git-rebase--interactive.sh

   1 #!/bin/sh
   2 #
   3 # Copyright (c) 2006 Johannes E. Schindelin
   4
   5 # SHORT DESCRIPTION
   6 #
   7 # This script makes it easy to fix up commits in the middle of a series,
   8 # and rearrange commits.
   9 #
  10 # The original idea comes from Eric W. Biederman, in
  11 # http://article.gmane.org/gmane.comp.version-control.git/22407
  12
  13 OPTIONS_KEEPDASHDASH=
  14 OPTIONS_SPEC="\
  15 git-rebase [-i] [options] [--] <upstream> [<branch>]
  16 git-rebase [-i] (--continue | --abort | --skip)
  17 --
  18  Available options are
  19 v,verbose          display a diffstat of what changed upstream
  20 onto=              rebase onto given branch instead of upstream
  21 p,preserve-merges  try to recreate merges instead of ignoring them
  22 s,strategy=        use the given merge strategy
  23 m,merge            always used (no-op)
  24 i,interactive      always used (no-op)
  25  Actions:
  26 continue           continue rebasing process
  27 abort              abort rebasing process and restore original branch
  28 skip               skip current patch and continue rebasing process
  29 no-verify          override pre-rebase hook from stopping the operation
  30 root               rebase all reachable commmits up to the root(s)
  31 "
  32
  33 . git-sh-setup
  34 require_work_tree
  35
  36 DOTEST="$GIT_DIR/rebase-merge"
  37 TODO="$DOTEST"/git-rebase-todo
  38 DONE="$DOTEST"/done
  39 MSG="$DOTEST"/message
  40 SQUASH_MSG="$DOTEST"/message-squash
  41 REWRITTEN="$DOTEST"/rewritten
  42 DROPPED="$DOTEST"/dropped
  43 PRESERVE_MERGES=
  44 STRATEGY=
  45 ONTO=
  46 VERBOSE=
  47 OK_TO_SKIP_PRE_REBASE=
  48 REBASE_ROOT=
  49
  50 GIT_CHERRY_PICK_HELP="  After resolving the conflicts,
  51 mark the corrected paths with 'git add <paths>', and
  52 run 'git rebase --continue'"
  53 export GIT_CHERRY_PICK_HELP
  54
  55 warn () {
  56         echo "$*" >&2
  57 }
  58
  59 output () {
  60         case "$VERBOSE" in
  61         '')
  62                 output=$("$@" 2>&1 )
  63                 status=$?
  64                 test $status != 0 && printf "%s\n" "$output"
  65                 return $status
  66                 ;;
  67         *)
  68                 "$@"
  69                 ;;
  70         esac
  71 }
  72
  73 run_pre_rebase_hook () {
  74         if test -z "$OK_TO_SKIP_PRE_REBASE" &&
  75            test -x "$GIT_DIR/hooks/pre-rebase"
  76         then
  77                 "$GIT_DIR/hooks/pre-rebase" ${1+"$@"} || {
  78                         echo >&2 "The pre-rebase hook refused to rebase."
