[Fix rubocop#11696] Add new Style/DataInheritance cop

changelog/new_add_new_style_data_inheritance_cop.md

@@ -0,0 +1 @@
+* [#11696](https://github.com/rubocop/rubocop/issues/11696): Add new `Style/DataInheritance` cop. ([@ktopolski][])

config/default.yml

@@ -3508,6 +3508,12 @@ Style/Copyright:
   Notice: '^Copyright (\(c\) )?2[0-9]{3} .+'
   AutocorrectNotice: ''
 
+Style/DataInheritance:
+  Description: 'Checks for inheritance from Data.define.'
+  StyleGuide: '#no-extend-data-define'
+  Enabled: pending
+  VersionAdded: '<<next>>'
+
 Style/DateTime:
   Description: 'Use Time over DateTime.'
   StyleGuide: '#date-time'

lib/rubocop.rb

@@ -480,6 +480,7 @@
 require_relative 'rubocop/cop/style/conditional_assignment'
 require_relative 'rubocop/cop/style/constant_visibility'
 require_relative 'rubocop/cop/style/copyright'
+require_relative 'rubocop/cop/style/data_inheritance'
 require_relative 'rubocop/cop/style/date_time'
 require_relative 'rubocop/cop/style/def_with_parentheses'
 require_relative 'rubocop/cop/style/dir'

lib/rubocop/cop/style/data_inheritance.rb

@@ -0,0 +1,75 @@
+# frozen_string_literal: true
+
+module RuboCop
+  module Cop
+    module Style
+      # Checks for inheritance from `Data.define` to avoid creating the anonymous parent class.
+      #
+      # @safety
+      #   Autocorrection is unsafe because it will change the inheritance
+      #   tree (e.g. return value of `Module#ancestors`) of the constant.
+      #
+      # @example
+      #   # bad
+      #   class Person < Data.define(:first_name, :last_name)
+      #     def age
+      #       42
+      #     end
+      #   end
+      #
+      #   # good
+      #   Person = Data.define(:first_name, :last_name) do
+      #     def age
+      #       42
+      #     end
+      #   end
+      class DataInheritance < Base
+        include RangeHelp
+        extend AutoCorrector
+        extend TargetRubyVersion
+
+        MSG = "Don't extend an instance initialized by `Data.define`. " \
+              'Use a block to customize the class.'
+
+        minimum_target_ruby_version 3.2
+
+        def on_class(node)
+          return unless data_define?(node.parent_class)
+
+          add_offense(node.parent_class.source_range) do |corrector|
+            corrector.remove(range_with_surrounding_space(node.loc.keyword, newlines: false))
+            corrector.replace(node.loc.operator, '=')
+
+            correct_parent(node.parent_class, corrector)
+          end
+        end
+
+        # @!method data_define?(node)
+        def_node_matcher :data_define?, <<~PATTERN
+          {(send (const {nil? cbase} :Data) :define ...)
+           (block (send (const {nil? cbase} :Data) :define ...) ...)}
+        PATTERN
+
+        private
+
+        def correct_parent(parent, corrector)
+          if parent.block_type?
+            corrector.remove(range_with_surrounding_space(parent.loc.end, newlines: false))
+          elsif (class_node = parent.parent).body.nil?
+            corrector.remove(range_for_empty_class_body(class_node, parent))
+          else
+            corrector.insert_after(parent, ' do')
+          end
+        end
+
+        def range_for_empty_class_body(class_node, data_define)
+          if class_node.single_line?
+            range_between(data_define.source_range.end_pos, class_node.source_range.end_pos)
+          else
+            range_by_whole_lines(class_node.loc.end, include_final_newline: true)
+          end
+        end
+      end
+    end
+  end
+end

