Merge commit 'mainstream/master'

11 files changed, 421 insertions, 87 deletions

diff --git a/activerecord/CHANGELOG b/activerecord/CHANGELOG
index 2bde8d402b..fbc71cddf1 100644
--- a/activerecord/CHANGELOG
+++ b/activerecord/CHANGELOG
@@ -1,5 +1,7 @@
 *2.3.0/3.0*
 
+* Support nested transactions using database savepoints.  #383 [Jonathan Viney, Hongli Lai]
+
 * Added dynamic scopes ala dynamic finders #1648 [Yaroslav Markin]
 
 * Fixed that ActiveRecord::Base#new_record? should return false (not nil) for existing records #1219 [Yaroslav Markin]
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb b/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb
index 189c6c7b5a..08601da00a 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb
@@ -53,36 +53,124 @@ module ActiveRecord
       def delete(sql, name = nil)
         delete_sql(sql, name)
       end
+      
+      # Checks whether there is currently no transaction active. This is done
+      # by querying the database driver, and does not use the transaction
+      # house-keeping information recorded by #increment_open_transactions and
+      # friends.
+      #
+      # Returns true if there is no transaction active, false if there is a
+      # transaction active, and nil if this information is unknown.
+      #
+      # Not all adapters supports transaction state introspection. Currently,
+      # only the PostgreSQL adapter supports this.
+      def outside_transaction?
+        nil
+      end
+
+      # Runs the given block in a database transaction, and returns the result
+      # of the block.
+      #
+      # == Nested transactions support
+      #
+      # Most databases don't support true nested transactions. At the time of
+      # writing, the only database that supports true nested transactions that
+      # we're aware of, is MS-SQL.
+      #
+      # In order to get around this problem, #transaction will emulate the effect
+      # of nested transactions, by using savepoints:
+      # http://dev.mysql.com/doc/refman/5.0/en/savepoints.html
+      # Savepoints are supported by MySQL and PostgreSQL, but not SQLite3.
+      #
+      # It is safe to call this method if a database transaction is already open,
+      # i.e. if #transaction is called within another #transaction block. In case
+      # of a nested call, #transaction will behave as follows:
+      #
+      # - The block will be run without doing anything. All database statements
+      #   that happen within the block are effectively appended to the already
+      #   open database transaction.
+      # - However, if +:requires_new+ is set, the block will be wrapped in a
+      #   database savepoint acting as a sub-transaction.
+      #
+      # === Caveats
+      #
+      # MySQL doesn't support DDL transactions. If you perform a DDL operation,
+      # then any created savepoints will be automatically released. For example,
+      # if you've created a savepoint, then you execute a CREATE TABLE statement,
+      # then the savepoint that was created will be automatically released.
+      #
+      # This means that, on MySQL, you shouldn't execute DDL operations inside
+      # a #transaction call that you know might create a savepoint. Otherwise,
+      # #transaction will raise exceptions when it tries to release the
+      # already-automatically-released savepoints:
+      #
+      #   Model.connection.transaction do  # BEGIN
+      #     Model.connection.transaction(:requires_new => true) do  # CREATE SAVEPOINT active_record_1
+      #       Model.connection.create_table(...)
+      #       # active_record_1 now automatically released
+      #     end  # RELEASE SAVEPOINT active_record_1  <--- BOOM! database error!
+      #   end
+      def transaction(options = {})
+        options.assert_valid_keys :requires_new, :joinable
+
+        last_transaction_joinable = @transaction_joinable
+        if options.has_key?(:joinable)
+          @transaction_joinable = options[:joinable]
+        else
+          @transaction_joinable = true
+        end
+        requires_new = options[:requires_new] || !last_transaction_joinable
 
