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 $# = 2 -o $# = 3
 377         b="$1"
 378         sq="$2"
 379         repository=""
 380         if test "$#" = 3
 381         then
 382                 repository="$3"
 383         fi
 384         fail_msg="fatal: could not rev-parse split hash $b from commit $sq"
 385         if ! sub="$(git rev-parse --verify --quiet "$b^{commit}")"
 386         then
 387                 # if 'repository' was given, try to fetch the 'git-subtree-split' hash
 388                 # before 'rev-parse'-ing it again, as it might be a tag that we do not have locally
 389                 if test -n "${repository}"
 390                 then
 391                         git fetch "$repository" "$b"
 392                         sub="$(git rev-parse --verify --quiet "$b^{commit}")" ||
 393                                 die "$fail_msg"
 394                 else
 395                         hint1=$(printf "hint: hash might be a tag, try fetching it from the subtree repository:")
 396                         hint2=$(printf "hint:    git fetch <subtree-repository> $b")
 397                         fail_msg=$(printf "$fail_msg\n$hint1\n$hint2")
 398                         die "$fail_msg"
 399                 fi
 400         fi
 401 }
 402
 403 # Usage: find_latest_squash DIR [REPOSITORY]
 404 find_latest_squash () {
 405         assert test $# = 1 -o $# = 2
 406         dir="$1"
 407         repository=""
 408         if test "$#" = 2
 409         then
 410                 repository="$2"
 411         fi
 412         debug "Looking for latest squash (dir=$dir, repository=$repository)..."
 413         local indent=$(($indent + 1))
 414
 415         sq=
 416         main=
 417         sub=
 418         git log --grep="^git-subtree-dir: $dir/*\$" \
 419                 --no-show-signature --pretty=format:'START %H%n%s%n%n%b%nEND%n' HEAD |
 420         while read a b junk
 421         do
 422                 debug "$a $b $junk"
 423                 debug "{{$sq/$main/$sub}}"
 424                 case "$a" in
 425                 START)
 426                         sq="$b"
 427                         ;;
 428                 git-subtree-mainline:)
 429                         main="$b"
 430                         ;;
 431                 git-subtree-split:)
 432                         process_subtree_split_trailer "$b" "$sq" "$repository"
 433                         ;;
 434                 END)
 435                         if test -n "$sub"
 436                         then
 437                                 if test -n "$main"
 438                                 then
 439                                         # a rejoin commit?
 440                                         # Pretend its sub was a squash.
 441                                         sq=$(git rev-parse --verify "$sq^2") ||
 442                                                 die
 443                                 fi
 444                                 debug "Squash found: $sq $sub"
 445                                 echo "$sq" "$sub"
 446                                 break
 447                         fi
 448                         sq=
 449                         main=
 450                         sub=
 451                         ;;
 452                 esac
 453         done || exit $?
 454 }
 455
 456 # Usage: find_existing_splits DIR REV [REPOSITORY]
 457 find_existing_splits () {
 458         assert test $# = 2 -o $# = 3
 459         debug "Looking for prior splits..."
 460         local indent=$(($indent + 1))
 461
 462         dir="$1"
 463         rev="$2"
 464         repository=""
 465         if test "$#" = 3
 466         then
 467                 repository="$3"
 468         fi
 469         main=
 470         sub=
 471         local grep_format="^git-subtree-dir: $dir/*\$"
 472         if test -n "$arg_split_ignore_joins"
 473         then
 474                 grep_format="^Add '$dir/' from commit '"
 475         fi
 476         git log --grep="$grep_format" \
 477                 --no-show-signature --pretty=format:'START %H%n%s%n%n%b%nEND%n' "$rev" |
 478         while read a b junk
 479         do
 480                 case "$a" in
 481                 START)
 482                         sq="$b"
 483                         ;;
 484                 git-subtree-mainline:)
 485                         main="$b"
 486                         ;;
 487                 git-subtree-split:)
 488                         process_subtree_split_trailer "$b" "$sq" "$repository"
 489                         ;;
 490                 END)
 491                         debug "Main is: '$main'"
 492                         if test -z "$main" -a -n "$sub"
 493                         then
 494                                 # squash commits refer to a subtree
 495                                 debug "  Squash: $sq from $sub"
 496                                 cache_set "$sq" "$sub"
 497                         fi
 498                         if test -n "$main" -a -n "$sub"
 499                         then
 500                                 debug "  Prior: $main -> $sub"
 501                                 cache_set $main $sub
 502                                 cache_set $sub $sub
 503                                 try_remove_previous "$main"
 504                                 try_remove_previous "$sub"
 505                         fi
 506                         main=
 507                         sub=
 508                         ;;
 509                 esac
 510         done || exit $?
