What is TombstonedTaskError from App Engine's Task Queue?

Question

What does the TombstonedTaskError mean? It is being raised while trying to add a task to the queue, from a cron-job:

Traceback (most recent call las         


        

Answer 1

You've added a task with that exact name before. Although it's already run, executed task names are kept around for some time to prevent accidental duplicates. If you're assigning task names, you should be using ones that are globally unique to prevent this occurring.