Undefined method log for RuboCop::Lsp::Server

[asartalo]

I had a bad .rubocop.yml configuration and the LSP server wanted to show the error but it couldn't find the log method to use for that. I use VSCode with a rubocop extension (https://github.com/rubocop/vscode-rubocop) that uses the LSP.

I was able to workaround the issue by manually editing the LSP server source code on disk and adding a log method:

module RuboCop
  module Lsp
    # Language Server Protocol of RuboCop.
    # @api private
    class Server

      # Inserted method below...
      def log(message)
        Logger.log(message)
      end

      def initialize(config_store)
        @reader = LanguageServer::Protocol::Transport::Io::Reader.new($stdin)
        @writer = LanguageServer::Protocol::Transport::Io::Writer.new($stdout)
        @runtime = RuboCop::Lsp::Runtime.new(config_store)
        @routes = Routes.new(self)
      end
      # ... more code ...
    end
  end
end

---

Expected behavior

I expected to see some error log.

Actual behavior

LSP Server crashes because of missing method with the following output:

undefined method `log' for #<RuboCop::Lsp::Server:0x000000010f357d38 @reader=#<LanguageServer::Protocol::Transport::Io::Reader:0x000000010f357c20 @io=#<IO:<STDIN>>>, @writer=#<LanguageServer::Protocol::Transport::Io::Writer:0x000000010f357b30 @io=#<IO:<STDOUT>>>, @runtime=#<RuboCop::Lsp::Runtime:0x000000010f357a68 @config_store=#<RuboCop::ConfigStore:0x000000010f11f890 @options_config=nil, @path_cache={"[redacted]"=>"[redacted]/.rubocop.yml"}, @object_cache={}, @validated=true>, @logged_paths=[]>, @routes=#<RuboCop::Lsp::Routes:0x000000010f357928 @server=#<RuboCop::Lsp::Server:0x000000010f357d38 ...>, @text_cache={"file:///[redacted]/api.rb"=>"# frozen_string_literal: true\n\nrequire_relative \"api/callbacks_delegator\"\n\nrequire_relative 'api/[source redacted]"}>>

          log("Error #{e.class} #{e.message[0..100]}")
          ^^^
Did you mean?  load
[redacted]/.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/rubocop-1.53.1/lib/rubocop/lsp/server.rb:39:in `rescue in block in start'
[redacted]/.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/rubocop-1.53.1/lib/rubocop/lsp/server.rb:31:in `block in start'
[redacted]/.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/language_server-protocol-3.17.0.3/lib/language_server/protocol/transport/io/reader.rb:20:in `read'
[redacted]/.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/rubocop-1.53.1/lib/rubocop/lsp/server.rb:30:in `start'
[redacted]/.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/rubocop-1.53.1/lib/rubocop/cli/command/lsp.rb:14:in `run'
[redacted]/.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/rubocop-1.53.1/lib/rubocop/cli/command.rb:11:in `run'
[redacted]/.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/rubocop-1.53.1/lib/rubocop/cli/environment.rb:18:in `run'
[redacted]/.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/rubocop-1.53.1/lib/rubocop/cli.rb:118:in `run_command'
[redacted]/.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/rubocop-1.53.1/lib/rubocop/cli.rb:184:in `handle_exiting_options'
[redacted]/.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/rubocop-1.53.1/lib/rubocop/cli.rb:158:in `act_on_options'
[redacted]/.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/rubocop-1.53.1/lib/rubocop/cli.rb:47:in `block in run'
[redacted]/.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/rubocop-1.53.1/lib/rubocop/cli.rb:77:in `profile_if_needed'
[redacted]/.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/rubocop-1.53.1/lib/rubocop/cli.rb:43:in `run'
[redacted]/.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/rubocop-1.53.1/exe/rubocop:19:in `block in <top (required)>'
[redacted]/.rbenv/versions/3.1.2/lib/ruby/3.1.0/benchmark.rb:311:in `realtime'
[redacted]/.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/rubocop-1.53.1/exe/rubocop:19:in `<top (required)>'
[redacted]/.rbenv/versions/3.1.2/bin/rubocop:25:in `load'
[redacted]/.rbenv/versions/3.1.2/bin/rubocop:25:in `<top (required)>'
[redacted]/.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/bundler-2.3.14/lib/bundler/cli/exec.rb:58:in `load'
[redacted]/.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/bundler-2.3.14/lib/bundler/cli/exec.rb:58:in `kernel_load'
[redacted]/.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/bundler-2.3.14/lib/bundler/cli/exec.rb:23:in `run'
[redacted]/.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/bundler-2.3.14/lib/bundler/cli.rb:483:in `exec'
[redacted]/.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/bundler-2.3.14/lib/bundler/vendor/thor/lib/thor/command.rb:27:in `run'
[redacted]/.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/bundler-2.3.14/lib/bundler/vendor/thor/lib/thor/invocation.rb:127:in `invoke_command'
[redacted]/.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/bundler-2.3.14/lib/bundler/vendor/thor/lib/thor.rb:392:in `dispatch'
[redacted]/.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/bundler-2.3.14/lib/bundler/cli.rb:31:in `dispatch'
[redacted]/.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/bundler-2.3.14/lib/bundler/vendor/thor/lib/thor/base.rb:485:in `start'
[redacted]/.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/bundler-2.3.14/lib/bundler/cli.rb:25:in `start'
[redacted]/.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/bundler-2.3.14/exe/bundle:48:in `block in <top (required)>'
[redacted]/.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/bundler-2.3.14/lib/bundler/friendly_errors.rb:103:in `with_friendly_errors'
[redacted]/.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/bundler-2.3.14/exe/bundle:36:in `<top (required)>'
[redacted]/.rbenv/versions/3.1.2/bin/bundle:25:in `load'
[redacted]/.rbenv/versions/3.1.2/bin/bundle:25:in `<main>'

I can't use rubocop --debug because the extension calls rubocop itself and I don't know how to modify it.

Steps to reproduce the problem

• Using VSCode, install the RuboCop extension https://marketplace.visualstudio.com/items?itemName=rubocop.vscode-rubocop
• Open a project and use rubocop
• Mess up your .rubocop.yml with faulty configuration like:

    inherit_gem:
      rubocop-rspec: config/rspec.yml

• See errors in the output log

RuboCop version

 bundle exec rubocop -V
1.53.1 (using Parser 3.2.2.3, rubocop-ast 1.29.0, running on ruby 3.1.2) [x86_64-darwin22]
  - rubocop-performance 1.18.0

[asartalo]

Thanks!