[Fix #9327] Change Layout/EmptyLineAfterMagicComment to accept top-…

…level `shareable_constant_values` directive

Closes #9327

changelog/change_empty_line_magic_comment_with_shareable_constant_value.md

@@ -0,0 +1 @@
+* [#9327](https://github.com/rubocop-hq/rubocop/issues/9327): Change `Layout/EmptyLineAfterMagicComment` to accept top-level `shareable_constant_values` directive. ([@tejasbubane][])

lib/rubocop/magic_comment.rb

@@ -27,7 +27,7 @@ def initialize(comment)
     end
 
     def any?
-      frozen_string_literal_specified? || encoding_specified?
+      frozen_string_literal_specified? || encoding_specified? || shareable_constant_value_specified?
     end
 
     # Does the magic comment enable the frozen string literal feature.
@@ -46,13 +46,24 @@ def valid_literal_value?
       [true, false].include?(frozen_string_literal)
     end
 
+    def valid_shareable_constant_value?
+      %w[none literal experimental_everything experimental_copy].include?(shareable_constant_values)
+    end
+
     # Was a magic comment for the frozen string literal found?
     #
     # @return [Boolean]
     def frozen_string_literal_specified?
       specified?(frozen_string_literal)
     end
 
+    # Was a shareable_constant_value specified?
+    #
+    # @return [Boolean]
+    def shareable_constant_value_specified?
+      specified?(shareable_constant_value)
+    end
+
     # Expose the `frozen_string_literal` value coerced to a boolean if possible.
     #
     # @return [Boolean] if value is `true` or `false`
@@ -69,6 +80,13 @@ def frozen_string_literal
       end
     end
 
+    # Expose the `shareable_constant_value` value coerced to a boolean if possible.
+    #
+    # @return [String] for shareable_constant_value config
+    def shareable_constant_value
+      extract_shareable_constant_value
+    end
+
     def encoding_specified?
       specified?(encoding)
     end
@@ -146,6 +164,10 @@ def encoding
       def extract_frozen_string_literal
         match('frozen[_-]string[_-]literal')
       end
+
+      def extract_shareable_constant_value
+        match('shareable[_-]constant[_-]values')
+      end
     end
 
     # Wrapper for Vim style magic comments.
@@ -176,6 +198,9 @@ def encoding
 
       # Vim comments cannot specify frozen string literal behavior.
       def frozen_string_literal; end
+
+      # Vim comments cannot specify shareable constant values behavior.
+      def shareable_constant_value; end
     end
 
     # Wrapper for regular magic comments not bound to an editor.
@@ -209,6 +234,10 @@ def encoding
       def extract_frozen_string_literal
         extract(/\A\s*#\s*frozen[_-]string[_-]literal:\s*(#{TOKEN})\s*\z/io)
       end
+
+      def extract_shareable_constant_value
+        extract(/\A\s*#\s*shareable[_-]constant[_-]value:\s*(#{TOKEN})\s*\z/io)
+      end
     end
   end
 end

spec/rubocop/cop/layout/empty_line_after_magic_comment_spec.rb

@@ -51,6 +51,47 @@ class Foo; end
     RUBY
   end
 
+  it 'accepts magic comment followed by encoding' do
+    expect_no_offenses(<<~RUBY)
+      # frozen_string_literal: true
+      # encoding: utf-8
+
+      class Foo; end
+    RUBY
+  end
+
+  it 'accepts magic comment with shareable_constant_value' do
+    expect_no_offenses(<<~RUBY)
+      # frozen_string_literal: true
+      # shareable_constant_value: literal
+
+      class Foo; end
+    RUBY
+
+    expect_no_offenses(<<~RUBY)
+      # shareable_constant_value: experimental_everything
+      # frozen_string_literal: true
+
+      class Foo; end
+    RUBY
+  end
+
+  it 'registers offense when frozen_string_literal used with shareable_constant_value without empty line' do
+    expect_offense(<<~RUBY)
+      # frozen_string_literal: true
+      # shareable_constant_value: none
+      class Foo; end
+      ^ Add an empty line after magic comments.
+    RUBY
+
+    expect_correction(<<~RUBY)
+      # frozen_string_literal: true
+      # shareable_constant_value: none
+
+      class Foo; end
+    RUBY
+  end
+
   it 'accepts code that separates the comment from the code with a newline' do
     expect_no_offenses(<<~RUBY)
       # frozen_string_literal: true