Add support for Code Actions under Ruby LSP

Follow up standardrb/standard#636.

Because standardrb/standard#636 alone does not behave as expected in VS Code,
this includes the content of the following commits related to the changes in
standardrb/standard#636.

- standardrb/standard@ab18144
- standardrb/standard@edd199b
- standardrb/standard@4240fc5
- standardrb/standard@2fcca8d
- standardrb/standard@84ee9f4

This ensures that the features related to standardrb/standard#636 will work,
so it is being submitted as an independent commit.

changelog/new_make_lsp_server_support_quick_fix_code_aciton.md

@@ -0,0 +1 @@
+* [#13628](https://github.com/rubocop/rubocop/pull/13628): Make LSP server support quick fix code action. ([@koic][])

lib/rubocop/lsp/diagnostic.rb

@@ -0,0 +1,189 @@
+# frozen_string_literal: true
+
+require_relative 'severity'
+
+#
+# This code is based on https://github.com/standardrb/standard.
+#
+# Copyright (c) 2023 Test Double, Inc.
+#
+# The MIT License (MIT)
+#
+# https://github.com/standardrb/standard/blob/main/LICENSE.txt
+#
+module RuboCop
+  module LSP
+    # Diagnostic for Language Server Protocol of RuboCop.
+    # @api private
+    class Diagnostic
+      def initialize(document_encoding, offense, uri, cop_class)
+        @document_encoding = document_encoding
+        @offense = offense
+        @uri = uri
+        @cop_class = cop_class
+      end
+
+      def to_lsp_code_actions
+        code_actions = []
+
+        code_actions << autocorrect_action if correctable?
+        code_actions << disable_line_action
+
+        code_actions
+      end
+
+      # rubocop:disable Metrics/AbcSize, Metrics/MethodLength
+      def to_lsp_diagnostic(config)
+        highlighted = @offense.highlighted_area
+
+        LanguageServer::Protocol::Interface::Diagnostic.new(
+          message: message,
+          source: 'RuboCop',
+          code: @offense.cop_name,
+          code_description: code_description(config),
+          severity: severity,
+          range: LanguageServer::Protocol::Interface::Range.new(
+            start: LanguageServer::Protocol::Interface::Position.new(
+              line: @offense.line - 1,
+              character: highlighted.begin_pos
+            ),
+            end: LanguageServer::Protocol::Interface::Position.new(
+              line: @offense.line - 1,
+              character: highlighted.end_pos
+            )
+          ),
+          data: {
+            correctable: correctable?,
+            code_actions: to_lsp_code_actions
+          }
+        )
+      end
+      # rubocop:enable Metrics/AbcSize, Metrics/MethodLength
+
+      private
+
+      def message
+        message = @offense.message
+        message += "\n\nThis offense is not autocorrectable.\n" unless correctable?
+        message
+      end
+
+      def severity
+        Severity.find_by(@offense.severity.name)
+      end
+
+      def code_description(config)
+        return unless @cop_class
+        return unless (doc_url = @cop_class.documentation_url(config))
+
+        LanguageServer::Protocol::Interface::CodeDescription.new(href: doc_url)
+      end
+
+      # rubocop:disable Layout/LineLength, Metrics/MethodLength
+      def autocorrect_action
+        LanguageServer::Protocol::Interface::CodeAction.new(
+          title: "Autocorrect #{@offense.cop_name}",
+          kind: LanguageServer::Protocol::Constant::CodeActionKind::QUICK_FIX,
+          edit: LanguageServer::Protocol::Interface::WorkspaceEdit.new(
+            document_changes: [
+              LanguageServer::Protocol::Interface::TextDocumentEdit.new(
+                text_document: LanguageServer::Protocol::Interface::OptionalVersionedTextDocumentIdentifier.new(
+                  uri: ensure_uri_scheme(@uri.to_s).to_s,
+                  version: nil
+                ),
+                edits: correctable? ? offense_replacements : []
+              )
+            ]
+          ),
+          is_preferred: true
+        )
+      end
+      # rubocop:enable Layout/LineLength, Metrics/MethodLength
+
+      # rubocop:disable Metrics/MethodLength
+      def offense_replacements
+        @offense.corrector.as_replacements.map do |range, replacement|
+          LanguageServer::Protocol::Interface::TextEdit.new(
+            range: LanguageServer::Protocol::Interface::Range.new(
+              start: LanguageServer::Protocol::Interface::Position.new(
+                line: range.line - 1,
+                character: range.column
+              ),
+              end: LanguageServer::Protocol::Interface::Position.new(
+                line: range.last_line - 1,
+                character: range.last_column
+              )
+            ),
+            new_text: replacement
+          )
+        end
+      end
+      # rubocop:enable Metrics/MethodLength
+
+      # rubocop:disable Layout/LineLength, Metrics/MethodLength
+      def disable_line_action
+        LanguageServer::Protocol::Interface::CodeAction.new(
+          title: "Disable #{@offense.cop_name} for this line",
+          kind: LanguageServer::Protocol::Constant::CodeActionKind::QUICK_FIX,
+          edit: LanguageServer::Protocol::Interface::WorkspaceEdit.new(
+            document_changes: [
+              LanguageServer::Protocol::Interface::TextDocumentEdit.new(
+                text_document: LanguageServer::Protocol::Interface::OptionalVersionedTextDocumentIdentifier.new(
+                  uri: ensure_uri_scheme(@uri.to_s).to_s,
+                  version: nil
+                ),
+                edits: line_disable_comment
+              )
+            ]
+          )
+        )
+      end
+      # rubocop:enable Layout/LineLength, Metrics/MethodLength
+
+      def line_disable_comment
+        new_text = if @offense.source_line.include?(' # rubocop:disable ')
+                     ",#{@offense.cop_name}"
+                   else
+                     " # rubocop:disable #{@offense.cop_name}"
+                   end
+
+        eol = LanguageServer::Protocol::Interface::Position.new(
+          line: @offense.line - 1,
+          character: length_of_line(@offense.source_line)
+        )
+
+        # TODO: fails for multiline strings - may be preferable to use block
+        # comments to disable some offenses
+        inline_comment = LanguageServer::Protocol::Interface::TextEdit.new(
+          range: LanguageServer::Protocol::Interface::Range.new(start: eol, end: eol),
+          new_text: new_text
+        )
+
+        [inline_comment]
+      end
+
+      def length_of_line(line)
+        if @document_encoding == Encoding::UTF_16LE
+          line_length = 0
+          line.codepoints.each do |codepoint|
+            line_length += 1
+            line_length += 1 if codepoint > RubyLsp::Document::Scanner::SURROGATE_PAIR_START
+          end
+          line_length
+        else
+          line.length
+        end
+      end
+
+      def correctable?
+        !@offense.corrector.nil?
+      end
+
+      def ensure_uri_scheme(uri)
+        uri = URI.parse(uri)
+        uri.scheme = 'file' if uri.scheme.nil?
+        uri
+      end
+    end
+  end
+end

