---
prelude: >
  - Adding locations to a non-active or non-queued image
    is no longer allowed.
critical:
  - |
    Attempting to set image locations to an image *not* in
    ``active`` or ``queued`` status will now result in a
    HTTP Conflict (HTTP status code 409) to the user.

    * Until now, no image status checks were in place while
      **adding** a location on it. In some circumstances,
      this may result in a bad user experience. It may also
      cause problems for a security team evaluating the
      condition of an image in ``deactivated`` status.
    * **Adding** locations is disallowed on the following
      image statuses - ``saving``, ``deactivated``,
      ``deleted``, ``pending_delete``, ``killed``.
    * Note that there are race conditions associated with
      adding a location to an image in the ``active``,
      ``queued``, ``saving``, or ``deactivated`` status.
      Because these are non-terminal image statuses, it is
      possible that when a user attempts to add a location,
      a status transition could occur that might block the
      **add** (or might appear to allow an add that should
      not be allowed).
    * For example, a user is not allowed to add a location
      to an image in ``saving`` status. Suppose a user
      decides to add a location anyway. It is possible that
      before the user's request is processed, the
      transmission of data being saved is completed and the
      image transitioned into ``active`` status, in which
      case the user's add location request will succeed. To
      the user, however, this success will appear anomalous
      because in most cases, an attempt to add a location to
      an image in ``saving`` status will fail.
    * We mention this so that you can be aware of this
      situation in your own testing.