Enable `Style/RedundantBegin` cop to avoid newly adding redundant begin block

Currently we sometimes find a redundant begin block in code review
(e.g. https://github.com/rails/rails/pull/33604#discussion_r209784205).

I'd like to enable `Style/RedundantBegin` cop to avoid that, since
rescue/else/ensure are allowed inside do/end blocks in Ruby 2.5
(https://bugs.ruby-lang.org/issues/12906), so we'd probably meets with
that situation than before.

1 files changed, 17 insertions, 19 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/abstract/transaction.rb b/activerecord/lib/active_record/connection_adapters/abstract/transaction.rb
index 0f2b1e85ff..718910b090 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/transaction.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/transaction.rb
@@ -283,26 +283,24 @@ module ActiveRecord
 
       def within_new_transaction(options = {})
         @connection.lock.synchronize do
-          begin
-            transaction = begin_transaction options
-            yield
-          rescue Exception => error
-            if transaction
+          transaction = begin_transaction options
+          yield
+        rescue Exception => error
+          if transaction
+            rollback_transaction
+            after_failure_actions(transaction, error)
+          end
+          raise
+        ensure
+          if !error && transaction
+            if Thread.current.status == "aborting"
               rollback_transaction
-              after_failure_actions(transaction, error)
-            end
-            raise
-          ensure
-            unless error
-              if Thread.current.status == "aborting"
-                rollback_transaction if transaction
-              else
-                begin
-                  commit_transaction if transaction
-                rescue Exception
-                  rollback_transaction(transaction) unless transaction.state.completed?
-                  raise
-                end
+            else
+              begin
+                commit_transaction
+              rescue Exception
+                rollback_transaction(transaction) unless transaction.state.completed?
+                raise
               end
             end
           end