Merge pull request #844 from koic/fix_a_false_positive_for_rails_acti…

…on_controller_flash_before_render

[Fix #843] Fix a false positive for `Rails/ActionControllerFlashBeforeRender`

changelog/fix_a_false_positive_for_rails_action_controller_flash_before_render.md

@@ -0,0 +1 @@
+* [#843](https://github.com/rubocop/rubocop-rails/issues/843): Fix a false positive for `Rails/ActionControllerFlashBeforeRender` when using `flash` in multiline `if` branch before `redirect_to`. ([@koic][])

lib/rubocop/cop/rails/action_controller_flash_before_render.rb

@@ -69,9 +69,12 @@ def on_send(flash_node)
  def followed_by_render?(flash_node)
  flash_assigment_node = find_ancestor(flash_node, type: :send)
  context = flash_assigment_node
- context = context.parent if context.parent.if_type?
+ if (if_node = context.each_ancestor(:if).first)
+ context = if_node
+ elsif context.right_siblings.empty?
+ return true
+ end
  context = context.right_siblings
- return true if context.empty?
 
  context.compact.any? do |node|
  render?(node)

spec/rubocop/cop/rails/action_controller_flash_before_render_spec.rb

@@ -152,6 +152,50 @@ def create
  end
  RUBY
  end
+
+ it 'registers an offense when using `flash` in multiline `if` branch before `render_to`' do
+ expect_offense(<<~RUBY)
+ class HomeController < #{parent_class}
+ def create
+ if condition
+ do_something
+ flash[:alert] = "msg"
+ ^^^^^ Use `flash.now` before `render`.
+ end
+
+ render :index
+ end
+ end
+ RUBY
+
+ expect_correction(<<~RUBY)
+ class HomeController < #{parent_class}
+ def create
+ if condition
+ do_something
+ flash.now[:alert] = "msg"
+ end
+
+ render :index
+ end
+ end
+ RUBY
+ end
+
+ it 'does not register an offense when using `flash` in multiline `if` branch before `redirect_to`' do
+ expect_no_offenses(<<~RUBY)
+ class HomeController < #{parent_class}
+ def create
+ if condition
+ do_something
+ flash[:alert] = "msg"
+ end
+
+ redirect_to :index
+ end
+ end
+ RUBY
+ end
  end
  end