  79                         exit 1
  80                 }
  81         fi
  82 }
  83
  84 require_clean_work_tree () {
  85         # test if working tree is dirty
  86         git rev-parse --verify HEAD > /dev/null &&
  87         git update-index --ignore-submodules --refresh &&
  88         git diff-files --quiet --ignore-submodules &&
  89         git diff-index --cached --quiet HEAD --ignore-submodules -- ||
  90         die "Working tree is dirty"
  91 }
  92
  93 ORIG_REFLOG_ACTION="$GIT_REFLOG_ACTION"
  94
  95 comment_for_reflog () {
  96         case "$ORIG_REFLOG_ACTION" in
  97         ''|rebase*)
  98                 GIT_REFLOG_ACTION="rebase -i ($1)"
  99                 export GIT_REFLOG_ACTION
 100                 ;;
 101         esac
 102 }
 103
 104 last_count=
 105 mark_action_done () {
 106         sed -e 1q < "$TODO" >> "$DONE"
 107         sed -e 1d < "$TODO" >> "$TODO".new
 108         mv -f "$TODO".new "$TODO"
 109         count=$(grep -c '^[^#]' < "$DONE")
 110         total=$(($count+$(grep -c '^[^#]' < "$TODO")))
 111         if test "$last_count" != "$count"
 112         then
 113                 last_count=$count
 114                 printf "Rebasing (%d/%d)\r" $count $total
 115                 test -z "$VERBOSE" || echo
 116         fi
 117 }
 118
 119 make_patch () {
 120         sha1_and_parents="$(git rev-list --parents -1 "$1")"
 121         case "$sha1_and_parents" in
 122         ?*' '?*' '?*)
 123                 git diff --cc $sha1_and_parents
 124                 ;;
 125         ?*' '?*)
 126                 git diff-tree -p "$1^!"
 127                 ;;
 128         *)
 129                 echo "Root commit"
 130                 ;;
 131         esac > "$DOTEST"/patch
 132         test -f "$DOTEST"/message ||
 133                 git cat-file commit "$1" | sed "1,/^$/d" > "$DOTEST"/message
 134         test -f "$DOTEST"/author-script ||
 135                 get_author_ident_from_commit "$1" > "$DOTEST"/author-script
 136 }
 137
 138 die_with_patch () {
 139         make_patch "$1"
 140         git rerere
 141         die "$2"
 142 }
 143
 144 die_abort () {
 145         rm -rf "$DOTEST"
 146         die "$1"
 147 }
 148
 149 has_action () {
 150         grep '^[^#]' "$1" >/dev/null
 151 }
 152
 153 pick_one () {
 154         no_ff=
 155         case "$1" in -n) sha1=$2; no_ff=t ;; *) sha1=$1 ;; esac
 156         output git rev-parse --verify $sha1 || die "Invalid commit name: $sha1"
 157         test -d "$REWRITTEN" &&
 158                 pick_one_preserving_merges "$@" && return
 159         if test ! -z "$REBASE_ROOT"
 160         then
 161                 output git cherry-pick "$@"
 162                 return
 163         fi
 164         parent_sha1=$(git rev-parse --verify $sha1^) ||
 165                 die "Could not get the parent of $sha1"
 166         current_sha1=$(git rev-parse --verify HEAD)
 167         if test "$no_ff$current_sha1" = "$parent_sha1"; then
 168                 output git reset --hard $sha1
 169                 test "a$1" = a-n && output git reset --soft $current_sha1
 170                 sha1=$(git rev-parse --short $sha1)
 171                 output warn Fast forward to $sha1
 172         else
 173                 output git cherry-pick "$@"
 174         fi
 175 }
 176
 177 pick_one_preserving_merges () {
 178         fast_forward=t
 179         case "$1" in
 180         -n)
 181                 fast_forward=f
 182                 sha1=$2
 183                 ;;
 184         *)
 185                 sha1=$1
 186                 ;;
 187         esac
 188         sha1=$(git rev-parse $sha1)
 189
 190         if test -f "$DOTEST"/current-commit
 191         then
 192                 if test "$fast_forward" = t
 193                 then
 194                         cat "$DOTEST"/current-commit | while read current_commit
 195                         do
 196                                 git rev-parse HEAD > "$REWRITTEN"/$current_commit
 197                         done
 198                         rm "$DOTEST"/current-commit ||
 199                         die "Cannot write current commit's replacement sha1"
 200                 fi
 201         fi
 202
 203         echo $sha1 >> "$DOTEST"/current-commit
 204
 205         # rewrite parents; if none were rewritten, we can fast-forward.
