Revert "mutate the transaction object to reflect state"

This reverts commit 393e65b4 and
ec51c3fe

We don't want the records to hold hard references to transactions
because they point at records that have callbacks.

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

 module ActiveRecord
   module ConnectionAdapters
     class TransactionState
-      def finalized?;  false; end
-      def committed?;  false; end
-      def rolledback?; false; end
-      def completed?;  false; end
+      VALID_STATES = Set.new([:committed, :rolledback, nil])
 
-      class Committed < TransactionState
-        def finalized?; true; end
-        def committed?; true; end
-        def completed?; true; end
+      def initialize(state = nil)
+        @state = state
       end
 
-      class RolledBack < TransactionState
-        def finalized?;  true; end
-        def rolledback?; true; end
-        def completed?;  true; end
+      def finalized?
+        @state
+      end
+
+      def committed?
+        @state == :committed
+      end
+
+      def rolledback?
+        @state == :rolledback
       end
 
-      ROLLED_BACK = RolledBack.new
-      COMMITTED   = Committed.new
-      NULL        = TransactionState.new
+      def completed?
+        committed? || rolledback?
+      end
 
-      def self.rolled_back; ROLLED_BACK; end
-      def self.committed;   COMMITTED; end
-      def self.null;        NULL; end
+      def set_state(state)
+        unless VALID_STATES.include?(state)
+          raise ArgumentError, "Invalid transaction state: #{state}"
+        end
+        @state = state
+      end
     end
 
     class NullTransaction #:nodoc:
@@ -42,7 +46,7 @@ class Transaction #:nodoc:
 
       def initialize(connection, options)
         @connection = connection
-        @state = TransactionState.null
+        @state = TransactionState.new
         @records = []
         @joinable = options.fetch(:joinable, true)
       end
@@ -52,15 +56,7 @@ def add_record(record)
       end
 
       def rollback
-        @state = TransactionState.rolled_back
-      end
-
-      def rolledback?
-        @state.rolledback?
-      end
-
-      def finalized?
-        @state.finalized?
+        @state.set_state(:rolledback)
       end
 
       def rollback_records
@@ -75,7 +71,7 @@ def rollback_records
       end
 
       def commit
-        @state = TransactionState.committed
+        @state.set_state(:committed)
       end
 
       def before_commit_records

activerecord/lib/active_record/core.rb

@@ -503,7 +503,7 @@ def init_internals
       @new_record               = true
       @txn                      = nil
       @_start_transaction_state = {}
-      @transaction              = nil
+      @transaction_state        = nil
     end
 
     def initialize_internals_callback

activerecord/lib/active_record/transactions.rb

@@ -356,7 +356,7 @@ def add_to_transaction
       if has_transactional_callbacks?
         self.class.connection.add_transaction_record(self)
       else
-        set_transaction(self.class.connection.current_transaction)
+        set_transaction_state(self.class.connection.transaction_state)
       end
       remember_transaction_record_state
     end
@@ -445,8 +445,8 @@ def transaction_include_any_action?(actions) #:nodoc:
 
     private
 
-    def set_transaction(txn) # :nodoc:
-      @transaction = txn
+    def set_transaction_state(state) # :nodoc:
+      @transaction_state = state
     end
 
     def has_transactional_callbacks? # :nodoc:
@@ -471,12 +471,12 @@ def has_transactional_callbacks? # :nodoc:
     # method recursively goes through the parent of the TransactionState and
     # checks if the ActiveRecord object reflects the state of the object.
     def sync_with_transaction_state
-      update_attributes_from_transaction_state(@transaction)
+      update_attributes_from_transaction_state(@transaction_state)
     end
 
-    def update_attributes_from_transaction_state(transaction)
-      if transaction && transaction.finalized?
-        restore_transaction_record_state if transaction.rolledback?
+    def update_attributes_from_transaction_state(transaction_state)
+      if transaction_state && transaction_state.finalized?
+        restore_transaction_record_state if transaction_state.rolledback?
         clear_transaction_record_state
       end
     end