comparison of bookmarks at incoming/outgoing

[Matt Mackall]

On Mon, 2012-08-20 at 11:49 -0500, Kevin Bullock wrote:
> On Aug 20, 2012, at 5:21 AM, FUJIWARA Katsunori wrote:
> 
> > So, what about adding HINT information like below ?
> > 
> >  - it is assumed that bookmarks points:
> >    - REV-L on local side
> >    - REV-R on remote side
> > 
> >  - if local repo has REV-R:
> > 
> >    - if common ancestor of REV-L and REV-R is none of each:
> >      show "divergent" as hint
> > 
> >    - otherwise:
> >      - if common ancestor of them is REV-L:
> >        show "advanced remotely" as hint
> > 
> >      - otherwise:
> >        show "advanced locally" as hint
> 
> …which, to summarize, is the case where we *can* tell reliably whether
> the remote bookmark is advanced remotely, advanced locally, or
> divergent. So far so good. I gather that the common ancestor
> calculation is O(n), where n <= count(ANC::REV1) + count(ANC::REV2).
> Someone with more than passing knowledge of the algorithm can correct
> me. In any case, I'm not sure it would make a huge difference relative
> to the network communications time.

> *waits for Bryan to jump in*

I'll jump in instead. The question of whether X and Y are divergent is
actually much simpler than actually finding a common ancestor, since we
already have a topologically sorted DAG.

- pick the greater of X and Y as start, smaller as target
- iterate back through its ancestors
  - stop if target is encountered -> linear
  - recurse on parents > target
- if we run out of things to visit -> divergent

The run time here is limited by the distance between X and Y in
revisions.

We should probably have a method somewhere for this.

> >  - otherwise:
> > 
> >    REV-R should be the revision newly added on remote, so "advanced
> >    locally" can be ignored in this case.
> > 
> >    but there is no other information (in reasonable costs) to
> >    determine relation between REV-L and REV-R, so show "advanced
> >    remotely or divergent" as hint
> 
> This also looks good to me, although I think we can probably come up with a better way to word it. Maybe something as simple as 'bookmark MARK changed on remote'
> 
> pacem in terris / мир / शान्ति / ‎‫سَلاَم‬ / 平和
> Kevin R. Bullock
> 
> _______________________________________________
> Mercurial-devel mailing list
> Mercurial-devel at selenic.com
> http://selenic.com/mailman/listinfo/mercurial-devel


-- 
Mathematics is the supreme nostalgia of our time.