 206         new_parents=
 207         pend=" $(git rev-list --parents -1 $sha1 | cut -d' ' -s -f2-)"
 208         if test "$pend" = " "
 209         then
 210                 pend=" root"
 211         fi
 212         while [ "$pend" != "" ]
 213         do
 214                 p=$(expr "$pend" : ' \([^ ]*\)')
 215                 pend="${pend# $p}"
 216
 217                 if test -f "$REWRITTEN"/$p
 218                 then
 219                         new_p=$(cat "$REWRITTEN"/$p)
 220
 221                         # If the todo reordered commits, and our parent is marked for
 222                         # rewriting, but hasn't been gotten to yet, assume the user meant to
 223                         # drop it on top of the current HEAD
 224                         if test -z "$new_p"
 225                         then
 226                                 new_p=$(git rev-parse HEAD)
 227                         fi
 228
 229                         test $p != $new_p && fast_forward=f
 230                         case "$new_parents" in
 231                         *$new_p*)
 232                                 ;; # do nothing; that parent is already there
 233                         *)
 234                                 new_parents="$new_parents $new_p"
 235                                 ;;
 236                         esac
 237                 else
 238                         if test -f "$DROPPED"/$p
 239                         then
 240                                 fast_forward=f
 241                                 replacement="$(cat "$DROPPED"/$p)"
 242                                 test -z "$replacement" && replacement=root
 243                                 pend=" $replacement$pend"
 244                         else
 245                                 new_parents="$new_parents $p"
 246                         fi
 247                 fi
 248         done
 249         case $fast_forward in
 250         t)
 251                 output warn "Fast forward to $sha1"
 252                 output git reset --hard $sha1 ||
 253                         die "Cannot fast forward to $sha1"
 254                 ;;
 255         f)
 256                 first_parent=$(expr "$new_parents" : ' \([^ ]*\)')
 257
 258                 if [ "$1" != "-n" ]
 259                 then
 260                         # detach HEAD to current parent
 261                         output git checkout $first_parent 2> /dev/null ||
 262                                 die "Cannot move HEAD to $first_parent"
 263                 fi
 264
 265                 case "$new_parents" in
 266                 ' '*' '*)
 267                         test "a$1" = a-n && die "Refusing to squash a merge: $sha1"
 268
 269                         # redo merge
 270                         author_script=$(get_author_ident_from_commit $sha1)
 271                         eval "$author_script"
 272                         msg="$(git cat-file commit $sha1 | sed -e '1,/^$/d')"
 273                         # No point in merging the first parent, that's HEAD
 274                         new_parents=${new_parents# $first_parent}
 275                         if ! GIT_AUTHOR_NAME="$GIT_AUTHOR_NAME" \
 276                                 GIT_AUTHOR_EMAIL="$GIT_AUTHOR_EMAIL" \
 277                                 GIT_AUTHOR_DATE="$GIT_AUTHOR_DATE" \
 278                                 output git merge $STRATEGY -m "$msg" \
 279                                         $new_parents
 280                         then
 281                                 printf "%s\n" "$msg" > "$GIT_DIR"/MERGE_MSG
 282                                 die_with_patch $sha1 "Error redoing merge $sha1"
 283                         fi
 284                         ;;
 285                 *)
 286                         output git cherry-pick "$@" ||
 287                                 die_with_patch $sha1 "Could not pick $sha1"
 288                         ;;
 289                 esac
 290                 ;;
 291         esac
 292 }
 293
 294 nth_string () {
 295         case "$1" in
 296         *1[0-9]|*[04-9]) echo "$1"th;;
 297         *1) echo "$1"st;;
 298         *2) echo "$1"nd;;
 299         *3) echo "$1"rd;;
 300         esac
 301 }
 302
 303 make_squash_message () {
 304         if test -f "$SQUASH_MSG"; then
 305                 COUNT=$(($(sed -n "s/^# This is [^0-9]*\([1-9][0-9]*\).*/\1/p" \
 306                         < "$SQUASH_MSG" | sed -ne '$p')+1))
 307                 echo "# This is a combination of $COUNT commits."
