[PATCH v2 0/2] Let the sequencer handle the grunt work of rebase -i

After all of these patch series y'all had to review, this is finally the one that switches things over.

Please note that it does not (yet) handle the `git rebase -i --root` invocation; I tried to focus on the common case, and I rarely use --root myself.

Please note also that --preserve-merges is *not* handled.

The way I designed --preserve-merges is totally stupid and idiotic and I do not want to spend any further time on it. You cannot "pick" merges and hope to be able to reorder commits, for example. I may work on porting Git garden shears' way to recreate the branch structure into rebase -i proper at some stage.

And please finally note that this pair of patches does not yet yield the full speed improvement that I promised earlier. After these patches, the time is dominated by pre- and post-processing the todo script, at least on Windows, so there is another patch series that ports those bits and pieces into the rebase--helper, too.

Changes since v1:

- rebased to current master

- this required a change in t3404 because I was bullied^Wasked to change
  some messages (which should not have been conflated with the work I
  actually wanted to do, but whatevs)

Johannes Schindelin (2):
  Add a builtin helper for interactive rebases
  rebase -i: use the rebase--helper builtin

 .gitignore                    |  1 +
 Makefile                      |  1 +
 builtin.h                     |  1 +
 builtin/rebase--helper.c      | 40 ++++++++++++++++++++++++++++++++++++++++
 git-rebase--interactive.sh    | 13 +++++++++++++
 git.c                         |  1 +
 t/t3404-rebase-interactive.sh |  2 +-
 7 files changed, 58 insertions(+), 1 deletion(-)
 create mode 100644 builtin/rebase--helper.c

base-commit: 6e3a7b3398559305c7a239a42e447c21a8f39ff8
Based-On: sequencer-i at https://github.com/dscho/git
Fetch-Base-Via: git fetch https://github.com/dscho/git sequencer-i
Published-As: https://github.com/dscho/git/releases/tag/rebase--helper-v2
Fetch-It-Via: git fetch https://github.com/dscho/git rebase--helper-v2

Interdiff vs v1:

 diff --git a/t/t3404-rebase-interactive.sh b/t/t3404-rebase-interactive.sh
 index e2f18d11f6..33d392ba11 100755
 --- a/t/t3404-rebase-interactive.sh
 +++ b/t/t3404-rebase-interactive.sh
 @@ -556,7 +556,7 @@ test_expect_success 'clean error after failed "exec"' '
  	echo "edited again" > file7 &&
  	git add file7 &&
  	test_must_fail git rebase --continue 2>error &&
 -	test_i18ngrep "You have staged changes in your working tree." error
 +	test_i18ngrep "you have staged changes in your working tree" error
  '
  
  test_expect_success 'rebase a detached HEAD' '