erp5_forge: possible to create new task if previous one is finished

bt5/erp5_forge/SkinTemplateItem/portal_skins/erp5_forge/Bug_newTask.py

 task = context.getFollowUpRelatedValue(portal_type='Task')
-if not task:
-  task = context.task_module.newContent(
+if task:
+  task_report = task.getCausalityRelatedValue(portal_type='Task Report')
+  if task_report is None or task_report.getSimulationState() not in ('delivered'):
+    message = context.Base_translateString("A task is already created for this bug")
+    return task.Base_redirect('view', keep_items={'portal_status_message': message})
+
+
+task = context.task_module.newContent(
     portal_type='Task',
     start_date=start_date,
     stop_date=stop_date,
@@ -12,8 +18,5 @@ if not task:
     source_project = context.getSourceProject(), #project
     follow_up_value = context
   )
-  message = context.Base_translateString("A new task is created for this bug")
-  return task.Base_redirect('view', keep_items={'portal_status_message': message})
-else:
-  message = context.Base_translateString("A task is already created for this bug")
-  return task.Base_redirect('view', keep_items={'portal_status_message': message})
+message = context.Base_translateString("A new task is created for this bug")
+return task.Base_redirect('view', keep_items={'portal_status_message': message})