[Fix #669] Fix a false positive for Rails/TransactionExitStatement

Fixes #669.

This PR fixes a false positive for `Rails/TransactionExitStatement`
when `return` is used in `rescue`.

changelog/fix_false_positive_for_rails_transaction_exit_statement.md

@@ -0,0 +1 @@
+* [#669](https://github.com/rubocop/rubocop-rails/issues/669): Fix a false positive for `Rails/TransactionExitStatement` when `return` is used in `rescue`. ([@koic][])

lib/rubocop/cop/rails/transaction_exit_statement.rb

@@ -58,7 +58,7 @@ def on_send(node)
           return unless parent.block_type? && parent.body
 
           exit_statements(parent.body).each do |statement_node|
-            next if statement_node.break_type? && nested_block?(statement_node)
+            next if in_rescue?(statement_node) || nested_block?(statement_node)
 
             statement = statement(statement_node)
             message = format(MSG, statement: statement)
@@ -79,7 +79,13 @@ def statement(statement_node)
           end
         end
 
+        def in_rescue?(statement_node)
+          statement_node.ancestors.find(&:rescue_type?)
+        end
+
         def nested_block?(statement_node)
+          return false unless statement_node.break_type?
+
           !statement_node.ancestors.find(&:block_type?).method?(:transaction)
         end
       end

spec/rubocop/cop/rails/transaction_exit_statement_spec.rb

@@ -76,6 +76,15 @@
     RUBY
   end
 
+  it 'does not register an offense when `return` is used in `rescue`' do
+    expect_no_offenses(<<~RUBY)
+      ApplicationRecord.transaction do
+      rescue
+        return do_something
+      end
+    RUBY
+  end
+
   it 'does not register an offense when transaction block is empty' do
     expect_no_offenses(<<~RUBY)
       ApplicationRecord.transaction do