 308                 sed -e 1d -e '2,/^./{
 309                         /^$/d
 310                 }' <"$SQUASH_MSG"
 311         else
 312                 COUNT=2
 313                 echo "# This is a combination of two commits."
 314                 echo "# The first commit's message is:"
 315                 echo
 316                 git cat-file commit HEAD | sed -e '1,/^$/d'
 317         fi
 318         echo
 319         echo "# This is the $(nth_string $COUNT) commit message:"
 320         echo
 321         git cat-file commit $1 | sed -e '1,/^$/d'
 322 }
 323
 324 peek_next_command () {
 325         sed -n "1s/ .*$//p" < "$TODO"
 326 }
 327
 328 do_next () {
 329         rm -f "$DOTEST"/message "$DOTEST"/author-script \
 330                 "$DOTEST"/amend || exit
 331         read command sha1 rest < "$TODO"
 332         case "$command" in
 333         '#'*|''|noop)
 334                 mark_action_done
 335                 ;;
 336         pick|p)
 337                 comment_for_reflog pick
 338
 339                 mark_action_done
 340                 pick_one $sha1 ||
 341                         die_with_patch $sha1 "Could not apply $sha1... $rest"
 342                 ;;
 343         edit|e)
 344                 comment_for_reflog edit
 345
 346                 mark_action_done
 347                 pick_one $sha1 ||
 348                         die_with_patch $sha1 "Could not apply $sha1... $rest"
 349                 make_patch $sha1
 350                 git rev-parse --verify HEAD > "$DOTEST"/amend
 351                 warn "Stopped at $sha1... $rest"
 352                 warn "You can amend the commit now, with"
 353                 warn
 354                 warn "  git commit --amend"
 355                 warn
 356                 warn "Once you are satisfied with your changes, run"
 357                 warn
 358                 warn "  git rebase --continue"
 359                 warn
 360                 exit 0
 361                 ;;
 362         squash|s)
 363                 comment_for_reflog squash
 364
 365                 test -f "$DONE" && has_action "$DONE" ||
 366                         die "Cannot 'squash' without a previous commit"
 367
 368                 mark_action_done
 369                 make_squash_message $sha1 > "$MSG"
 370                 failed=f
 371                 author_script=$(get_author_ident_from_commit HEAD)
 372                 output git reset --soft HEAD^
 373                 pick_one -n $sha1 || failed=t
 374                 case "$(peek_next_command)" in
 375                 squash|s)
 376                         USE_OUTPUT=output
 377                         MSG_OPT=-F
 378                         EDIT_OR_FILE="$MSG"
 379                         cp "$MSG" "$SQUASH_MSG"
 380                         ;;
 381                 *)
 382                         USE_OUTPUT=
 383                         MSG_OPT=
 384                         EDIT_OR_FILE=-e
 385                         rm -f "$SQUASH_MSG" || exit
 386                         cp "$MSG" "$GIT_DIR"/SQUASH_MSG
 387                         rm -f "$GIT_DIR"/MERGE_MSG || exit
 388                         ;;
 389                 esac
 390                 echo "$author_script" > "$DOTEST"/author-script
 391                 if test $failed = f
 392                 then
 393                         # This is like --amend, but with a different message
 394                         eval "$author_script"
 395                         GIT_AUTHOR_NAME="$GIT_AUTHOR_NAME" \
 396                         GIT_AUTHOR_EMAIL="$GIT_AUTHOR_EMAIL" \
 397                         GIT_AUTHOR_DATE="$GIT_AUTHOR_DATE" \
 398                         $USE_OUTPUT git commit --no-verify \
 399                                 $MSG_OPT "$EDIT_OR_FILE" || failed=t
 400                 fi
 401                 if test $failed = t
 402                 then
 403                         cp "$MSG" "$GIT_DIR"/MERGE_MSG
 404                         warn
 405                         warn "Could not apply $sha1... $rest"
 406                         die_with_patch $sha1 ""
 407                 fi
 408                 ;;
 409         *)
 410                 warn "Unknown command: $command $sha1 $rest"
 411                 if git rev-parse --verify -q "$sha1" >/dev/null
 412                 then
 413                         die_with_patch $sha1 "Please fix this in the file $TODO."
