Add --regenerate-todo command line option to rebuild .rubocop_todo.yml using its previous options

CHANGELOG.md

@@ -4,6 +4,7 @@
 
 ### New features
 
+* [#8778](https://github.com/rubocop-hq/rubocop/pull/8778): Add command line option `--regenerate-todo`. ([@dvandersluis][])
 * [#8790](https://github.com/rubocop-hq/rubocop/pull/8790): Add `AllowedMethods` option to `Style/OptionalBooleanParameter` cop. ([@fatkodima][])
 * [#8738](https://github.com/rubocop-hq/rubocop/issues/8738): Add autocorrection to `Style/DateTime`. ([@dvandersluis][])
 

docs/modules/ROOT/pages/configuration.adoc

@@ -586,7 +586,8 @@ behavior of a cop instead of disabling it completely.
 
 Then you can start removing the entries in the generated
 `.rubocop_todo.yml` file one by one as you work through all the offenses
-in the code.
+in the code. You can also regenerate your `.rubocop_todo.yml` using
+the same options by running `rubocop --regenerate-todo`.
 
 Another way of silencing offense reports, aside from configuration, is
 through source code comments. These can be added manually or

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

@@ -199,11 +199,14 @@ $ rubocop -h
 | `-L/--list-target-files`
 | List all files RuboCop will inspect.
 
-| `--no-auto-gen-timestamp`
-| Don't include the date and time when --auto-gen-config was run in the config file it generates
+| `--[no-]auto-gen-only-exclude`
+| Generate only `Exclude` parameters and not `Max` when running `--auto-gen-config`, except if the number of files with offenses is bigger than `exclude-limit`. Default is false
 
-| `--no-offense-counts`
-| Don't show offense counts in config file generated by --auto-gen-config
+| `--[no-]auto-gen-timestamp`
+| Include the date and time when `--auto-gen-config` was run in the config file it generates. Default is true.
+
+| `--[no-]offense-counts`
+| Show offense counts in config file generated by `--auto-gen-config`. Default is true.
 
 | `--only`
 | Run only the specified cop(s) and/or cops in the specified departments.
@@ -217,6 +220,9 @@ $ rubocop -h
 | `-r/--require`
 | Require Ruby file (see xref:extensions.adoc#loading-extensions[Loading Extensions]).
 
+| `--regenerate-todo`
+| Regenerate the TODO list using the same options as the last time it was generated with `--auto-gen-config` (generation options can be overridden).
+
 | `--safe`
 | Run only safe cops.
 

lib/rubocop.rb

@@ -629,6 +629,7 @@
 require_relative 'rubocop/cli/command/init_dotfile'
 require_relative 'rubocop/cli/command/show_cops'
 require_relative 'rubocop/cli/command/version'
+require_relative 'rubocop/config_regeneration'
 require_relative 'rubocop/options'
 require_relative 'rubocop/remote_config'
 require_relative 'rubocop/target_ruby'

lib/rubocop/config_regeneration.rb

@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+module RuboCop
+  # This class handles collecting the options for regenerating a TODO file.
+  # @api private
+  class ConfigRegeneration
+    AUTO_GENERATED_FILE = RuboCop::CLI::Command::AutoGenerateConfig::AUTO_GENERATED_FILE
+    COMMAND_REGEX = /(?<=`rubocop )(.*?)(?=`)/.freeze
+    DEFAULT_OPTIONS = { auto_gen_config: true }.freeze
+
+    # Get options from the comment in the TODO file, and parse them as options
+    def options
+      # If there's no existing TODO file, generate one
+      return DEFAULT_OPTIONS unless todo_exists?
+
+      match = generation_command.match(COMMAND_REGEX)
+      return DEFAULT_OPTIONS unless match
+
+      options = match[1].split(' ')
+      Options.new.parse(options).first
+    end
+
+    private
+
+    def todo_exists?
+      File.exist?(AUTO_GENERATED_FILE) && !File.empty?(AUTO_GENERATED_FILE)
+    end
+
+    def generation_command
+      File.foreach(AUTO_GENERATED_FILE).take(2).last
+    end
+  end
+end

lib/rubocop/formatter/disabled_config_formatter.rb

@@ -32,7 +32,6 @@ def file_started(_file, _file_info)
         @exclude_limit_option = @options[:exclude_limit]
         @exclude_limit = Integer(@exclude_limit_option ||
           RuboCop::Options::DEFAULT_MAXIMUM_EXCLUSION_ITEMS)
-        @show_offense_counts = !@options[:no_offense_counts]
       end
 
       def file_finished(file, offenses)
@@ -56,6 +55,14 @@ def finished(_inspected_files)
 
       private
 
+      def show_timestamp?
+        @options.fetch(:auto_gen_timestamp, true)
+      end
+
+      def show_offense_counts?
+        @options.fetch(:offense_counts, true)
+      end
+
       def command
         command = 'rubocop --auto-gen-config'
 
@@ -66,15 +73,15 @@ def command
             format(' --exclude-limit %<limit>d',
                    limit: Integer(@exclude_limit_option))
         end
-        command += ' --no-offense-counts' if @options[:no_offense_counts]
+        command += ' --no-offense-counts' unless show_offense_counts?
 
