contrib/subtree/git-subtree.sh

   1 #!/bin/sh
   2 #
   3 # git-subtree.sh: split/join git repositories in subdirectories of this one
   4 #
   5 # Copyright (C) 2009 Avery Pennarun <apenwarr@gmail.com>
   6 #
   7
   8 if test -z "$GIT_EXEC_PATH" || ! test -f "$GIT_EXEC_PATH/git-sh-setup" || {
   9         test "${PATH#"${GIT_EXEC_PATH}:"}" = "$PATH" &&
  10         test ! "$GIT_EXEC_PATH" -ef "${PATH%%:*}" 2>/dev/null
  11 }
  12 then
  13         basename=${0##*[/\\]}
  14         echo >&2 'It looks like either your git installation or your'
  15         echo >&2 'git-subtree installation is broken.'
  16         echo >&2
  17         echo >&2 "Tips:"
  18         echo >&2 " - If \`git --exec-path\` does not print the correct path to"
  19         echo >&2 "   your git install directory, then set the GIT_EXEC_PATH"
  20         echo >&2 "   environment variable to the correct directory."
  21         echo >&2 " - Make sure that your \`$basename\` file is either in your"
  22         echo >&2 "   PATH or in your git exec path (\`$(git --exec-path)\`)."
  23         echo >&2 " - You should run git-subtree as \`git ${basename#git-}\`,"
  24         echo >&2 "   not as \`$basename\`." >&2
  25         exit 126
  26 fi
  27
  28 OPTS_SPEC="\
  29 git subtree add   --prefix=<prefix> <commit>
  30 git subtree add   --prefix=<prefix> <repository> <ref>
  31 git subtree merge --prefix=<prefix> <commit>
  32 git subtree split --prefix=<prefix> [<commit>]
  33 git subtree pull  --prefix=<prefix> <repository> <ref>
  34 git subtree push  --prefix=<prefix> <repository> <refspec>
  35 --
  36 h,help!       show the help
  37 q,quiet!      quiet
  38 d,debug!      show debug messages
  39 P,prefix=     the name of the subdir to split out
  40  options for 'split' (also: 'push')
  41 annotate=     add a prefix to commit message of new commits
  42 b,branch!=    create a new branch from the split subtree
  43 ignore-joins  ignore prior --rejoin commits
  44 onto=         try connecting new tree to an existing one
  45 rejoin        merge the new branch back into HEAD
  46  options for 'add' and 'merge' (also: 'pull', 'split --rejoin', and 'push --rejoin')
  47 squash        merge subtree changes as a single commit
  48 m,message!=   use the given message as the commit message for the merge commit
  49 "
  50
  51 indent=0
  52
  53 # Usage: say [MSG...]
  54 say () {
  55         if test -z "$arg_quiet"
  56         then
  57                 printf '%s\n' "$*"
  58         fi
  59 }
  60
  61 # Usage: debug [MSG...]
  62 debug () {
  63         if test -n "$arg_debug"
  64         then
  65                 printf "%$(($indent * 2))s%s\n" '' "$*" >&2
  66         fi
  67 }
  68
  69 # Usage: progress [MSG...]
  70 progress () {
  71         if test -z "$arg_quiet"
  72         then
  73                 if test -z "$arg_debug"
  74                 then
  75                         # Debug mode is off.
  76                         #
  77                         # Print one progress line that we keep updating (use
  78                         # "\r" to return to the beginning of the line, rather
  79                         # than "\n" to start a new line).  This only really
  80                         # works when stderr is a terminal.
  81                         printf "%s\r" "$*" >&2
  82                 else
  83                         # Debug mode is on.  The `debug` function is regularly
  84                         # printing to stderr.
  85                         #
  86                         # Don't do the one-line-with-"\r" thing, because on a
  87                         # terminal the debug output would overwrite and hide the
  88                         # progress output.  Add a "progress:" prefix to make the
  89                         # progress output and the debug output easy to
  90                         # distinguish.  This ensures maximum readability whether
  91                         # stderr is a terminal or a file.
  92                         printf "progress: %s\n" "$*" >&2
  93                 fi
  94         fi
  95 }
  96
  97 # Usage: assert CMD...
  98 assert () {
  99         if ! "$@"
 100         then
 101                 die "fatal: assertion failed: $*"
 102         fi
 103 }
 104
 105 # Usage: die_incompatible_opt OPTION COMMAND
 106 die_incompatible_opt () {
 107         assert test "$#" = 2
 108         opt="$1"
 109         arg_command="$2"
 110         die "fatal: the '$opt' flag does not make sense with 'git subtree $arg_command'."
 111 }
 112
 113 main () {
 114         if test $# -eq 0
 115         then
 116                 set -- -h
 117         fi
 118         set_args="$(echo "$OPTS_SPEC" | git rev-parse --parseopt -- "$@" || echo exit $?)"