 414                 else
 415                         die "Please fix this in the file $TODO."
 416                 fi
 417                 ;;
 418         esac
 419         test -s "$TODO" && return
 420
 421         comment_for_reflog finish &&
 422         HEADNAME=$(cat "$DOTEST"/head-name) &&
 423         OLDHEAD=$(cat "$DOTEST"/head) &&
 424         SHORTONTO=$(git rev-parse --short $(cat "$DOTEST"/onto)) &&
 425         NEWHEAD=$(git rev-parse HEAD) &&
 426         case $HEADNAME in
 427         refs/*)
 428                 message="$GIT_REFLOG_ACTION: $HEADNAME onto $SHORTONTO" &&
 429                 git update-ref -m "$message" $HEADNAME $NEWHEAD $OLDHEAD &&
 430                 git symbolic-ref HEAD $HEADNAME
 431                 ;;
 432         esac && {
 433                 test ! -f "$DOTEST"/verbose ||
 434                         git diff-tree --stat $(cat "$DOTEST"/head)..HEAD
 435         } &&
 436         rm -rf "$DOTEST" &&
 437         git gc --auto &&
 438         warn "Successfully rebased and updated $HEADNAME."
 439
 440         exit
 441 }
 442
 443 do_rest () {
 444         while :
 445         do
 446                 do_next
 447         done
 448 }
 449
 450 # skip picking commits whose parents are unchanged
 451 skip_unnecessary_picks () {
 452         fd=3
 453         while read command sha1 rest
 454         do
 455                 # fd=3 means we skip the command
 456                 case "$fd,$command,$(git rev-parse --verify --quiet $sha1^)" in
 457                 3,pick,"$ONTO"*|3,p,"$ONTO"*)
 458                         # pick a commit whose parent is current $ONTO -> skip
 459                         ONTO=$sha1
 460                         ;;
 461                 3,#*|3,,*)
 462                         # copy comments
 463                         ;;
 464                 *)
 465                         fd=1
 466                         ;;
 467                 esac
 468                 echo "$command${sha1:+ }$sha1${rest:+ }$rest" >&$fd
 469         done <"$TODO" >"$TODO.new" 3>>"$DONE" &&
 470         mv -f "$TODO".new "$TODO" ||
 471         die "Could not skip unnecessary pick commands"
 472 }
 473
 474 # check if no other options are set
 475 is_standalone () {
 476         test $# -eq 2 -a "$2" = '--' &&
 477         test -z "$ONTO" &&
 478         test -z "$PRESERVE_MERGES" &&
 479         test -z "$STRATEGY" &&
 480         test -z "$VERBOSE"
 481 }
 482
 483 get_saved_options () {
 484         test -d "$REWRITTEN" && PRESERVE_MERGES=t
 485         test -f "$DOTEST"/strategy && STRATEGY="$(cat "$DOTEST"/strategy)"
 486         test -f "$DOTEST"/verbose && VERBOSE=t
 487         test -f "$DOTEST"/rebase-root && REBASE_ROOT=t
 488 }
 489
 490 while test $# != 0
 491 do
 492         case "$1" in
 493         --no-verify)
 494                 OK_TO_SKIP_PRE_REBASE=yes
 495                 ;;
 496         --verify)
 497                 ;;
 498         --continue)
 499                 is_standalone "$@" || usage
 500                 get_saved_options
 501                 comment_for_reflog continue
 502
 503                 test -d "$DOTEST" || die "No interactive rebase running"
 504
 505                 # Sanity check
 506                 git rev-parse --verify HEAD >/dev/null ||
 507                         die "Cannot read HEAD"
 508                 git update-index --ignore-submodules --refresh &&
 509                         git diff-files --quiet --ignore-submodules ||
 510                         die "Working tree is dirty"
 511
 512                 # do we have anything to commit?