lib/rubocop/lsp/logger.rb

@@ -14,8 +14,8 @@ module LSP
     # Log for Language Server Protocol of RuboCop.
     # @api private
     class Logger
-      def self.log(message)
-        warn("[server] #{message}")
+      def self.log(message, prefix: '[server]')
+        warn("#{prefix} #{message}")
       end
     end
   end

lib/rubocop/lsp/routes.rb

@@ -16,6 +16,11 @@ module LSP
     # Routes for Language Server Protocol of RuboCop.
     # @api private
     class Routes
+      CONFIGURATION_FILE_PATTERNS = [
+        RuboCop::ConfigFinder::DOTFILE,
+        RuboCop::CLI::Command::AutoGenerateConfig::AUTO_GENERATED_FILE
+      ].freeze
+
       def self.handle(name, &block)
         define_method(:"handle_#{name}", &block)
       end
@@ -96,7 +101,7 @@ def for(name)
 
       handle 'workspace/didChangeWatchedFiles' do |request|
         changed = request[:params][:changes].any? do |change|
-          change[:uri].end_with?(RuboCop::ConfigFinder::DOTFILE)
+          CONFIGURATION_FILE_PATTERNS.any? { |path| change[:uri].end_with?(path) }
         end
 
         if changed
@@ -204,40 +209,19 @@ def format_file(file_uri, command: nil)
 
       def diagnostic(file_uri, text)
         @text_cache[file_uri] = text
-        offenses = @server.offenses(remove_file_protocol_from(file_uri), text)
-        diagnostics = offenses.map { |offense| to_diagnostic(offense) }
 
