Merge pull request #666 from koic/fix_an_error_for_rails_transaction_exit_statement

Fix an error for `Rails/TransactionExitStatement`

Author: koic

changelog/fix_an_error_for_rails_transaction_exit_statement.md

@@ -0,0 +1 @@
+* [#666](https://github.com/rubocop/rubocop-rails/pull/666): Fix an error for `Rails/TransactionExitStatement` when transaction block is empty. ([@koic][])

lib/rubocop/cop/rails/transaction_exit_statement.rb

@@ -54,9 +54,8 @@ class TransactionExitStatement < Base
         PATTERN
 
         def on_send(node)
-          parent = node.parent
-
-          return unless parent&.block_type?
+          return unless (parent = node.parent)
+          return unless parent.block_type? && parent.body
 
           exit_statements(parent.body).each do |statement_node|
             next unless statement_node.ancestors.find(&:block_type?).method?(:transaction)

spec/rubocop/cop/rails/transaction_exit_statement_spec.rb

@@ -53,4 +53,11 @@
       end
     RUBY
   end
+
+  it 'does not register an offense when transaction block is empty' do
+    expect_no_offenses(<<~RUBY)
+      ApplicationRecord.transaction do
+      end
+    RUBY
+  end
 end