Add --editor-mode CLI option

Follow up rubocop#12657 (comment).

This PR adds `--editor-mode` CLI option, which optimize real-time feedback in editors,
adjusting behaviors for editing experience.

Editors that run RuboCop directly (e.g., by shelling out) encounter the same issues as with `--lsp`.
This option is designed for such editors.

changelog/new_add_editor_mode_option.md

@@ -0,0 +1 @@
+* [#12682](https://github.com/rubocop/rubocop/issues/12682): Add `--editor-mode` CLI option. ([@koic][])

docs/modules/ROOT/pages/configuration.adoc

@@ -587,7 +587,7 @@ Style/PerlBackrefs:
 ==== `contextual`
 
 This setting enables autocorrection when launched from the `rubocop` command, but it is not available through LSP.
-e.g., `rubocop --lsp` or a program where `RuboCop::LSP.enable` has been applied.
+e.g., `rubocop --lsp`, `rubocop --editor-mode`, or a program where `RuboCop::LSP.enable` has been applied.
 
 Inspections via the command line are treated as code that has been finalized.
 

docs/modules/ROOT/pages/usage/basic_usage.adoc

@@ -267,6 +267,9 @@ $ rubocop --only Rails/Blank,Layout/HeredocIndentation,Naming/FileName
 | `-s/--stdin`
 | Pipe source from STDIN. This is useful for editor integration. Takes one argument, a path, relative to the root of the project. RuboCop will use this path to determine which cops are enabled (via eg. Include/Exclude), and so that certain cops like Naming/FileName can be checked.
 
+| `--editor-mode`
+| Optimize real-time feedback in editors, adjusting behaviors for editing experience. Editors that run RuboCop directly (e.g., by shelling out) encounter the same issues as with `--lsp`. This option is designed for such editors.
+
 | `-S/--display-style-guide`
 | Display style guide URLs in offense messages.
 

lib/rubocop/cli.rb

@@ -12,7 +12,7 @@ class CLI
     STATUS_INTERRUPTED = Signal.list['INT'] + 128
     DEFAULT_PARALLEL_OPTIONS = %i[
       color config debug display_style_guide display_time display_only_fail_level_offenses
-      display_only_failed except extra_details fail_level fix_layout format
+      display_only_failed editor_mode except extra_details fail_level fix_layout format
       ignore_disable_comments lint only only_guide_cops require safe
       autocorrect safe_autocorrect autocorrect_all
     ].freeze
@@ -151,6 +151,7 @@ def parallel_by_default!
 
     def act_on_options
       set_options_to_config_loader
+      handle_editor_mode
 
       @config_store.options_config = @options[:config] if @options[:config]
       @config_store.force_default_config! if @options[:force_default_config]
@@ -174,6 +175,10 @@ def set_options_to_config_loader
       ConfigLoader.ignore_unrecognized_cops = @options[:ignore_unrecognized_cops]
     end
 
+    def handle_editor_mode
+      RuboCop::LSP.enable if @options[:editor_mode]
+    end
+
     # rubocop:disable Metrics/CyclomaticComplexity
     def handle_exiting_options
       return unless Options::EXITING_OPTIONS.any? { |o| @options.key? o }

lib/rubocop/options.rb

@@ -95,6 +95,7 @@ def add_check_options(opts) # rubocop:disable Metrics/AbcSize, Metrics/MethodLen
         option(opts, '--ignore-unrecognized-cops')
         option(opts, '--force-default-config')
         option(opts, '-s', '--stdin FILE')
+        option(opts, '--editor-mode')
         option(opts, '-P', '--[no-]parallel')
         option(opts, '--raise-cop-error')
         add_severity_option(opts)
@@ -369,6 +370,7 @@ def validate_compatibility # rubocop:disable Metrics/MethodLength
       validate_display_only_failed
       validate_display_only_failed_and_display_only_correctable
       validate_display_only_correctable_and_autocorrect
+      validate_lsp_and_editor_mode
       disable_parallel_when_invalid_option_combo
 
       return if incompatible_options.size <= 1
@@ -416,6 +418,13 @@ def validate_display_only_failed_and_display_only_correctable
             format('--display-only-failed cannot be used together with other display options.')
     end
 
