git rebase and merge commits

[Dominique Quatravaux <domq@google.com>]

Hi all, I'm trying to write "git shove", a wrapper around git rebase
--interactive that would turn this


#        A---B---C---K targetbranch
#       /         \
#  D---E---F---G---H---I--J srcbranch

into this:

#   A---B---C---I'---K'  targetbranch
#  /             \
# D---E---F---G---H'---J' srcbranch
#

(ie I has been shoved into targetbranch).

It seemed to me that the first step should be to simply rebase I, H, and J (in
this order) onto C. Unfortunately git rebase --interactive -p C proposes a
git-rebase-todo that contains only "noop"; if I forcefully put this instead,

edit iiii I
edit hhhh H
edit jjjj J

it seems to me that the HEAD jumps backward to the original H on the second
rebase step, instead of daisy-chaining H behind I.  This is with git 1.7.3.1.

Here are the outputs of git log --graph --pretty=oneline --abbrev-commit at each
rebase step:

1/3

* a810395 I
*   1cfccc7 H
|\
| * c477d4e C
| * 7002290 B
| * aa9f1d0 A
* | b614d31 G
* | 2ad4496 F
|/
* 0d512e9 E
* b6cbc2b D

2/3

*   1cfccc7 H
|\
| * c477d4e C
| * 7002290 B
| * aa9f1d0 A
* | b614d31 G
* | 2ad4496 F
|/
* 0d512e9 E
* b6cbc2b D

3/3

* 3a41a45 J
* a810395 I
*   1cfccc7 H
|\
| * c477d4e C
| * 7002290 B
| * aa9f1d0 A
* | b614d31 G
* | 2ad4496 F
|/
* 0d512e9 E
* b6cbc2b D


Is there a way to do a real rebase of a merge commit?

FWIW, here is the script I use to create my toy environment in the current
directory:

function _make_commit() {
  echo "$1" > "$1"
  git add "$1"
  git commit -a -m "$1"
  git tag "$1" HEAD
}

function _prepare_merged_history() {
  git init
  _make_commit "D"
  git checkout -b targetbranch
  _make_commit "E"
  _make_commit "A"
  _make_commit "B"
  _make_commit "C"
  _make_commit "K"
  git checkout E
  git checkout -b srcbranch
  _make_commit "F"
  _make_commit "G"
  git merge  -m "H" C
  git tag H HEAD
  _make_commit "I"
  _make_commit "J"
}

function _git_rebase_todo_line() {
  echo -n "pick "
  git rev-list -n 1 --pretty=oneline --abbrev-commit --abbrev=7 "$1"
}

function _make_git_rebase_todo() {
  {
    _git_rebase_todo_line refs/tags/I
    _git_rebase_todo_line refs/tags/H
    _git_rebase_todo_line refs/tags/J
  } > git-rebase-todo
}

[ -d ".git" ] && exit
_prepare_merged_history
_make_git_rebase_todo


Thanks in advance,

-- 
  Dominique Quatravaux
  +41 79 609 40 72