雷克中止！无法加载此类文件 -- arel/visitor/mysql

Question

当我尝试运行 Rake（也使用 Rails 命令）命令时，我收到了这个错误：

Rake aborted! cannot load such file -- arel/visitor/mysql
/config/application.rb:7:in <top (required)>
/Rakefile:4:in 'require_relative'

MySql 数据库完美运行，我在 Gemfile 中添加了 gem 'mysql2'。

使用 --trace 参数：

rake aborted!
LoadError: cannot load such file -- arel/visitors/mysql
/home/sneffar/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/activesupport-6.0.3.1/lib/active_support/dependencies.rb:324:in `require'
/home/sneffar/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/activesupport-6.0.3.1/lib/active_support/dependencies.rb:324:in `block in require'
/home/sneffar/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/activesupport-6.0.3.1/lib/active_support/dependencies.rb:291:in `load_dependency'
/home/sneffar/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/activesupport-6.0.3.1/lib/active_support/dependencies.rb:324:in `require'
/home/sneffar/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/activerecord-6.0.3.1/lib/arel/visitors.rb:8:in `<top (required)>'
/home/sneffar/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/activesupport-6.0.3.1/lib/active_support/dependencies.rb:324:in `require'
/home/sneffar/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/activesupport-6.0.3.1/lib/active_support/dependencies.rb:324:in `block in require'
/home/sneffar/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/activesupport-6.0.3.1/lib/active_support/dependencies.rb:291:in `load_dependency'
/home/sneffar/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/activesupport-6.0.3.1/lib/active_support/dependencies.rb:324:in `require'
/home/sneffar/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/activerecord-6.0.3.1/lib/arel.rb:17:in `<top (required)>'
/home/sneffar/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/activesupport-6.0.3.1/lib/active_support/dependencies.rb:324:in `require'
/home/sneffar/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/activesupport-6.0.3.1/lib/active_support/dependencies.rb:324:in `block in require'
/home/sneffar/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/activesupport-6.0.3.1/lib/active_support/dependencies.rb:291:in `load_dependency'
/home/sneffar/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/activesupport-6.0.3.1/lib/active_support/dependencies.rb:324:in `require'
/home/sneffar/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/activerecord-6.0.3.1/lib/active_record.rb:29:in `<top (required)>'
/home/sneffar/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/activesupport-6.0.3.1/lib/active_support/dependencies.rb:324:in `require'
/home/sneffar/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/activesupport-6.0.3.1/lib/active_support/dependencies.rb:324:in `block in require'
/home/sneffar/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/activesupport-6.0.3.1/lib/active_support/dependencies.rb:291:in `load_dependency'
/home/sneffar/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/activesupport-6.0.3.1/lib/active_support/dependencies.rb:324:in `require'
/home/sneffar/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/activerecord-6.0.3.1/lib/active_record/railtie.rb:3:in `<top (required)>'
/home/sneffar/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/activesupport-6.0.3.1/lib/active_support/dependencies.rb:324:in `require'
/home/sneffar/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/activesupport-6.0.3.1/lib/active_support/dependencies.rb:324:in `block in require'
/home/sneffar/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/activesupport-6.0.3.1/lib/active_support/dependencies.rb:291:in `load_dependency'
/home/sneffar/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/activesupport-6.0.3.1/lib/active_support/dependencies.rb:324:in `require'
/home/sneffar/working-dir/permission/config/application.rb:7:in `<top (required)>'
/home/sneffar/working-dir/permission/Rakefile:4:in `require_relative'
/home/sneffar/working-dir/permission/Rakefile:4:in `<top (required)>'
/home/sneffar/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rake-13.0.1/lib/rake/rake_module.rb:29:in `load'
/home/sneffar/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rake-13.0.1/lib/rake/rake_module.rb:29:in `load_rakefile'
/home/sneffar/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rake-13.0.1/lib/rake/application.rb:703:in `raw_load_rakefile'
/home/sneffar/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rake-13.0.1/lib/rake/application.rb:104:in `block in load_rakefile'
/home/sneffar/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rake-13.0.1/lib/rake/application.rb:186:in `standard_exception_handling'
/home/sneffar/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rake-13.0.1/lib/rake/application.rb:103:in `load_rakefile'
/home/sneffar/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rake-13.0.1/lib/rake/application.rb:82:in `block in run'
/home/sneffar/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rake-13.0.1/lib/rake/application.rb:186:in `standard_exception_handling'
/home/sneffar/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rake-13.0.1/lib/rake/application.rb:80:in `run'
/home/sneffar/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rake-13.0.1/exe/rake:27:in `<top (required)>'
/home/sneffar/.rbenv/versions/2.6.6/bin/rake:23:in `load'
/home/sneffar/.rbenv/versions/2.6.6/bin/rake:23:in `<main>'

Ruby --版本：2.6.6 导轨--版本：6.0.3.1 耙--版本：13.0.1

Answer 1

我认为你应该删除 arel：

gem uninstall arel

运行之后：

bundle install

这应该可以解决问题。

Answer 2

我也遇到过这个问题，并且同意 Nezir 的观点。 我相信就我而言，这是由于以下行为而发生的： MySQL 5.7.30 -> MySQL 8.0.20 -> MySQL 5.7.30 我第一次使用 MySQL 5.7.30 很好 bundle exec rake db:create db:structure:load