-        command += ' --no-auto-gen-timestamp' if @options[:no_auto_gen_timestamp]
+        command += ' --no-auto-gen-timestamp' unless show_timestamp?
 
         command
       end
 
       def timestamp
-        @options[:no_auto_gen_timestamp] ? '' : "on #{Time.now.utc} "
+        show_timestamp? ? "on #{Time.now.utc} " : ''
       end
 
       def output_offenses
@@ -112,7 +119,7 @@ def set_max(cfg, cop_name)
       end
 
       def output_cop_comments(output_buffer, cfg, cop_name, offense_count)
-        output_buffer.puts "# Offense count: #{offense_count}" if @show_offense_counts
+        output_buffer.puts "# Offense count: #{offense_count}" if show_offense_counts?
 
         cop_class = Cop::Registry.global.find_by_cop_name(cop_name)
         output_buffer.puts '# Cop supports --auto-correct.' if cop_class&.support_autocorrect?

lib/rubocop/options.rb

@@ -114,20 +114,19 @@ def add_configuration_options(opts)
     def add_auto_gen_options(opts)
       option(opts, '--auto-gen-config')
 
+      option(opts, '--regenerate-todo') do
+        @options.replace(ConfigRegeneration.new.options.merge(@options))
+      end
+
       option(opts, '--exclude-limit COUNT') do
         @validator.validate_exclude_limit_option
       end
 
       option(opts, '--disable-uncorrectable')
 
-      option(opts, '--no-offense-counts') do
-        @options[:no_offense_counts] = true
-      end
-
-      option(opts, '--auto-gen-only-exclude')
-      option(opts, '--no-auto-gen-timestamp') do
-        @options[:no_auto_gen_timestamp] = true
-      end
+      option(opts, '--[no-]offense-counts')
+      option(opts, '--[no-]auto-gen-only-exclude')
+      option(opts, '--[no-]auto-gen-timestamp')
 
       option(opts, '--init')
     end
@@ -318,7 +317,7 @@ def validate_auto_gen_config
 
       message = '--%<flag>s can only be used together with --auto-gen-config.'
 
-      %i[exclude_limit no_offense_counts no_auto_gen_timestamp
+      %i[exclude_limit offense_counts auto_gen_timestamp
          auto_gen_only_exclude].each do |option|
         if @options.key?(option)
           raise OptionArgumentError,
@@ -423,17 +422,20 @@ module OptionsHelp
       config:                           'Specify configuration file.',
       auto_gen_config:                  ['Generate a configuration file acting as a',
                                          'TODO list.'],
-      no_offense_counts:                ['Do not include offense counts in configuration',
-                                         'file generated by --auto-gen-config.'],
-      no_auto_gen_timestamp:
-                                        ['Do not include the date and time when',
-                                         'the --auto-gen-config was run in the file it',
-                                         'generates.'],
+      regenerate_todo:                  ['Regenerate the TODO configuration file using',
+                                         'the last configuration. If there is no existing',
+                                         'TODO file, acts like --auto-gen-config.'],
+      offense_counts:                   ['Include offense counts in configuration',
+                                         'file generated by --auto-gen-config.',
+                                         'Default is true.'],
+      auto_gen_timestamp:
+                                        ['Include the date and time when the --auto-gen-config',
+                                         'was run in the file it generates. Default is true.'],
       auto_gen_only_exclude:
                                         ['Generate only Exclude parameters and not Max',
                                          'when running --auto-gen-config, except if the',
                                          'number of files with offenses is bigger than',
-                                         'exclude-limit.'],
+                                         'exclude-limit. Default is false.'],
       exclude_limit:                    ['Used together with --auto-gen-config to',
                                          'set the limit for how many Exclude',
                                          "properties to generate. Default is #{MAX_EXCL}."],

