Comment 12 for bug 1730730

Reviewed: https://review.openstack.org/528591
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=449f3402dbe86917fedb02b9b176ec532e6f6008
Submitter: Zuul
Branch: master

commit 449f3402dbe86917fedb02b9b176ec532e6f6008
Author: Tetsuro Nakamura <email address hidden>
Date: Sun Dec 17 13:01:40 2017 +0900

    Fix duplicate allocation candidates

    Some combinations of resource providers were duplicated in
    allocation candidates.

    This can happen when multiple sharing RPs are in the same aggregates,
    because both sharing RPs visit each other during the algorithm to
    see if it can be used as an allocation candidate's mate.

    This patch adds to _alloc_candidates_with_shared() function a check
    if we already have that combination in allocation candidates by
    adding `alloc_prov_ids`, which is a list of sets of allocation
    candidates's rp_ids.

    Change-Id: Iefd3137ec68029d27081a743e52e327625585081
    Closes-Bug:#1730730