Check if RuboCop is available before searching for add-on

lib/ruby_lsp/global_state.rb

@@ -94,7 +94,8 @@ def apply_options(options)
       @workspace_uri = URI(workspace_uri) if workspace_uri
 
       specified_formatter = options.dig(:initializationOptions, :formatter)
-      rubocop_has_addon = Gem::Requirement.new(">= 1.70.0").satisfied_by?(Gem::Version.new(::RuboCop::Version::STRING))
+      rubocop_has_addon = defined?(::RuboCop::Version::STRING) &&
+        Gem::Requirement.new(">= 1.70.0").satisfied_by?(Gem::Version.new(::RuboCop::Version::STRING))
 
       if specified_formatter
         @formatter = specified_formatter

test/integration_test.rb

@@ -226,6 +226,13 @@ def launch(workspace_path, exec = "ruby-lsp-launcher", extra_env = {})
         workspaceFolders: [{ uri: URI::Generic.from_path(path: workspace_path).to_s }],
       },
     })
+
+    # First message is the log of initializing Ruby LSP
+    read_message(stdout)
+    # Verify that initialization didn't fail
+    initialize_response = read_message(stdout)
+    refute(initialize_response[:error], initialize_response.dig(:error, :message))
+
     send_message(stdin, { id: 2, method: "shutdown" })
     send_message(stdin, { method: "exit" })
 
@@ -253,6 +260,12 @@ def send_message(stdin, message)
     stdin.flush
   end
 
+  def read_message(stdout)
+    headers = stdout.gets("\r\n\r\n")
+    length = headers[/Content-Length: (\d+)/i, 1].to_i
+    JSON.parse(stdout.read(length), symbolize_names: true)
+  end
+
   def in_temp_dir
     Dir.mktmpdir do |dir|
       Dir.chdir(dir) do