No "t." for the migration DSL!

Now you can omit |t| block parameter and all the t. from your migration code, that means, the syntax looks more Rails-3-ish, like the routes DSL and ActionMailer DSL.
Also, this change won't break any of your existing migration files, since the traditional syntax is still available.

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

@@ -154,11 +154,11 @@ def column_exists?(table_name, column_name, type = nil, options = {})
       #  )
       #
       # See also TableDefinition#column for details on how to create columns.
-      def create_table(table_name, options = {})
+      def create_table(table_name, options = {}, &blk)
         td = table_definition
         td.primary_key(options[:primary_key] || Base.get_primary_key(table_name.to_s.singularize)) unless options[:id] == false
 
-        yield td if block_given?
+        td.instance_eval(&blk) if blk
 
         if options[:force] && table_exists?(table_name)
           drop_table(table_name, options)

activerecord/lib/active_record/connection_adapters/sqlite_adapter.rb

@@ -394,27 +394,29 @@ def move_table(from, to, options = {}, &block) #:nodoc:
           drop_table(from)
         end
 
-        def copy_table(from, to, options = {}) #:nodoc:
-          options = options.merge(:id => (!columns(from).detect{|c| c.name == 'id'}.nil? && 'id' == primary_key(from).to_s))
+        def copy_table(from, to, options = {}, &block) #:nodoc:
+          from_columns, from_primary_key = columns(from), primary_key(from)
+          options = options.merge(:id => (!from_columns.detect {|c| c.name == 'id'}.nil? && 'id' == primary_key(from).to_s))
+          table_definition = nil
           create_table(to, options) do |definition|
-            @definition = definition
-            columns(from).each do |column|
+            table_definition = definition
+            from_columns.each do |column|
               column_name = options[:rename] ?
                 (options[:rename][column.name] ||
                  options[:rename][column.name.to_sym] ||
                  column.name) : column.name
 
-              @definition.column(column_name, column.type,
+              table_definition.column(column_name, column.type,
                 :limit => column.limit, :default => column.default,
                 :null => column.null)
             end
-            @definition.primary_key(primary_key(from)) if primary_key(from)
-            yield @definition if block_given?
+            table_definition.primary_key from_primary_key if from_primary_key
+            table_definition.instance_eval(&block) if block
           end
 
           copy_table_indexes(from, to, options[:rename] || {})
           copy_table_contents(from, to,
-            @definition.columns.map {|column| column.name},
+            table_definition.columns.map {|column| column.name},
             options[:rename] || {})
         end
 

activerecord/lib/active_record/session_store.rb

@@ -64,12 +64,13 @@ def drop_table!
       end
 
       def create_table!
+        id_col_name, data_col_name = session_id_column, data_column_name
         connection_pool.clear_table_cache!(table_name)
         connection.create_table(table_name) do |t|
-          t.string session_id_column, :limit => 255
-          t.text data_column_name
+          t.string id_col_name, :limit => 255
+          t.text data_col_name
         end
-        connection.add_index table_name, session_id_column, :unique => true
+        connection.add_index table_name, id_col_name, :unique => true
       end
     end