 513                 if git diff-index --cached --quiet --ignore-submodules HEAD --
 514                 then
 515                         : Nothing to commit -- skip this
 516                 else
 517                         . "$DOTEST"/author-script ||
 518                                 die "Cannot find the author identity"
 519                         amend=
 520                         if test -f "$DOTEST"/amend
 521                         then
 522                                 amend=$(git rev-parse --verify HEAD)
 523                                 test "$amend" = $(cat "$DOTEST"/amend) ||
 524                                 die "\
 525 You have uncommitted changes in your working tree. Please, commit them
 526 first and then run 'git rebase --continue' again."
 527                                 git reset --soft HEAD^ ||
 528                                 die "Cannot rewind the HEAD"
 529                         fi
 530                         export GIT_AUTHOR_NAME GIT_AUTHOR_EMAIL GIT_AUTHOR_DATE &&
 531                         git commit --no-verify -F "$DOTEST"/message -e || {
 532                                 test -n "$amend" && git reset --soft $amend
 533                                 die "Could not commit staged changes."
 534                         }
 535                 fi
 536
 537                 require_clean_work_tree
 538                 do_rest
 539                 ;;
 540         --abort)
 541                 is_standalone "$@" || usage
 542                 get_saved_options
 543                 comment_for_reflog abort
 544
 545                 git rerere clear
 546                 test -d "$DOTEST" || die "No interactive rebase running"
 547
 548                 HEADNAME=$(cat "$DOTEST"/head-name)
 549                 HEAD=$(cat "$DOTEST"/head)
 550                 case $HEADNAME in
 551                 refs/*)
 552                         git symbolic-ref HEAD $HEADNAME
 553                         ;;
 554                 esac &&
 555                 output git reset --hard $HEAD &&
 556                 rm -rf "$DOTEST"
 557                 exit
 558                 ;;
 559         --skip)
 560                 is_standalone "$@" || usage
 561                 get_saved_options
 562                 comment_for_reflog skip
 563
 564                 git rerere clear
 565                 test -d "$DOTEST" || die "No interactive rebase running"
 566
 567                 output git reset --hard && do_rest
 568                 ;;
 569         -s)
 570                 case "$#,$1" in
 571                 *,*=*)
 572                         STRATEGY="-s "$(expr "z$1" : 'z-[^=]*=\(.*\)') ;;
 573                 1,*)
 574                         usage ;;
 575                 *)
 576                         STRATEGY="-s $2"
 577                         shift ;;
 578                 esac
 579                 ;;
 580         -m)
 581                 # we use merge anyway
 582                 ;;
 583         -v)
 584                 VERBOSE=t
 585                 ;;
 586         -p)
 587                 PRESERVE_MERGES=t
 588                 ;;
 589         -i)
 590                 # yeah, we know
 591                 ;;
 592         --root)
 593                 REBASE_ROOT=t
 594                 ;;
 595         --onto)
 596                 shift
 597                 ONTO=$(git rev-parse --verify "$1") ||
 598                         die "Does not point to a valid commit: $1"
 599                 ;;
 600         --)
 601                 shift
 602                 test -z "$REBASE_ROOT" -a $# -ge 1 -a $# -le 2 ||
 603                 test ! -z "$REBASE_ROOT" -a $# -le 1 || usage
 604                 test -d "$DOTEST" &&
 605                         die "Interactive rebase already started"
 606
 607                 git var GIT_COMMITTER_IDENT >/dev/null ||
 608                         die "You need to set your committer info first"
 609
 610                 if test -z "$REBASE_ROOT"
 611                 then
 612                         UPSTREAM_ARG="$1"
 613                         UPSTREAM=$(git rev-parse --verify "$1") || die "Invalid base"
 614                         test -z "$ONTO" && ONTO=$UPSTREAM
 615                         shift
 616                 else
 617                         UPSTREAM=
 618                         UPSTREAM_ARG=--root
 619                         test -z "$ONTO" &&
 620                                 die "You must specify --onto when using --root"
 621                 fi
 622                 run_pre_rebase_hook "$UPSTREAM_ARG" "$@"
 623
 624                 comment_for_reflog start
 625
 626                 require_clean_work_tree
 627
 628                 if test ! -z "$1"
 629                 then
 630                         output git show-ref --verify --quiet "refs/heads/$1" ||
 631                                 die "Invalid branchname: $1"
 632                         output git checkout "$1" ||
 633                                 die "Could not checkout $1"
