尝试在 Rails 上启动 ruby​​ 时出错

Question

I created a new app with ruby on rails and tried to start it, then got this error.

1 - have ruby-dev-kit

2 - ruby version 2.7.0

Tried to fix this error in many ways. I use Linux

Traceback

       11: from /usr/lib/ruby/2.7.0/psych/nodes.rb:2:in `<main>'
        10: from /var/lib/gems/2.7.0/gems/bootsnap-1.9.1/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:31:in `require'
         9: from /var/lib/gems/2.7.0/gems/bootsnap-1.9.1/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `require_with_bootsnap_lfi'
         8: from /var/lib/gems/2.7.0/gems/bootsnap-1.9.1/lib/bootsnap/load_path_cache/loaded_features_index.rb:92:in `register'
         7: from /var/lib/gems/2.7.0/gems/bootsnap-1.9.1/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:23:in `block in require_with_bootsnap_lfi'
         6: from /var/lib/gems/2.7.0/gems/bootsnap-1.9.1/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:23:in `require'
         5: from /usr/lib/ruby/2.7.0/psych/nodes/node.rb:2:in `<main>'
         4: from /var/lib/gems/2.7.0/gems/bootsnap-1.9.1/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:31:in `require'
         3: from /var/lib/gems/2.7.0/gems/bootsnap-1.9.1/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `require_with_bootsnap_lfi'
         2: from /var/lib/gems/2.7.0/gems/bootsnap-1.9.1/lib/bootsnap/load_path_cache/loaded_features_index.rb:92:in `register'
         1: from /var/lib/gems/2.7.0/gems/bootsnap-1.9.1/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:23:in `block in require_with_bootsnap_lfi'
/var/lib/gems/2.7.0/gems/bootsnap-1.9.1/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:23:in `require': superclass mismatch for class StringIO (TypeError)

Answer 1

The method is already defined somewhere else

You can test that by using the defined? method and update gem version accordingly.