[Fix rubocop#9328] Honour shareable_constant_value magic comment

CHANGELOG.md

@@ -5743,3 +5743,4 @@
 [@AirWick219]: https://github.com/AirWick219
 [@markburns]: https://github.com/markburns
 [@gregfletch]: https://github.com/gregfletch
+[@thearjunmdas]: https://github.com/thearjunmdas

changelog/change_recognize_shareable_constant_value_magic.md

@@ -0,0 +1 @@
+* [#9328](https://github.com/rubocop/rubocop/issues/9328): Recognize shareable_constant_value magic comment. ([@thearjunmdas][])

lib/rubocop.rb

@@ -113,6 +113,7 @@
 require_relative 'rubocop/cop/mixin/rational_literal'
 require_relative 'rubocop/cop/mixin/rescue_node'
 require_relative 'rubocop/cop/mixin/safe_assignment'
+require_relative 'rubocop/cop/mixin/shareable_constant_value'
 require_relative 'rubocop/cop/mixin/space_after_punctuation'
 require_relative 'rubocop/cop/mixin/space_before_punctuation'
 require_relative 'rubocop/cop/mixin/surrounding_space'

lib/rubocop/cop/mixin/shareable_constant_value.rb

@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+module RuboCop
+  module Cop
+    # Common functionality for dealing with Shareable Constant Value
+    module ShareableConstantValue
+      module_function
+
+      def recent_shareable_value?(node)
+        shareable_constant_comment = magic_comment_in_scope node
+        return false if shareable_constant_comment.nil?
+
+        shareable_constant_value = MagicComment.parse(shareable_constant_comment)
+                                               .shareable_constant_value
+        shareable_constant_value_enabled? shareable_constant_value
+      end
+
+      # Identifies the most recent magic comment with valid shareable constant values
+      # thats in scope for this node
+      def magic_comment_in_scope(node)
+        processed_source_till_node(node).reverse_each.find do |line|
+          MagicComment.parse(line).valid_shareable_constant_value?
+        end
+      end
+
+      private
+
+      def processed_source_till_node(node)
+        processed_source.lines[0..(node.last_line - 1)]
+      end
+
+      def shareable_constant_value_enabled?(value)
+        %w[literal experimental_everything experimental_copy].include? value
+      end
+    end
+  end
+end

lib/rubocop/cop/style/mutable_constant.rb

@@ -53,6 +53,7 @@ module Style
       #     end
       #   end.freeze
       class MutableConstant < Base
+        include ShareableConstantValue
         include FrozenStringLiteral
         include ConfigurableEnforcedStyle
         extend AutoCorrector
@@ -83,6 +84,7 @@ def on_assignment(value)
         end
 
         def strict_check(value)
+          return if shareable_constant_value?(value)
           return if immutable_literal?(value)
           return if operation_produces_immutable_object?(value)
           return if frozen_string_literal?(value)
@@ -91,11 +93,11 @@ def strict_check(value)
         end
 
         def check(value)
-          range_enclosed_in_parentheses = range_enclosed_in_parentheses?(value)
+          return if shareable_constant_value?(value)
 
+          range_enclosed_in_parentheses = range_enclosed_in_parentheses?(value)
           return unless mutable_literal?(value) ||
                         target_ruby_version <= 2.7 && range_enclosed_in_parentheses
-
           return if FROZEN_STRING_LITERAL_TYPES.include?(value.type) &&
                     frozen_string_literals_enabled?
 
@@ -132,6 +134,13 @@ def frozen_string_literal?(node)
           FROZEN_STRING_LITERAL_TYPES.include?(node.type) && frozen_string_literals_enabled?
         end
 
+        def shareable_constant_value?(node)
+          return false if target_ruby_version < 3.0
+          return false if node.nil?
+
+          recent_shareable_value? node
+        end
+
         def frozen_regexp_or_range_literals?(node)
           target_ruby_version >= 3.0 && (node.regexp_type? || node.range_type?)
         end

lib/rubocop/magic_comment.rb

@@ -166,7 +166,7 @@ def extract_frozen_string_literal
       end
 
       def extract_shareable_constant_value
-        match('shareable[_-]constant[_-]values')
+        match('shareable[_-]constant[_-]value')
       end
     end
 

