Interaction.py: fix interaction guard generator.

product/ERP5Workflow/Document/Interaction.py

@@ -31,7 +31,7 @@ import transaction
 from AccessControl import getSecurityManager, ClassSecurityInfo
 from Acquisition import aq_inner, aq_parent
 from Products.DCWorkflow.Guard import Guard
-from Products.DCWorkflow.Expression import Expression, StateChangeInfo
+from Products.DCWorkflow.Expression import Expression
 from Products.ERP5Type import Globals, Permissions, PropertySheet
 from Products.ERP5Type.Globals import PersistentMapping
 from Products.ERP5Type.id_as_reference import IdAsReferenceMixin
@@ -102,19 +102,20 @@ class Interaction(IdAsReferenceMixin('interaction_', "prefix"), XMLObject):
     return self.guard
 
   def generateGuard(self):
-    if self.guard == None:
+    if self.guard is None:
       self.guard = Guard(permissions=self.getPermissionList(),
                     roles=self.getRoleList(),
                     groups=self.getGroupList(),
-                    expr=self.getExpression())
-    if self.guard.roles != self.getRoleList():
+                    expr=Expression(self.getExpression()))
+
+    if self.getRoleList() is not None:
       self.guard.roles = self.getRoleList()
-    elif self.guard.permissions != self.getPermissionList():
+    if self.getPermissionList() is not None:
       self.guard.permissions = self.getPermissionList()
-    elif self.guard.groups != self.getGroupList():
+    if self.getGroupList() is not None:
       self.guard.groups = self.getGroupList()
-    elif self.guard.expr != self.getExpression():
-      self.guard.expr = self.getExpression()
+    if self.getExpression() is not None:
+      self.guard.expr = Expression(self.getExpression())
 
   def getMethodId(self):
     if type(self.method_id) is type(''):