 634                 fi
 635
 636                 HEAD=$(git rev-parse --verify HEAD) || die "No HEAD?"
 637                 mkdir "$DOTEST" || die "Could not create temporary $DOTEST"
 638
 639                 : > "$DOTEST"/interactive || die "Could not mark as interactive"
 640                 git symbolic-ref HEAD > "$DOTEST"/head-name 2> /dev/null ||
 641                         echo "detached HEAD" > "$DOTEST"/head-name
 642
 643                 echo $HEAD > "$DOTEST"/head
 644                 case "$REBASE_ROOT" in
 645                 '')
 646                         rm -f "$DOTEST"/rebase-root ;;
 647                 *)
 648                         : >"$DOTEST"/rebase-root ;;
 649                 esac
 650                 echo $ONTO > "$DOTEST"/onto
 651                 test -z "$STRATEGY" || echo "$STRATEGY" > "$DOTEST"/strategy
 652                 test t = "$VERBOSE" && : > "$DOTEST"/verbose
 653                 if test t = "$PRESERVE_MERGES"
 654                 then
 655                         # $REWRITTEN contains files for each commit that is
 656                         # reachable by at least one merge base of $HEAD and
 657                         # $UPSTREAM. They are not necessarily rewritten, but
 658                         # their children might be.
 659                         # This ensures that commits on merged, but otherwise
 660                         # unrelated side branches are left alone. (Think "X"
 661                         # in the man page's example.)
 662                         if test -z "$REBASE_ROOT"
 663                         then
 664                                 mkdir "$REWRITTEN" &&
 665                                 for c in $(git merge-base --all $HEAD $UPSTREAM)
 666                                 do
 667                                         echo $ONTO > "$REWRITTEN"/$c ||
 668                                                 die "Could not init rewritten commits"
 669                                 done
 670                         else
 671                                 mkdir "$REWRITTEN" &&
 672                                 echo $ONTO > "$REWRITTEN"/root ||
 673                                         die "Could not init rewritten commits"
 674                         fi
 675                         # No cherry-pick because our first pass is to determine
 676                         # parents to rewrite and skipping dropped commits would
 677                         # prematurely end our probe
 678                         MERGES_OPTION=
 679                         first_after_upstream="$(git rev-list --reverse --first-parent $UPSTREAM..$HEAD | head -n 1)"
 680                 else
 681                         MERGES_OPTION="--no-merges --cherry-pick"
 682                 fi
 683
 684                 SHORTHEAD=$(git rev-parse --short $HEAD)
 685                 SHORTONTO=$(git rev-parse --short $ONTO)
 686                 if test -z "$REBASE_ROOT"
 687                         # this is now equivalent to ! -z "$UPSTREAM"
 688                 then
 689                         SHORTUPSTREAM=$(git rev-parse --short $UPSTREAM)
 690                         REVISIONS=$UPSTREAM...$HEAD
 691                         SHORTREVISIONS=$SHORTUPSTREAM..$SHORTHEAD
 692                 else
 693                         REVISIONS=$ONTO...$HEAD
 694                         SHORTREVISIONS=$SHORTHEAD
 695                 fi
 696                 git rev-list $MERGES_OPTION --pretty=oneline --abbrev-commit \
 697                         --abbrev=7 --reverse --left-right --topo-order \
 698                         $REVISIONS | \
 699                         sed -n "s/^>//p" | while read shortsha1 rest
 700                 do
 701                         if test t != "$PRESERVE_MERGES"
 702                         then
 703                                 echo "pick $shortsha1 $rest" >> "$TODO"
 704                         else
 705                                 sha1=$(git rev-parse $shortsha1)