 511 }
 512
 513 # Usage: copy_commit REV TREE FLAGS_STR
 514 copy_commit () {
 515         assert test $# = 3
 516         # We're going to set some environment vars here, so
 517         # do it in a subshell to get rid of them safely later
 518         debug copy_commit "{$1}" "{$2}" "{$3}"
 519         git log -1 --no-show-signature --pretty=format:'%an%n%ae%n%aD%n%cn%n%ce%n%cD%n%B' "$1" |
 520         (
 521                 read GIT_AUTHOR_NAME
 522                 read GIT_AUTHOR_EMAIL
 523                 read GIT_AUTHOR_DATE
 524                 read GIT_COMMITTER_NAME
 525                 read GIT_COMMITTER_EMAIL
 526                 read GIT_COMMITTER_DATE
 527                 export  GIT_AUTHOR_NAME \
 528                         GIT_AUTHOR_EMAIL \
 529                         GIT_AUTHOR_DATE \
 530                         GIT_COMMITTER_NAME \
 531                         GIT_COMMITTER_EMAIL \
 532                         GIT_COMMITTER_DATE
 533                 (
 534                         printf "%s" "$arg_split_annotate"
 535                         cat
 536                 ) |
 537                 git commit-tree "$2" $3  # reads the rest of stdin
 538         ) || die "fatal: can't copy commit $1"
 539 }
 540
 541 # Usage: add_msg DIR LATEST_OLD LATEST_NEW
 542 add_msg () {
 543         assert test $# = 3
 544         dir="$1"
 545         latest_old="$2"
 546         latest_new="$3"
 547         if test -n "$arg_addmerge_message"
 548         then
 549                 commit_message="$arg_addmerge_message"
 550         else
 551                 commit_message="Add '$dir/' from commit '$latest_new'"
 552         fi
 553         if test -n "$arg_split_rejoin"
 554         then
 555                 # If this is from a --rejoin, then rejoin_msg has
 556                 # already inserted the `git-subtree-xxx:` tags
 557                 echo "$commit_message"
 558                 return
 559         fi
 560         cat <<-EOF
 561                 $commit_message
 562
 563                 git-subtree-dir: $dir
 564                 git-subtree-mainline: $latest_old
 565                 git-subtree-split: $latest_new
 566         EOF
 567 }
 568
 569 # Usage: add_squashed_msg REV DIR
 570 add_squashed_msg () {
 571         assert test $# = 2
 572         if test -n "$arg_addmerge_message"
 573         then
 574                 echo "$arg_addmerge_message"
 575         else
 576                 echo "Merge commit '$1' as '$2'"
 577         fi
 578 }
 579
 580 # Usage: rejoin_msg DIR LATEST_OLD LATEST_NEW
 581 rejoin_msg () {
 582         assert test $# = 3
 583         dir="$1"
 584         latest_old="$2"
 585         latest_new="$3"
 586         if test -n "$arg_addmerge_message"
 587         then
 588                 commit_message="$arg_addmerge_message"
 589         else
 590                 commit_message="Split '$dir/' into commit '$latest_new'"
 591         fi
 592         cat <<-EOF
 593                 $commit_message
 594
 595                 git-subtree-dir: $dir
 596                 git-subtree-mainline: $latest_old
 597                 git-subtree-split: $latest_new
 598         EOF
 599 }
 600
 601 # Usage: squash_msg DIR OLD_SUBTREE_COMMIT NEW_SUBTREE_COMMIT
 602 squash_msg () {
 603         assert test $# = 3
 604         dir="$1"
 605         oldsub="$2"
 606         newsub="$3"
 607         newsub_short=$(git rev-parse --short "$newsub")
 608
 609         if test -n "$oldsub"
 610         then
 611                 oldsub_short=$(git rev-parse --short "$oldsub")
 612                 echo "Squashed '$dir/' changes from $oldsub_short..$newsub_short"
 613                 echo
 614                 git log --no-show-signature --pretty=tformat:'%h %s' "$oldsub..$newsub"
 615                 git log --no-show-signature --pretty=tformat:'REVERT: %h %s' "$newsub..$oldsub"
 616         else
 617                 echo "Squashed '$dir/' content from commit $newsub_short"
 618         fi
 619
 620         echo
 621         echo "git-subtree-dir: $dir"
 622         echo "git-subtree-split: $newsub"
 623 }
 624
 625 # Usage: toptree_for_commit COMMIT
 626 toptree_for_commit () {
 627         assert test $# = 1
 628         commit="$1"
 629         git rev-parse --verify "$commit^{tree}" || exit $?
