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 -z "$no_ff" -a "$current_sha1" = "$parent_sha1"
 168         then
 169                 output git reset --hard $sha1
 170                 output warn Fast-forward to $(git rev-parse --short $sha1)
 171         else
 172                 output git cherry-pick "$@"
 173         fi
 174 }
 175
 176 pick_one_preserving_merges () {
 177         fast_forward=t
 178         case "$1" in
 179         -n)
 180                 fast_forward=f
 181                 sha1=$2
 182                 ;;
 183         *)
 184                 sha1=$1
 185                 ;;
 186         esac
 187         sha1=$(git rev-parse $sha1)
 188
 189         if test -f "$DOTEST"/current-commit
 190         then
 191                 if test "$fast_forward" = t
 192                 then
 193                         cat "$DOTEST"/current-commit | while read current_commit
 194                         do
 195                                 git rev-parse HEAD > "$REWRITTEN"/$current_commit
 196                         done
 197                         rm "$DOTEST"/current-commit ||
 198                         die "Cannot write current commit's replacement sha1"
 199                 fi
 200         fi
 201
 202         echo $sha1 >> "$DOTEST"/current-commit
 203
 204         # rewrite parents; if none were rewritten, we can fast-forward.
 205         new_parents=
 206         pend=" $(git rev-list --parents -1 $sha1 | cut -d' ' -s -f2-)"
 207         if test "$pend" = " "
 208         then
 209                 pend=" root"
 210         fi
 211         while [ "$pend" != "" ]
 212         do
 213                 p=$(expr "$pend" : ' \([^ ]*\)')
 214                 pend="${pend# $p}"
 215
 216                 if test -f "$REWRITTEN"/$p
 217                 then
 218                         new_p=$(cat "$REWRITTEN"/$p)
 219
 220                         # If the todo reordered commits, and our parent is marked for
 221                         # rewriting, but hasn't been gotten to yet, assume the user meant to
 222                         # drop it on top of the current HEAD
 223                         if test -z "$new_p"
 224                         then
 225                                 new_p=$(git rev-parse HEAD)
 226                         fi
 227
 228                         test $p != $new_p && fast_forward=f
 229                         case "$new_parents" in
 230                         *$new_p*)
 231                                 ;; # do nothing; that parent is already there
 232                         *)
 233                                 new_parents="$new_parents $new_p"
 234                                 ;;
 235                         esac
 236                 else
 237                         if test -f "$DROPPED"/$p
 238                         then
 239                                 fast_forward=f
 240                                 replacement="$(cat "$DROPPED"/$p)"
 241                                 test -z "$replacement" && replacement=root
 242                                 pend=" $replacement$pend"
 243                         else
 244                                 new_parents="$new_parents $p"
 245                         fi
 246                 fi
 247         done
 248         case $fast_forward in
 249         t)
 250                 output warn "Fast-forward to $sha1"
 251                 output git reset --hard $sha1 ||
 252                         die "Cannot fast-forward to $sha1"
 253                 ;;
 254         f)
 255                 first_parent=$(expr "$new_parents" : ' \([^ ]*\)')
 256
 257                 if [ "$1" != "-n" ]
 258                 then
 259                         # detach HEAD to current parent
 260                         output git checkout $first_parent 2> /dev/null ||
 261                                 die "Cannot move HEAD to $first_parent"
 262                 fi
 263
 264                 case "$new_parents" in
 265                 ' '*' '*)
 266                         test "a$1" = a-n && die "Refusing to squash a merge: $sha1"
 267
 268                         # redo merge
 269                         author_script=$(get_author_ident_from_commit $sha1)
 270                         eval "$author_script"
 271                         msg="$(git cat-file commit $sha1 | sed -e '1,/^$/d')"
 272                         # No point in merging the first parent, that's HEAD
 273                         new_parents=${new_parents# $first_parent}
 274                         if ! GIT_AUTHOR_NAME="$GIT_AUTHOR_NAME" \
 275                                 GIT_AUTHOR_EMAIL="$GIT_AUTHOR_EMAIL" \
 276                                 GIT_AUTHOR_DATE="$GIT_AUTHOR_DATE" \
 277                                 output git merge $STRATEGY -m "$msg" \
 278                                         $new_parents
 279                         then
 280                                 printf "%s\n" "$msg" > "$GIT_DIR"/MERGE_MSG
 281                                 die_with_patch $sha1 "Error redoing merge $sha1"
 282                         fi
 283                         ;;
 284                 *)
 285                         output git cherry-pick "$@" ||
 286                                 die_with_patch $sha1 "Could not pick $sha1"
 287                         ;;
 288                 esac
 289                 ;;
 290         esac
 291 }
 292
 293 nth_string () {
 294         case "$1" in
 295         *1[0-9]|*[04-9]) echo "$1"th;;
 296         *1) echo "$1"st;;
 297         *2) echo "$1"nd;;
 298         *3) echo "$1"rd;;
 299         esac
 300 }
 301
 302 make_squash_message () {
 303         if test -f "$SQUASH_MSG"; then
 304                 # We want to be careful about matching only the commit
 305                 # message comment lines generated by this function.
