On Fri, Jan 4, 2013 at 4:26 AM, Thibault Kruse <kruset@in.tum.de> wrote:

> On 04.01.2013 00:29, Jack O'Quin wrote:
>
>>
>> My understanding of REP 9 is that ABI consistency is only required
>> *within* an even-cycle release, such as Fuerte or Groovy. Not *between*
>> releases.
>>
>>  Hi Jack,
>
> note that Groovy packages were released with 1.9 as version numbers, not
> 1.10, so there is no "even-cycle" anymore.
> I don't think there has been any formal announcement of this decision.
>

I did notice that, but assumed it was an oversight. You are saying it was
intentional.

This would mean the documentation at http://www.ros.org/wiki/**
> StackVersionPolicy <http://www.ros.org/wiki/StackVersionPolicy> and REP9
> referencing it became a little problematic with reference to "even cycles".
>

It could be updated to maintaining ABI compatibility any time the major and
minor numbers remain unchanged. That leaves a period of user uncertainty
during the unstable period before a release when ABI-breaking changes are
actually allowed.

So, perhaps this could use some discussion. What was the rationale for
abandoning the former practice?

The only problem I know about is that the even-number rule frequently
forces additional package releases just to bump version numbers from 1.9.x
to 1.10.0.
-- 
 joq