Re: [CFT] rewrite of the merge(1) utility

On 8/13/15 11:23 PM, John Baldwin wrote:
> On Thursday, August 13, 2015 04:13:43 PM Slawa Olhovchenkov wrote:
>> On Tue, Aug 04, 2015 at 10:00:06PM -0700, John Baldwin wrote:
>>
>>> On Sunday, July 26, 2015 03:26:22 AM Baptiste Daroussin wrote:
>>>> Hi all,
>>>>
>>>> I was botherd to not have the merge(1) utility available in base (for etcupdate)
>>>> when building base WITHOUT_RCS.
>>>>
>>>> So I have rewritten a merge(1) utility which should be compatible.
>>>>
>>>> I used the 3-way merge code from the fossil VCS instead of making it call diff3.
>>>> All I have done from the fossil code is adapting it to use sbuf(9).
>>>>
>>>> The bonus for end users is the merge from fossil can resolve situation where the
>>>> diff3 in base cannot. (which explains a "failure" with the GNU RCS test suite)
>>>>
>>>> meaning etcupdate will be more happy merge configuration files.
>>> Thanks!  This will save me from having to hack etcupdate to use diff3 instead
>>> of merge.
>> Hi, can I use etcupdate to update /etc w/o source tree?
>> I.e. I take from new distro /var/db/etcupdate and try to update /etc?
> etcupdate does a 3-way merge of an "old" stock /etc and a "new" stock /etc
> into /etc.  The "old" stock /etc is always stored in /var/db/etcupdate.
> The "new" stock /etc has to come from somewhere.  One option is to generate
> it from /usr/src (e.g. after a buildworld).  However, you can also pregenerate
> tarballs from a /usr/src tree on one machine and then use those tarballs
> instead of generating an /etc tree from /usr/src on another machine.  I've
> used this for upgrades of a cluster of machines where a single machine would
> build release "images" that were basically a buildworld + an 'etcupdate build'
> from the corresponding src tree.  I then used 'etcupdate -t /path/to/tarball'
> to update /etc after installing the new world.
>
> The idea is that for something like freebsd-update one could ship the latest
> etcupdate build tarball on each update to do a full 3-way merge of /etc.
>
what is the rational for using etcupdate instead of mergemaster when 
upgrading?