Add AllowedMethods option to Style/OptionalBooleanParameter cop

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## master (unreleased)
 
+### New features
+
+* [#8790](https://github.com/rubocop-hq/rubocop/pull/8790): Add `AllowedMethods` option to `Style/OptionalBooleanParameter` cop. ([@fatkodima][])
+
 ### Bug fixes
 
 * [#8774](https://github.com/rubocop-hq/rubocop/issues/8774): Fix a false positive for `Layout/ArrayAlignment` with parallel assignment. ([@dvandersluis][])

config/default.yml

@@ -3725,6 +3725,8 @@ Style/OptionalBooleanParameter:
   Enabled: pending
   Safe: false
   VersionAdded: '0.89'
+  AllowedMethods:
+    - respond_to_missing?
 
 Style/OrAssignment:
   Description: 'Recommend usage of double pipe equals (||=) where applicable.'

docs/modules/ROOT/pages/cops_style.adoc

@@ -6888,7 +6888,8 @@ end
 |===
 
 This cop checks for places where keyword arguments can be used instead of
-boolean arguments when defining methods.
+boolean arguments when defining methods. `respond_to_missing?` method is allowed by default.
+These are customizable with `AllowedMethods` option.
 
 === Examples
 
@@ -6911,6 +6912,26 @@ def some_method(bar: false)
 end
 ----
 
+==== AllowedMethods: ['some_method']
+
+[source,ruby]
+----
+# good
+def some_method(bar = false)
+  puts bar
+end
+----
+
+=== Configurable attributes
+
+|===
+| Name | Default value | Configurable values
+
+| AllowedMethods
+| `respond_to_missing?`
+| Array
+|===
+
 === References
 
 * https://rubystyle.guide#boolean-keyword-arguments

lib/rubocop/cop/style/optional_boolean_parameter.rb

@@ -4,7 +4,8 @@ module RuboCop
   module Cop
     module Style
       # This cop checks for places where keyword arguments can be used instead of
-      # boolean arguments when defining methods.
+      # boolean arguments when defining methods. `respond_to_missing?` method is allowed by default.
+      # These are customizable with `AllowedMethods` option.
       #
       # @example
       #   # bad
@@ -23,13 +24,20 @@ module Style
       #     puts bar
       #   end
       #
+      # @example AllowedMethods: ['some_method']
+      #   # good
+      #   def some_method(bar = false)
+      #     puts bar
+      #   end
+      #
       class OptionalBooleanParameter < Base
+        include AllowedMethods
+
         MSG = 'Use keyword arguments when defining method with boolean argument.'
         BOOLEAN_TYPES = %i[true false].freeze
-        METHODS_EXCLUDED = %i[respond_to_missing?].freeze
 
         def on_def(node)
-          return if METHODS_EXCLUDED.include?(node.method_name)
+          return if allowed_method?(node.method_name)
 
           node.arguments.each do |arg|
             next unless arg.optarg_type?

spec/rubocop/cop/style/optional_boolean_parameter_spec.rb

@@ -1,7 +1,9 @@
 # frozen_string_literal: true
 
-RSpec.describe RuboCop::Cop::Style::OptionalBooleanParameter do
-  subject(:cop) { described_class.new }
+RSpec.describe RuboCop::Cop::Style::OptionalBooleanParameter, :config do
+  let(:cop_config) do
+    { 'AllowedMethods' => [] }
+  end
 
   it 'registers an offense when defining method with optional boolean arg' do
     expect_offense(<<~RUBY)
@@ -49,10 +51,16 @@ def some_method(bar = 'foo')
     RUBY
   end
 
-  it 'does not register an offense when defining respond_to_missing? method with boolean arg' do
-    expect_no_offenses(<<~RUBY)
-      def respond_to_missing?(arg, bar = false)
-      end
-    RUBY
+  context 'when AllowedMethods is not empty' do
+    let(:cop_config) do
+      { 'AllowedMethods' => %w[respond_to_missing?] }
+    end
+
+    it 'does not register an offense' do
+      expect_no_offenses(<<~RUBY)
+        def respond_to_missing?(method, include_all = false)
+        end
+      RUBY
+    end
   end
 end