diff --git a/addons/product/pricelist.py b/addons/product/pricelist.py
index 7047cebb1f6..8a88ee059c0 100644
--- a/addons/product/pricelist.py
+++ b/addons/product/pricelist.py
@@ -324,10 +324,12 @@ class product_pricelist_item(osv.osv):
         'company_id': fields.related('pricelist_id','company_id',type='many2one',
             readonly=True, relation='res.company', string='Company', store={
                 'product.pricelist': (_get_product_pricelist, ['company_id'], 30),
+                'product.pricelist.item': (lambda self, cr, uid, ids, c=None: ids, ['pricelist_id'], 30),
             }),
         'currency_id': fields.related('pricelist_id', 'currency_id', type='many2one',
             readonly=True, relation='res.currency', string='Currency', store={
                 'product.pricelist': (_get_product_pricelist, ['currency_id'], 30),
+                'product.pricelist.item': (lambda self, cr, uid, ids, c=None: ids, ['pricelist_id'], 30),
             }),
         'date_start': fields.date('Start Date', help="Starting date for the pricelist item validation"),
         'date_end': fields.date('End Date', help="Ending valid for the pricelist item validation"),
diff --git a/addons/stock/stock.py b/addons/stock/stock.py
index f305332e707..ae6b3888dc2 100644
--- a/addons/stock/stock.py
+++ b/addons/stock/stock.py
@@ -4278,7 +4278,6 @@ class stock_package(osv.osv):
         context = dict(context or {}, active_ids=ids)
         return self.pool.get("report").get_action(cr, uid, ids, 'stock.report_package_barcode_small', context=context)
     
-    
     def unpack(self, cr, uid, ids, context=None):
         quant_obj = self.pool.get('stock.quant')
         for package in self.browse(cr, uid, ids, context=context):
@@ -4286,8 +4285,6 @@ class stock_package(osv.osv):
             quant_obj.write(cr, SUPERUSER_ID, quant_ids, {'package_id': package.parent_id.id or False}, context=context)
             children_package_ids = [child_package.id for child_package in package.children_ids]
             self.write(cr, uid, children_package_ids, {'parent_id': package.parent_id.id or False}, context=context)
-        #delete current package since it contains nothing anymore
-        self.unlink(cr, uid, ids, context=context)
         return self.pool.get('ir.actions.act_window').for_xml_id(cr, uid, 'stock', 'action_package_view', context=context)
 
     def get_content(self, cr, uid, ids, context=None):
diff --git a/openerp/models.py b/openerp/models.py
index 42fec7535ae..2af2ec78d09 100644
--- a/openerp/models.py
+++ b/openerp/models.py
@@ -747,8 +747,11 @@ class BaseModel(object):
         cls = type(self)
         methods = []
         for attr, func in getmembers(cls, is_constraint):
-            if not all(name in cls._fields for name in func._constrains):
-                _logger.warning("@constrains%r parameters must be field names", func._constrains)
+            for name in func._constrains:
+                if name not in cls._fields:
+                    _logger.warning("method %s.%s: @constrains parameter %r is not a field name", cls._name, attr, name)
+                if not cls._fields[name].store:
+                    _logger.warning("method %s.%s: @constrains parameter %r is not stored", cls._name, attr, name)
             methods.append(func)
 
         # optimization: memoize result on cls, it will not be recomputed