您使用的功能和包含的宝石。从 Ruby 2.4 开始，它统一了 Fixnum 和 Bignum，以及 unicode 更改——这可能会产生影响。

我建议你将 Rails 版本升级到 6 或将 Ruby 版本降级到 2.2。

【讨论】：