 306                 # "[snrt][tdh]" matches the nth_string endings.
 307                 COUNT=$(($(sed -n "s/^# Th[^0-9]*\([1-9][0-9]*\)[snrt][tdh] commit message.*:/\1/p" \
 308                         < "$SQUASH_MSG" | sed -ne '$p')+1))
 309                 echo "# This is a combination of $COUNT commits."
 310                 sed -e 1d -e '2,/^./{
 311                         /^$/d
 312                 }' <"$SQUASH_MSG"
 313         else
 314                 COUNT=2
 315                 echo "# This is a combination of two commits."
 316                 echo "# The first commit's message is:"
 317                 echo
 318                 git cat-file commit HEAD | sed -e '1,/^$/d'
 319         fi
 320         case $1 in
 321         squash)
 322                 echo
 323                 echo "# This is the $(nth_string $COUNT) commit message:"
 324                 echo
 325                 git cat-file commit $2 | sed -e '1,/^$/d'
 326                 ;;
 327         fixup)
 328                 echo
 329                 echo "# The $(nth_string $COUNT) commit message will be skipped:"
 330                 echo
 331                 # Comment the lines of the commit message out using
 332                 # "#    " rather than "# " to make them less likely to
 333                 # confuse the sed regexp above.
 334                 git cat-file commit $2 | sed -e '1,/^$/d' -e 's/^/#     /'
 335                 ;;
 336         esac
 337 }
 338
 339 peek_next_command () {
 340         sed -n -e "/^#/d" -e "/^$/d" -e "s/ .*//p" -e "q" < "$TODO"
 341 }
 342
 343 do_next () {
 344         rm -f "$DOTEST"/message "$DOTEST"/author-script \
 345                 "$DOTEST"/amend || exit
 346         read command sha1 rest < "$TODO"
 347         case "$command" in
 348         '#'*|''|noop)
 349                 mark_action_done
 350                 ;;
 351         pick|p)
 352                 comment_for_reflog pick
 353
 354                 mark_action_done
 355                 pick_one $sha1 ||
 356                         die_with_patch $sha1 "Could not apply $sha1... $rest"
 357                 ;;
 358         reword|r)
 359                 comment_for_reflog reword
 360
 361                 mark_action_done
 362                 pick_one $sha1 ||
 363                         die_with_patch $sha1 "Could not apply $sha1... $rest"
 364                 git commit --amend
 365                 ;;
 366         edit|e)
 367                 comment_for_reflog edit
 368
 369                 mark_action_done
 370                 pick_one $sha1 ||
 371                         die_with_patch $sha1 "Could not apply $sha1... $rest"
 372                 make_patch $sha1
 373                 git rev-parse --verify HEAD > "$DOTEST"/amend
 374                 warn "Stopped at $sha1... $rest"
 375                 warn "You can amend the commit now, with"
 376                 warn
 377                 warn "  git commit --amend"
 378                 warn
 379                 warn "Once you are satisfied with your changes, run"
 380                 warn
 381                 warn "  git rebase --continue"
 382                 warn
 383                 exit 0
 384                 ;;
 385         squash|s|fixup|f)
 386                 case "$command" in
 387                 squash|s)
 388                         squash_style=squash
 389                         ;;
 390                 fixup|f)
 391                         squash_style=fixup
 392                         ;;
 393                 esac
 394                 comment_for_reflog $squash_style
 395
 396                 test -f "$DONE" && has_action "$DONE" ||
 397                         die "Cannot '$squash_style' without a previous commit"
 398
 399                 mark_action_done
 400                 make_squash_message $squash_style $sha1 > "$MSG"
 401                 failed=f
 402                 author_script=$(get_author_ident_from_commit HEAD)
 403                 output git reset --soft HEAD^
 404                 pick_one -n $sha1 || failed=t
 405                 case "$(peek_next_command)" in
 406                 squash|s|fixup|f)
 407                         USE_OUTPUT=output
 408                         MSG_OPT=-F
 409                         EDIT_OR_FILE="$MSG"
 410                         cp "$MSG" "$SQUASH_MSG"
 411                         ;;
 412                 *)
 413                         USE_OUTPUT=
 414                         MSG_OPT=
 415                         EDIT_OR_FILE=-e
 416                         rm -f "$SQUASH_MSG" || exit
 417                         cp "$MSG" "$GIT_DIR"/SQUASH_MSG
 418                         rm -f "$GIT_DIR"/MERGE_MSG || exit
 419                         ;;
 420                 esac
 421                 echo "$author_script" > "$DOTEST"/author-script
 422                 if test $failed = f
 423                 then
 424                         # This is like --amend, but with a different message
 425                         eval "$author_script"
 426                         GIT_AUTHOR_NAME="$GIT_AUTHOR_NAME" \
 427                         GIT_AUTHOR_EMAIL="$GIT_AUTHOR_EMAIL" \
 428                         GIT_AUTHOR_DATE="$GIT_AUTHOR_DATE" \
 429                         $USE_OUTPUT git commit --no-verify \
 430                                 $MSG_OPT "$EDIT_OR_FILE" || failed=t
 431                 fi
 432                 if test $failed = t
 433                 then
 434                         cp "$MSG" "$GIT_DIR"/MERGE_MSG
 435                         warn
 436                         warn "Could not apply $sha1... $rest"
 437                         die_with_patch $sha1 ""
 438                 fi
 439                 ;;
 440         *)
 441                 warn "Unknown command: $command $sha1 $rest"
 442                 if git rev-parse --verify -q "$sha1" >/dev/null
 443                 then
 444                         die_with_patch $sha1 "Please fix this in the file $TODO."
 445                 else
 446                         die "Please fix this in the file $TODO."
 447                 fi
 448                 ;;
 449         esac
 450         test -s "$TODO" && return
 451
 452         comment_for_reflog finish &&
 453         HEADNAME=$(cat "$DOTEST"/head-name) &&
 454         OLDHEAD=$(cat "$DOTEST"/head) &&
 455         SHORTONTO=$(git rev-parse --short $(cat "$DOTEST"/onto)) &&
 456         NEWHEAD=$(git rev-parse HEAD) &&
 457         case $HEADNAME in
 458         refs/*)
 459                 message="$GIT_REFLOG_ACTION: $HEADNAME onto $SHORTONTO" &&
 460                 git update-ref -m "$message" $HEADNAME $NEWHEAD $OLDHEAD &&
 461                 git symbolic-ref HEAD $HEADNAME
 462                 ;;
 463         esac && {
 464                 test ! -f "$DOTEST"/verbose ||
 465                         git diff-tree --stat $(cat "$DOTEST"/head)..HEAD
 466         } &&
 467         rm -rf "$DOTEST" &&
 468         git gc --auto &&
 469         warn "Successfully rebased and updated $HEADNAME."
 470
 471         exit
 472 }
 473
 474 do_rest () {
 475         while :
 476         do
 477                 do_next
 478         done
 479 }
 480
 481 # skip picking commits whose parents are unchanged
 482 skip_unnecessary_picks () {
 483         fd=3
 484         while read command sha1 rest
 485         do
 486                 # fd=3 means we skip the command
 487                 case "$fd,$command,$(git rev-parse --verify --quiet $sha1^)" in
 488                 3,pick,"$ONTO"*|3,p,"$ONTO"*)
 489                         # pick a commit whose parent is current $ONTO -> skip
 490                         ONTO=$sha1
 491                         ;;
 492                 3,#*|3,,*)
 493                         # copy comments
 494                         ;;
 495                 *)
 496                         fd=1
 497                         ;;
 498                 esac
 499                 echo "$command${sha1:+ }$sha1${rest:+ }$rest" >&$fd
 500         done <"$TODO" >"$TODO.new" 3>>"$DONE" &&
 501         mv -f "$TODO".new "$TODO" ||
 502         die "Could not skip unnecessary pick commands"
 503 }
 504
 505 # check if no other options are set
 506 is_standalone () {
 507         test $# -eq 2 -a "$2" = '--' &&
 508         test -z "$ONTO" &&
 509         test -z "$PRESERVE_MERGES" &&
 510         test -z "$STRATEGY" &&
 511         test -z "$VERBOSE"
 512 }
 513
 514 get_saved_options () {
 515         test -d "$REWRITTEN" && PRESERVE_MERGES=t
 516         test -f "$DOTEST"/strategy && STRATEGY="$(cat "$DOTEST"/strategy)"
 517         test -f "$DOTEST"/verbose && VERBOSE=t
 518         test -f "$DOTEST"/rebase-root && REBASE_ROOT=t
 519 }
 520
 521 while test $# != 0
 522 do
 523         case "$1" in
 524         --no-verify)
 525                 OK_TO_SKIP_PRE_REBASE=yes
 526                 ;;
 527         --verify)
 528                 ;;
 529         --continue)
 530                 is_standalone "$@" || usage
 531                 get_saved_options
 532                 comment_for_reflog continue
 533
 534                 test -d "$DOTEST" || die "No interactive rebase running"
 535
 536                 # Sanity check
 537                 git rev-parse --verify HEAD >/dev/null ||
 538                         die "Cannot read HEAD"
 539                 git update-index --ignore-submodules --refresh &&
 540                         git diff-files --quiet --ignore-submodules ||
 541                         die "Working tree is dirty"
 542
 543                 # do we have anything to commit?
 544                 if git diff-index --cached --quiet --ignore-submodules HEAD --
 545                 then
 546                         : Nothing to commit -- skip this
 547                 else
 548                         . "$DOTEST"/author-script ||
 549                                 die "Cannot find the author identity"
 550                         amend=
 551                         if test -f "$DOTEST"/amend
 552                         then
 553                                 amend=$(git rev-parse --verify HEAD)
 554                                 test "$amend" = $(cat "$DOTEST"/amend) ||
 555                                 die "\
 556 You have uncommitted changes in your working tree. Please, commit them
 557 first and then run 'git rebase --continue' again."
 558                                 git reset --soft HEAD^ ||
 559                                 die "Cannot rewind the HEAD"
 560                         fi
 561                         export GIT_AUTHOR_NAME GIT_AUTHOR_EMAIL GIT_AUTHOR_DATE &&
 562                         git commit --no-verify -F "$DOTEST"/message -e || {
 563                                 test -n "$amend" && git reset --soft $amend
 564                                 die "Could not commit staged changes."
 565                         }
 566                 fi
 567
 568                 require_clean_work_tree
 569                 do_rest
 570                 ;;
 571         --abort)
 572                 is_standalone "$@" || usage
 573                 get_saved_options
 574                 comment_for_reflog abort
 575
 576                 git rerere clear
 577                 test -d "$DOTEST" || die "No interactive rebase running"
 578
 579                 HEADNAME=$(cat "$DOTEST"/head-name)
 580                 HEAD=$(cat "$DOTEST"/head)
 581                 case $HEADNAME in
 582                 refs/*)
 583                         git symbolic-ref HEAD $HEADNAME
 584                         ;;
 585                 esac &&
 586                 output git reset --hard $HEAD &&
 587                 rm -rf "$DOTEST"
 588                 exit
 589                 ;;
 590         --skip)
 591                 is_standalone "$@" || usage
 592                 get_saved_options
 593                 comment_for_reflog skip
 594
 595                 git rerere clear
 596                 test -d "$DOTEST" || die "No interactive rebase running"
 597
 598                 output git reset --hard && do_rest
 599                 ;;
 600         -s)
 601                 case "$#,$1" in
 602                 *,*=*)
 603                         STRATEGY="-s "$(expr "z$1" : 'z-[^=]*=\(.*\)') ;;
 604                 1,*)
 605                         usage ;;
 606                 *)
 607                         STRATEGY="-s $2"
 608                         shift ;;
 609                 esac
 610                 ;;
 611         -m)
 612                 # we use merge anyway
 613                 ;;
 614         -v)
 615                 VERBOSE=t
 616                 ;;
 617         -p)
 618                 PRESERVE_MERGES=t
 619                 ;;
 620         -i)
 621                 # yeah, we know
 622                 ;;
 623         --root)
 624                 REBASE_ROOT=t
 625                 ;;
 626         --onto)
 627                 shift
 628                 ONTO=$(git rev-parse --verify "$1") ||
 629                         die "Does not point to a valid commit: $1"
 630                 ;;
 631         --)
 632                 shift
 633                 test -z "$REBASE_ROOT" -a $# -ge 1 -a $# -le 2 ||
 634                 test ! -z "$REBASE_ROOT" -a $# -le 1 || usage
 635                 test -d "$DOTEST" &&
 636                         die "Interactive rebase already started"
 637
 638                 git var GIT_COMMITTER_IDENT >/dev/null ||
 639                         die "You need to set your committer info first"
 640
 641                 if test -z "$REBASE_ROOT"
 642                 then
 643                         UPSTREAM_ARG="$1"
 644                         UPSTREAM=$(git rev-parse --verify "$1") || die "Invalid base"
 645                         test -z "$ONTO" && ONTO=$UPSTREAM
 646                         shift
 647                 else
 648                         UPSTREAM=
 649                         UPSTREAM_ARG=--root
 650                         test -z "$ONTO" &&
 651                                 die "You must specify --onto when using --root"
 652                 fi
 653                 run_pre_rebase_hook "$UPSTREAM_ARG" "$@"
 654
 655                 comment_for_reflog start
 656
 657                 require_clean_work_tree
 658
 659                 if test ! -z "$1"
 660                 then
 661                         output git show-ref --verify --quiet "refs/heads/$1" ||
 662                                 die "Invalid branchname: $1"
 663                         output git checkout "$1" ||
 664                                 die "Could not checkout $1"
 665                 fi
 666
 667                 HEAD=$(git rev-parse --verify HEAD) || die "No HEAD?"
 668                 mkdir "$DOTEST" || die "Could not create temporary $DOTEST"
 669
 670                 : > "$DOTEST"/interactive || die "Could not mark as interactive"
 671                 git symbolic-ref HEAD > "$DOTEST"/head-name 2> /dev/null ||
 672                         echo "detached HEAD" > "$DOTEST"/head-name
 673
 674                 echo $HEAD > "$DOTEST"/head
 675                 case "$REBASE_ROOT" in
 676                 '')
 677                         rm -f "$DOTEST"/rebase-root ;;
 678                 *)
 679                         : >"$DOTEST"/rebase-root ;;
 680                 esac
 681                 echo $ONTO > "$DOTEST"/onto
 682                 test -z "$STRATEGY" || echo "$STRATEGY" > "$DOTEST"/strategy
 683                 test t = "$VERBOSE" && : > "$DOTEST"/verbose
 684                 if test t = "$PRESERVE_MERGES"
 685                 then
 686                         # $REWRITTEN contains files for each commit that is
 687                         # reachable by at least one merge base of $HEAD and
 688                         # $UPSTREAM. They are not necessarily rewritten, but
 689                         # their children might be.
 690                         # This ensures that commits on merged, but otherwise
 691                         # unrelated side branches are left alone. (Think "X"
 692                         # in the man page's example.)
 693                         if test -z "$REBASE_ROOT"
 694                         then
 695                                 mkdir "$REWRITTEN" &&
 696                                 for c in $(git merge-base --all $HEAD $UPSTREAM)
 697                                 do
 698                                         echo $ONTO > "$REWRITTEN"/$c ||
 699                                                 die "Could not init rewritten commits"
 700                                 done
 701                         else
 702                                 mkdir "$REWRITTEN" &&
 703                                 echo $ONTO > "$REWRITTEN"/root ||
 704                                         die "Could not init rewritten commits"
 705                         fi
 706                         # No cherry-pick because our first pass is to determine
 707                         # parents to rewrite and skipping dropped commits would
 708                         # prematurely end our probe
 709                         MERGES_OPTION=
 710                         first_after_upstream="$(git rev-list --reverse --first-parent $UPSTREAM..$HEAD | head -n 1)"
 711                 else
 712                         MERGES_OPTION="--no-merges --cherry-pick"
 713                 fi
 714
 715                 SHORTHEAD=$(git rev-parse --short $HEAD)
 716                 SHORTONTO=$(git rev-parse --short $ONTO)
 717                 if test -z "$REBASE_ROOT"
 718                         # this is now equivalent to ! -z "$UPSTREAM"
 719                 then
 720                         SHORTUPSTREAM=$(git rev-parse --short $UPSTREAM)
 721                         REVISIONS=$UPSTREAM...$HEAD
 722                         SHORTREVISIONS=$SHORTUPSTREAM..$SHORTHEAD
 723                 else
 724                         REVISIONS=$ONTO...$HEAD
 725                         SHORTREVISIONS=$SHORTHEAD
 726                 fi
 727                 git rev-list $MERGES_OPTION --pretty=oneline --abbrev-commit \
 728                         --abbrev=7 --reverse --left-right --topo-order \
 729                         $REVISIONS | \
 730                         sed -n "s/^>//p" | while read shortsha1 rest
 731                 do
 732                         if test t != "$PRESERVE_MERGES"
 733                         then
 734                                 echo "pick $shortsha1 $rest" >> "$TODO"
 735                         else
 736                                 sha1=$(git rev-parse $shortsha1)
 737                                 if test -z "$REBASE_ROOT"
 738                                 then
 739                                         preserve=t
 740                                         for p in $(git rev-list --parents -1 $sha1 | cut -d' ' -s -f2-)
 741                                         do
 742                                                 if test -f "$REWRITTEN"/$p -a \( $p != $ONTO -o $sha1 = $first_after_upstream \)
 743                                                 then
 744                                                         preserve=f
 745                                                 fi
 746                                         done
 747                                 else
 748                                         preserve=f
 749                                 fi
 750                                 if test f = "$preserve"
 751                                 then
 752                                         touch "$REWRITTEN"/$sha1
 753                                         echo "pick $shortsha1 $rest" >> "$TODO"
 754                                 fi
 755                         fi
 756                 done
 757
 758                 # Watch for commits that been dropped by --cherry-pick
 759                 if test t = "$PRESERVE_MERGES"
 760                 then
 761                         mkdir "$DROPPED"
 762                         # Save all non-cherry-picked changes
 763                         git rev-list $REVISIONS --left-right --cherry-pick | \
 764                                 sed -n "s/^>//p" > "$DOTEST"/not-cherry-picks
 765                         # Now all commits and note which ones are missing in
 766                         # not-cherry-picks and hence being dropped
 767                         git rev-list $REVISIONS |
 768                         while read rev
 769                         do
 770                                 if test -f "$REWRITTEN"/$rev -a "$(sane_grep "$rev" "$DOTEST"/not-cherry-picks)" = ""
 771                                 then
 772                                         # Use -f2 because if rev-list is telling us this commit is
 773                                         # not worthwhile, we don't want to track its multiple heads,
 774                                         # just the history of its first-parent for others that will
 775                                         # be rebasing on top of it
 776                                         git rev-list --parents -1 $rev | cut -d' ' -s -f2 > "$DROPPED"/$rev
 777                                         short=$(git rev-list -1 --abbrev-commit --abbrev=7 $rev)
 778                                         sane_grep -v "^[a-z][a-z]* $short" <"$TODO" > "${TODO}2" ; mv "${TODO}2" "$TODO"
 779                                         rm "$REWRITTEN"/$rev
 780                                 fi
 781                         done
 782                 fi
 783
 784                 test -s "$TODO" || echo noop >> "$TODO"
 785                 cat >> "$TODO" << EOF
 786
 787 # Rebase $SHORTREVISIONS onto $SHORTONTO
 788 #
 789 # Commands:
 790 #  p, pick = use commit
 791 #  r, reword = use commit, but edit the commit message
 792 #  e, edit = use commit, but stop for amending
 793 #  s, squash = use commit, but meld into previous commit
 794 #  f, fixup = like "squash", but discard this commit's log message
 795 #
 796 # If you remove a line here THAT COMMIT WILL BE LOST.
 797 # However, if you remove everything, the rebase will be aborted.
 798 #
 799 EOF
 800
 801                 has_action "$TODO" ||
 802                         die_abort "Nothing to do"
 803
 804                 cp "$TODO" "$TODO".backup
 805                 git_editor "$TODO" ||
 806                         die "Could not execute editor"
 807
 808                 has_action "$TODO" ||
 809                         die_abort "Nothing to do"
 810
 811                 test -d "$REWRITTEN" || skip_unnecessary_picks
 812
 813                 git update-ref ORIG_HEAD $HEAD
 814                 output git checkout $ONTO && do_rest
 815                 ;;
 816         esac
 817         shift
 818 done