Merge pull request rubocop#9987 from dvandersluis/internal/undefined-…

…config

Add `InternalAffairs/UndefinedConfig` cop.

.rubocop.yml

@@ -140,3 +140,10 @@ RSpec/StubbedMock:
 InternalAffairs/ExampleDescription:
   Include:
     - 'spec/rubocop/cop/**/*.rb'
+
+InternalAffairs/UndefinedConfig:
+  Include:
+    - 'lib/rubocop/cop/**/*.rb'
+  Exclude:
+    - 'lib/rubocop/cop/correctors/**/*.rb'
+    - 'lib/rubocop/cop/mixin/**/*.rb'

config/default.yml

@@ -1824,7 +1824,6 @@ Lint/MultipleComparison:
   Enabled: true
   VersionAdded: '0.47'
   VersionChanged: '1.1'
-  AllowMethodComparison: true
 
 Lint/NestedMethodDefinition:
   Description: 'Do not use nested method definitions.'
@@ -3931,6 +3930,7 @@ Style/MultipleComparison:
   Enabled: true
   VersionAdded: '0.49'
   VersionChanged: '1.1'
+  AllowMethodComparison: true
 
 Style/MutableConstant:
   Description: 'Do not assign mutable objects to constants.'
@@ -4154,6 +4154,7 @@ Style/OptionHash:
     - args
     - params
     - parameters
+  Allowlist: []
 
 Style/OptionalArguments:
   Description: >-

lib/rubocop/cop/internal_affairs.rb

@@ -13,4 +13,5 @@
 require_relative 'internal_affairs/redundant_location_argument'
 require_relative 'internal_affairs/redundant_message_argument'
 require_relative 'internal_affairs/style_detected_api_use'
+require_relative 'internal_affairs/undefined_config'
 require_relative 'internal_affairs/useless_message_assertion'

lib/rubocop/cop/internal_affairs/undefined_config.rb

@@ -0,0 +1,71 @@
+# frozen_string_literal: true
+
+module RuboCop
+  module Cop
+    module InternalAffairs
+      # Looks for references to a cop configuration key that isn't defined in config/default.yml.
+      class UndefinedConfig < Base
+        ALLOWED_CONFIGURATIONS = %w[
+          Safe SafeAutoCorrect AutoCorrect Severity StyleGuide Details Reference Include Exclude
+        ].freeze
+        RESTRICT_ON_SEND = %i[[] fetch].freeze
+        MSG = '`%<name>s` is not defined in the configuration for `%<cop>s` ' \
+              'in `config/default.yml`.'
+
+        # @!method cop_class_def(node)
+        def_node_search :cop_class_def, <<~PATTERN
+          (class _ (const _ {:Base :Cop}) ...)
+        PATTERN
+
+        # @!method cop_config_accessor?(node)
+        def_node_matcher :cop_config_accessor?, <<~PATTERN
+          (send (send nil? :cop_config) {:[] :fetch} ${str sym}...)
+        PATTERN
+
+        def on_new_investigation
+          super
+          return unless processed_source.ast
+
+          cop_class = cop_class_def(processed_source.ast).first
+          return unless (@cop_class_name = extract_cop_name(cop_class))
+
+          @config_for_cop = RuboCop::ConfigLoader.default_configuration.for_cop(@cop_class_name)
+        end
+
+        def on_send(node)
+          return unless cop_class_name
+          return unless (config_name_node = cop_config_accessor?(node))
+          return if always_allowed?(config_name_node)
+          return if configuration_key_defined?(config_name_node)
+
+          message = format(MSG, name: config_name_node.value, cop: cop_class_name)
+          add_offense(config_name_node, message: message)
+        end
+
+        private
+
+        attr_reader :config_for_cop, :cop_class_name
+
+        def extract_cop_name(class_node)
+          return unless class_node
+
+          segments = [class_node].concat(
+            class_node.each_ancestor(:class, :module).take_while do |n|
+              n.identifier.short_name != :Cop
+            end
+          )
+
+          segments.reverse_each.map { |s| s.identifier.short_name }.join('/')
+        end
+
+        def always_allowed?(node)
+          ALLOWED_CONFIGURATIONS.include?(node.value)
+        end
+
+        def configuration_key_defined?(node)
+          config_for_cop.key?(node.value)
+        end
+      end
+    end
+  end
+end