 630 }
 631
 632 # Usage: subtree_for_commit COMMIT DIR
 633 subtree_for_commit () {
 634         assert test $# = 2
 635         commit="$1"
 636         dir="$2"
 637         git ls-tree "$commit" -- "$dir" |
 638         while read mode type tree name
 639         do
 640                 assert test "$name" = "$dir"
 641                 assert test "$type" = "tree" -o "$type" = "commit"
 642                 test "$type" = "commit" && continue  # ignore submodules
 643                 echo $tree
 644                 break
 645         done || exit $?
 646 }
 647
 648 # Usage: tree_changed TREE [PARENTS...]
 649 tree_changed () {
 650         assert test $# -gt 0
 651         tree=$1
 652         shift
 653         if test $# -ne 1
 654         then
 655                 return 0   # weird parents, consider it changed
 656         else
 657                 ptree=$(toptree_for_commit $1) || exit $?
 658                 if test "$ptree" != "$tree"
 659                 then
 660                         return 0   # changed
 661                 else
 662                         return 1   # not changed
 663                 fi
 664         fi
 665 }
 666
 667 # Usage: new_squash_commit OLD_SQUASHED_COMMIT OLD_NONSQUASHED_COMMIT NEW_NONSQUASHED_COMMIT
 668 new_squash_commit () {
 669         assert test $# = 3
 670         old="$1"
 671         oldsub="$2"
 672         newsub="$3"
 673         tree=$(toptree_for_commit $newsub) || exit $?
 674         if test -n "$old"
 675         then
 676                 squash_msg "$dir" "$oldsub" "$newsub" |
 677                 git commit-tree "$tree" -p "$old" || exit $?
 678         else
 679                 squash_msg "$dir" "" "$newsub" |
 680                 git commit-tree "$tree" || exit $?
 681         fi
 682 }
 683
 684 # Usage: copy_or_skip REV TREE NEWPARENTS
 685 copy_or_skip () {
 686         assert test $# = 3
 687         rev="$1"
 688         tree="$2"
 689         newparents="$3"
 690         assert test -n "$tree"
 691
 692         identical=
 693         nonidentical=
 694         p=
 695         gotparents=
 696         copycommit=
 697         for parent in $newparents
 698         do
 699                 ptree=$(toptree_for_commit $parent) || exit $?
 700                 test -z "$ptree" && continue
 701                 if test "$ptree" = "$tree"
 702                 then
 703                         # an identical parent could be used in place of this rev.
 704                         if test -n "$identical"
 705                         then
 706                                 # if a previous identical parent was found, check whether
 707                                 # one is already an ancestor of the other
 708                                 mergebase=$(git merge-base $identical $parent)
 709                                 if test "$identical" = "$mergebase"
 710                                 then
 711                                         # current identical commit is an ancestor of parent
 712                                         identical="$parent"
 713                                 elif test "$parent" != "$mergebase"
 714                                 then
 715                                         # no common history; commit must be copied
 716                                         copycommit=1
 717                                 fi
 718                         else
 719                                 # first identical parent detected
 720                                 identical="$parent"
 721                         fi
 722                 else
 723                         nonidentical="$parent"
 724                 fi
 725
 726                 # sometimes both old parents map to the same newparent;
 727                 # eliminate duplicates
 728                 is_new=1
 729                 for gp in $gotparents
 730                 do
 731                         if test "$gp" = "$parent"
 732                         then
 733                                 is_new=
 734                                 break
 735                         fi
 736                 done
 737                 if test -n "$is_new"
 738                 then
 739                         gotparents="$gotparents $parent"
 740                         p="$p -p $parent"
 741                 fi
 742         done
 743
 744         if test -n "$identical" && test -n "$nonidentical"
 745         then
 746                 extras=$(git rev-list --count $identical..$nonidentical)
 747                 if test "$extras" -ne 0
 748                 then
 749                         # we need to preserve history along the other branch
 750                         copycommit=1
 751                 fi
 752         fi
 753         if test -n "$identical" && test -z "$copycommit"
 754         then
 755                 echo $identical
 756         else
 757                 copy_commit "$rev" "$tree" "$p" || exit $?
 758         fi
 759 }
 760
 761 # Usage: ensure_clean
 762 ensure_clean () {
 763         assert test $# = 0
 764         if ! git diff-index HEAD --exit-code --quiet 2>&1
 765         then
 766                 die "fatal: working tree has modifications.  Cannot add."
 767         fi
 768         if ! git diff-index --cached HEAD --exit-code --quiet 2>&1
 769         then
 770                 die "fatal: index has modifications.  Cannot add."
 771         fi
 772 }
 773
 774 # Usage: ensure_valid_ref_format REF
 775 ensure_valid_ref_format () {
 776         assert test $# = 1
 777         git check-ref-format "refs/heads/$1" ||
 778                 die "fatal: '$1' does not look like a ref"
 779 }
 780
 781 # Usage: process_split_commit REV PARENTS
 782 process_split_commit () {
 783         assert test $# = 2
 784         local rev="$1"
 785         local parents="$2"
 786
 787         if test $indent -eq 0
 788         then
 789                 revcount=$(($revcount + 1))
 790         else
 791                 # processing commit without normal parent information;
 792                 # fetch from repo
 793                 parents=$(git rev-parse "$rev^@")
 794                 extracount=$(($extracount + 1))
 795         fi
 796
 797         progress "$revcount/$revmax ($createcount) [$extracount]"
 798
 799         debug "Processing commit: $rev"
 800         local indent=$(($indent + 1))
 801         exists=$(cache_get "$rev") || exit $?
 802         if test -n "$exists"
 803         then
 804                 debug "prior: $exists"
 805                 return
 806         fi
 807         createcount=$(($createcount + 1))
 808         debug "parents: $parents"
 809         check_parents $parents
 810         newparents=$(cache_get $parents) || exit $?
 811         debug "newparents: $newparents"
 812
 813         tree=$(subtree_for_commit "$rev" "$dir") || exit $?
 814         debug "tree is: $tree"
 815
 816         # ugly.  is there no better way to tell if this is a subtree
 817         # vs. a mainline commit?  Does it matter?
 818         if test -z "$tree"
 819         then
 820                 set_notree "$rev"
 821                 if test -n "$newparents"
 822                 then
 823                         cache_set "$rev" "$rev"
 824                 fi
 825                 return
 826         fi
 827
 828         newrev=$(copy_or_skip "$rev" "$tree" "$newparents") || exit $?
 829         debug "newrev is: $newrev"
 830         cache_set "$rev" "$newrev"
 831         cache_set latest_new "$newrev"
 832         cache_set latest_old "$rev"
 833 }
 834
 835 # Usage: cmd_add REV
 836 #    Or: cmd_add REPOSITORY REF
 837 cmd_add () {
 838
 839         ensure_clean
 840
 841         if test $# -eq 1
 842         then
 843                 git rev-parse -q --verify "$1^{commit}" >/dev/null ||
 844                         die "fatal: '$1' does not refer to a commit"
 845
 846                 cmd_add_commit "$@"
 847
 848         elif test $# -eq 2
 849         then
 850                 # Technically we could accept a refspec here but we're
 851                 # just going to turn around and add FETCH_HEAD under the
 852                 # specified directory.  Allowing a refspec might be
 853                 # misleading because we won't do anything with any other
 854                 # branches fetched via the refspec.
 855                 ensure_valid_ref_format "$2"
 856
 857                 cmd_add_repository "$@"
 858         else
 859                 say >&2 "fatal: parameters were '$*'"
 860                 die "Provide either a commit or a repository and commit."