 706                                 if test -z "$REBASE_ROOT"
 707                                 then
 708                                         preserve=t
 709                                         for p in $(git rev-list --parents -1 $sha1 | cut -d' ' -s -f2-)
 710                                         do
 711                                                 if test -f "$REWRITTEN"/$p -a \( $p != $ONTO -o $sha1 = $first_after_upstream \)
 712                                                 then
 713                                                         preserve=f
 714                                                 fi
 715                                         done
 716                                 else
 717                                         preserve=f
 718                                 fi
 719                                 if test f = "$preserve"
 720                                 then
 721                                         touch "$REWRITTEN"/$sha1
 722                                         echo "pick $shortsha1 $rest" >> "$TODO"
 723                                 fi
 724                         fi
 725                 done
 726
 727                 # Watch for commits that been dropped by --cherry-pick
 728                 if test t = "$PRESERVE_MERGES"
 729                 then
 730                         mkdir "$DROPPED"
 731                         # Save all non-cherry-picked changes
 732                         git rev-list $REVISIONS --left-right --cherry-pick | \
 733                                 sed -n "s/^>//p" > "$DOTEST"/not-cherry-picks
 734                         # Now all commits and note which ones are missing in
 735                         # not-cherry-picks and hence being dropped
 736                         git rev-list $REVISIONS |
 737                         while read rev
 738                         do
 739                                 if test -f "$REWRITTEN"/$rev -a "$(grep "$rev" "$DOTEST"/not-cherry-picks)" = ""
 740                                 then
 741                                         # Use -f2 because if rev-list is telling us this commit is
 742                                         # not worthwhile, we don't want to track its multiple heads,
 743                                         # just the history of its first-parent for others that will
 744                                         # be rebasing on top of it
 745                                         git rev-list --parents -1 $rev | cut -d' ' -s -f2 > "$DROPPED"/$rev
 746                                         short=$(git rev-list -1 --abbrev-commit --abbrev=7 $rev)
 747                                         grep -v "^[a-z][a-z]* $short" <"$TODO" > "${TODO}2" ; mv "${TODO}2" "$TODO"
 748                                         rm "$REWRITTEN"/$rev
 749                                 fi
 750                         done
 751                 fi
 752
 753                 test -s "$TODO" || echo noop >> "$TODO"
 754                 cat >> "$TODO" << EOF
 755
 756 # Rebase $SHORTREVISIONS onto $SHORTONTO
 757 #
 758 # Commands:
 759 #  p, pick = use commit
 760 #  e, edit = use commit, but stop for amending
 761 #  s, squash = use commit, but meld into previous commit
 762 #
 763 # If you remove a line here THAT COMMIT WILL BE LOST.
 764 # However, if you remove everything, the rebase will be aborted.
 765 #
 766 EOF
 767
 768                 has_action "$TODO" ||
 769                         die_abort "Nothing to do"
 770
 771                 cp "$TODO" "$TODO".backup
 772                 git_editor "$TODO" ||
 773                         die "Could not execute editor"
 774
 775                 has_action "$TODO" ||
 776                         die_abort "Nothing to do"
 777
 778                 test -d "$REWRITTEN" || skip_unnecessary_picks
 779
 780                 git update-ref ORIG_HEAD $HEAD
 781                 output git checkout $ONTO && do_rest
 782                 ;;
 783         esac
 784         shift
 785 done