Re: [PATCH 0/2] RFC: implement new zdiff3 conflict style

> > Thanks for figuring that out. I agree that the output after the patch
> > you showed is correct, in the sense that the common lines show up in the
> > base now. It does feel like it's working against the point of zdiff3,
> > though, which is to reduce the number of common lines shown in the
> > "ours" and "theirs" hunks.
> 
> I agree - the output is longer rather than shorter. As we only want to trim
> the common prefix and suffix from the conflicts I wonder if it would be
> better to special case zdiff3 rather than piggy backing on the existing
> XDL_MERGE_ZEALOUS implementation. We can trim the common lines by looping
> over the begging and end of the hunk comparing the lines with xdl_recmatch()
> without going to the trouble of diffing them as XDL_MERGE_ZEALOUS does. I
> don't think we need to worry about coalescing adjacent conflicts for zdiff3.
> It makes sense to coalesce in the XDL_MERGE_ZEALOUS case as it can
> potentially split a  N line conflict hunk into N/2 single line conflict
> hunks but zdiff3 does not split conflict hunks.

> Yes, I think the heuristic for coalescing conflict hunks could be improved.
> It would be fairly simple to only join two hunks if the conflicts are longer
> that the context between them and the existing XDL_MERGE_ZEALOUS_ALNUM logic
> allows conflicts with more context between them to be coalesced if the
> context lines are uninteresting. I think XDL_MERGE_ZEALOUS_ALNUM is only
> used by `git merge-file` at the moment, with everything else going through
> ll_merge() which uses XDL_MERGE_ZEALOUS