Cleanup Transaction inheritance.

Transaction class doesnt need to encapsulate the transaction state using
inheritance.
This removes all Transaction subclasses, and let the Transaction object
controls different actions based on its own state. Basically the only
actions would behave differently are `being`,`commit`,`rollback` as they
could act in a savepoint or in a real transaction.

activerecord/lib/active_record/connection_adapters/abstract/transaction.rb

@@ -30,49 +30,24 @@ def set_state(state)
       end
     end
 
-    class Transaction #:nodoc:
-      attr_reader :connection, :state
-
-      def initialize(connection)
-        @connection = connection
-        @state = TransactionState.new
-      end
-
-      def savepoint_name
-        nil
-      end
-    end
-
-    class NullTransaction < Transaction #:nodoc:
+    class NullTransaction #:nodoc:
       def initialize; end
       def closed?; true; end
       def open?; false; end
       def joinable?; false; end
-      # This is a noop when there are no open transactions
       def add_record(record); end
     end
 
-    class OpenTransaction < Transaction #:nodoc:
-      attr_reader :records
-      attr_writer :joinable
-
-      def initialize(connection, options = {})
-        super connection
-
-        @records   = []
-        @joinable  = options.fetch(:joinable, true)
-      end
-
-      def joinable?
-        @joinable
-      end
+    class Transaction #:nodoc:
 
-      def rollback
-        perform_rollback
-      end
+      attr_reader :connection, :state, :records, :savepoint_name
+      attr_writer :joinable
 
-      def commit
-        perform_commit
+      def initialize(connection, options)
+        @connection = connection
+        @state = TransactionState.new
+        @records = []
+        @joinable = options.fetch(:joinable, true)
       end
 
       def add_record(record)
@@ -83,19 +58,25 @@ def add_record(record)
         end
       end
 
-      def rollback_records
+      def rollback
         @state.set_state(:rolledback)
+      end
+
+      def rollback_records
         records.uniq.each do |record|
           begin
-            record.rolledback!(self.is_a?(RealTransaction))
+            record.rolledback! full_rollback?
           rescue => e
             record.logger.error(e) if record.respond_to?(:logger) && record.logger
           end
         end
       end
 
-      def commit_records
+      def commit
         @state.set_state(:committed)
+      end
+
+      def commit_records
         records.uniq.each do |record|
           begin
             record.committed!
@@ -105,57 +86,57 @@ def commit_records
         end
       end
 
-      def closed?
-        false
-      end
-
-      def open?
-        true
-      end
+      def full_rollback?; true; end
+      def joinable?; @joinable; end
+      def closed?; false; end
+      def open?; !closed?; end
     end
 
-    class RealTransaction < OpenTransaction #:nodoc:
-      def initialize(connection, _, options = {})
-        super(connection,  options)
+    class SavepointTransaction < Transaction
 
+      def initialize(connection, savepoint_name, options)
+        super(connection, options)
         if options[:isolation]
-          connection.begin_isolated_db_transaction(options[:isolation])
-        else
-          connection.begin_db_transaction
+          raise ActiveRecord::TransactionIsolationError, "cannot set transaction isolation in a nested transaction"
         end
+        connection.create_savepoint(@savepoint_name = savepoint_name)
       end
 
-      def perform_rollback
-        connection.rollback_db_transaction
+      def rollback
+        super
+        connection.rollback_to_savepoint(savepoint_name)
         rollback_records
       end
 
-      def perform_commit
-        connection.commit_db_transaction
-        commit_records
+      def commit
+        super
+        connection.release_savepoint(savepoint_name)
       end
+
+      def full_rollback?; false; end
     end
 
-    class SavepointTransaction < OpenTransaction #:nodoc:
-      attr_reader :savepoint_name
+    class RealTransaction < Transaction
 
-      def initialize(connection, savepoint_name, options = {})
+      def initialize(connection, options)
+        super
         if options[:isolation]
-          raise ActiveRecord::TransactionIsolationError, "cannot set transaction isolation in a nested transaction"
+          connection.begin_isolated_db_transaction(options[:isolation])
+        else
+          connection.begin_db_transaction
         end
-
-        super(connection, options)
-        connection.create_savepoint(@savepoint_name = savepoint_name)
       end
 
-      def perform_rollback
-        connection.rollback_to_savepoint(savepoint_name)
+      def rollback
+        super
+        connection.rollback_db_transaction
         rollback_records
       end
 
-      def perform_commit
-        @state.set_state(:committed)
-        connection.release_savepoint(savepoint_name)
+      def commit
+        super
+        connection.commit_db_transaction
+        commit_records
       end
     end
 
@@ -166,9 +147,12 @@ def initialize(connection)
       end
 
       def begin_transaction(options = {})
-        transaction_class = @stack.empty? ? RealTransaction : SavepointTransaction
-        transaction = transaction_class.new(@connection, "active_record_#{@stack.size}", options)
-
+        transaction =
+          if @stack.empty?
+            RealTransaction.new(@connection, options)
+          else
+            SavepointTransaction.new(@connection, "active_record_#{@stack.size}", options)
+          end
         @stack.push(transaction)
         transaction
       end

activerecord/test/cases/transactions_test.rb

@@ -552,7 +552,7 @@ def test_transactions_state_from_rollback
     assert !transaction.state.rolledback?
     assert !transaction.state.committed?
 
-    transaction.perform_rollback
+    transaction.rollback
 
     assert transaction.state.rolledback?
     assert !transaction.state.committed?
@@ -566,7 +566,7 @@ def test_transactions_state_from_commit
     assert !transaction.state.rolledback?
     assert !transaction.state.committed?
 
-    transaction.perform_commit
+    transaction.commit
 
     assert !transaction.state.rolledback?
     assert transaction.state.committed?