Re: [PATCH 3/6] rebase -i --root: let the sequencer handle even the initial part

> On Fri, Apr 27, 2018 at 3:31 PM, Johannes Schindelin
> <johannes.schindelin@gmx.de> wrote:
> > In this developer's earlier attempt to accelerate interactive rebases by
> > converting large parts from Unix shell script into portable, performant
> > C, the --root handling was specifically excluded (to simplify the task a
> > little bit; it still took over a year to get that reduced set of patches
> > into Git proper).
> >
> > This patch ties up that loose end: now only --preserve-merges uses the
> > slow Unix shell script implementation to perform the interactive rebase.
> >
> > As the rebase--helper reports progress to stderr (unlike the scripted
> > interactive rebase, which reports it to stdout, of all places), we have
> > to adjust a couple of tests that did not expect that for `git rebase -i
> > --root`.
> >
> > This patch fixes -- at long last! -- the really old bug reported in
> > 6a6bc5bdc4d (add tests for rebasing root, 2013-06-06) that rebasing with
> > --root *always* rewrote the root commit, even if there were no changes.
> >
> > The bug still persists in --preserve-merges mode, of course, but that
> > mode will be deprecated as soon as the new --rebase-merges mode
> > stabilizes, anyway.
> >
> > Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
> > ---
> >  git-rebase--interactive.sh        |  4 +++-
> >  t/t3404-rebase-interactive.sh     | 19 +++++++++++++------
> >  t/t3421-rebase-topology-linear.sh |  6 +++---
> >  3 files changed, 19 insertions(+), 10 deletions(-)
> >
> > diff --git a/git-rebase--interactive.sh b/git-rebase--interactive.sh
> > index cbf44f86482..2f4941d0fc9 100644
> > --- a/git-rebase--interactive.sh
> > +++ b/git-rebase--interactive.sh
> > @@ -894,6 +894,8 @@ init_revisions_and_shortrevisions () {
> >         else
> >                 revisions=$onto...$orig_head
> >                 shortrevisions=$shorthead
> > +               test -z "$squash_onto" ||
> > +               echo "$squash_onto" >"$state_dir"/squash-onto
> >         fi
> >  }
> >
> > @@ -948,7 +950,7 @@ EOF
> >         die "Could not skip unnecessary pick commands"
> >
> >         checkout_onto
> > -       if test -z "$rebase_root" && test ! -d "$rewritten"
> > +       if test ! -d "$rewritten"
> 
> I have the impression this is the line that is really well
> explained in the commit message ("migrate to rebase
> helper even when there is $rebase_root set")
> 
> The rest of the patch is covered as "a couple of places
> where we adjust stdout to stderr"?