Add new Style/OptionalBooleanParameter cop

CHANGELOG.md

@@ -7,6 +7,7 @@
 * [#8322](https://github.com/rubocop-hq/rubocop/pull/8322): Support autocorrect for `Style/CaseEquality` cop. ([@fatkodima][])
 * [#8291](https://github.com/rubocop-hq/rubocop/pull/8291): Add new `Lint/SelfAssignment` cop. ([@fatkodima][])
 * [#8389](https://github.com/rubocop-hq/rubocop/pull/8389): Add new `Lint/DuplicateRescueException` cop. ([@fatkodima][])
+* [#8412](https://github.com/rubocop-hq/rubocop/pull/8412): Add new `Style/OptionalBooleanParameter` cop. ([@fatkodima][])
 * [#8376](https://github.com/rubocop-hq/rubocop/pull/8376): Add new `Lint/MissingSuper` cop. ([@fatkodima][])
 * [#8339](https://github.com/rubocop-hq/rubocop/pull/8339): Add `Config#for_badge` as an efficient way to get a cop's config merged with its department's. ([@marcandre][])
 * [#5067](https://github.com/rubocop-hq/rubocop/issues/5067): Add new `Style/StringConcatenation` cop. ([@fatkodima][])

config/default.yml

@@ -3583,6 +3583,13 @@ Style/OptionalArguments:
   VersionAdded: '0.33'
   VersionChanged: '0.83'
 
+Style/OptionalBooleanParameter:
+  Description: 'Use keyword arguments when defining method with boolean argument.'
+  StyleGuide: '#boolean-keyword-arguments'
+  Enabled: pending
+  Safe: false
+  VersionAdded: '0.89'
+
 Style/OrAssignment:
   Description: 'Recommend usage of double pipe equals (||=) where applicable.'
   StyleGuide: '#double-pipe-for-uninit'

docs/modules/ROOT/pages/cops.adoc

@@ -430,6 +430,7 @@ In the following section you find all available cops:
 * xref:cops_style.adoc#styleonelineconditional[Style/OneLineConditional]
 * xref:cops_style.adoc#styleoptionhash[Style/OptionHash]
 * xref:cops_style.adoc#styleoptionalarguments[Style/OptionalArguments]
+* xref:cops_style.adoc#styleoptionalbooleanparameter[Style/OptionalBooleanParameter]
 * xref:cops_style.adoc#styleorassignment[Style/OrAssignment]
 * xref:cops_style.adoc#styleparallelassignment[Style/ParallelAssignment]
 * xref:cops_style.adoc#styleparenthesesaroundcondition[Style/ParenthesesAroundCondition]

docs/modules/ROOT/pages/cops_style.adoc

@@ -6547,6 +6547,46 @@ end
 
 * https://rubystyle.guide#optional-arguments
 
+== Style/OptionalBooleanParameter
+
+|===
+| Enabled by default | Safe | Supports autocorrection | VersionAdded | VersionChanged
+
+| Pending
+| No
+| No
+| 0.89
+| -
+|===
+
+This cop checks for places where keyword arguments can be used instead of
+boolean arguments when defining methods.
+
+=== Examples
+
+[source,ruby]
+----
+# bad
+def some_method(bar = false)
+  puts bar
+end
+
+# bad - common hack before keyword args were introduced
+def some_method(options = {})
+  bar = options.fetch(:bar, false)
+  puts bar
+end
+
+# good
+def some_method(bar: false)
+  puts bar
+end
+----
+
+=== References
+
+* https://rubystyle.guide#boolean-keyword-arguments
+
 == Style/OrAssignment
 
 |===

lib/rubocop.rb

@@ -480,6 +480,7 @@
 require_relative 'rubocop/cop/style/or_assignment'
 require_relative 'rubocop/cop/style/option_hash'
 require_relative 'rubocop/cop/style/optional_arguments'
+require_relative 'rubocop/cop/style/optional_boolean_parameter'
 require_relative 'rubocop/cop/style/parallel_assignment'
 require_relative 'rubocop/cop/style/parentheses_around_condition'
 require_relative 'rubocop/cop/style/percent_literal_delimiters'

lib/rubocop/cli/command/execute_runner.rb

@@ -55,7 +55,7 @@ def display_error_summary(errors)
             #{Gem.loaded_specs['rubocop'].metadata['bug_tracker_uri']}
 
