[FIX] lunch : do not display empty alert on form view

addons/lunch/models/lunch.py

@@ -62,7 +62,7 @@ class LunchOrder(models.Model):
                      if alert.display]
 
         if self.state == 'new':
-            self.alerts = '\n'.join(alert_msg)
+            self.alerts = alert_msg and '\n'.join(alert_msg) or False
 
     @api.depends('state')
     def _compute_get_previous_order_ids(self):

addons/lunch/views/lunch_views.xml

@@ -394,7 +394,9 @@
                                 </div>
                             </group>
                         </group>
-                        <field name='alerts' attrs="{'invisible': ['|',('state','!=','new'),('alerts','=',False)]}" class="oe_inline alert alert-danger"/>
+                        <div attrs="{'invisible': ['|',('state','!=','new'),('alerts','=',False)]}" class="oe_inline alert alert-danger">
+                            <field name='alerts'/>
+                        </div>
                         <field name='previous_order_ids' widget='previous_order'/>
                         <separator string='Select your order'/>
                         <field name='order_line_ids' nolabel='1'>