Robert Watson wrote:
> On Thu, 25 Oct 2007, Andrey Chernov wrote:
>
>> On Thu, Oct 25, 2007 at 12:05:40PM -0700, LI Xin wrote:
>>> Well, I think the problem is not exposing a new symbol by itself, but
>>> __mb_sb_limit is being used in _ctype.h, in a form of __inline
>>> functions. Therefore, the change will break new binaries running on
>>> older systems.
>>
>> Yes. Only vice versa compatibility supported.
>
> I think the issue here is that the change occurred very quickly after
> the branch, and when users wanted to 'change gears' back to RELENG_7
> from HEAD once it was created immediately ran into the problem. It
> seems like a useful piece of post-branch advice to developers in the
> future will be, "Please don't do things that make switching branches --
> back or forward -- for the first few weeks after the branch is
> created". In general, I don't think we care about forward
> compatibility, but we are currently getting lots of reports because this
> is one of those few times where a lot of moving backward happens.
>
We do care about forward compatibility within STABLE branches, as Ken
and I have discussed in side threads. But yes, forward compat between
major branches is merely desired; i.e. changes will happen, and
hopefully not for gratuitous reasons.
Scott