[service-announce] Zuul behavior change with Depends-On across queues

[Jeremy Stanley]

A recent improvement to more accurately report Zuul's enqueuing has
resulted in an unanticipated difference in behavior for changes
declaring a Depends-On relationship between projects which don't
share a dependent queue. If you approve the depending change before
the dependency has merged, Zuul will now report a Verified -2 vote
on the depending change (where previously it just ignored your
approval entirely). As a result, because the openstack tenant is
configured to require a positive Verified vote before enqueuing into
the gate pipeline, this means the depending change will need to be
rechecked in order to replace that -2 vote with a +1 in that tenant.
For tenants without such a "clean check" rule, the change in
behavior is entirely cosmetic.

One thing you can do to avoid this is make sure any projects which
regularly utilize Depends-On between their changes are configured to
belong to the same named queue, which will result in Zuul enqueuing
those approved changes into the gate pipeline together without
needing to wait for one to merge before the other can be tested.
Zuul expects related projects to share a queue and, on approval,
will only look up parent and child changes to enqueue within the
related projects list, as determined by the queue to which they
belong. An alternative workaround is to only approve a change once
you've confirmed that any Depends-On has merged, if that dependency
is in another project which does not share the same queue.

Feel free to follow up on the service-discuss ML with any
comments/concerns, or find us in the #opendev channel on OFTC as
usual.
-- 
Jeremy Stanley
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 963 bytes
Desc: not available
URL: <http://lists.opendev.org/pipermail/service-announce/attachments/20220405/0fb71b60/attachment.sig>