 119         eval "$set_args"
 120         . git-sh-setup
 121         require_work_tree
 122
 123         # First figure out the command and whether we use --rejoin, so
 124         # that we can provide more helpful validation when we do the
 125         # "real" flag parsing.
 126         arg_split_rejoin=
 127         allow_split=
 128         allow_addmerge=
 129         while test $# -gt 0
 130         do
 131                 opt="$1"
 132                 shift
 133                 case "$opt" in
 134                         --annotate|-b|-P|-m|--onto)
 135                                 shift
 136                                 ;;
 137                         --rejoin)
 138                                 arg_split_rejoin=1
 139                                 ;;
 140                         --no-rejoin)
 141                                 arg_split_rejoin=
 142                                 ;;
 143                         --)
 144                                 break
 145                                 ;;
 146                 esac
 147         done
 148         arg_command=$1
 149         case "$arg_command" in
 150         add|merge|pull)
 151                 allow_addmerge=1
 152                 ;;
 153         split|push)
 154                 allow_split=1
 155                 allow_addmerge=$arg_split_rejoin
 156                 ;;
 157         *)
 158                 die "fatal: unknown command '$arg_command'"
 159                 ;;
 160         esac
 161         # Reset the arguments array for "real" flag parsing.
 162         eval "$set_args"
 163
 164         # Begin "real" flag parsing.
 165         arg_quiet=
 166         arg_debug=
 167         arg_prefix=
 168         arg_split_branch=
 169         arg_split_onto=
 170         arg_split_ignore_joins=
 171         arg_split_annotate=
 172         arg_addmerge_squash=
 173         arg_addmerge_message=
 174         while test $# -gt 0
 175         do
 176                 opt="$1"
 177                 shift
 178
 179                 case "$opt" in
 180                 -q)
 181                         arg_quiet=1
 182                         ;;
 183                 -d)
 184                         arg_debug=1
 185                         ;;
 186                 --annotate)
 187                         test -n "$allow_split" || die_incompatible_opt "$opt" "$arg_command"
 188                         arg_split_annotate="$1"
 189                         shift
 190                         ;;
 191                 --no-annotate)
 192                         test -n "$allow_split" || die_incompatible_opt "$opt" "$arg_command"
 193                         arg_split_annotate=
 194                         ;;
 195                 -b)
 196                         test -n "$allow_split" || die_incompatible_opt "$opt" "$arg_command"
 197                         arg_split_branch="$1"
 198                         shift
 199                         ;;
 200                 -P)
 201                         arg_prefix="${1%/}"
 202                         shift
 203                         ;;
 204                 -m)
 205                         test -n "$allow_addmerge" || die_incompatible_opt "$opt" "$arg_command"
 206                         arg_addmerge_message="$1"
 207                         shift
 208                         ;;
 209                 --no-prefix)
 210                         arg_prefix=
 211                         ;;
 212                 --onto)
 213                         test -n "$allow_split" || die_incompatible_opt "$opt" "$arg_command"
 214                         arg_split_onto="$1"
 215                         shift
 216                         ;;
 217                 --no-onto)
 218                         test -n "$allow_split" || die_incompatible_opt "$opt" "$arg_command"
 219                         arg_split_onto=
 220                         ;;
 221                 --rejoin)
 222                         test -n "$allow_split" || die_incompatible_opt "$opt" "$arg_command"
 223                         ;;
 224                 --no-rejoin)
 225                         test -n "$allow_split" || die_incompatible_opt "$opt" "$arg_command"
 226                         ;;
 227                 --ignore-joins)
 228                         test -n "$allow_split" || die_incompatible_opt "$opt" "$arg_command"
 229                         arg_split_ignore_joins=1
 230                         ;;
 231                 --no-ignore-joins)
 232                         test -n "$allow_split" || die_incompatible_opt "$opt" "$arg_command"
 233                         arg_split_ignore_joins=
 234                         ;;
 235                 --squash)
 236                         test -n "$allow_addmerge" || die_incompatible_opt "$opt" "$arg_command"
 237                         arg_addmerge_squash=1
 238                         ;;
 239                 --no-squash)
 240                         test -n "$allow_addmerge" || die_incompatible_opt "$opt" "$arg_command"
 241                         arg_addmerge_squash=
 242                         ;;
 243                 --)
 244                         break
 245                         ;;
 246                 *)
 247                         die "fatal: unexpected option: $opt"
 248                         ;;
 249                 esac
 250         done
 251         shift
 252
 253         if test -z "$arg_prefix"
 254         then
 255                 die "fatal: you must provide the --prefix option."
 256         fi
 257
 258         case "$arg_command" in
 259         add)
 260                 test -e "$arg_prefix" &&
 261                         die "fatal: prefix '$arg_prefix' already exists."
 262                 ;;
 263         *)
 264                 test -e "$arg_prefix" ||
 265                         die "fatal: '$arg_prefix' does not exist; use 'git subtree add'"
 266                 ;;
 267         esac
 268
 269         dir="$(dirname "$arg_prefix/.")"