-      # Wrap a block in a transaction.  Returns result of block.
-      def transaction(start_db_transaction = true)
         transaction_open = false
         begin
           if block_given?
-            if start_db_transaction
-              begin_db_transaction
+            if requires_new || open_transactions == 0
+              if open_transactions == 0
+                begin_db_transaction
+              elsif requires_new
+                create_savepoint
+              end
+              increment_open_transactions
               transaction_open = true
             end
             yield
           end
         rescue Exception => database_transaction_rollback
-          if transaction_open
+          if transaction_open && !outside_transaction?
             transaction_open = false
-            rollback_db_transaction
+            decrement_open_transactions
+            if open_transactions == 0
+              rollback_db_transaction
+            else
+              rollback_to_savepoint
+            end
           end
-          raise unless database_transaction_rollback.is_a? ActiveRecord::Rollback
+          raise unless database_transaction_rollback.is_a?(ActiveRecord::Rollback)
         end
       ensure
-        if transaction_open
+        @transaction_joinable = last_transaction_joinable
+
+        if outside_transaction?
+          @open_transactions = 0
+        elsif transaction_open
+          decrement_open_transactions
           begin
-            commit_db_transaction
+            if open_transactions == 0
+              commit_db_transaction
+            else
+              release_savepoint
+            end
           rescue Exception => database_transaction_rollback
-            rollback_db_transaction
+            if open_transactions == 0
+              rollback_db_transaction
+            else
+              rollback_to_savepoint
+            end
             raise
           end
         end
       end
-
+      
       # Begins the transaction (and turns off auto-committing).
       def begin_db_transaction()    end
 
diff --git a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
index bfafcfb3ab..a8cd9f033b 100755
--- a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
@@ -66,6 +66,12 @@ module ActiveRecord
       def supports_ddl_transactions?
         false
       end
+      
+      # Does this adapter support savepoints? PostgreSQL and MySQL do, SQLite
+      # does not.
+      def supports_savepoints?
+        false
+      end
 
       # Should primary key values be selected from their corresponding
       # sequence before the insert statement?  If true, next_sequence_value
@@ -160,6 +166,23 @@ module ActiveRecord
         @open_transactions -= 1
       end
 
+      def transaction_joinable=(joinable)
+        @transaction_joinable = joinable
+      end
+
+      def create_savepoint
+      end
+
+      def rollback_to_savepoint
+      end
+
+      def release_savepoint
+      end
+
+      def current_savepoint_name
+        "active_record_#{open_transactions}"
+      end
+
       def log_info(sql, name, ms)
         if @logger && @logger.debug?
           name = '%s (%.1fms)' % [name || 'SQL', ms]
diff --git a/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
index 60729c63db..b2345fd571 100644
--- a/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
@@ -210,6 +210,10 @@ module ActiveRecord
       def supports_migrations? #:nodoc:
         true
       end
+      
+      def supports_savepoints? #:nodoc:
+        true
+      end
 
       def native_database_types #:nodoc:
         NATIVE_DATABASE_TYPES
@@ -349,6 +353,17 @@ module ActiveRecord
         # Transactions aren't supported
       end
 
+      def create_savepoint
+        execute("SAVEPOINT #{current_savepoint_name}")
+      end
+
+      def rollback_to_savepoint
+        execute("ROLLBACK TO SAVEPOINT #{current_savepoint_name}")
+      end
+
+      def release_savepoint
+        execute("RELEASE SAVEPOINT #{current_savepoint_name}")
+      end
 
       def add_limit_offset!(sql, options) #:nodoc:
         if limit = options[:limit]
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
index 6685cb8663..913bb521ca 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
@@ -272,6 +272,10 @@ module ActiveRecord
       def supports_ddl_transactions?
         true
       end
+      
+      def supports_savepoints?
+        true
+      end
 
       # Returns the configured supported identifier length supported by PostgreSQL,
       # or report the default of 63 on PostgreSQL 7.x.
@@ -528,45 +532,26 @@ module ActiveRecord
       def rollback_db_transaction
         execute "ROLLBACK"
       end
+      
+      if defined?(PGconn::PQTRANS_IDLE)
+        # The ruby-pg driver supports inspecting the transaction status,
+        # while the ruby-postgres driver does not.
+        def outside_transaction?
+          @connection.transaction_status == PGconn::PQTRANS_IDLE
+        end
+      end
 
-      # ruby-pg defines Ruby constants for transaction status,
-      # ruby-postgres does not.
-      PQTRANS_IDLE = defined?(PGconn::PQTRANS_IDLE) ? PGconn::PQTRANS_IDLE : 0
-
-      # Check whether a transaction is active.
-      def transaction_active?
-        @connection.transaction_status != PQTRANS_IDLE
+      def create_savepoint
+        execute("SAVEPOINT #{current_savepoint_name}")
       end
 
