Use required on states for dashboard_layout

Extending a Model by adding hard required breaks the migration

CHANGELOG

@@ -1,3 +1,5 @@
+* Use required on states for dashboard_layout
+
 Version 1.6.0 - 2010-05-09
 * Bug fixes (see mercurial logs for details)
 

res.py

@@ -1,6 +1,7 @@
 #This file is part of Tryton.  The COPYRIGHT file at the top level of
 #this repository contains the full copyright notices and license terms.
 from trytond.model import Model, fields
+from trytond.backend import TableHandler
 
 
 class User(Model):
@@ -12,7 +13,10 @@ class User(Model):
         ('stack_left', 'Stack Left'),
         ('stack_top', 'Stack Top'),
         ('stack_bottom', 'Stack Bottom'),
-        ], string='Dashboard Layout', required=True)
+        ], string='Dashboard Layout',
+        states={
+            'required': True,
+        })
     dashboard_actions = fields.One2Many('dashboard.action', 'user',
             'Dashboard Actions')
 
@@ -23,6 +27,13 @@ class User(Model):
             'dashboard_actions',
         ]
 
+    def init(self, cursor, module_name):
+        super(User, self).init(cursor, module_name)
+        table = TableHandler(cursor, self, module_name)
+
+        # Migration from 1.6
+        table.not_null_action('dashboard_layout', action='remove')
+
     def default_dashboard_layout(self, cursor, user, context=None):
         return 'square'