Re: [Monotone-devel] Re: [cdv-devel] more merging stuff (bit long...)

[Nathaniel Smith]

On Thu, Aug 11, 2005 at 01:25:04PM -0700, Bram Cohen wrote:
> Nathaniel Smith wrote:
> 
> > Well, it's that weird edge case that has me wondering, actually.  For
> > those who don't follow the minutiae of our conversations with creepy
> > detail, the example is (with "ab" meaning "line a, then line b"):
> >  <nothing>
> >    /  \
> >   a    b
> >   |\  /|
> >   | \/ |
> >   | /\ |
> >   |/  \|
> >   ab   ba
> >    \  /
> >     ??
> >
> >  [...]
> >
> > AFAICT, the here problem really is just that the global ordering
> > assumption pcdv makes is wrong.  What this is is an ordering conflict...
> > but the very phrase "ordering conflict" makes no sense at all in pcdv
> > terms.  Thinking about it in an abstract sort of way, this seems an odd
> > fact about pcdv merge, since the structure of the domain is "an ordered
> > list", it's all _about_ ordering...
> 
> I think you're incorrect, and the problem is that the ab ordering is
> something new even though a and b individually aren't new, and that there
> is a way of making this be a proper conflict without allowing reordering
> (in other words, having the weave be aba). This is getting fairly
> technical though, and my ideas on this subject are rather half-baked, and
> related to the much more ambitious and important problem of supporting
> convergence, so I'll explain them when they're more coherent.

"The ab ordering is something new even though a and b individually
aren't new" sounds like exactly what I'm saying -- it's not about the
individual lines, it's about the ordering; and yet all our versioning
is of individual lines, and not at all about the ordering.

I'd be interested to hear how to make this a conflict, but whenever
you're ready :-).

-- Nathaniel

-- 
When the flush of a new-born sun fell first on Eden's green and gold,
Our father Adam sat under the Tree and scratched with a stick in the mould;
And the first rude sketch that the world had seen was joy to his mighty heart,
Till the Devil whispered behind the leaves, "It's pretty, but is it Art?"
  -- The Conundrum of the Workshops, Rudyard Kipling