             Mention the following information in the issue report:
-            #{RuboCop::Version.version(true)}
+            #{RuboCop::Version.version(debug: true)}
           WARNING
         end
 

lib/rubocop/cli/command/version.rb

@@ -8,8 +8,8 @@ class Version < Base
         self.command_name = :version
 
         def run
-          puts RuboCop::Version.version(false) if @options[:version]
-          puts RuboCop::Version.version(true) if @options[:verbose_version]
+          puts RuboCop::Version.version(debug: false) if @options[:version]
+          puts RuboCop::Version.version(debug: true) if @options[:verbose_version]
         end
       end
     end

lib/rubocop/cop/migration/department_name.rb

@@ -51,7 +51,7 @@ def check_cop_name(name, comment, offset)
 
           add_offense(range) do |corrector|
             cop_name = range.source
-            qualified_cop_name = Cop.registry.qualified_cop_name(cop_name, nil, false)
+            qualified_cop_name = Cop.registry.qualified_cop_name(cop_name, nil, warn: false)
 
             unless qualified_cop_name.include?('/')
               qualified_cop_name = qualified_legacy_cop_name(cop_name)

lib/rubocop/cop/registry.rb

@@ -100,9 +100,9 @@ def contains_cop_matching?(names)
       # @note Emits a warning if the provided name has an incorrect namespace
       #
       # @return [String] Qualified cop name
-      def qualified_cop_name(name, path, shall_warn = true)
+      def qualified_cop_name(name, path, warn: true)
         badge = Badge.parse(name)
-        print_warning(name, path) if shall_warn && department_missing?(badge, name)
+        print_warning(name, path) if warn && department_missing?(badge, name)
         return name if registered?(badge)
 
         potential_badges = qualify_badge(badge)
@@ -149,7 +149,7 @@ def length
         @registry.size
       end
 
-      def enabled(config, only = [], only_safe = false)
+      def enabled(config, only = [], only_safe: false)
         select do |cop|
           only.include?(cop.cop_name) || enabled?(cop, config, only_safe)
         end

lib/rubocop/cop/style/documentation.rb

@@ -112,17 +112,17 @@ def compact_namespace?(node)
         # proceeds to check its ancestors for :nodoc: all.
         # Note: How end-of-line comments are associated with code changed in
         # parser-2.2.0.4.
-        def nodoc_comment?(node, require_all = false)
+        def nodoc_comment?(node, require_all: false)
           return false unless node&.children&.first
 
           nodoc = nodoc(node)
 
-          return true if same_line?(nodoc, node) && nodoc?(nodoc, require_all)
+          return true if same_line?(nodoc, node) && nodoc?(nodoc, require_all: require_all)
 
-          nodoc_comment?(node.parent, true)
+          nodoc_comment?(node.parent, require_all: true)
         end
 
-        def nodoc?(comment, require_all = false)
+        def nodoc?(comment, require_all: false)
           /^#\s*:nodoc:#{"\s+all\s*$" if require_all}/.match?(comment.text)
         end
 

lib/rubocop/cop/style/guard_clause.rb

@@ -87,7 +87,7 @@ def on_if(node)
         private
 
         def check_ending_if(node)
-          return if accepted_form?(node, true) || !min_body_length?(node)
+          return if accepted_form?(node, ending: true) || !min_body_length?(node)
 
           register_offense(node, 'return', opposite_keyword(node))
         end
@@ -125,7 +125,7 @@ def too_long_for_single_line?(node, example)
           max && node.source_range.column + example.length > max
         end
 
