Ruby on Rails创建新应用遇语法错误，寻求解决办法

问题详情 #

执行命令创建Rails项目：

rails new abc -d mysql

环境信息：

• Ruby版本：2.7.0
• 尝试的Rails版本：7.1.3.2、7.1.5.1

错误触发前控制台输出：

rails importmap:install

完整错误信息：

bin/rails aborted!
SyntaxError: /var/lib/gems/2.7.0/gems/activerecord-7.1.5.1/lib/active_record/attribute_methods.rb:482: syntax error, unexpected (...
...   def method_missing(name, ...)
...                            ^~~
/var/lib/gems/2.7.0/gems/activerecord-7.1.5.1/lib/active_record/attribute_methods.rb:491: unexpected ...
/var/lib/gems/2.7.0/gems/activerecord-7.1.5.1/lib/active_record/attribute_methods.rb:495: syntax error, unexpected ')'
...  return public_send(name, ...)
...                              ^
/var/lib/gems/2.7.0/gems/activerecord-7.1.5.1/lib/active_record/attribute_methods.rb:551: syntax error, unexpected end-of-input, expecting `end'
/var/lib/gems/2.7.0/gems/bootsnap-1.18.4/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:30:in `require'
/var/lib/gems/2.7.0/gems/bootsnap-1.18.4/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:30:in `require'
/var/lib/gems/2.7.0/gems/activerecord-7.1.5.1/lib/active_record.rb:128:in `<module:ActiveRecord>'
/var/lib/gems/2.7.0/gems/activerecord-7.1.5.1/lib/active_record.rb:38:in `<main>'
/var/lib/gems/2.7.0/gems/bootsnap-1.18.4/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:30:in `require'
/var/lib/gems/2.7.0/gems/bootsnap-1.18.4/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:30:in `require'
/var/lib/gems/2.7.0/gems/activerecord-7.1.5.1/lib/active_record/railtie.rb:3:in `<main>'
/var/lib/gems/2.7.0/gems/bootsnap-1.18.4/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:30:in `require'
/var/lib/gems/2.7.0/gems/bootsnap-1.18.4/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:30:in `require'
/var/lib/gems/2.7.0/gems/railties-7.1.5.1/lib/rails/all.rb:20:in `block in <main>'
/var/lib/gems/2.7.0/gems/railties-7.1.5.1/lib/rails/all.rb:18:in `each'
/var/lib/gems/2.7.0/gems/railties-7.1.5.1/lib/rails/all.rb:18:in `<main>'
/var/lib/gems/2.7.0/gems/bootsnap-1.18.4/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:30:in `require'
/var/lib/gems/2.7.0/gems/bootsnap-1.18.4/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:30:in `require'
/home/akanksha/Work/Projects/materials_generator/abc/config/application.rb:3:in `<main>'
/home/akanksha/Work/Projects/materials_generator/abc/Rakefile:4:in `require_relative'
/home/akanksha/Work/Projects/materials_generator/abc/Rakefile:4:in `<main>'
/var/lib/gems/2.7.0/gems/railties-7.1.5.1/lib/rails/commands/rake/rake_command.rb:43:in `block in with_rake'
/var/lib/gems/2.7.0/gems/railties-7.1.5.1/lib/rails/commands/rake/rake_command.rb:41:in `with_rake'
/var/lib/gems/2.7.0/gems/railties-7.1.5.1/lib/rails/commands/rake/rake_command.rb:20:in `perform'
/var/lib/gems/2.7.0/gems/railties-7.1.5.1/lib/rails/command.rb:156:in `invoke_rake'
/var/lib/gems/2.7.0/gems/railties-7.1.5.1/lib/rails/command.rb:73:in `block in invoke'
/var/lib/gems/2.7.0/gems/railties-7.1.5.1/lib/rails/command.rb:149:in `with_argv'
/var/lib/gems/2.7.0/gems/railties-7.1.5.1/lib/rails/command.rb:69:in `invoke'
/var/lib/gems/2.7.0/gems/railties-7.1.5.1/lib/rails/commands.rb:18:in `<main>'
/var/lib/gems/2.7.0/gems/bootsnap-1.18.4/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:30:in `require'
/var/lib/gems/2.7.0/gems/bootsnap-1.18.4/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:30:in `require'
bin/rails:4:in `<main>'
(See full trace by running task with --trace)

错误原因 #

Rails 7.1.x 版本引入了Ruby 3.0+专属的省略号参数语法（...），比如def method_missing(name, ...)这种写法，而Ruby 2.7.0并不支持该语法，导致ActiveRecord代码加载时触发语法错误。

解决方法 #

• 方案一：升级Ruby版本（推荐）
  Rails 7.1官方要求最低Ruby版本为3.0.0，将Ruby升级到3.0或更高版本（如3.1、3.2）即可解决该兼容性问题。

• 方案二：降级Rails版本
  如果暂时无法升级Ruby，可将Rails版本降级到7.0.x系列（该系列兼容Ruby 2.7.0），创建项目时指定版本：

  rails _7.0.8_ new abc -d mysql
  

内容的提问来源于stack exchange，提问作者Akanksha