Merge branch 'master' into 3-0-unstable

Conflicts:
	ci/cruise_config.rb

7 files changed, 210 insertions, 93 deletions

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/query_cache.rb b/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb
index 950bd72101..00c71090f3 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb
@@ -14,12 +14,12 @@ module ActiveRecord
         def dirties_query_cache(base, *method_names)
           method_names.each do |method_name|
             base.class_eval <<-end_code, __FILE__, __LINE__
-              def #{method_name}_with_query_dirty(*args)
-                clear_query_cache if @query_cache_enabled
-                #{method_name}_without_query_dirty(*args)
-              end
-
-              alias_method_chain :#{method_name}, :query_dirty
+              def #{method_name}_with_query_dirty(*args)        # def update_with_query_dirty(*args)
+                clear_query_cache if @query_cache_enabled       #   clear_query_cache if @query_cache_enabled
+                #{method_name}_without_query_dirty(*args)       #   update_without_query_dirty(*args)
+              end                                               # end
+                                                                #
+              alias_method_chain :#{method_name}, :query_dirty  # alias_method_chain :update, :query_dirty
             end_code
           end
         end
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
index fe9cbcf024..273f823e7f 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
@@ -476,12 +476,12 @@ module ActiveRecord
 
       %w( string text integer float decimal datetime timestamp time date binary boolean ).each do |column_type|
         class_eval <<-EOV
-          def #{column_type}(*args)
-            options = args.extract_options!
-            column_names = args
-
-            column_names.each { |name| column(name, '#{column_type}', options) }
-          end
+          def #{column_type}(*args)                                               # def string(*args)
+            options = args.extract_options!                                       #   options = args.extract_options!
+            column_names = args                                                   #   column_names = args
+                                                                                  #
+            column_names.each { |name| column(name, '#{column_type}', options) }  #   column_names.each { |name| column(name, 'string', options) }
+          end                                                                     # end
         EOV
       end
 
@@ -676,24 +676,24 @@ module ActiveRecord
       #  t.string(:goat, :sheep)
       %w( string text integer float decimal datetime timestamp time date binary boolean ).each do |column_type|
         class_eval <<-EOV
-          def #{column_type}(*args)
-            options = args.extract_options!
-            column_names = args
-
-            column_names.each do |name|
-              column = ColumnDefinition.new(@base, name, '#{column_type}')
-              if options[:limit]
-                column.limit = options[:limit]
-              elsif native['#{column_type}'.to_sym].is_a?(Hash)
-                column.limit = native['#{column_type}'.to_sym][:limit]
-              end
-              column.precision = options[:precision]
-              column.scale = options[:scale]
-              column.default = options[:default]
-              column.null = options[:null]
-              @base.add_column(@table_name, name, column.sql_type, options)
-            end
-          end
+          def #{column_type}(*args)                                          # def string(*args)
+            options = args.extract_options!                                  #   options = args.extract_options!
+            column_names = args                                              #   column_names = args
+                                                                             #
+            column_names.each do |name|                                      #   column_names.each do |name|
+              column = ColumnDefinition.new(@base, name, '#{column_type}')   #     column = ColumnDefinition.new(@base, name, 'string')
+              if options[:limit]                                             #     if options[:limit]
+                column.limit = options[:limit]                               #       column.limit = options[:limit]
+              elsif native['#{column_type}'.to_sym].is_a?(Hash)              #     elsif native['string'.to_sym].is_a?(Hash)
+                column.limit = native['#{column_type}'.to_sym][:limit]       #       column.limit = native['string'.to_sym][:limit]
+              end                                                            #     end
+              column.precision = options[:precision]                         #     column.precision = options[:precision]
+              column.scale = options[:scale]                                 #     column.scale = options[:scale]
+              column.default = options[:default]                             #     column.default = options[:default]
+              column.null = options[:null]                                   #     column.null = options[:null]
+              @base.add_column(@table_name, name, column.sql_type, options)  #     @base.add_column(@table_name, name, column.sql_type, options)
+            end                                                              #   end
+          end                                                                # end
         EOV
       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 46d4b6c89c..b2345fd571 100644
--- a/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
@@ -13,23 +13,25 @@ module MysqlCompat #:nodoc:
     # C driver >= 2.7 returns null values in each_hash
     if Mysql.const_defined?(:VERSION) && (Mysql::VERSION.is_a?(String) || Mysql::VERSION >= 20700)
       target.class_eval <<-'end_eval'
-      def all_hashes
-        rows = []
-        each_hash { |row| rows << row }
-        rows
-      end
+      def all_hashes                     # def all_hashes
+        rows = []                        #   rows = []
+        each_hash { |row| rows << row }  #   each_hash { |row| rows << row }
+        rows                             #   rows
+      end                                # end
       end_eval
 
     # adapters before 2.7 don't have a version constant
     # and don't return null values in each_hash
     else
       target.class_eval <<-'end_eval'
-      def all_hashes
-        rows = []
-        all_fields = fetch_fields.inject({}) { |fields, f| fields[f.name] = nil; fields }
-        each_hash { |row| rows << all_fields.dup.update(row) }
-        rows
-      end
+      def all_hashes                                            # def all_hashes
+        rows = []                                               #   rows = []
+        all_fields = fetch_fields.inject({}) { |fields, f|      #   all_fields = fetch_fields.inject({}) { |fields, f|
+          fields[f.name] = nil; fields                          #     fields[f.name] = nil; fields
+        }                                                       #   }
+        each_hash { |row| rows << all_fields.dup.update(row) }  #   each_hash { |row| rows << all_fields.dup.update(row) }
+        rows                                                    #   rows
+      end                                                       # end
       end_eval
     end
 
@@ -208,6 +210,10 @@ module ActiveRecord
       def supports_migrations? #:nodoc:
         true
       end
+      
+      def supports_savepoints? #:nodoc:
+        true
+      end
 
       def native_database_types #:nodoc:
         NATIVE_DATABASE_TYPES
@@ -347,6 +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 60ec01b95e..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 ========================================
 
@@ -950,13 +935,13 @@ module ActiveRecord
           # should know about this but can't detect it there, so deal with it here.
           money_precision = (postgresql_version >= 80300) ? 19 : 10
           PostgreSQLColumn.module_eval(<<-end_eval)
-            def extract_precision(sql_type)
-              if sql_type =~ /^money$/
-                #{money_precision}
-              else
-                super
-              end
-            end
+            def extract_precision(sql_type)  # def extract_precision(sql_type)
+              if sql_type =~ /^money$/       #   if sql_type =~ /^money$/
+                #{money_precision}           #     19
+              else                           #   else
+                super                        #     super
+              end                            #   end
+            end                              # end
           end_eval
 
           configure_connection
diff --git a/activerecord/lib/active_record/connection_adapters/sqlite_adapter.rb b/activerecord/lib/active_record/connection_adapters/sqlite_adapter.rb
index 84f8c0284e..9387cf8827 100644
--- a/activerecord/lib/active_record/connection_adapters/sqlite_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/sqlite_adapter.rb
@@ -402,6 +402,10 @@ module ActiveRecord
       end
 
       def add_column(table_name, column_name, type, options = {}) #:nodoc:
+        if @connection.respond_to?(:transaction_active?) && @connection.transaction_active?
+          raise StatementInvalid, 'Cannot add columns to a SQLite database while inside a transaction'
+        end
+
         alter_table(table_name) do |definition|
           definition.column(column_name, type, options)
         end