Hi Peff, On Wed, 28 Feb 2018, Jeff King wrote:
> On Tue, Feb 27, 2018 at 12:33:56AM +0100, Johannes Schindelin wrote: > > > > So something like this helps: > > > > > > diff --git a/git-rebase--interactive.sh b/git-rebase--interactive.sh > > > index 81c5b42875..71e6cbb388 100644 > > > --- a/git-rebase--interactive.sh > > > +++ b/git-rebase--interactive.sh > > > @@ -921,15 +921,20 @@ else > > > > > > if test -z "$rebase_root" > > > then > > > preserve=t > > > + p= > > > for p in $(git rev-list --parents -1 $sha1 | cut -d' ' > > > -s -f2-) > > > do > > > if test -f "$rewritten"/$p > > > then > > > preserve=f > > > fi > > > done > > > + if test -z "$p" > > > + then > > > + preserve=f > > > + fi > > > else > > > preserve=f > > > fi > > > if test f = "$preserve" > > > > > > Because it at least adds "two" to the list of commits to pick. But > > > oddly, it picks it directly as a root commit again. Whereas a rebase > > > without --preserve-merges (and even "-i") picks it on top of commit > > > "one" (which is what I'd expect). > > > > > > +cc Dscho, as the --preserve-merges guru. > > > > Your analysis makes sense to me. Please note, though, that I would not > > consider myself a guru on preserve-merges. I think this mode is broken by > > design (you can blame me if you want). > > I think that is doing the right thing for half of the problem. But > there's something else funny where we do not include the "upstream" > commits from the split history (i.e., we rebase onto nothing, > whereas a normal "git rebase" with a split history will graft the two > together). Let me ask to make sure I am understanding you correctly. Are you referring to "split history" as the case where the commit graph has *two* root commits? If so: when you perform a merge-preserving rebase, then those two root commits will be recreated as new root commits, by design. The non-merge-preserving mode cannot create two root commits, as it does not allow for introducing merge commits (and you'd need that to combine the two strands). It is quite possible that I misunderstand completely, though. Care to enlighten me? Ciao, Dscho