spec/rubocop/cop/style/mutable_constant_spec.rb

@@ -157,6 +157,123 @@
           RUBY
         end
       end
+
+      context 'when using shareable_constant_value: literal' do
+        let(:prefix) { '# shareable_constant_value: literal' }
+
+        it_behaves_like 'immutable objects', '[1, 2, 3]'
+        it_behaves_like 'immutable objects', '%w(a b c)'
+        it_behaves_like 'immutable objects', '{ a: 1, b: 2 }'
+        it_behaves_like 'immutable objects', "'str'"
+        it_behaves_like 'immutable objects', '"top#{1 + 2}"'
+        it_behaves_like 'immutable objects', '1'
+        it_behaves_like 'immutable objects', '1.5'
+        it_behaves_like 'immutable objects', ':sym'
+        it_behaves_like 'immutable objects', 'FOO + BAR'
+        it_behaves_like 'immutable objects', 'FOO - BAR'
+        it_behaves_like 'immutable objects', "'foo' + 'bar'"
+        it_behaves_like 'immutable objects', "ENV['foo']"
+        it_behaves_like 'immutable objects', "::ENV['foo']"
+      end
+
+      context 'when using shareable_constant_value: experimental_everything' do
+        let(:prefix) { '# shareable_constant_value: experimental_everything' }
+
+        it_behaves_like 'immutable objects', '[1, 2, 3]'
+        it_behaves_like 'immutable objects', '%w(a b c)'
+        it_behaves_like 'immutable objects', '{ a: 1, b: 2 }'
+        it_behaves_like 'immutable objects', "'str'"
+        it_behaves_like 'immutable objects', '"top#{1 + 2}"'
+        it_behaves_like 'immutable objects', '1'
+        it_behaves_like 'immutable objects', '1.5'
+        it_behaves_like 'immutable objects', ':sym'
+        it_behaves_like 'immutable objects', 'FOO + BAR'
+        it_behaves_like 'immutable objects', 'FOO - BAR'
+        it_behaves_like 'immutable objects', "'foo' + 'bar'"
+        it_behaves_like 'immutable objects', "ENV['foo']"
+        it_behaves_like 'immutable objects', "::ENV['foo']"
+      end
+
+      context 'when using shareable_constant_value: experimental_copy' do
+        let(:prefix) { '# shareable_constant_value: experimental_copy' }
+
+        it_behaves_like 'immutable objects', '[1, 2, 3]'
+        it_behaves_like 'immutable objects', '%w(a b c)'
+        it_behaves_like 'immutable objects', '{ a: 1, b: 2 }'
+        it_behaves_like 'immutable objects', "'str'"
+        it_behaves_like 'immutable objects', '"top#{1 + 2}"'
+        it_behaves_like 'immutable objects', '1'
+        it_behaves_like 'immutable objects', '1.5'
+        it_behaves_like 'immutable objects', ':sym'
+        it_behaves_like 'immutable objects', 'FOO + BAR'
+        it_behaves_like 'immutable objects', 'FOO - BAR'
+        it_behaves_like 'immutable objects', "'foo' + 'bar'"
+        it_behaves_like 'immutable objects', "ENV['foo']"
+        it_behaves_like 'immutable objects', "::ENV['foo']"
+      end
+
+      it 'raises offense only for shareable_constant_value as none when set in the order of: literal and none' do
+        expect_offense(<<~RUBY)
+          # shareable_constant_value: literal
+          X = [1, 2, 3]
+          # shareable_constant_value: none
+          Y = [4, 5, 6]
+              ^^^^^^^^^ Freeze mutable objects assigned to constants.
+        RUBY
+      end
+
+      it 'raises offense only for shareable_constant_value as none when set in the order of:  experimental_everything and none' do
+        expect_offense(<<~RUBY)
+          # shareable_constant_value: experimental_everything
+          X = [1, 2, 3]
+          # shareable_constant_value: none
+          Y = [4, 5, 6]
+              ^^^^^^^^^ Freeze mutable objects assigned to constants.
+        RUBY
+      end
+
+      it 'raises offense only for shareable_constant_value as none when set in the order of: literal, none and experimental_everything' do
+        expect_offense(<<~RUBY)
+          # shareable_constant_value: literal
+          X = [1, 2, 3]
+          # shareable_constant_value: none
+          Y = [4, 5, 6]
+              ^^^^^^^^^ Freeze mutable objects assigned to constants.
+          # shareable_constant_value: experimental_everything
+          Z = [7, 8, 9]
+        RUBY
+      end
+
+      it 'raises offense only for shareable_constant_value as none when set in the order of: none, experimental_everything and literal' do
+        expect_offense(<<~RUBY)
+          # shareable_constant_value: none
+          X = [1, 2, 3]
+              ^^^^^^^^^ Freeze mutable objects assigned to constants.
+          # shareable_constant_value: experimental_everything
+          Y = [4, 5, 6]
+          # shareable_constant_value: literal
+          Z = [7, 8, 9]
+        RUBY
+      end
+
+      it 'does not raise offense for invalid shareable_constant_value when set in the order of: literal, invalid' do
+        expect_no_offenses(<<~RUBY)
+          # shareable_constant_value: literal
+          Y = [4, 5, 6]
+          # shareable_constant_value: invalid
+          Z = [7, 8, 9]
+        RUBY
+      end
+
+      it 'raises offense only for invalid shareable_constant_value when set in the order of: invalid, literal' do
+        expect_offense(<<~RUBY)
+          # shareable_constant_value: invalid
+          Y = [4, 5, 6]
+              ^^^^^^^^^ Freeze mutable objects assigned to constants.
+          # shareable_constant_value: literal
+          Z = [7, 8, 9]
+        RUBY
+      end
     end
 