-      # Wrap a block in a transaction.  Returns result of block.
-      def transaction(start_db_transaction = true)
-        transaction_open = false
-        begin
-          if block_given?
-            if start_db_transaction
-              begin_db_transaction
-              transaction_open = true
-            end
-            yield
-          end
-        rescue Exception => database_transaction_rollback
-          if transaction_open && transaction_active?
-            transaction_open = false
-            rollback_db_transaction
-          end
-          raise unless database_transaction_rollback.is_a? ActiveRecord::Rollback
-        end
-      ensure
-        if transaction_open && transaction_active?
-          begin
-            commit_db_transaction
-          rescue Exception => database_transaction_rollback
-            rollback_db_transaction
-            raise
-          end
-        end
+      def rollback_to_savepoint
+        execute("ROLLBACK TO SAVEPOINT #{current_savepoint_name}")
       end
 
+      def release_savepoint
+        execute("RELEASE SAVEPOINT #{current_savepoint_name}")
+      end
 
       # SCHEMA STATEMENTS ========================================
 
diff --git a/activerecord/lib/active_record/fixtures.rb b/activerecord/lib/active_record/fixtures.rb
index 129306d335..0131d9fac5 100644
--- a/activerecord/lib/active_record/fixtures.rb
+++ b/activerecord/lib/active_record/fixtures.rb
@@ -516,7 +516,7 @@ class Fixtures < (RUBY_VERSION < '1.9' ? YAML::Omap : Hash)
 
           all_loaded_fixtures.update(fixtures_map)
 
-          connection.transaction(connection.open_transactions.zero?) do
+          connection.transaction(:requires_new => true) do
             fixtures.reverse.each { |fixture| fixture.delete_existing_fixtures }
             fixtures.each { |fixture| fixture.insert_fixtures }
 
@@ -937,6 +937,7 @@ module ActiveRecord
           @@already_loaded_fixtures[self.class] = @loaded_fixtures
         end
         ActiveRecord::Base.connection.increment_open_transactions
+        ActiveRecord::Base.connection.transaction_joinable = false
         ActiveRecord::Base.connection.begin_db_transaction
       # Load fixtures for every test.
       else
diff --git a/activerecord/lib/active_record/session_store.rb b/activerecord/lib/active_record/session_store.rb
index bd198c03b2..5e45cf65ab 100644
--- a/activerecord/lib/active_record/session_store.rb
+++ b/activerecord/lib/active_record/session_store.rb
@@ -53,11 +53,6 @@ module ActiveRecord
       before_save :raise_on_session_data_overflow!
 