spec/rubocop/cop/style/data_inheritance_spec.rb

@@ -0,0 +1,218 @@
+# frozen_string_literal: true
+
+RSpec.describe RuboCop::Cop::Style::DataInheritance, :config do
+  context 'Ruby >= 3.2', :ruby32 do
+    it 'registers an offense when extending instance of `Data.define`' do
+      expect_offense(<<~RUBY)
+        class Person < Data.define(:first_name, :last_name)
+                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Don't extend an instance initialized by `Data.define`. Use a block to customize the class.
+          def foo; end
+        end
+      RUBY
+
+      expect_correction(<<~RUBY)
+        Person = Data.define(:first_name, :last_name) do
+          def foo; end
+        end
+      RUBY
+    end
+
+    it 'registers an offense when extending instance of `::Data.define`' do
+      expect_offense(<<~RUBY)
+        class Person < ::Data.define(:first_name, :last_name)
+                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Don't extend an instance initialized by `Data.define`. Use a block to customize the class.
+          def foo; end
+        end
+      RUBY
+
+      expect_correction(<<~RUBY)
+        Person = ::Data.define(:first_name, :last_name) do
+          def foo; end
+        end
+      RUBY
+    end
+
+    it 'registers an offense when extending instance of `Data.define` with do ... end' do
+      expect_offense(<<~RUBY)
+        class Person < Data.define(:first_name, :last_name) do end
+                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Don't extend an instance initialized by `Data.define`. Use a block to customize the class.
+        end
+      RUBY
+
+      expect_correction(<<~RUBY)
+        Person = Data.define(:first_name, :last_name) do
+        end
+      RUBY
+    end
+
+    it 'registers an offense when extending instance of `Data.define` without `do` ... `end` and class body is empty' do
+      expect_offense(<<~RUBY)
+        class Person < Data.define(:first_name, :last_name)
+                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Don't extend an instance initialized by `Data.define`. Use a block to customize the class.
+        end
+      RUBY
+
+      expect_correction(<<~RUBY)
+        Person = Data.define(:first_name, :last_name)
+      RUBY
+    end
+
+    it 'registers an offense when extending instance of `Data.define` without `do` ... `end` and class body is empty and single line definition' do
+      expect_offense(<<~RUBY)
+        class Person < Data.define(:first_name, :last_name); end
+                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Don't extend an instance initialized by `Data.define`. Use a block to customize the class.
+      RUBY
+
+      expect_correction(<<~RUBY)
+        Person = Data.define(:first_name, :last_name)
+      RUBY
+    end
+
+    it 'registers an offense when extending instance of `::Data.define` with do ... end' do
+      expect_offense(<<~RUBY)
+        class Person < ::Data.define(:first_name, :last_name) do end
+                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Don't extend an instance initialized by `Data.define`. Use a block to customize the class.
+        end
+      RUBY
+
+      expect_correction(<<~RUBY)
+        Person = ::Data.define(:first_name, :last_name) do
+        end
+      RUBY
+    end
+
+    it 'registers an offense when extending instance of `Data.define` when there is a comment ' \
+       'before class declaration' do
+      expect_offense(<<~RUBY)
+        # comment
+        class Person < Data.define(:first_name, :last_name) do end
+                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Don't extend an instance initialized by `Data.define`. Use a block to customize the class.
+        end
+      RUBY
+
+      expect_correction(<<~RUBY)
+        # comment
+        Person = Data.define(:first_name, :last_name) do
+        end
+      RUBY
+    end
+
+    it 'accepts plain class' do
+      expect_no_offenses(<<~RUBY)
+        class Person
+        end
+      RUBY
+    end
+
+    it 'accepts extending DelegateClass' do
+      expect_no_offenses(<<~RUBY)
+        class Person < DelegateClass(Animal)
+        end
+      RUBY
+    end
+
+    it 'accepts assignment to `Data.define`' do
+      expect_no_offenses('Person = Data.define(:first_name, :last_name)')
+    end
+
+    it 'accepts assignment to `::Data.define`' do
+      expect_no_offenses('Person = ::Data.define(:first_name, :last_name)')
+    end
+
+    it 'accepts assignment to block form of `Data.define`' do
+      expect_no_offenses(<<~RUBY)
+        Person = Data.define(:first_name, :last_name) do
+          def age
+            42
+          end
+        end
+      RUBY
+    end
+  end
+
+  context 'Ruby <= 3.1', :ruby31 do
+    it 'accepts extending instance of `Data.define`' do
+      expect_no_offenses(<<~RUBY)
+        class Person < Data.define(:first_name, :last_name)
+          def foo; end
+        end
+      RUBY
+    end
+
+    it 'accepts extending instance of `::Data.define`' do
+      expect_no_offenses(<<~RUBY)
+        class Person < ::Data.define(:first_name, :last_name)
+          def foo; end
+        end
+      RUBY
+    end
+
+    it 'accepts extending instance of `Data.define` with do ... end' do
+      expect_no_offenses(<<~RUBY)
+        class Person < Data.define(:first_name, :last_name) do end
+        end
+      RUBY
+    end
+
+    it 'accepts extending instance of `Data.define` without `do` ... `end` and class body is empty' do
+      expect_no_offenses(<<~RUBY)
+        class Person < Data.define(:first_name, :last_name)
+        end
+      RUBY
+    end
+
+    it 'accepts extending instance of `Data.define` without `do` ... `end` and class body is empty and single line definition' do
+      expect_no_offenses(<<~RUBY)
+        class Person < Data.define(:first_name, :last_name); end
+      RUBY
+    end
+
+    it 'accepts extending instance of `::Data.define` with do ... end' do
+      expect_no_offenses(<<~RUBY)
+        class Person < ::Data.define(:first_name, :last_name) do end
+        end
+      RUBY
+    end
+
+    it 'accepts extending instance of `Data.define` when there is a comment ' \
+       'before class declaration' do
+      expect_no_offenses(<<~RUBY)
+        # comment
+        class Person < Data.define(:first_name, :last_name) do end
+        end
+      RUBY
+    end
+
+    it 'accepts plain class' do
+      expect_no_offenses(<<~RUBY)
+        class Person
+        end
+      RUBY
+    end
+
+    it 'accepts extending DelegateClass' do
+      expect_no_offenses(<<~RUBY)
+        class Person < DelegateClass(Animal)
+        end
+      RUBY
+    end
+
+    it 'accepts assignment to `Data.define`' do
+      expect_no_offenses('Person = Data.define(:first_name, :last_name)')
+    end
+
+    it 'accepts assignment to `::Data.define`' do
+      expect_no_offenses('Person = ::Data.define(:first_name, :last_name)')
+    end
+
+    it 'accepts assignment to block form of `Data.define`' do
+      expect_no_offenses(<<~RUBY)
+        Person = Data.define(:first_name, :last_name) do
+          def age
+            42
+          end
+        end
+      RUBY
+    end
+  end
+end