spec/rubocop/config_regeneration_spec.rb

@@ -0,0 +1,51 @@
+# frozen_string_literal: true
+
+RSpec.describe RuboCop::ConfigRegeneration, :isolated_environment do
+  include FileHelper
+
+  subject(:config_regeneration) { described_class.new }
+
+  describe '#options' do
+    subject { config_regeneration.options }
+
+    context 'when no todo file exists' do
+      it { is_expected.to eq(auto_gen_config: true) }
+    end
+
+    context 'when there is a blank todo file' do
+      before { create_file('.rubocop_todo.yml', nil) }
+
+      it { is_expected.to eq(auto_gen_config: true) }
+    end
+
+    context 'when the todo file is malformed' do
+      before { create_file('.rubocop_todo.yml', 'todo') }
+
+      it { is_expected.to eq(auto_gen_config: true) }
+    end
+
+    context 'it parses options from the generation comment' do
+      let(:header) do
+        <<~HEADER
+          # This configuration was generated by
+          # `rubocop --auto-gen-config --auto-gen-only-exclude --exclude-limit 100 --no-offense-counts --no-auto-gen-timestamp`
+          # on 2020-06-12 17:42:47 UTC using RuboCop version 0.85.1.
+        HEADER
+      end
+
+      let(:expected_options) do
+        {
+          auto_gen_config: true,
+          auto_gen_only_exclude: true,
+          exclude_limit: '100',
+          offense_counts: false,
+          auto_gen_timestamp: false
+        }
+      end
+
+      before { create_file('.rubocop_todo.yml', header) }
+
+      it { is_expected.to eq(expected_options) }
+    end
+  end
+end

spec/rubocop/options_spec.rb

@@ -52,21 +52,24 @@ def abs(path)
                                                files are present in the directory tree.
                   --auto-gen-config            Generate a configuration file acting as a
                                                TODO list.
+                  --regenerate-todo            Regenerate the TODO configuration file using
+                                               the last configuration. If there is no existing
+                                               TODO file, acts like --auto-gen-config.
                   --exclude-limit COUNT        Used together with --auto-gen-config to
                                                set the limit for how many Exclude
                                                properties to generate. Default is 15.
                   --disable-uncorrectable      Used with --auto-correct to annotate any
                                                offenses that do not support autocorrect
                                                with `rubocop:todo` comments.
-                  --no-offense-counts          Do not include offense counts in configuration
+                  --[no-]offense-counts        Include offense counts in configuration
                                                file generated by --auto-gen-config.
-                  --auto-gen-only-exclude      Generate only Exclude parameters and not Max
+                                               Default is true.
+                  --[no-]auto-gen-only-exclude Generate only Exclude parameters and not Max
                                                when running --auto-gen-config, except if the
                                                number of files with offenses is bigger than
-                                               exclude-limit.
-                  --no-auto-gen-timestamp      Do not include the date and time when
-                                               the --auto-gen-config was run in the file it
-                                               generates.
+                                               exclude-limit. Default is false.
+                  --[no-]auto-gen-timestamp    Include the date and time when the --auto-gen-config
+                                               was run in the file it generates. Default is true.
                   --init                       Generate a .rubocop.yml file in the current directory.
               -f, --format FORMATTER           Choose an output formatter. This option
                                                can be specified multiple times to enable
@@ -370,6 +373,75 @@ def abs(path)
       end
     end
 
+    describe '--regenerate-todo' do
+      subject(:parsed_options) { options.parse(command_line_options).first }
+
+      let(:config_regeneration) do
+        instance_double(RuboCop::ConfigRegeneration, options: todo_options)
+      end
+      let(:todo_options) { { auto_gen_config: true, exclude_limit: '100', offense_counts: false } }
+
+      before do
+        allow(RuboCop::ConfigRegeneration).to receive(:new).and_return(config_regeneration)
+      end
+
+      context 'when no other options are given' do
+        let(:command_line_options) { %w[--regenerate-todo] }
+        let(:expected_options) do
+          {
+            auto_gen_config: true,
+            exclude_limit: '100',
+            offense_counts: false,
+            regenerate_todo: true
+          }
+        end
+
+        it { is_expected.to eq(expected_options) }
+      end
+
+      context 'when todo options are overridden before --regenerate-todo' do
+        let(:command_line_options) { %w[--exclude-limit 50 --regenerate-todo] }
+        let(:expected_options) do
+          {
+            auto_gen_config: true,
+            exclude_limit: '50',
+            offense_counts: false,
+            regenerate_todo: true
+          }
+        end
+
+        it { is_expected.to eq(expected_options) }
+      end
+
+      context 'when todo options are overridden after --regenerate-todo' do
+        let(:command_line_options) { %w[--regenerate-todo --exclude-limit 50] }
+        let(:expected_options) do
+          {
+            auto_gen_config: true,
+            exclude_limit: '50',
+            offense_counts: false,
+            regenerate_todo: true
+          }
+        end
+
+        it { is_expected.to eq(expected_options) }
+      end
+
+      context 'when disabled options are overridden to be enabled' do
+        let(:command_line_options) { %w[--regenerate-todo --offense-counts] }
+        let(:expected_options) do
+          {
+            auto_gen_config: true,
+            exclude_limit: '100',
+            offense_counts: true,
+            regenerate_todo: true
+          }
+        end
+
+        it { is_expected.to eq(expected_options) }
+      end
+    end
+
     describe '-s/--stdin' do
       before do
         $stdin = StringIO.new