Catch error generated by bad formed tales expression.

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@4388 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ERP5Type/Base.py

@@ -950,7 +950,11 @@ class Base( CopyContainer, PortalContent, ActiveObject, ERP5PropertyManager ):
         elif hasattr(self, accessor_name):
           #LOG("Calling: ",0, accessor_name)
           method = getattr(self, accessor_name)
-          old_value = method() # XXX Why not use getProperty ???
+          try:
+            old_value = method() # XXX Why not use getProperty ???
+          except TypeError:
+            # Catch error generated by bad formed tales expression error
+            old_value = None
           #LOG("Old value: ",0, str(old_value))
           #LOG("New value: ",0, str(kw[key]))
         else: