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 "$TODO"
 109         count=$(sane_grep -c '^[^#]' < "$DONE")
 110         total=$(($count+$(sane_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         sane_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         reword|r)
 344                 comment_for_reflog reword
 345
 346                 mark_action_done
 347                 pick_one $sha1 ||
 348                         die_with_patch $sha1 "Could not apply $sha1... $rest"
 349                 git commit --amend
 350                 ;;
 351         edit|e)
 352                 comment_for_reflog edit
 353
 354                 mark_action_done
 355                 pick_one $sha1 ||
 356                         die_with_patch $sha1 "Could not apply $sha1... $rest"
 357                 make_patch $sha1
 358                 git rev-parse --verify HEAD > "$DOTEST"/amend
 359                 warn "Stopped at $sha1... $rest"
 360                 warn "You can amend the commit now, with"
 361                 warn
 362                 warn "  git commit --amend"
 363                 warn
 364                 warn "Once you are satisfied with your changes, run"
 365                 warn
 366                 warn "  git rebase --continue"
 367                 warn
 368                 exit 0
 369                 ;;
 370         squash|s)
 371                 comment_for_reflog squash
 372
 373                 test -f "$DONE" && has_action "$DONE" ||
 374                         die "Cannot 'squash' without a previous commit"
 375
 376                 mark_action_done
 377                 make_squash_message $sha1 > "$MSG"
 378                 failed=f
 379                 author_script=$(get_author_ident_from_commit HEAD)
 380                 output git reset --soft HEAD^
 381                 pick_one -n $sha1 || failed=t
 382                 case "$(peek_next_command)" in
 383                 squash|s)
 384                         USE_OUTPUT=output
 385                         MSG_OPT=-F
 386                         EDIT_OR_FILE="$MSG"
 387                         cp "$MSG" "$SQUASH_MSG"
 388                         ;;
 389                 *)
 390                         USE_OUTPUT=
 391                         MSG_OPT=
 392                         EDIT_OR_FILE=-e
 393                         rm -f "$SQUASH_MSG" || exit
 394                         cp "$MSG" "$GIT_DIR"/SQUASH_MSG
 395                         rm -f "$GIT_DIR"/MERGE_MSG || exit
 396                         ;;
 397                 esac
 398                 echo "$author_script" > "$DOTEST"/author-script
 399                 if test $failed = f
 400                 then
 401                         # This is like --amend, but with a different message
 402                         eval "$author_script"
 403                         GIT_AUTHOR_NAME="$GIT_AUTHOR_NAME" \
 404                         GIT_AUTHOR_EMAIL="$GIT_AUTHOR_EMAIL" \
 405                         GIT_AUTHOR_DATE="$GIT_AUTHOR_DATE" \
 406                         $USE_OUTPUT git commit --no-verify \
 407                                 $MSG_OPT "$EDIT_OR_FILE" || failed=t
 408                 fi
 409                 if test $failed = t
 410                 then
 411                         cp "$MSG" "$GIT_DIR"/MERGE_MSG
 412                         warn
 413                         warn "Could not apply $sha1... $rest"
 414                         die_with_patch $sha1 ""
 415                 fi
 416                 ;;
 417         *)
 418                 warn "Unknown command: $command $sha1 $rest"
 419                 if git rev-parse --verify -q "$sha1" >/dev/null
 420                 then
 421                         die_with_patch $sha1 "Please fix this in the file $TODO."
 422                 else
 423                         die "Please fix this in the file $TODO."
 424                 fi
 425                 ;;
 426         esac
 427         test -s "$TODO" && return
 428
 429         comment_for_reflog finish &&
 430         HEADNAME=$(cat "$DOTEST"/head-name) &&
 431         OLDHEAD=$(cat "$DOTEST"/head) &&
 432         SHORTONTO=$(git rev-parse --short $(cat "$DOTEST"/onto)) &&
 433         NEWHEAD=$(git rev-parse HEAD) &&
 434         case $HEADNAME in
 435         refs/*)
 436                 message="$GIT_REFLOG_ACTION: $HEADNAME onto $SHORTONTO" &&
 437                 git update-ref -m "$message" $HEADNAME $NEWHEAD $OLDHEAD &&
 438                 git symbolic-ref HEAD $HEADNAME
 439                 ;;
 440         esac && {
 441                 test ! -f "$DOTEST"/verbose ||
 442                         git diff-tree --stat $(cat "$DOTEST"/head)..HEAD
 443         } &&
 444         rm -rf "$DOTEST" &&
 445         git gc --auto &&
 446         warn "Successfully rebased and updated $HEADNAME."
 447
 448         exit
 449 }
 450
 451 do_rest () {
 452         while :
 453         do
 454                 do_next
 455         done
 456 }
 457
 458 # skip picking commits whose parents are unchanged
 459 skip_unnecessary_picks () {
 460         fd=3
 461         while read command sha1 rest
 462         do
 463                 # fd=3 means we skip the command
 464                 case "$fd,$command,$(git rev-parse --verify --quiet $sha1^)" in
 465                 3,pick,"$ONTO"*|3,p,"$ONTO"*)
 466                         # pick a commit whose parent is current $ONTO -> skip
 467                         ONTO=$sha1
 468                         ;;
 469                 3,#*|3,,*)
 470                         # copy comments
 471                         ;;
 472                 *)
 473                         fd=1
 474                         ;;
 475                 esac
 476                 echo "$command${sha1:+ }$sha1${rest:+ }$rest" >&$fd
 477         done <"$TODO" >"$TODO.new" 3>>"$DONE" &&
 478         mv -f "$TODO".new "$TODO" ||
 479         die "Could not skip unnecessary pick commands"
 480 }
 481
 482 # check if no other options are set
 483 is_standalone () {
 484         test $# -eq 2 -a "$2" = '--' &&
 485         test -z "$ONTO" &&
 486         test -z "$PRESERVE_MERGES" &&
 487         test -z "$STRATEGY" &&
 488         test -z "$VERBOSE"
 489 }
 490
 491 get_saved_options () {
 492         test -d "$REWRITTEN" && PRESERVE_MERGES=t
 493         test -f "$DOTEST"/strategy && STRATEGY="$(cat "$DOTEST"/strategy)"
 494         test -f "$DOTEST"/verbose && VERBOSE=t
 495         test -f "$DOTEST"/rebase-root && REBASE_ROOT=t
 496 }
 497
 498 while test $# != 0
 499 do
 500         case "$1" in
 501         --no-verify)
 502                 OK_TO_SKIP_PRE_REBASE=yes
 503                 ;;
 504         --verify)
 505                 ;;
 506         --continue)
 507                 is_standalone "$@" || usage
 508                 get_saved_options
 509                 comment_for_reflog continue
 510
 511                 test -d "$DOTEST" || die "No interactive rebase running"
 512
 513                 # Sanity check
 514                 git rev-parse --verify HEAD >/dev/null ||
 515                         die "Cannot read HEAD"
 516                 git update-index --ignore-submodules --refresh &&
 517                         git diff-files --quiet --ignore-submodules ||
 518                         die "Working tree is dirty"
 519
 520                 # do we have anything to commit?
 521                 if git diff-index --cached --quiet --ignore-submodules HEAD --
 522                 then
 523                         : Nothing to commit -- skip this
 524                 else
 525                         . "$DOTEST"/author-script ||
 526                                 die "Cannot find the author identity"
 527                         amend=
 528                         if test -f "$DOTEST"/amend
 529                         then
 530                                 amend=$(git rev-parse --verify HEAD)
 531                                 test "$amend" = $(cat "$DOTEST"/amend) ||
 532                                 die "\
 533 You have uncommitted changes in your working tree. Please, commit them
 534 first and then run 'git rebase --continue' again."
 535                                 git reset --soft HEAD^ ||
 536                                 die "Cannot rewind the HEAD"
 537                         fi
 538                         export GIT_AUTHOR_NAME GIT_AUTHOR_EMAIL GIT_AUTHOR_DATE &&
 539                         git commit --no-verify -F "$DOTEST"/message -e || {
 540                                 test -n "$amend" && git reset --soft $amend
 541                                 die "Could not commit staged changes."
 542                         }
 543                 fi
 544
 545                 require_clean_work_tree
 546                 do_rest
 547                 ;;
 548         --abort)
 549                 is_standalone "$@" || usage
 550                 get_saved_options
 551                 comment_for_reflog abort
 552
 553                 git rerere clear
 554                 test -d "$DOTEST" || die "No interactive rebase running"
 555
 556                 HEADNAME=$(cat "$DOTEST"/head-name)
 557                 HEAD=$(cat "$DOTEST"/head)
 558                 case $HEADNAME in
 559                 refs/*)
 560                         git symbolic-ref HEAD $HEADNAME
 561                         ;;
 562                 esac &&
 563                 output git reset --hard $HEAD &&
 564                 rm -rf "$DOTEST"
 565                 exit
 566                 ;;
 567         --skip)
 568                 is_standalone "$@" || usage
 569                 get_saved_options
 570                 comment_for_reflog skip
 571
 572                 git rerere clear
 573                 test -d "$DOTEST" || die "No interactive rebase running"
 574
 575                 output git reset --hard && do_rest
 576                 ;;
 577         -s)
 578                 case "$#,$1" in
 579                 *,*=*)
 580                         STRATEGY="-s "$(expr "z$1" : 'z-[^=]*=\(.*\)') ;;
 581                 1,*)
 582                         usage ;;
 583                 *)
 584                         STRATEGY="-s $2"
 585                         shift ;;
 586                 esac
 587                 ;;
 588         -m)
 589                 # we use merge anyway
 590                 ;;
 591         -v)
 592                 VERBOSE=t
 593                 ;;
 594         -p)
 595                 PRESERVE_MERGES=t
 596                 ;;
 597         -i)
 598                 # yeah, we know
 599                 ;;
 600         --root)
 601                 REBASE_ROOT=t
 602                 ;;
 603         --onto)
 604                 shift
 605                 ONTO=$(git rev-parse --verify "$1") ||
 606                         die "Does not point to a valid commit: $1"
 607                 ;;
 608         --)
 609                 shift
 610                 test -z "$REBASE_ROOT" -a $# -ge 1 -a $# -le 2 ||
 611                 test ! -z "$REBASE_ROOT" -a $# -le 1 || usage
 612                 test -d "$DOTEST" &&
 613                         die "Interactive rebase already started"
 614
 615                 git var GIT_COMMITTER_IDENT >/dev/null ||
 616                         die "You need to set your committer info first"
 617
 618                 if test -z "$REBASE_ROOT"
 619                 then
 620                         UPSTREAM_ARG="$1"
 621                         UPSTREAM=$(git rev-parse --verify "$1") || die "Invalid base"
 622                         test -z "$ONTO" && ONTO=$UPSTREAM
 623                         shift
 624                 else
 625                         UPSTREAM=
 626                         UPSTREAM_ARG=--root
 627                         test -z "$ONTO" &&
 628                                 die "You must specify --onto when using --root"
 629                 fi
 630                 run_pre_rebase_hook "$UPSTREAM_ARG" "$@"
 631
 632                 comment_for_reflog start
 633
 634                 require_clean_work_tree
 635
 636                 if test ! -z "$1"
 637                 then
 638                         output git show-ref --verify --quiet "refs/heads/$1" ||
 639                                 die "Invalid branchname: $1"
 640                         output git checkout "$1" ||
 641                                 die "Could not checkout $1"
 642                 fi
 643
 644                 HEAD=$(git rev-parse --verify HEAD) || die "No HEAD?"
 645                 mkdir "$DOTEST" || die "Could not create temporary $DOTEST"
 646
 647                 : > "$DOTEST"/interactive || die "Could not mark as interactive"
 648                 git symbolic-ref HEAD > "$DOTEST"/head-name 2> /dev/null ||
 649                         echo "detached HEAD" > "$DOTEST"/head-name
 650
 651                 echo $HEAD > "$DOTEST"/head
 652                 case "$REBASE_ROOT" in
 653                 '')
 654                         rm -f "$DOTEST"/rebase-root ;;
 655                 *)
 656                         : >"$DOTEST"/rebase-root ;;
 657                 esac
 658                 echo $ONTO > "$DOTEST"/onto
 659                 test -z "$STRATEGY" || echo "$STRATEGY" > "$DOTEST"/strategy
 660                 test t = "$VERBOSE" && : > "$DOTEST"/verbose
 661                 if test t = "$PRESERVE_MERGES"
 662                 then
 663                         # $REWRITTEN contains files for each commit that is
 664                         # reachable by at least one merge base of $HEAD and
 665                         # $UPSTREAM. They are not necessarily rewritten, but
 666                         # their children might be.
 667                         # This ensures that commits on merged, but otherwise
 668                         # unrelated side branches are left alone. (Think "X"
 669                         # in the man page's example.)
 670                         if test -z "$REBASE_ROOT"
 671                         then
 672                                 mkdir "$REWRITTEN" &&
 673                                 for c in $(git merge-base --all $HEAD $UPSTREAM)
 674                                 do
 675                                         echo $ONTO > "$REWRITTEN"/$c ||
 676                                                 die "Could not init rewritten commits"
 677                                 done
 678                         else
 679                                 mkdir "$REWRITTEN" &&
 680                                 echo $ONTO > "$REWRITTEN"/root ||
 681                                         die "Could not init rewritten commits"
 682                         fi
 683                         # No cherry-pick because our first pass is to determine
 684                         # parents to rewrite and skipping dropped commits would
 685                         # prematurely end our probe
 686                         MERGES_OPTION=
 687                         first_after_upstream="$(git rev-list --reverse --first-parent $UPSTREAM..$HEAD | head -n 1)"
 688                 else
 689                         MERGES_OPTION="--no-merges --cherry-pick"
 690                 fi
 691
 692                 SHORTHEAD=$(git rev-parse --short $HEAD)
 693                 SHORTONTO=$(git rev-parse --short $ONTO)
 694                 if test -z "$REBASE_ROOT"
 695                         # this is now equivalent to ! -z "$UPSTREAM"
 696                 then
 697                         SHORTUPSTREAM=$(git rev-parse --short $UPSTREAM)
 698                         REVISIONS=$UPSTREAM...$HEAD
 699                         SHORTREVISIONS=$SHORTUPSTREAM..$SHORTHEAD
 700                 else
 701                         REVISIONS=$ONTO...$HEAD
 702                         SHORTREVISIONS=$SHORTHEAD
 703                 fi
 704                 git rev-list $MERGES_OPTION --pretty=oneline --abbrev-commit \
 705                         --abbrev=7 --reverse --left-right --topo-order \
 706                         $REVISIONS | \
 707                         sed -n "s/^>//p" | while read shortsha1 rest
 708                 do
 709                         if test t != "$PRESERVE_MERGES"
 710                         then
 711                                 echo "pick $shortsha1 $rest" >> "$TODO"
 712                         else
 713                                 sha1=$(git rev-parse $shortsha1)
 714                                 if test -z "$REBASE_ROOT"
 715                                 then
 716                                         preserve=t
 717                                         for p in $(git rev-list --parents -1 $sha1 | cut -d' ' -s -f2-)
 718                                         do
 719                                                 if test -f "$REWRITTEN"/$p -a \( $p != $ONTO -o $sha1 = $first_after_upstream \)
 720                                                 then
 721                                                         preserve=f
 722                                                 fi
 723                                         done
 724                                 else
 725                                         preserve=f
 726                                 fi
 727                                 if test f = "$preserve"
 728                                 then
 729                                         touch "$REWRITTEN"/$sha1
 730                                         echo "pick $shortsha1 $rest" >> "$TODO"
 731                                 fi
 732                         fi
 733                 done
 734
 735                 # Watch for commits that been dropped by --cherry-pick
 736                 if test t = "$PRESERVE_MERGES"
 737                 then
 738                         mkdir "$DROPPED"
 739                         # Save all non-cherry-picked changes
 740                         git rev-list $REVISIONS --left-right --cherry-pick | \
 741                                 sed -n "s/^>//p" > "$DOTEST"/not-cherry-picks
 742                         # Now all commits and note which ones are missing in
 743                         # not-cherry-picks and hence being dropped
 744                         git rev-list $REVISIONS |
 745                         while read rev
 746                         do
 747                                 if test -f "$REWRITTEN"/$rev -a "$(sane_grep "$rev" "$DOTEST"/not-cherry-picks)" = ""
 748                                 then
 749                                         # Use -f2 because if rev-list is telling us this commit is
 750                                         # not worthwhile, we don't want to track its multiple heads,
 751                                         # just the history of its first-parent for others that will
 752                                         # be rebasing on top of it
 753                                         git rev-list --parents -1 $rev | cut -d' ' -s -f2 > "$DROPPED"/$rev
 754                                         short=$(git rev-list -1 --abbrev-commit --abbrev=7 $rev)
 755                                         sane_grep -v "^[a-z][a-z]* $short" <"$TODO" > "${TODO}2" ; mv "${TODO}2" "$TODO"
 756                                         rm "$REWRITTEN"/$rev
 757                                 fi
 758                         done
 759                 fi
 760
 761                 test -s "$TODO" || echo noop >> "$TODO"
 762                 cat >> "$TODO" << EOF
 763
 764 # Rebase $SHORTREVISIONS onto $SHORTONTO
 765 #
 766 # Commands:
 767 #  p, pick = use commit
 768 #  r, reword = use commit, but edit the commit message
 769 #  e, edit = use commit, but stop for amending
 770 #  s, squash = use commit, but meld into previous commit
 771 #
 772 # If you remove a line here THAT COMMIT WILL BE LOST.
 773 # However, if you remove everything, the rebase will be aborted.
 774 #
 775 EOF
 776
 777                 has_action "$TODO" ||
 778                         die_abort "Nothing to do"
 779
 780                 cp "$TODO" "$TODO".backup
 781                 git_editor "$TODO" ||
 782                         die_abort "Could not execute editor"
 783
 784                 has_action "$TODO" ||
 785                         die_abort "Nothing to do"
 786
 787                 test -d "$REWRITTEN" || skip_unnecessary_picks
 788
 789                 git update-ref ORIG_HEAD $HEAD
 790                 output git checkout $ONTO && do_rest
 791                 ;;
 792         esac
 793         shift
 794 done