-        def accepted_form?(node, ending = false)
+        def accepted_form?(node, ending: false)
           accepted_if?(node, ending) || node.condition.multiline? ||
             node.parent&.assignment?
         end

lib/rubocop/cop/style/optional_boolean_parameter.rb

@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+module RuboCop
+  module Cop
+    module Style
+      # This cop checks for places where keyword arguments can be used instead of
+      # boolean arguments when defining methods.
+      #
+      # @example
+      #   # bad
+      #   def some_method(bar = false)
+      #     puts bar
+      #   end
+      #
+      #   # bad - common hack before keyword args were introduced
+      #   def some_method(options = {})
+      #     bar = options.fetch(:bar, false)
+      #     puts bar
+      #   end
+      #
+      #   # good
+      #   def some_method(bar: false)
+      #     puts bar
+      #   end
+      #
+      class OptionalBooleanParameter < Base
+        MSG = 'Use keyword arguments when defining method with boolean argument.'
+        BOOLEAN_TYPES = %i[true false].freeze
+
+        def on_def(node)
+          node.arguments.each do |arg|
+            next unless arg.optarg_type?
+
+            _name, value = *arg
+            add_offense(arg) if BOOLEAN_TYPES.include?(value.type)
+          end
+        end
+        alias on_defs on_def
+      end
+    end
+  end
+end

lib/rubocop/cop/team.rb

@@ -43,7 +43,7 @@ def self.mobilize_cops(cop_classes, config, options = {})
         cop_classes = Registry.new(cop_classes.to_a) unless cop_classes.is_a?(Registry)
         only = options.fetch(:only, [])
         safe = options.fetch(:safe, false)
-        cop_classes.enabled(config, only, safe).map do |cop_class|
+        cop_classes.enabled(config, only, only_safe: safe).map do |cop_class|
           cop_class.new(config, options)
         end
       end

lib/rubocop/version.rb

@@ -9,7 +9,7 @@ module Version
           'rubocop-ast %<rubocop_ast_version>s, ' \
           'running on %<ruby_engine>s %<ruby_version>s %<ruby_platform>s)'
 
-    def self.version(debug = false)
+    def self.version(debug: false)
       if debug
         format(MSG, version: STRING, parser_version: Parser::VERSION,
                     rubocop_ast_version: RuboCop::AST::Version::STRING,

spec/rubocop/cop/registry_spec.rb

@@ -196,7 +196,7 @@
     end
 
     it 'selects only safe cops if :safe passed' do
-      enabled_cops = registry.enabled(config, [], true)
+      enabled_cops = registry.enabled(config, [], only_safe: true)
       expect(enabled_cops).not_to include(RuboCop::Cop::RSpec::Foo)
     end
 

spec/rubocop/cop/style/optional_boolean_parameter_spec.rb

@@ -0,0 +1,51 @@
+# frozen_string_literal: true
+
+RSpec.describe RuboCop::Cop::Style::OptionalBooleanParameter do
+  subject(:cop) { described_class.new }
+
+  it 'registers an offense when defining method with optional boolean arg' do
+    expect_offense(<<~RUBY)
+      def some_method(bar = false)
+                      ^^^^^^^^^^^ Use keyword arguments when defining method with boolean argument.
+      end
+    RUBY
+  end
+
+  it 'registers an offense when defining class method with optional boolean arg' do
+    expect_offense(<<~RUBY)
+      def self.some_method(bar = false)
+                           ^^^^^^^^^^^ Use keyword arguments when defining method with boolean argument.
+      end
+    RUBY
+  end
+
+  it 'registers an offense when defining method with multiple optional boolean args' do
+    expect_offense(<<~RUBY)
+      def some_method(foo = true, bar = 1, baz = false, quux: true)
+                      ^^^^^^^^^^ Use keyword arguments when defining method with boolean argument.
+                                           ^^^^^^^^^^^ Use keyword arguments when defining method with boolean argument.
+      end
+    RUBY
+  end
+
+  it 'does not register an offense when defining method with keyword boolean arg' do
+    expect_no_offenses(<<~RUBY)
+      def some_method(bar: false)
+      end
+    RUBY
+  end
+
+  it 'does not register an offense when defining method without args' do
+    expect_no_offenses(<<~RUBY)
+      def some_method
+      end
+    RUBY
+  end
+
+  it 'does not register an offense when defining method with optonal non-boolean arg' do
+    expect_no_offenses(<<~RUBY)
+      def some_method(bar = 'foo')
+      end
+    RUBY
+  end
+end