 270
 271         debug "command: {$arg_command}"
 272         debug "quiet: {$arg_quiet}"
 273         debug "dir: {$dir}"
 274         debug "opts: {$*}"
 275         debug
 276
 277         "cmd_$arg_command" "$@"
 278 }
 279
 280 # Usage: cache_setup
 281 cache_setup () {
 282         assert test $# = 0
 283         cachedir="$GIT_DIR/subtree-cache/$$"
 284         rm -rf "$cachedir" ||
 285                 die "fatal: can't delete old cachedir: $cachedir"
 286         mkdir -p "$cachedir" ||
 287                 die "fatal: can't create new cachedir: $cachedir"
 288         mkdir -p "$cachedir/notree" ||
 289                 die "fatal: can't create new cachedir: $cachedir/notree"
 290         debug "Using cachedir: $cachedir" >&2
 291 }
 292
 293 # Usage: cache_get [REVS...]
 294 cache_get () {
 295         for oldrev in "$@"
 296         do
 297                 if test -r "$cachedir/$oldrev"
 298                 then
 299                         read newrev <"$cachedir/$oldrev"
 300                         echo $newrev
 301                 fi
 302         done
 303 }
 304
 305 # Usage: cache_miss [REVS...]
 306 cache_miss () {
 307         for oldrev in "$@"
 308         do
 309                 if ! test -r "$cachedir/$oldrev"
 310                 then
 311                         echo $oldrev
 312                 fi
 313         done
 314 }
 315
 316 # Usage: check_parents [REVS...]
 317 check_parents () {
 318         missed=$(cache_miss "$@") || exit $?
 319         local indent=$(($indent + 1))
 320         for miss in $missed
 321         do
 322                 if ! test -r "$cachedir/notree/$miss"
 323                 then
 324                         debug "incorrect order: $miss"
 325                         process_split_commit "$miss" ""
 326                 fi
 327         done
 328 }
 329
 330 # Usage: set_notree REV
 331 set_notree () {
 332         assert test $# = 1
 333         echo "1" > "$cachedir/notree/$1"
 334 }
 335
 336 # Usage: cache_set OLDREV NEWREV
 337 cache_set () {
 338         assert test $# = 2
 339         oldrev="$1"
 340         newrev="$2"
 341         if test "$oldrev" != "latest_old" &&
 342                 test "$oldrev" != "latest_new" &&
 343                 test -e "$cachedir/$oldrev"
 344         then
 345                 die "fatal: cache for $oldrev already exists!"
 346         fi
 347         echo "$newrev" >"$cachedir/$oldrev"
 348 }
 349
 350 # Usage: rev_exists REV
 351 rev_exists () {
 352         assert test $# = 1
 353         if git rev-parse "$1" >/dev/null 2>&1
 354         then
 355                 return 0
 356         else
 357                 return 1
 358         fi
 359 }
 360
 361 # Usage: try_remove_previous REV
 362 #
 363 # If a commit doesn't have a parent, this might not work.  But we only want
 364 # to remove the parent from the rev-list, and since it doesn't exist, it won't
 365 # be there anyway, so do nothing in that case.
 366 try_remove_previous () {
 367         assert test $# = 1
 368         if rev_exists "$1^"
 369         then
 370                 echo "^$1^"
 371         fi
 372 }
 373
 374 # Usage: process_subtree_split_trailer SPLIT_HASH MAIN_HASH [REPOSITORY]
 375 process_subtree_split_trailer () {
 376         assert test $# -ge 2
 377         assert test $# -le 3
 378         b="$1"
 379         sq="$2"
 380         repository=""
 381         if test "$#" = 3
 382         then
 383                 repository="$3"
 384         fi
 385         fail_msg="fatal: could not rev-parse split hash $b from commit $sq"
 386         if ! sub="$(git rev-parse --verify --quiet "$b^{commit}")"
 387         then
 388                 # if 'repository' was given, try to fetch the 'git-subtree-split' hash
 389                 # before 'rev-parse'-ing it again, as it might be a tag that we do not have locally
 390                 if test -n "${repository}"
 391                 then
 392                         git fetch "$repository" "$b"
 393                         sub="$(git rev-parse --verify --quiet "$b^{commit}")" ||
 394                                 die "$fail_msg"
 395                 else
 396                         hint1=$(printf "hint: hash might be a tag, try fetching it from the subtree repository:")
 397                         hint2=$(printf "hint:    git fetch <subtree-repository> $b")
 398                         fail_msg=$(printf "$fail_msg\n$hint1\n$hint2")
 399                         die "$fail_msg"
 400                 fi
 401         fi
 402 }
 403
 404 # Usage: find_latest_squash DIR [REPOSITORY]
 405 find_latest_squash () {
 406         assert test $# -ge 1
 407         assert test $# -le 2
 408         dir="$1"
 409         repository=""
 410         if test "$#" = 2
 411         then
 412                 repository="$2"
 413         fi
 414         debug "Looking for latest squash (dir=$dir, repository=$repository)..."
