Interdependent DELETE requests in a change set

[HeikoTheissen]

Consider a batch request with a change set/atomicity group that contains DELETE requests for two entities:

DELETE OrgUnits(1)
DELETE OrgUnits(2)

If DELETE OrgUnits(1) implicitly deletes OrgUnits(2) (because it is a subordinate org unit), what is the response code of DELETE OrgUnits(2)?

• Is it 404 Not Found because the entity does not exist?
• Or is it 204 No Content because the change set was successfully executed overall?

Analogous question for

PATCH /OrgUnits

{"@context": "#$delta",
  "value": [{
    "@removed": {"reason": "deleted"},
    "ID": 1
  }, {
    "@removed": {"reason": "deleted"},
    "ID": 2
  }]}

Is there a Core.DataModificationException for the second deletion?

[ralfhandl]

11.7.7.4 Processing a Multipart Batch Request says

The service MAY execute the requests within a change set in any order and MAY return the responses to the individual requests in any order.

So the service can

1. sort by dependency and (logically) delete the second entity before the first, or
2. delete them in request order and tolerate the unnecessary second delete because it does not change the overall outcome, or
3. stupidly return an error for the second request and roll back the change set.

Whatever fits best to the existing business logic of the system underneath the OData API and can be sold to its customers.