[Fix #11361] Make Style/MethodDefParentheses aware of anonymous res…

…t and keyword rest args

Fixes #11361

This PR fixes a false positive for `Style/MethodDefParentheses` when using `EnforcedStyle: require_no_parentheses`
and Ruby 3.2's anonymous rest and keyword rest arguments.

changelog/fix_false_positive_for_style_method_def_parentheses.md

@@ -0,0 +1 @@
+* [#11361](https://github.com/rubocop/rubocop/issues/11361): Make `Style/MethodDefParentheses` aware of Ruby 3.2's anonymous rest and keyword rest arguments. ([@koic][])

lib/rubocop/cop/style/method_def_parentheses.rb

@@ -10,7 +10,9 @@ module Style
       #
       # 1. Endless methods
       # 2. Argument lists containing a `forward-arg` (`...`)
-      # 3. Argument lists containing an anonymous block forwarding (`&`)
+      # 3. Argument lists containing an anonymous rest arguments forwarding (`*`)
+      # 4. Argument lists containing an anonymous keyword rest arguments forwarding (`**`)
+      # 5. Argument lists containing an anonymous block forwarding (`&`)
       #
       # Removing the parens would be a syntax error here.
       #
@@ -130,9 +132,11 @@ def forced_parentheses?(node)
           # Regardless of style, parentheses are necessary for:
           # 1. Endless methods
           # 2. Argument lists containing a `forward-arg` (`...`)
-          # 3. Argument lists containing an anonymous block forwarding (`&`)
+          # 3. Argument lists containing an anonymous rest arguments forwarding (`*`)
+          # 4. Argument lists containing an anonymous keyword rest arguments forwarding (`**`)
+          # 5. Argument lists containing an anonymous block forwarding (`&`)
           # Removing the parens would be a syntax error here.
-          node.endless? || node.arguments.any?(&:forward_arg_type?) || anonymous_block_arg?(node)
+          node.endless? || anonymous_arguments?(node)
         end
 
         def require_parentheses?(args)
@@ -162,7 +166,10 @@ def unwanted_parentheses(args)
           end
         end
 
-        def anonymous_block_arg?(node)
+        def anonymous_arguments?(node)
+          return true if node.arguments.any? do |arg|
+            arg.forward_arg_type? || arg.restarg_type? || arg.kwrestarg_type?
+          end
           return false unless (last_argument = node.arguments.last)
 
           last_argument.blockarg_type? && last_argument.name.nil?

spec/rubocop/cop/style/method_def_parentheses_spec.rb

@@ -107,6 +107,22 @@ def foo(&)
         end
       RUBY
     end
+
+    it 'requires parens for anonymous rest arguments forwarding', :ruby32 do
+      expect_no_offenses(<<~RUBY)
+        def foo(*)
+          bar(*)
+        end
+      RUBY
+    end
+
+    it 'requires parens for anonymous keyword rest arguments forwarding', :ruby32 do
+      expect_no_offenses(<<~RUBY)
+        def foo(**)
+          bar(**)
+        end
+      RUBY
+    end
   end
 
   shared_examples 'endless methods' do