Google App Engine, we need to have a talk about your datastore keys.

Your keys can have names but they cannot start with a number. Keys can also have IDs, which are numeric. We can read those, but can't set them.

When I put an entity into the datastore for the first time, you assign it a numeric ID. I'd love to be able to create an entity on a different instance with the same ID you've assigned it but I can't. I'd love to be able to create an entity with the same key that you've assigned it (again, on a separate instance -- say the local SDK or a different app), but I can't set keys directly.

(more...)