spec/rubocop/cop/internal_affairs/undefined_config_spec.rb

@@ -0,0 +1,234 @@
+# frozen_string_literal: true
+
+RSpec.describe RuboCop::Cop::InternalAffairs::UndefinedConfig, :config, :isolated_environment do
+  include FileHelper
+
+  before do
+    create_file('config/default.yml', <<~YAML)
+      Test/Foo:
+        Defined: true
+
+      X/Y/Z:
+        Defined: true
+    YAML
+
+    allow(RuboCop::ConfigLoader).to receive(:default_configuration).and_return(
+      RuboCop::ConfigLoader.load_file('config/default.yml', check: false)
+    )
+  end
+
+  it 'does not register an offense for implicit configuration keys' do
+    expect_no_offenses(<<~RUBY)
+      module RuboCop
+        module Cop
+          module Test
+            class Foo < Base
+              def configured?
+                cop_config['Safe']
+                cop_config['SafeAutoCorrect']
+                cop_config['AutoCorrect']
+                cop_config['Severity']
+              end
+            end
+          end
+        end
+      end
+    RUBY
+  end
+
+  it 'registers an offense when the cop has no configuration at all' do
+    expect_offense(<<~RUBY)
+      module RuboCop
+        module Cop
+          module Test
+            class Bar < Base
+              def configured?
+                cop_config['Missing']
+                           ^^^^^^^^^ `Missing` is not defined in the configuration for `Test/Bar` in `config/default.yml`.
+              end
+            end
+          end
+        end
+      end
+    RUBY
+  end
+
+  it 'registers an offense when the cop is not within the `RuboCop::Cop` namespace' do
+    expect_offense(<<~RUBY)
+      module Test
+        class Foo < Base
+          def configured?
+            cop_config['Defined']
+            cop_config['Missing']
+                       ^^^^^^^^^ `Missing` is not defined in the configuration for `Test/Foo` in `config/default.yml`.
+          end
+        end
+      end
+    RUBY
+  end
+
+  context 'element lookup' do
+    it 'does not register an offense for defined configuration keys' do
+      expect_no_offenses(<<~RUBY)
+        module RuboCop
+          module Cop
+            module Test
+              class Foo < Base
+                def configured?
+                  cop_config['Defined']
+                end
+              end
+            end
+          end
+        end
+      RUBY
+    end
+
+    it 'registers an offense for missing configuration keys' do
+      expect_offense(<<~RUBY)
+        module RuboCop
+          module Cop
+            module Test
+              class Foo < Base
+                def configured?
+                  cop_config['Missing']
+                             ^^^^^^^^^ `Missing` is not defined in the configuration for `Test/Foo` in `config/default.yml`.
+                end
+              end
+            end
+          end
+        end
+      RUBY
+    end
+  end
+
+  context 'fetch' do
+    it 'does not register an offense for defined configuration keys' do
+      expect_no_offenses(<<~RUBY)
+        module RuboCop
+          module Cop
+            module Test
+              class Foo < Base
+                def configured?
+                  cop_config.fetch('Defined')
+                end
+              end
+            end
+          end
+        end
+      RUBY
+    end
+
+    it 'registers an offense for missing configuration keys' do
+      expect_offense(<<~RUBY)
+        module RuboCop
+          module Cop
+            module Test
+              class Foo < Base
+                def configured?
+                  cop_config.fetch('Missing')
+                                   ^^^^^^^^^ `Missing` is not defined in the configuration for `Test/Foo` in `config/default.yml`.
+                end
+              end
+            end
+          end
+        end
+      RUBY
+    end
+
+    context 'with a default value' do
+      it 'does not register an offense for defined configuration keys' do
+        expect_no_offenses(<<~RUBY)
+          module RuboCop
+            module Cop
+              module Test
+                class Foo < Base
+                  def configured?
+                    cop_config.fetch('Defined', default)
+                  end
+                end
+              end
+            end
+          end
+        RUBY
+      end
+
+      it 'registers an offense for missing configuration keys' do
+        expect_offense(<<~RUBY)
+          module RuboCop
+            module Cop
+              module Test
+                class Foo < Base
+                  def configured?
+                    cop_config.fetch('Missing', default)
+                                     ^^^^^^^^^ `Missing` is not defined in the configuration for `Test/Foo` in `config/default.yml`.
+                  end
+                end
+              end
+            end
+          end
+        RUBY
+      end
+    end
+  end
+
+  it 'works with deeper nested cop names' do
+    expect_offense(<<~RUBY)
+      module RuboCop
+        module Cop
+          module X
+            module Y
+              class Z < Base
+                def configured?
+                  cop_config['Defined']
+                  cop_config['Missing']
+                             ^^^^^^^^^ `Missing` is not defined in the configuration for `X/Y/Z` in `config/default.yml`.
+                end
+              end
+            end
+          end
+        end
+      end
+    RUBY
+  end
+
+  it 'works when the base class is `Cop` instead of `Base`' do
+    expect_offense(<<~RUBY)
+      module RuboCop
+        module Cop
+          module Test
+            class Foo < Cop
+              def configured?
+                cop_config['Defined']
+                cop_config['Missing']
+                           ^^^^^^^^^ `Missing` is not defined in the configuration for `Test/Foo` in `config/default.yml`.
+              end
+            end
+          end
+        end
+      end
+    RUBY
+  end
+
+  it 'ignores `cop_config` in non-cop classes' do
+    expect_no_offenses(<<~RUBY)
+      class Test
+        def configured?
+          cop_config['Missing']
+        end
+      end
+    RUBY
+  end
+
+  it 'does not register an offense if using `cop_config` outside of a cop class' do
+    expect_no_offenses(<<~RUBY)
+      def configured?
+        cop_config['Missing']
+      end
+    RUBY
+  end
+
+  it 'can handle an empty file' do
+    expect_no_offenses('')
+  end
+end