Invalid policy rules generated when a target is deprecated

[Ben Nemec]

If the target for a policy rule is deprecated but the rule name remains the same, the policy generator improperly creates a rule that looks something like "my_rule: rule:my_rule". This is a circular reference and will break policy handling.

We already fixed this on master (for Train), but didn't open a bug about it. Since we should backport the fix I'm opening this bug so we have one to reference.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/684316
Committed: https://git.openstack.org/cgit/openstack/oslo.policy/commit/?id=1e9b2f0dac27e2865a26a085f76525c7a93ddcee
Submitter: Zuul
Branch: stable/stein

commit 1e9b2f0dac27e2865a26a085f76525c7a93ddcee
Author: Lance Bragstad <email address hidden>
Date: Thu Jul 25 16:28:01 2019 +0000

    Only alias when policy names change

    Previously, oslo.policy would generate policy files with aliased names
    in the event the name was changing for backwards compatibility. This
    isn't needed if the name isn't changing and only the check string is
    changing.

    This patch adds a conditional to the generator logic that only aliases
    the old name to the new name if the name is changing. Otherwise, it
    only outputs comments about the deprecation.

    Co-Authored-By: Ben Nemec <email address hidden>
    Closes-Bug: 1845209
    Change-Id: I89ff60354e4751a5096832023441d2e6166db92a
    (cherry picked from commit 9641e5ca0d758376fb7f7f5156056d5206d71046)

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/oslo.policy 2.1.2 release.