       class << self
-        # Don't try to reload ARStore::Session in dev mode.
-        def reloadable? #:nodoc:
-          false
-        end
-
         def data_column_size_limit
           @data_column_size_limit ||= columns_hash[@@data_column_name].limit
         end
diff --git a/activerecord/lib/active_record/transactions.rb b/activerecord/lib/active_record/transactions.rb
index 0a27ea980e..0b6e52c79b 100644
--- a/activerecord/lib/active_record/transactions.rb
+++ b/activerecord/lib/active_record/transactions.rb
@@ -120,16 +120,66 @@ module ActiveRecord
     #   end
     #
     # One should restart the entire transaction if a StatementError occurred.
+    #
+    # == Nested transactions
+    #
+    # #transaction calls can be nested. By default, this makes all database
+    # statements in the nested transaction block become part of the parent
+    # transaction. For example:
+    #
+    #   User.transaction do
+    #     User.create(:username => 'Kotori')
+    #     User.transaction do
+    #       User.create(:username => 'Nemu')
+    #       raise ActiveRecord::Rollback
+    #     end
+    #   end
+    #   
+    #   User.find(:all)  # => empty
+    #
+    # It is also possible to requires a sub-transaction by passing
+    # <tt>:requires_new => true</tt>.  If anything goes wrong, the
+    # database rolls back to the beginning of the sub-transaction
+    # without rolling back the parent transaction. For example:
+    #
+    #   User.transaction do
+    #     User.create(:username => 'Kotori')
+    #     User.transaction(:requires_new => true) do
+    #       User.create(:username => 'Nemu')
+    #       raise ActiveRecord::Rollback
+    #     end
+    #   end
+    #   
+    #   User.find(:all)  # => Returns only Kotori
+    #
+    # Most databases don't support true nested transactions. At the time of
+    # writing, the only database that we're aware of that supports true nested
+    # transactions, is MS-SQL. Because of this, Active Record emulates nested
+    # transactions by using savepoints. See
+    # http://dev.mysql.com/doc/refman/5.0/en/savepoints.html
+    # for more information about savepoints.
+    #
+    # === Caveats
+    #
+    # If you're on MySQL, then do not use DDL operations in nested transactions
+    # blocks that are emulated with savepoints. That is, do not execute statements
+    # like 'CREATE TABLE' inside such blocks. This is because MySQL automatically
+    # releases all savepoints upon executing a DDL operation. When #transaction
+    # is finished and tries to release the savepoint it created earlier, a
+    # database error will occur because the savepoint has already been
+    # automatically released. The following example demonstrates the problem:
+    # 
+    #   Model.connection.transaction do                           # BEGIN
+    #     Model.connection.transaction(:requires_new => true) do  # CREATE SAVEPOINT active_record_1
+    #       Model.connection.create_table(...)                    # active_record_1 now automatically released
+    #     end                                                     # RELEASE savepoint active_record_1
+    #                                                             # ^^^^ BOOM! database error!
+    #   end
     module ClassMethods
       # See ActiveRecord::Transactions::ClassMethods for detailed documentation.
-      def transaction(&block)
-        connection.increment_open_transactions
-
-        begin
-          connection.transaction(connection.open_transactions == 1, &block)
-        ensure
-          connection.decrement_open_transactions
-        end
+      def transaction(options = {}, &block)
+        # See the ConnectionAdapters::DatabaseStatements#transaction API docs.
+        connection.transaction(options, &block)
       end
     end
 
diff --git a/activerecord/test/cases/defaults_test.rb b/activerecord/test/cases/defaults_test.rb
index 38e4853dc0..b4032c23e6 100644
--- a/activerecord/test/cases/defaults_test.rb
+++ b/activerecord/test/cases/defaults_test.rb
@@ -18,11 +18,43 @@ class DefaultTest < ActiveRecord::TestCase
     end
   end
 
-  if current_adapter?(:MysqlAdapter)
+  if current_adapter?(:PostgreSQLAdapter, :FirebirdAdapter, :OpenBaseAdapter, :OracleAdapter)
+    def test_default_integers
+      default = Default.new
+      assert_instance_of Fixnum, default.positive_integer
+      assert_equal 1, default.positive_integer
+      assert_instance_of Fixnum, default.negative_integer
+      assert_equal -1, default.negative_integer
+      assert_instance_of BigDecimal, default.decimal_number
+      assert_equal BigDecimal.new("2.78"), default.decimal_number
+    end
+  end
+  
+  if current_adapter?(:PostgreSQLAdapter)
+    def test_multiline_default_text
+      # older postgres versions represent the default with escapes ("\\012" for a newline)
+      assert ( "--- []\n\n" == Default.columns_hash['multiline_default'].default ||
+               "--- []\\012\\012" == Default.columns_hash['multiline_default'].default)
+    end
+  end
+end
 
