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On Mon, Jun 16, 2014 at 12:19 PM, Tomas Sedovic <tsedovic at redhat.com> wrote:
> All,
>
> After having proposed some changes[1][2] to tripleo-heat-templates[3],
> reviewers suggested adding a deprecation period for the merge.py script.
>
> While TripleO is an official OpenStack program, none of the projects
> under its umbrella (including tripleo-heat-templates) have gone through
> incubation and integration nor have they been shipped with Icehouse.
>
> So there is no implicit compatibility guarantee and I have not found
> anything about maintaining backwards compatibility neither on the
> TripleO wiki page[4], tripleo-heat-template's readme[5] or
> tripleo-incubator's readme[6].
>
> The Release Management wiki page[7] suggests that we follow Semantic
> Versioning[8], under which prior to 1.0.0 (t-h-t is ) anything goes.
> According to that wiki, we are using a stronger guarantee where we do
> promise to bump the minor version on incompatible changes -- but this
> again suggests that we do not promise to maintain backwards
> compatibility -- just that we document whenever we break it.
>
> According to Robert, there are now downstreams that have shipped things
> (with the implication that they don't expect things to change without a
> deprecation period) so there's clearly a disconnect here.
>
> If we do promise backwards compatibility, we should document it
> somewhere and if we don't we should probably make that more visible,
> too, so people know what to expect.
>
> I prefer the latter, because it will make the merge.py cleanup easier
> and every published bit of information I could find suggests that's our
> current stance anyway.
>
> Tomas
>
> [1]: https://review.openstack.org/#/c/99384/
> [2]: https://review.openstack.org/#/c/97939/
> [3]: https://github.com/openstack/tripleo-heat-templates
> [4]: https://wiki.openstack.org/wiki/TripleO
> [5]:
> https://github.com/openstack/tripleo-heat-templates/blob/master/README.md
> [6]: https://github.com/openstack/tripleo-incubator/blob/master/README.rst
> [7]: https://wiki.openstack.org/wiki/TripleO/ReleaseManagement
> [8]: http://semver.org/
>
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Hi Tomas,

By and large, I think you are correct in your conclusions about the
current state of backwards compatibility in TripleO.

Much of this is the reason why I pushed for the stable branches that
we cut for icehouse. I'm not sure what "downstreams that have shipped
things" are being referred to, but perhaps those needs could be served
by the stable/icehouse branches that exist today?  I know at least for
the RDO downstream, the packages are being built off of releases done
from the stable branches. So, honestly, I'm not that concerned about
your proposed changes to rip stuff out without any deprecation from
that point of view :).

That being said, just because TripleO has taken the stance that
backwards compatibility is not guaranteed, I agree with some of the
other sentiments in this thread: that we should at least try if there
are easy things we can do.

-- 
-- James Slagle
--