initializing instance variables

activerecord/lib/active_record/session_store.rb

@@ -119,6 +119,11 @@ def self.find_by_session_id(session_id)
           end
       end
 
+      def initialize(attributes = nil)
+        @data = nil
+        super
+      end
+
       # Lazy-unmarshal session state.
       def data
         @data ||= self.class.unmarshal(read_attribute(@@data_column_name)) || {}
@@ -128,7 +133,7 @@ def data
 
       # Has the session been loaded yet?
       def loaded?
-        !!@data
+        @data
       end
 
       private

activerecord/test/cases/session_store/session_test.rb

+require 'cases/helper'
+require 'action_dispatch'
+require 'active_record/session_store'
+
+module ActiveRecord
+  class SessionStore
+    class SessionTest < ActiveRecord::TestCase
+      def setup
+        super
+        Session.drop_table! if Session.table_exists?
+      end
+
+      def test_data_column_name
+        # default column name is 'data'
+        assert_equal 'data', Session.data_column_name
+      end
+
+      def test_table_name
+        assert_equal 'sessions', Session.table_name
+      end
+
+      def test_create_table!
+        assert !Session.table_exists?
+        Session.create_table!
+        assert Session.table_exists?
+        Session.drop_table!
+        assert !Session.table_exists?
+      end
+
+      def test_find_by_sess_id_compat
+        klass = Class.new(Session) do
+          def self.session_id_column
+            'sessid'
+          end
+        end
+        klass.create_table!
+
+        assert klass.columns_hash['sessid'], 'sessid column exists'
+        session = klass.new(:data => 'hello')
+        session.sessid = 100
+        session.save!
+
+        found = klass.find_by_session_id(100)
+        assert_equal session, found
+        assert_equal session.sessid, found.session_id.to_i
+      ensure
+        klass.drop_table!
+      end
+
+      def test_find_by_session_id
+        Session.create_table!
+        s = Session.create!(:data => 'world', :session_id => 10)
+        assert_equal s, Session.find_by_session_id(10)
+        Session.drop_table!
+      end
+
+      def test_loaded?
+        s = Session.new
+        assert !s.loaded?, 'session is not loaded'
+      end
+    end
+  end
+end