     context 'Ruby 2.7 or lower', :ruby27 do
@@ -220,6 +337,63 @@
           RUBY
         end
       end
+
+      context 'when using shareable_constant_value: literal' do
+        let(:prefix) { '# shareable_constant_value: literal' }
+
+        it_behaves_like 'mutable objects', '[1, 2, 3]'
+        it_behaves_like 'mutable objects', '%w(a b c)'
+        it_behaves_like 'mutable objects', '{ a: 1, b: 2 }'
+        it_behaves_like 'mutable objects', "'str'"
+        it_behaves_like 'mutable objects', '"top#{1 + 2}"'
+
+        it_behaves_like 'immutable objects', '1'
+        it_behaves_like 'immutable objects', '1.5'
+        it_behaves_like 'immutable objects', ':sym'
+        it_behaves_like 'immutable objects', 'FOO + BAR'
+        it_behaves_like 'immutable objects', 'FOO - BAR'
+        it_behaves_like 'immutable objects', "'foo' + 'bar'"
+        it_behaves_like 'immutable objects', "ENV['foo']"
+        it_behaves_like 'immutable objects', "::ENV['foo']"
+      end
+
+      context 'when using shareable_constant_value: experimental_everything' do
+        let(:prefix) { '# shareable_constant_value: experimental_everything' }
+
+        it_behaves_like 'mutable objects', '[1, 2, 3]'
+        it_behaves_like 'mutable objects', '%w(a b c)'
+        it_behaves_like 'mutable objects', '{ a: 1, b: 2 }'
+        it_behaves_like 'mutable objects', "'str'"
+        it_behaves_like 'mutable objects', '"top#{1 + 2}"'
+
+        it_behaves_like 'immutable objects', '1'
+        it_behaves_like 'immutable objects', '1.5'
+        it_behaves_like 'immutable objects', ':sym'
+        it_behaves_like 'immutable objects', 'FOO + BAR'
+        it_behaves_like 'immutable objects', 'FOO - BAR'
+        it_behaves_like 'immutable objects', "'foo' + 'bar'"
+        it_behaves_like 'immutable objects', "ENV['foo']"
+        it_behaves_like 'immutable objects', "::ENV['foo']"
+      end
+
+      context 'when using shareable_constant_value: experimental_copy' do
+        let(:prefix) { '# shareable_constant_value: experimental_copy' }
+
+        it_behaves_like 'mutable objects', '[1, 2, 3]'
+        it_behaves_like 'mutable objects', '%w(a b c)'
+        it_behaves_like 'mutable objects', '{ a: 1, b: 2 }'
+        it_behaves_like 'mutable objects', "'str'"
+        it_behaves_like 'mutable objects', '"top#{1 + 2}"'
+
+        it_behaves_like 'immutable objects', '1'
+        it_behaves_like 'immutable objects', '1.5'
+        it_behaves_like 'immutable objects', ':sym'
+        it_behaves_like 'immutable objects', 'FOO + BAR'
+        it_behaves_like 'immutable objects', 'FOO - BAR'
+        it_behaves_like 'immutable objects', "'foo' + 'bar'"
+        it_behaves_like 'immutable objects', "ENV['foo']"
+        it_behaves_like 'immutable objects', "::ENV['foo']"
+      end
     end
 
     context 'when the constant is a frozen string literal' do

spec/rubocop/magic_comment_spec.rb

@@ -4,6 +4,7 @@
   shared_examples 'magic comment' do |comment, expectations = {}|
     encoding = expectations[:encoding]
     frozen_string = expectations[:frozen_string_literal]
+    shareable_constant_value = expectations[:shareable_constant_value]
 
     it "returns #{encoding.inspect} for encoding when comment is #{comment}" do
       expect(described_class.parse(comment).encoding).to eql(encoding)
@@ -12,6 +13,12 @@
     it "returns #{frozen_string.inspect} for frozen_string_literal when comment is #{comment}" do
       expect(described_class.parse(comment).frozen_string_literal).to eql(frozen_string)
     end
+
+    it "returns #{shareable_constant_value.inspect} for shareable_constant_value " \
+       "when comment is #{comment}" do
+      expect(described_class.parse(comment)
+                            .shareable_constant_value).to eql(shareable_constant_value)
+    end
   end
 
   include_examples 'magic comment', '#'
@@ -46,6 +53,22 @@
 
   include_examples 'magic comment', '# fRoZeN-sTrInG_lItErAl: true', frozen_string_literal: true
 
+  include_examples 'magic comment', '# shareable_constant_value: literal', shareable_constant_value: 'literal'
+
+  include_examples 'magic comment', '# shareable_constant_value: none', shareable_constant_value: 'none'
+
+  include_examples(
+    'magic comment',
+    '# shareable_constant_value: experimental_everything',
+    shareable_constant_value: 'experimental_everything'
+  )
+
+  include_examples(
+    'magic comment',
+    '# shareable_constant_value: experimental_copy',
+    shareable_constant_value: 'experimental_copy'
+  )
+
   include_examples 'magic comment',
                    '# -*- frozen-string-literal: true -*-',
                    frozen_string_literal: true