 415         local indent=$(($indent + 1))
 416
 417         sq=
 418         main=
 419         sub=
 420         git log --grep="^git-subtree-dir: $dir/*\$" \
 421                 --no-show-signature --pretty=format:'START %H%n%s%n%n%b%nEND%n' HEAD |
 422         while read a b junk
 423         do
 424                 debug "$a $b $junk"
 425                 debug "{{$sq/$main/$sub}}"
 426                 case "$a" in
 427                 START)
 428                         sq="$b"
 429                         ;;
 430                 git-subtree-mainline:)
 431                         main="$b"
 432                         ;;
 433                 git-subtree-split:)
 434                         process_subtree_split_trailer "$b" "$sq" "$repository"
 435                         ;;
 436                 END)
 437                         if test -n "$sub"
 438                         then
 439                                 if test -n "$main"
 440                                 then
 441                                         # a rejoin commit?
 442                                         # Pretend its sub was a squash.
 443                                         sq=$(git rev-parse --verify "$sq^2") ||
 444                                                 die
 445                                 fi
 446                                 debug "Squash found: $sq $sub"
 447                                 echo "$sq" "$sub"
 448                                 break
 449                         fi
 450                         sq=
 451                         main=
 452                         sub=
 453                         ;;
 454                 esac
 455         done || exit $?
 456 }
 457
 458 # Usage: find_existing_splits DIR REV [REPOSITORY]
 459 find_existing_splits () {
 460         assert test $# -ge 2
 461         assert test $# -le 3
 462         debug "Looking for prior splits..."
 463         local indent=$(($indent + 1))
 464
 465         dir="$1"
 466         rev="$2"
 467         repository=""
 468         if test "$#" = 3
 469         then
 470                 repository="$3"
 471         fi
 472         main=
 473         sub=
 474         local grep_format="^git-subtree-dir: $dir/*\$"
 475         if test -n "$arg_split_ignore_joins"
 476         then
 477                 grep_format="^Add '$dir/' from commit '"
 478         fi
 479         git log --grep="$grep_format" \
 480                 --no-show-signature --pretty=format:'START %H%n%s%n%n%b%nEND%n' "$rev" |
 481         while read a b junk
 482         do
 483                 case "$a" in
 484                 START)
 485                         sq="$b"
 486                         ;;
 487                 git-subtree-mainline:)
 488                         main="$b"
 489                         ;;
 490                 git-subtree-split:)
 491                         process_subtree_split_trailer "$b" "$sq" "$repository"
 492                         ;;
 493                 END)
 494                         debug "Main is: '$main'"
 495                         if test -z "$main" && test -n "$sub"
 496                         then
 497                                 # squash commits refer to a subtree
 498                                 debug "  Squash: $sq from $sub"
 499                                 cache_set "$sq" "$sub"
 500                         fi
 501                         if test -n "$main" && test -n "$sub"
 502                         then
 503                                 debug "  Prior: $main -> $sub"
 504                                 cache_set $main $sub
 505                                 cache_set $sub $sub
 506                                 try_remove_previous "$main"
 507                                 try_remove_previous "$sub"
 508                         fi
 509                         main=
 510                         sub=
 511                         ;;
 512                 esac
 513         done || exit $?
 514 }
 515
 516 # Usage: copy_commit REV TREE FLAGS_STR
 517 copy_commit () {
 518         assert test $# = 3
 519         # We're going to set some environment vars here, so
 520         # do it in a subshell to get rid of them safely later
 521         debug copy_commit "{$1}" "{$2}" "{$3}"
 522         git log -1 --no-show-signature --pretty=format:'%an%n%ae%n%aD%n%cn%n%ce%n%cD%n%B' "$1" |
 523         (
 524                 read GIT_AUTHOR_NAME
 525                 read GIT_AUTHOR_EMAIL
 526                 read GIT_AUTHOR_DATE
 527                 read GIT_COMMITTER_NAME
 528                 read GIT_COMMITTER_EMAIL
 529                 read GIT_COMMITTER_DATE
 530                 export  GIT_AUTHOR_NAME \
 531                         GIT_AUTHOR_EMAIL \
 532                         GIT_AUTHOR_DATE \
 533                         GIT_COMMITTER_NAME \
 534                         GIT_COMMITTER_EMAIL \
 535                         GIT_COMMITTER_DATE
 536                 (
 537                         printf "%s" "$arg_split_annotate"
 538                         cat
 539                 ) |
 540                 git commit-tree "$2" $3  # reads the rest of stdin
 541         ) || die "fatal: can't copy commit $1"
 542 }
 543
 544 # Usage: add_msg DIR LATEST_OLD LATEST_NEW
 545 add_msg () {
 546         assert test $# = 3
 547         dir="$1"
 548         latest_old="$2"
 549         latest_new="$3"
 550         if test -n "$arg_addmerge_message"
 551         then
 552                 commit_message="$arg_addmerge_message"
 553         else
 554                 commit_message="Add '$dir/' from commit '$latest_new'"
 555         fi
 556         if test -n "$arg_split_rejoin"
 557         then
 558                 # If this is from a --rejoin, then rejoin_msg has
 559                 # already inserted the `git-subtree-xxx:` tags
 560                 echo "$commit_message"
 561                 return
 562         fi
 563         cat <<-EOF
 564                 $commit_message
 565
 566                 git-subtree-dir: $dir
 567                 git-subtree-mainline: $latest_old
 568                 git-subtree-split: $latest_new
 569         EOF
 570 }
 571
 572 # Usage: add_squashed_msg REV DIR
 573 add_squashed_msg () {
 574         assert test $# = 2
 575         if test -n "$arg_addmerge_message"
 576         then
 577                 echo "$arg_addmerge_message"
 578         else
 579                 echo "Merge commit '$1' as '$2'"
 580         fi
 581 }
 582
 583 # Usage: rejoin_msg DIR LATEST_OLD LATEST_NEW
 584 rejoin_msg () {
 585         assert test $# = 3
 586         dir="$1"
 587         latest_old="$2"
 588         latest_new="$3"
 589         if test -n "$arg_addmerge_message"
 590         then
 591                 commit_message="$arg_addmerge_message"
 592         else
 593                 commit_message="Split '$dir/' into commit '$latest_new'"
 594         fi
 595         cat <<-EOF
 596                 $commit_message
 597
 598                 git-subtree-dir: $dir
 599                 git-subtree-mainline: $latest_old
 600                 git-subtree-split: $latest_new
 601         EOF
 602 }
 603
 604 # Usage: squash_msg DIR OLD_SUBTREE_COMMIT NEW_SUBTREE_COMMIT
 605 squash_msg () {
 606         assert test $# = 3
 607         dir="$1"
 608         oldsub="$2"
 609         newsub="$3"
 610         newsub_short=$(git rev-parse --short "$newsub")
 611
 612         if test -n "$oldsub"
 613         then
 614                 oldsub_short=$(git rev-parse --short "$oldsub")
 615                 echo "Squashed '$dir/' changes from $oldsub_short..$newsub_short"
 616                 echo
 617                 git log --no-show-signature --pretty=tformat:'%h %s' "$oldsub..$newsub"
 618                 git log --no-show-signature --pretty=tformat:'REVERT: %h %s' "$newsub..$oldsub"
 619         else
 620                 echo "Squashed '$dir/' content from commit $newsub_short"
 621         fi
 622
 623         echo
 624         echo "git-subtree-dir: $dir"
 625         echo "git-subtree-split: $newsub"
 626 }
 627
 628 # Usage: toptree_for_commit COMMIT
 629 toptree_for_commit () {
 630         assert test $# = 1
 631         commit="$1"
 632         git rev-parse --verify "$commit^{tree}" || exit $?
 633 }
 634
 635 # Usage: subtree_for_commit COMMIT DIR
 636 subtree_for_commit () {
 637         assert test $# = 2
 638         commit="$1"
 639         dir="$2"
 640         git ls-tree "$commit" -- "$dir" |
 641         while read mode type tree name
 642         do
 643                 assert test "$name" = "$dir"
 644                 assert test "$type" = "tree" -o "$type" = "commit"
 645                 test "$type" = "commit" && continue  # ignore submodules
 646                 echo $tree
 647                 break
 648         done || exit $?
 649 }
 650
 651 # Usage: tree_changed TREE [PARENTS...]
 652 tree_changed () {
 653         assert test $# -gt 0
 654         tree=$1
 655         shift
 656         if test $# -ne 1
 657         then
 658                 return 0   # weird parents, consider it changed
 659         else
 660                 ptree=$(toptree_for_commit $1) || exit $?
 661                 if test "$ptree" != "$tree"
 662                 then
 663                         return 0   # changed
 664                 else
 665                         return 1   # not changed
 666                 fi
 667         fi
 668 }
 669
 670 # Usage: new_squash_commit OLD_SQUASHED_COMMIT OLD_NONSQUASHED_COMMIT NEW_NONSQUASHED_COMMIT
 671 new_squash_commit () {
 672         assert test $# = 3
 673         old="$1"
 674         oldsub="$2"
 675         newsub="$3"
 676         tree=$(toptree_for_commit $newsub) || exit $?
 677         if test -n "$old"
 678         then
 679                 squash_msg "$dir" "$oldsub" "$newsub" |
 680                 git commit-tree "$tree" -p "$old" || exit $?
 681         else
 682                 squash_msg "$dir" "" "$newsub" |
 683                 git commit-tree "$tree" || exit $?
 684         fi
 685 }
 686
 687 # Usage: copy_or_skip REV TREE NEWPARENTS
 688 copy_or_skip () {
 689         assert test $# = 3
 690         rev="$1"
 691         tree="$2"
 692         newparents="$3"
 693         assert test -n "$tree"
 694
 695         identical=
 696         nonidentical=
 697         p=
 698         gotparents=
 699         copycommit=
 700         for parent in $newparents
 701         do
 702                 ptree=$(toptree_for_commit $parent) || exit $?
 703                 test -z "$ptree" && continue
 704                 if test "$ptree" = "$tree"
 705                 then
 706                         # an identical parent could be used in place of this rev.
 707                         if test -n "$identical"
 708                         then
 709                                 # if a previous identical parent was found, check whether
 710                                 # one is already an ancestor of the other
 711                                 mergebase=$(git merge-base $identical $parent)
 712                                 if test "$identical" = "$mergebase"
 713                                 then
 714                                         # current identical commit is an ancestor of parent
 715                                         identical="$parent"
 716                                 elif test "$parent" != "$mergebase"
 717                                 then
 718                                         # no common history; commit must be copied
 719                                         copycommit=1
 720                                 fi
 721                         else
 722                                 # first identical parent detected
 723                                 identical="$parent"
 724                         fi
 725                 else
 726                         nonidentical="$parent"
 727                 fi
 728
 729                 # sometimes both old parents map to the same newparent;
 730                 # eliminate duplicates
 731                 is_new=1
 732                 for gp in $gotparents
 733                 do
 734                         if test "$gp" = "$parent"
 735                         then
 736                                 is_new=
 737                                 break
 738                         fi
 739                 done
 740                 if test -n "$is_new"
 741                 then
 742                         gotparents="$gotparents $parent"
 743                         p="$p -p $parent"
 744                 fi
 745         done
 746
 747         if test -n "$identical" && test -n "$nonidentical"
 748         then
 749                 extras=$(git rev-list --count $identical..$nonidentical)
 750                 if test "$extras" -ne 0
 751                 then
 752                         # we need to preserve history along the other branch
 753                         copycommit=1
 754                 fi
 755         fi
 756         if test -n "$identical" && test -z "$copycommit"
 757         then
 758                 echo $identical
 759         else
 760                 copy_commit "$rev" "$tree" "$p" || exit $?
 761         fi
 762 }
 763
 764 # Usage: ensure_clean
 765 ensure_clean () {
 766         assert test $# = 0
 767         if ! git diff-index HEAD --exit-code --quiet 2>&1
 768         then
 769                 die "fatal: working tree has modifications.  Cannot add."
 770         fi
 771         if ! git diff-index --cached HEAD --exit-code --quiet 2>&1
 772         then
 773                 die "fatal: index has modifications.  Cannot add."
 774         fi
 775 }
 776
 777 # Usage: ensure_valid_ref_format REF
 778 ensure_valid_ref_format () {
 779         assert test $# = 1
 780         git check-ref-format "refs/heads/$1" ||
 781                 die "fatal: '$1' does not look like a ref"
 782 }
 783
 784 # Usage: process_split_commit REV PARENTS
 785 process_split_commit () {
 786         assert test $# = 2
 787         local rev="$1"
 788         local parents="$2"
 789
 790         if test $indent -eq 0
 791         then
 792                 revcount=$(($revcount + 1))
 793         else
 794                 # processing commit without normal parent information;
 795                 # fetch from repo
 796                 parents=$(git rev-parse "$rev^@")
 797                 extracount=$(($extracount + 1))
 798         fi
 799
 800         progress "$revcount/$revmax ($createcount) [$extracount]"
 801
 802         debug "Processing commit: $rev"
 803         local indent=$(($indent + 1))
 804         exists=$(cache_get "$rev") || exit $?
 805         if test -n "$exists"
 806         then
 807                 debug "prior: $exists"
 808                 return
 809         fi
 810         createcount=$(($createcount + 1))
 811         debug "parents: $parents"
 812         check_parents $parents
 813         newparents=$(cache_get $parents) || exit $?
 814         debug "newparents: $newparents"
 815
 816         tree=$(subtree_for_commit "$rev" "$dir") || exit $?
 817         debug "tree is: $tree"
 818
 819         # ugly.  is there no better way to tell if this is a subtree
 820         # vs. a mainline commit?  Does it matter?
 821         if test -z "$tree"
 822         then
 823                 set_notree "$rev"
 824                 if test -n "$newparents"
 825                 then
 826                         cache_set "$rev" "$rev"
 827                 fi
 828                 return
 829         fi
 830
 831         newrev=$(copy_or_skip "$rev" "$tree" "$newparents") || exit $?
 832         debug "newrev is: $newrev"
 833         cache_set "$rev" "$newrev"
 834         cache_set latest_new "$newrev"
 835         cache_set latest_old "$rev"
 836 }
 837
 838 # Usage: cmd_add REV
 839 #    Or: cmd_add REPOSITORY REF
 840 cmd_add () {
 841
 842         ensure_clean
 843
 844         if test $# -eq 1
 845         then
 846                 git rev-parse -q --verify "$1^{commit}" >/dev/null ||
 847                         die "fatal: '$1' does not refer to a commit"
 848
 849                 cmd_add_commit "$@"
 850
 851         elif test $# -eq 2
 852         then
 853                 # Technically we could accept a refspec here but we're
 854                 # just going to turn around and add FETCH_HEAD under the
 855                 # specified directory.  Allowing a refspec might be
 856                 # misleading because we won't do anything with any other
 857                 # branches fetched via the refspec.
 858                 ensure_valid_ref_format "$2"
 859
 860                 cmd_add_repository "$@"
 861         else
 862                 say >&2 "fatal: parameters were '$*'"
 863                 die "Provide either a commit or a repository and commit."
 864         fi
 865 }
 866
 867 # Usage: cmd_add_repository REPOSITORY REFSPEC
 868 cmd_add_repository () {
 869         assert test $# = 2
 870         echo "git fetch" "$@"
 871         repository=$1
 872         refspec=$2
 873         git fetch "$@" || exit $?
 874         cmd_add_commit FETCH_HEAD
 875 }
 876
 877 # Usage: cmd_add_commit REV
 878 cmd_add_commit () {
 879         # The rev has already been validated by cmd_add(), we just
 880         # need to normalize it.
 881         assert test $# = 1
 882         rev=$(git rev-parse --verify "$1^{commit}") || exit $?
 883
 884         debug "Adding $dir as '$rev'..."
 885         if test -z "$arg_split_rejoin"
 886         then
 887                 # Only bother doing this if this is a genuine 'add',
 888                 # not a synthetic 'add' from '--rejoin'.
 889                 git read-tree --prefix="$dir" $rev || exit $?
 890         fi
 891         git checkout -- "$dir" || exit $?
 892         tree=$(git write-tree) || exit $?
 893
 894         headrev=$(git rev-parse --verify HEAD) || exit $?
 895         if test -n "$headrev" && test "$headrev" != "$rev"
 896         then
 897                 headp="-p $headrev"
 898         else
 899                 headp=
 900         fi
 901
 902         if test -n "$arg_addmerge_squash"
 903         then
 904                 rev=$(new_squash_commit "" "" "$rev") || exit $?
 905                 commit=$(add_squashed_msg "$rev" "$dir" |
 906                         git commit-tree "$tree" $headp -p "$rev") || exit $?
 907         else
 908                 revp=$(peel_committish "$rev") || exit $?
 909                 commit=$(add_msg "$dir" $headrev "$rev" |
 910                         git commit-tree "$tree" $headp -p "$revp") || exit $?
 911         fi
 912         git reset "$commit" || exit $?
 913
 914         say >&2 "Added dir '$dir'"
 915 }
 916
 917 # Usage: cmd_split [REV] [REPOSITORY]
 918 cmd_split () {
 919         if test $# -eq 0
 920         then
 921                 rev=$(git rev-parse HEAD)
 922         elif test $# -eq 1 || test $# -eq 2
 923         then
 924                 rev=$(git rev-parse -q --verify "$1^{commit}") ||
 925                         die "fatal: '$1' does not refer to a commit"
 926         else
 927                 die "fatal: you must provide exactly one revision, and optionnally a repository.  Got: '$*'"
 928         fi
 929         repository=""
 930         if test "$#" = 2
 931         then
 932                 repository="$2"
 933         fi
 934
 935         if test -n "$arg_split_rejoin"
 936         then
 937                 ensure_clean
 938         fi
 939
 940         debug "Splitting $dir..."
 941         cache_setup || exit $?
 942
 943         if test -n "$arg_split_onto"
 944         then
 945                 debug "Reading history for --onto=$arg_split_onto..."
 946                 git rev-list $arg_split_onto |
 947                 while read rev
 948                 do
 949                         # the 'onto' history is already just the subdir, so
 950                         # any parent we find there can be used verbatim
 951                         debug "cache: $rev"
 952                         cache_set "$rev" "$rev"
 953                 done || exit $?
 954         fi
 955
 956         unrevs="$(find_existing_splits "$dir" "$rev" "$repository")" || exit $?
 957
 958         # We can't restrict rev-list to only $dir here, because some of our
 959         # parents have the $dir contents the root, and those won't match.
 960         # (and rev-list --follow doesn't seem to solve this)
 961         grl='git rev-list --topo-order --reverse --parents $rev $unrevs'
 962         revmax=$(eval "$grl" | wc -l)
 963         revcount=0
 964         createcount=0
 965         extracount=0
 966         eval "$grl" |
 967         while read rev parents
 968         do
 969                 process_split_commit "$rev" "$parents"
 970         done || exit $?
 971
 972         latest_new=$(cache_get latest_new) || exit $?
 973         if test -z "$latest_new"
 974         then
 975                 die "fatal: no new revisions were found"
 976         fi
 977
 978         if test -n "$arg_split_rejoin"
 979         then
 980                 debug "Merging split branch into HEAD..."
 981                 latest_old=$(cache_get latest_old) || exit $?
 982                 arg_addmerge_message="$(rejoin_msg "$dir" "$latest_old" "$latest_new")" || exit $?
 983                 if test -z "$(find_latest_squash "$dir")"
 984                 then
 985                         cmd_add "$latest_new" >&2 || exit $?
 986                 else
 987                         cmd_merge "$latest_new" >&2 || exit $?
 988                 fi
 989         fi
 990         if test -n "$arg_split_branch"
 991         then
 992                 if rev_exists "refs/heads/$arg_split_branch"
 993                 then
 994                         if ! git merge-base --is-ancestor "$arg_split_branch" "$latest_new"
 995                         then
 996                                 die "fatal: branch '$arg_split_branch' is not an ancestor of commit '$latest_new'."
 997                         fi
 998                         action='Updated'
 999                 else
1000                         action='Created'
1001                 fi
1002                 git update-ref -m 'subtree split' \
1003                         "refs/heads/$arg_split_branch" "$latest_new" || exit $?
1004                 say >&2 "$action branch '$arg_split_branch'"
1005         fi
1006         echo "$latest_new"
1007         exit 0
1008 }
1009
1010 # Usage: cmd_merge REV [REPOSITORY]
1011 cmd_merge () {
1012         if test $# -lt 1 || test $# -gt 2
1013         then
1014                 die "fatal: you must provide exactly one revision, and optionally a repository. Got: '$*'"
1015         fi
1016
1017         rev=$(git rev-parse -q --verify "$1^{commit}") ||
1018                 die "fatal: '$1' does not refer to a commit"
1019         repository=""
1020         if test "$#" = 2
1021         then
1022                 repository="$2"
1023         fi
1024         ensure_clean
1025
1026         if test -n "$arg_addmerge_squash"
1027         then
1028                 first_split="$(find_latest_squash "$dir" "$repository")" || exit $?
1029                 if test -z "$first_split"
1030                 then
1031                         die "fatal: can't squash-merge: '$dir' was never added."
1032                 fi
1033                 set $first_split
1034                 old=$1
1035                 sub=$2
1036                 if test "$sub" = "$rev"
1037                 then
1038                         say >&2 "Subtree is already at commit $rev."
1039                         exit 0
1040                 fi
1041                 new=$(new_squash_commit "$old" "$sub" "$rev") || exit $?
1042                 debug "New squash commit: $new"
1043                 rev="$new"
1044         fi
1045
1046         if test -n "$arg_addmerge_message"
1047         then
1048                 git merge --no-ff -Xsubtree="$arg_prefix" \
1049                         --message="$arg_addmerge_message" "$rev"
1050         else
1051                 git merge --no-ff -Xsubtree="$arg_prefix" $rev
1052         fi
1053 }
1054
1055 # Usage: cmd_pull REPOSITORY REMOTEREF
1056 cmd_pull () {
1057         if test $# -ne 2
1058         then
1059                 die "fatal: you must provide <repository> <ref>"
1060         fi
1061         repository="$1"
1062         ref="$2"
1063         ensure_clean
1064         ensure_valid_ref_format "$ref"
1065         git fetch "$repository" "$ref" || exit $?
1066         cmd_merge FETCH_HEAD "$repository"
1067 }
1068
1069 # Usage: cmd_push REPOSITORY [+][LOCALREV:]REMOTEREF
1070 cmd_push () {
1071         if test $# -ne 2
1072         then
1073                 die "fatal: you must provide <repository> <refspec>"
1074         fi
1075         if test -e "$dir"
1076         then
1077                 repository=$1
1078                 refspec=${2#+}
1079                 remoteref=${refspec#*:}
1080                 if test "$remoteref" = "$refspec"
1081                 then
1082                         localrevname_presplit=HEAD
1083                 else
1084                         localrevname_presplit=${refspec%%:*}
1085                 fi
1086                 ensure_valid_ref_format "$remoteref"
1087                 localrev_presplit=$(git rev-parse -q --verify "$localrevname_presplit^{commit}") ||
1088                         die "fatal: '$localrevname_presplit' does not refer to a commit"
1089
1090                 echo "git push using: " "$repository" "$refspec"
1091                 localrev=$(cmd_split "$localrev_presplit" "$repository") || die
1092                 git push "$repository" "$localrev":"refs/heads/$remoteref"
1093         else
1094                 die "fatal: '$dir' must already exist. Try 'git subtree add'."
1095         fi
1096 }
1097
1098 main "$@"