         {
           method: 'textDocument/publishDiagnostics',
           params: {
             uri: file_uri,
-            diagnostics: diagnostics
+            diagnostics: @server.offenses(remove_file_protocol_from(file_uri), text)
           }
         }
       end
 
       def remove_file_protocol_from(uri)
         uri.delete_prefix('file://')
       end
-
-      def to_diagnostic(offense)
-        code = offense[:cop_name]
-        message = offense[:message]
-        loc = offense[:location]
-        rubocop_severity = offense[:severity]
-        severity = Severity.find_by(rubocop_severity)
-
-        {
-          code: code, message: message, range: to_range(loc), severity: severity, source: 'rubocop'
-        }
-      end
-
-      def to_range(location)
-        {
-          start: { character: location[:start_column] - 1, line: location[:start_line] - 1 },
-          end: { character: location[:last_column], line: location[:last_line] - 1 }
-        }
-      end
     end
   end
 end

lib/rubocop/lsp/runtime.rb

@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
-require 'stringio'
+require_relative 'diagnostic'
+require_relative 'stdin_runner'
 
 #
 # This code is based on https://github.com/standardrb/standard.
@@ -19,59 +20,38 @@ class Runtime
       attr_writer :safe_autocorrect, :lint_mode, :layout_mode
 
       def initialize(config_store)
-        @config_store = config_store
-        @logged_paths = []
+        @runner = RuboCop::Lsp::StdinRunner.new(config_store)
+        @cop_registry = RuboCop::Cop::Registry.global.to_h
+
         @safe_autocorrect = true
         @lint_mode = false
         @layout_mode = false
       end
 
-      # This abuses the `--stdin` option of rubocop and reads the formatted text
-      # from the `options[:stdin]` that rubocop mutates. This depends on
-      # `parallel: false` as well as the fact that RuboCop doesn't otherwise dup
-      # or reassign that options object. Risky business!
-      #
-      # Reassigning `options[:stdin]` is done here:
-      #   https://github.com/rubocop/rubocop/blob/v1.52.0/lib/rubocop/cop/team.rb#L131
-      # Printing `options[:stdin]`
-      #   https://github.com/rubocop/rubocop/blob/v1.52.0/lib/rubocop/cli/command/execute_runner.rb#L95
-      # Setting `parallel: true` would break this here:
-      #   https://github.com/rubocop/rubocop/blob/v1.52.0/lib/rubocop/runner.rb#L72
       def format(path, text, command:)
         safe_autocorrect = if command
                              command == 'rubocop.formatAutocorrects'
                            else
                              @safe_autocorrect
                            end
 
-        formatting_options = {
-          stdin: text, force_exclusion: true, autocorrect: true, safe_autocorrect: safe_autocorrect
-        }
+        formatting_options = { autocorrect: true, safe_autocorrect: safe_autocorrect }
         formatting_options[:only] = config_only_options if @lint_mode || @layout_mode
 
-        redirect_stdout { run_rubocop(formatting_options, path) }
-
-        formatting_options[:stdin]
+        @runner.run(path, text, formatting_options)
+        @runner.formatted_source
       end
 
-      def offenses(path, text)
-        diagnostic_options = {
-          stdin: text, force_exclusion: true, formatters: ['json'], format: 'json'
-        }
+      def offenses(path, text, document_encoding = nil)
+        diagnostic_options = {}
         diagnostic_options[:only] = config_only_options if @lint_mode || @layout_mode
 
-        json = redirect_stdout { run_rubocop(diagnostic_options, path) }
-        results = JSON.parse(json, symbolize_names: true)
-
-        if results[:files].empty?
-          unless @logged_paths.include?(path)
-            Logger.log "Ignoring file, per configuration: #{path}"
-            @logged_paths << path
-          end
-          return []
+        @runner.run(path, text, diagnostic_options)
+        @runner.offenses.map do |offense|
+          Diagnostic.new(
+            document_encoding, offense, path, @cop_registry[offense.cop_name]&.first
+          ).to_lsp_diagnostic(@runner.config_for_working_directory)
         end
-
-        results.dig(:files, 0, :offenses)
       end
 
       private
@@ -82,20 +62,6 @@ def config_only_options
         only_options << 'Layout' if @layout_mode
         only_options
       end
-
-      def redirect_stdout(&block)
-        stdout = StringIO.new
-
-        RuboCop::Server::Helper.redirect(stdout: stdout, &block)
-
-        stdout.string
-      end
-
-      def run_rubocop(options, path)
-        runner = RuboCop::Runner.new(options, @config_store)
-
-        runner.run([path])
-      end
     end
   end
 end