-    #MySQL 5 and higher is quirky with not null text/blob columns.
-    #With MySQL Text/blob columns cannot have defaults. If the column is not null MySQL will report that the column has a null default
-    #but it behaves as though the column had a default of ''
+if current_adapter?(:MysqlAdapter)
+  class DefaultsTestWithoutTransactionalFixtures < ActiveRecord::TestCase
+    # ActiveRecord::Base#create! (and #save and other related methods) will
+    # open a new transaction. When in transactional fixtures mode, this will
+    # cause ActiveRecord to create a new savepoint. However, since MySQL doesn't
+    # support DDL transactions, creating a table will result in any created
+    # savepoints to be automatically released. This in turn causes the savepoint
+    # release code in AbstractAdapter#transaction to fail.
+    #
+    # We don't want that to happen, so we disable transactional fixtures here.
+    self.use_transactional_fixtures = false
+    
+    # MySQL 5 and higher is quirky with not null text/blob columns.
+    # With MySQL Text/blob columns cannot have defaults. If the column is not
+    # null MySQL will report that the column has a null default
+    # but it behaves as though the column had a default of ''
     def test_mysql_text_not_null_defaults
       klass = Class.new(ActiveRecord::Base)
       klass.table_name = 'test_mysql_text_not_null_defaults'
@@ -48,8 +80,7 @@ class DefaultTest < ActiveRecord::TestCase
     ensure
       klass.connection.drop_table(klass.table_name) rescue nil
     end
-
-
+    
     # MySQL uses an implicit default 0 rather than NULL unless in strict mode.
     # We use an implicit NULL so schema.rb is compatible with other databases.
     def test_mysql_integer_not_null_defaults
@@ -77,24 +108,4 @@ class DefaultTest < ActiveRecord::TestCase
       klass.connection.drop_table(klass.table_name) rescue nil
     end
   end
-
-  if current_adapter?(:PostgreSQLAdapter, :FirebirdAdapter, :OpenBaseAdapter, :OracleAdapter)
-    def test_default_integers
-      default = Default.new
-      assert_instance_of Fixnum, default.positive_integer
-      assert_equal 1, default.positive_integer
-      assert_instance_of Fixnum, default.negative_integer
-      assert_equal -1, default.negative_integer
-      assert_instance_of BigDecimal, default.decimal_number
-      assert_equal BigDecimal.new("2.78"), default.decimal_number
-    end
-  end
-
-  if current_adapter?(:PostgreSQLAdapter)
-    def test_multiline_default_text
-      # older postgres versions represent the default with escapes ("\\012" for a newline)
-      assert ( "--- []\n\n" == Default.columns_hash['multiline_default'].default ||
-               "--- []\\012\\012" == Default.columns_hash['multiline_default'].default)
-    end
-  end
 end
diff --git a/activerecord/test/cases/helper.rb b/activerecord/test/cases/helper.rb
index 2043138ca3..ccd04b67f6 100644
--- a/activerecord/test/cases/helper.rb
+++ b/activerecord/test/cases/helper.rb
@@ -34,7 +34,7 @@ rescue LoadError
 end
 
 ActiveRecord::Base.connection.class.class_eval do
-  IGNORED_SQL = [/^PRAGMA/, /^SELECT currval/, /^SELECT CAST/, /^SELECT @@IDENTITY/, /^SELECT @@ROWCOUNT/]
+  IGNORED_SQL = [/^PRAGMA/, /^SELECT currval/, /^SELECT CAST/, /^SELECT @@IDENTITY/, /^SELECT @@ROWCOUNT/, /^SAVEPOINT/, /^ROLLBACK TO SAVEPOINT/, /^RELEASE SAVEPOINT/]
 
   def execute_with_query_record(sql, name = nil, &block)
     $queries_executed ||= []
diff --git a/activerecord/test/cases/transactions_test.rb b/activerecord/test/cases/transactions_test.rb
index b12ec36455..4a07a8bb1d 100644
--- a/activerecord/test/cases/transactions_test.rb
+++ b/activerecord/test/cases/transactions_test.rb
@@ -213,11 +213,104 @@ class TransactionTest < ActiveRecord::TestCase
     assert Topic.find(2).approved?, "Second should still be approved"
   end
 
