same as r34695 (do not raise IndexError if an empty list is saved as a recorded property).

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@34696 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ERP5Legacy/Document/Rule.py

@@ -510,7 +510,10 @@ class Rule(Predicate, XMLObject):
                 if movement.isPropertyRecorded(k):
                   movement_value = movement.getRecordedProperty(k)
                   if isinstance(movement_value, list) and not isinstance(v, list):
-                    movement_value = movement_value[0]
+                    try:
+                      movement_value = movement_value[0]
+                    except IndexError:
+                      movement_value = None
                 else:
                   movement_value = movement.getProperty(k)
                 if v != movement_value: