Merge pull request #1450 from vlad-pisanov/vp_fix_lexically_scoped_action_filter_2

Fix false positive for `Rails/LexicallyScopedActionFilter` when action methods are delegated

Author: koic

changelog/fix_a_false_positive_for_rails_lexically_scoped_action_filter.md

@@ -0,0 +1 @@
+* [#1447](https://github.com/rubocop/rubocop-rails/issues/1447): Fix false positive for `Rails/LexicallyScopedActionFilter` when action methods are delegated. ([@vlad-pisanov][])

lib/rubocop/cop/rails/lexically_scoped_action_filter.rb

@@ -115,6 +115,10 @@ class LexicallyScopedActionFilter < Base
                 $_)))
         PATTERN
 
+        def_node_matcher :delegated_methods, <<~PATTERN
+          (send nil? :delegate (sym $_)+ (hash <(pair (sym :to) _) ...>))
+        PATTERN
+
         def on_send(node)
           methods_node = only_or_except_filter_methods(node)
           return unless methods_node
@@ -139,7 +143,13 @@ def defined_action_methods(block)
           return [] unless block
 
           defined_methods = block.each_child_node(:def).map(&:method_name)
-          defined_methods + aliased_action_methods(block, defined_methods)
+          defined_methods + delegated_action_methods(block) + aliased_action_methods(block, defined_methods)
+        end
+
+        def delegated_action_methods(node)
+          node.each_child_node(:send).flat_map do |child_node|
+            delegated_methods(child_node) || []
+          end
         end
 
         def aliased_action_methods(node, defined_methods)

spec/rubocop/cop/rails/lexically_scoped_action_filter_spec.rb

@@ -159,6 +159,27 @@ def authorize!
     RUBY
   end
 
+  it 'does not register an offense when action method is delegated' do
+    expect_no_offenses(<<~RUBY)
+      class FooController < ApplicationController
+        before_action :authorize!, only: %i[index show]
+
+        delegate :index, :show, to: :foo
+      end
+    RUBY
+  end
+
+  it 'registers an offense when action method is not delegated' do
+    expect_offense(<<~RUBY)
+      class FooController < ApplicationController
+        before_action :authorize!, only: %i[foo show]
+        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `foo` is not explicitly defined on the class.
+
+        delegate :show, to: :bar
+      end
+    RUBY
+  end
+
   it 'does not register an offense when action method is aliased by `alias`' do
     expect_no_offenses(<<~RUBY)
       class FooController < ApplicationController