[openstack-dev] [nova] Backwards incompatible API changes

Christopher Yeoh cbkyeoh at gmail.com
Mon Mar 24 05:11:05 UTC 2014


On Fri, 21 Mar 2014 13:34:08 -0400
David Kranz <dkranz at redhat.com> wrote:

> On 03/21/2014 05:04 AM, Christopher Yeoh wrote:
> Nope.  IMO we should just accept that an incompatible change was made 
> that should not have been, revert it, and move on. I hope that saying 
> our code base is going to support CD does not mean that any
> incompatible change that slips through our very limited gate cannot
> be reverted. October was a while back but I'm not sure what principle
> we would use to draw the line. I am also not sure why this is phrased
> as a CD vs. not issue. Are the *users* of a system that happens to be
> managed using CD thought to be more tolerant of their code breaking?

Yea we probably want to have discussion about this at summit. If only
so we know that the people doing CD and the developers have a common
expectation of what we'll do in these sorts of situations.

> Perhaps it would be a good time to review 
> https://wiki.openstack.org/wiki/Governance/Approved/APIStability and
> the details of https://wiki.openstack.org/wiki/APIChangeGuidelines to
> make sure they still reflect the will of the TC and our community.

I totally agree. I know some people disagree that even changing
error return codes should be considered API backwards
compatible. 

Perhaps its appropriate that projects in the very early days of
adoption can be a bit more flexible. But I think part of the price of
maturity and lots of users is having to live with mistakes we make,
especially when there are reasonable workarounds even if we think
they're ugly - at least until a major version rev (or if we can sort
out some other alternative). 

Chris



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