Accept actions defined via alias in Rails/LexicallyScopedActionFilter

Author: fatkodima

changelog/change_accept_actions_defined_via_alias_in_lexically_scoped_action_filter.md

@@ -0,0 +1 @@
+* [#263](https://github.com/rubocop/rubocop-rails/pull/263): Accept actions defined via `alias` in `Rails/LexicallyScopedActionFilter`. ([@fatkodima][])

lib/rubocop/cop/rails/lexically_scoped_action_filter.rb

@@ -144,19 +144,29 @@ def defined_action_methods(block)
         end
 
         def aliased_action_methods(node, defined_methods)
-          alias_methods = node.each_child_node(:send).select { |send_node| send_node.method?(:alias_method) }
-
-          hash_of_alias_methods = alias_methods.each_with_object({}) do |alias_method, result|
-            result[alias_method.last_argument.value] = alias_method.first_argument.value
-          end
-
+          alias_methods = alias_methods(node)
           defined_methods.each_with_object([]) do |defined_method, aliased_method|
-            if (new_method_name = hash_of_alias_methods[defined_method])
+            if (new_method_name = alias_methods[defined_method])
               aliased_method << new_method_name
             end
           end
         end
 
+        def alias_methods(node)
+          result = {}
+          node.each_child_node(:send, :alias) do |child_node|
+            case child_node.type
+            when :send
+              if child_node.method?(:alias_method)
+                result[child_node.last_argument.value] = child_node.first_argument.value
+              end
+            when :alias
+              result[child_node.old_identifier.value] = child_node.new_identifier.value
+            end
+          end
+          result
+        end
+
         # @param node [RuboCop::AST::Node]
         # @return [Array<Symbol>]
         def array_values(node) # rubocop:disable Metrics/MethodLength

spec/rubocop/cop/rails/lexically_scoped_action_filter_spec.rb

@@ -150,6 +150,41 @@ def authorize!
     RUBY
   end
 
+  it 'does not register an offense when action method is aliased by `alias`' do
+    expect_no_offenses(<<~RUBY)
+      class FooController < ApplicationController
+        before_action :authorize!, only: %i[index show]
+
+        def index
+        end
+        alias show index
+
+        private
+
+        def authorize!
+        end
+      end
+    RUBY
+  end
+
+  it 'registers an offense when action method is not aliased by `alias`' do
+    expect_offense(<<~RUBY)
+      class FooController < ApplicationController
+        before_action :authorize!, only: %i[foo show]
+        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `foo` is not explicitly defined on the class.
+
+        def index
+        end
+        alias show index
+
+        private
+
+        def authorize!
+        end
+      end
+    RUBY
+  end
+
   it "doesn't register an offense when using conditional statements" do
     expect_no_offenses <<~RUBY
       class Test < ActionController