Revert "mutate the transaction object to reflect state"

This reverts commit 393e65b4170608593ad82377a9eadc918e85698d and
ec51c3fedd16b561d096dcc1a6705fdc02ab7666

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

3 files changed, 33 insertions, 37 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/abstract/transaction.rb b/activerecord/lib/active_record/connection_adapters/abstract/transaction.rb
index 081ec1528a..c74f4e8fa5 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/transaction.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/transaction.rb
@@ -1,30 +1,34 @@
 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 @@ module ActiveRecord
 
       def initialize(connection, options)
         @connection = connection
-        @state = TransactionState.null
+        @state = TransactionState.new
         @records = []
         @joinable = options.fetch(:joinable, true)
       end
@@ -52,15 +56,7 @@ module ActiveRecord
       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 @@ module ActiveRecord
       end
 
       def commit
-        @state = TransactionState.committed
+        @state.set_state(:committed)
       end
 
       def before_commit_records
diff --git a/activerecord/lib/active_record/core.rb b/activerecord/lib/active_record/core.rb
index a89931b157..97ce4642aa 100644
--- a/activerecord/lib/active_record/core.rb
+++ b/activerecord/lib/active_record/core.rb
@@ -503,7 +503,7 @@ module ActiveRecord
       @new_record               = true
       @txn                      = nil
       @_start_transaction_state = {}
-      @transaction              = nil
+      @transaction_state        = nil
     end
 
     def initialize_internals_callback
diff --git a/activerecord/lib/active_record/transactions.rb b/activerecord/lib/active_record/transactions.rb
index 283e1f8736..ffe7c4ae42 100644
--- a/activerecord/lib/active_record/transactions.rb
+++ b/activerecord/lib/active_record/transactions.rb
@@ -356,7 +356,7 @@ module ActiveRecord
       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 @@ module ActiveRecord
 
     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 @@ module ActiveRecord
     # 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