+  def test_invalid_keys_for_transaction
+    assert_raises ArgumentError do
+      Topic.transaction :nested => true do
+      end
+    end
+  end
+
+  def test_force_savepoint_in_nested_transaction
+    Topic.transaction do
+      @first.approved = true
+      @second.approved = false
+      @first.save!
+      @second.save!
+
+      begin
+        Topic.transaction :requires_new => true do
+          @first.happy = false
+          @first.save!
+          raise
+        end
+      rescue
+      end
+    end
+
+    assert @first.reload.approved?
+    assert !@second.reload.approved?
+  end if Topic.connection.supports_savepoints?
+
+  def test_no_savepoint_in_nested_transaction_without_force
+    Topic.transaction do
+      @first.approved = true
+      @second.approved = false
+      @first.save!
+      @second.save!
+
+      begin
+        Topic.transaction do
+          @first.approved = false
+          @first.save!
+          raise
+        end
+      rescue
+      end
+    end
+
+    assert !@first.reload.approved?
+    assert !@second.reload.approved?
+  end if Topic.connection.supports_savepoints?
+  
+  def test_many_savepoints
+    Topic.transaction do
+      @first.content = "One"
+      @first.save!
+      
+      begin
+        Topic.transaction :requires_new => true do
+          @first.content = "Two"
+          @first.save!
+          
+          begin
+            Topic.transaction :requires_new => true do
+              @first.content = "Three"
+              @first.save!
+              
+              begin
+                Topic.transaction :requires_new => true do
+                  @first.content = "Four"
+                  @first.save!
+                  raise
+                end
+              rescue
+              end
+              
+              @three = @first.reload.content
+              raise
+            end
+          rescue
+          end
+          
+          @two = @first.reload.content
+          raise
+        end
+      rescue
+      end
+      
+      @one = @first.reload.content
+    end
+    
+    assert_equal "One", @one
+    assert_equal "Two", @two
+    assert_equal "Three", @three
+  end if Topic.connection.supports_savepoints?
+
   uses_mocha 'mocking connection.commit_db_transaction' do
     def test_rollback_when_commit_raises
       Topic.connection.expects(:begin_db_transaction)
-      Topic.connection.expects(:transaction_active?).returns(true) if current_adapter?(:PostgreSQLAdapter)
       Topic.connection.expects(:commit_db_transaction).raises('OH NOES')
+      Topic.connection.expects(:outside_transaction?).returns(false)
       Topic.connection.expects(:rollback_db_transaction)
 
       assert_raise RuntimeError do
@@ -227,6 +320,38 @@ class TransactionTest < ActiveRecord::TestCase
       end
     end
   end
+  
+  if current_adapter?(:PostgreSQLAdapter) && defined?(PGconn::PQTRANS_IDLE)
+    def test_outside_transaction_works
+      assert Topic.connection.outside_transaction?
+      Topic.connection.begin_db_transaction
+      assert !Topic.connection.outside_transaction?
+      Topic.connection.rollback_db_transaction
+      assert Topic.connection.outside_transaction?
+    end
+    
+    uses_mocha 'mocking connection.rollback_db_transaction' do
+      def test_rollback_wont_be_executed_if_no_transaction_active
+        assert_raise RuntimeError do
+          Topic.transaction do
+            Topic.connection.rollback_db_transaction
+            Topic.connection.expects(:rollback_db_transaction).never
+            raise "Rails doesn't scale!"
+          end
+        end
+      end
+    end
+    
+    def test_open_transactions_count_is_reset_to_zero_if_no_transaction_active
+      Topic.transaction do
+        Topic.transaction do
+          Topic.connection.rollback_db_transaction
+        end
+        assert_equal 0, Topic.connection.open_transactions
+      end
+      assert_equal 0, Topic.connection.open_transactions
+    end
+  end
 
   def test_sqlite_add_column_in_transaction_raises_statement_invalid
     return true unless current_adapter?(:SQLite3Adapter, :SQLiteAdapter)
@@ -282,6 +407,45 @@ class TransactionTest < ActiveRecord::TestCase
     end
 end
 
+class TransactionsWithTransactionalFixturesTest < ActiveRecord::TestCase
+  self.use_transactional_fixtures = true
+  fixtures :topics
+
+  def test_automatic_savepoint_in_outer_transaction
+    @first = Topic.find(1)
+    
+    begin
+      Topic.transaction do
+        @first.approved = true
+        @first.save!
+        raise
+      end
+    rescue
+      assert !@first.reload.approved?
+    end
+  end
+
+  def test_no_automatic_savepoint_for_inner_transaction
+    @first = Topic.find(1)
+
+    Topic.transaction do
+      @first.approved = true
+      @first.save!
+
+      begin
+        Topic.transaction do
+          @first.approved = false
+          @first.save!
+          raise
+        end
+      rescue
+      end
+    end
+
+    assert !@first.reload.approved?
+  end
+end if Topic.connection.supports_savepoints?
+
 if current_adapter?(:PostgreSQLAdapter)
   class ConcurrentTransactionTest < TransactionTest
     use_concurrent_connections