This is an error message I got after extending record rules following the 'Odoo Development Essentials,

You initially create a new module called 'todo_app' and then extend it 'todo_user', when creating the todo_app module you define record level rules so that users can only view their own records. because the rules were created using 'data noupdate="1" when extending the rules for the todo_user module which is an mutl-user extension of the todo_app module the new xml rules record first deletes the original rule record and then defines the new rules:

<?xml version="1.0" encoding="utf-8"?>

<openerp>

  <data noupdate="0">

    <delete model="ir.rule" search="[('id','=',

     ref('todo_app.todo_task_user_rule'))]" />

    <record id="todo_task_per_user_rule" model="ir.rule">

        <field name="name">ToDo Tasks only for owner</field>

        <field name="model_id" ref="model_todo_task"/>

        <field name="groups" eval="[(4,ref('base.group_user'))]"/>

        <field name="domain_force">

          ['|',('user_id','in',[user.id,False]),

            ('message_follower_ids','in',[user.partner_id.id])]

        </field>

    </record>

  </data>

</openerp>