+    def validate_lsp_and_editor_mode
+      return if !@options.key?(:lsp) || !@options.key?(:editor_mode)
+
+      raise OptionArgumentError,
+            format('Do not specify `--editor-mode` as it is redundant in `--lsp`.')
+    end
+
     def validate_autocorrect
       if @options.key?(:safe_autocorrect) && @options.key?(:autocorrect_all)
         message = Rainbow(<<~MESSAGE).red
@@ -609,6 +618,8 @@ module OptionsHelp
                                          'parallel. Default is true.'],
       stdin:                            ['Pipe source from STDIN, using FILE in offense',
                                          'reports. This is useful for editor integration.'],
+      editor_mode:                      ['Optimize real-time feedback in editors,',
+                                         'adjusting behaviors for editing experience.'],
       init:                             'Generate a .rubocop.yml file in the current directory.',
       server:                           ['If a server process has not been started yet, start',
                                          'the server process and execute inspection with server.',

spec/rubocop/cli/options_spec.rb

@@ -2230,6 +2230,76 @@ def f
     end
   end
 
+  describe '--editor-mode' do
+    let(:target_file) { 'example.rb' }
+
+    before do
+      create_file(target_file, <<~RUBY)
+        def empty_method
+        end
+      RUBY
+
+      create_file('.rubocop.yml', <<~YAML)
+        AllCops:
+          SuggestExtensions: false
+
+        Layout/EmptyLineAfterMagicComment:
+          AutoCorrect: contextual
+      YAML
+    end
+
+    after { RuboCop::LSP.disable }
+
+    context 'when using `--editor-mode`' do
+      it 'registers an offense, but does not correct for `Layout/EmptyLineAfterMagicComment` with `AutoCorrect: contextual`' do
+        status_code = cli.run(['--editor-mode', '-a', '--only', 'Style/EmptyMethod', target_file])
+
+        expect(status_code).to eq(1)
+        expect($stderr.string).to eq('')
+        expect(File.read('example.rb')).to eq(<<~RUBY)
+          def empty_method
+          end
+        RUBY
+        expect($stdout.string).to eq(<<~RESULT)
+          Inspecting 1 file
+          C
+
+          Offenses:
+
+          example.rb:1:1: C: Style/EmptyMethod: Put empty method definitions on a single line.
+          def empty_method ...
+          ^^^^^^^^^^^^^^^^
+
+          1 file inspected, 1 offense detected
+        RESULT
+      end
+    end
+
+    context 'when not using `--editor-mode`' do
+      it 'registers an offense and corrects for `Layout/EmptyLineAfterMagicComment` with `AutoCorrect: contextual`' do
+        status_code = cli.run(['-a', '--only', 'Style/EmptyMethod', target_file])
+
+        expect(status_code).to eq(0)
+        expect($stderr.string).to eq('')
+        expect(File.read('example.rb')).to eq(<<~RUBY)
+          def empty_method; end
+        RUBY
+        expect($stdout.string).to eq(<<~RESULT)
+          Inspecting 1 file
+          C
+
+          Offenses:
+
+          example.rb:1:1: C: [Corrected] Style/EmptyMethod: Put empty method definitions on a single line.
+          def empty_method ...
+          ^^^^^^^^^^^^^^^^
+
+          1 file inspected, 1 offense detected, 1 offense corrected
+        RESULT
+      end
+    end
+  end
+
   describe '--require', :restore_registry do
     context 'when adding an extension' do
       before do

spec/rubocop/options_spec.rb

@@ -68,6 +68,8 @@ def abs(path)
                                                files are present in the directory tree.
               -s, --stdin FILE                 Pipe source from STDIN, using FILE in offense
                                                reports. This is useful for editor integration.
+                  --editor-mode                Optimize real-time feedback in editors,
+                                               adjusting behaviors for editing experience.
               -P, --[no-]parallel              Use available CPUs to execute inspection in
                                                parallel. Default is true.
                   --raise-cop-error            Raise cop-related errors with cause and location.
@@ -262,6 +264,13 @@ def abs(path)
           .to raise_error(RuboCop::OptionArgumentError, msg)
       end
 
+      it 'rejects using `--lsp` with `--editor-mode`' do
+        msg = 'Do not specify `--editor-mode` as it is redundant in `--lsp`.'
+        expect do
+          options.parse %w[--lsp --editor-mode]
+        end.to raise_error(RuboCop::OptionArgumentError, msg)
+      end
+
       it 'mentions all incompatible options when more than two are used' do
         msg = 'Incompatible cli options: [:version, :verbose_version, :show_cops]'
         expect { options.parse %w[-vV --show-cops] }