 861         fi
 862 }
 863
 864 # Usage: cmd_add_repository REPOSITORY REFSPEC
 865 cmd_add_repository () {
 866         assert test $# = 2
 867         echo "git fetch" "$@"
 868         repository=$1
 869         refspec=$2
 870         git fetch "$@" || exit $?
 871         cmd_add_commit FETCH_HEAD
 872 }
 873
 874 # Usage: cmd_add_commit REV
 875 cmd_add_commit () {
 876         # The rev has already been validated by cmd_add(), we just
 877         # need to normalize it.
 878         assert test $# = 1
 879         rev=$(git rev-parse --verify "$1^{commit}") || exit $?
 880
 881         debug "Adding $dir as '$rev'..."
 882         if test -z "$arg_split_rejoin"
 883         then
 884                 # Only bother doing this if this is a genuine 'add',
 885                 # not a synthetic 'add' from '--rejoin'.
 886                 git read-tree --prefix="$dir" $rev || exit $?
 887         fi
 888         git checkout -- "$dir" || exit $?
 889         tree=$(git write-tree) || exit $?
 890
 891         headrev=$(git rev-parse --verify HEAD) || exit $?
 892         if test -n "$headrev" && test "$headrev" != "$rev"
 893         then
 894                 headp="-p $headrev"
 895         else
 896                 headp=
 897         fi
 898
 899         if test -n "$arg_addmerge_squash"
 900         then
 901                 rev=$(new_squash_commit "" "" "$rev") || exit $?
 902                 commit=$(add_squashed_msg "$rev" "$dir" |
 903                         git commit-tree "$tree" $headp -p "$rev") || exit $?
 904         else
 905                 revp=$(peel_committish "$rev") || exit $?
 906                 commit=$(add_msg "$dir" $headrev "$rev" |
 907                         git commit-tree "$tree" $headp -p "$revp") || exit $?
 908         fi
 909         git reset "$commit" || exit $?
 910
 911         say >&2 "Added dir '$dir'"
 912 }
 913
 914 # Usage: cmd_split [REV] [REPOSITORY]
 915 cmd_split () {
 916         if test $# -eq 0
 917         then
 918                 rev=$(git rev-parse HEAD)
 919         elif test $# -eq 1 -o $# -eq 2
 920         then
 921                 rev=$(git rev-parse -q --verify "$1^{commit}") ||
 922                         die "fatal: '$1' does not refer to a commit"
 923         else
 924                 die "fatal: you must provide exactly one revision, and optionnally a repository.  Got: '$*'"
 925         fi
 926         repository=""
 927         if test "$#" = 2
 928         then
 929                 repository="$2"
 930         fi
 931
 932         if test -n "$arg_split_rejoin"
 933         then
 934                 ensure_clean
 935         fi
 936
 937         debug "Splitting $dir..."
 938         cache_setup || exit $?
 939
 940         if test -n "$arg_split_onto"
 941         then
 942                 debug "Reading history for --onto=$arg_split_onto..."
 943                 git rev-list $arg_split_onto |
 944                 while read rev
 945                 do
 946                         # the 'onto' history is already just the subdir, so
 947                         # any parent we find there can be used verbatim
 948                         debug "cache: $rev"
 949                         cache_set "$rev" "$rev"
 950                 done || exit $?
 951         fi
 952
 953         unrevs="$(find_existing_splits "$dir" "$rev" "$repository")" || exit $?
 954
 955         # We can't restrict rev-list to only $dir here, because some of our
 956         # parents have the $dir contents the root, and those won't match.
 957         # (and rev-list --follow doesn't seem to solve this)
 958         grl='git rev-list --topo-order --reverse --parents $rev $unrevs'
 959         revmax=$(eval "$grl" | wc -l)
 960         revcount=0
 961         createcount=0
 962         extracount=0
 963         eval "$grl" |
 964         while read rev parents
 965         do
 966                 process_split_commit "$rev" "$parents"
 967         done || exit $?
 968
 969         latest_new=$(cache_get latest_new) || exit $?
 970         if test -z "$latest_new"
 971         then
 972                 die "fatal: no new revisions were found"
 973         fi
 974
 975         if test -n "$arg_split_rejoin"
 976         then
 977                 debug "Merging split branch into HEAD..."
 978                 latest_old=$(cache_get latest_old) || exit $?
 979                 arg_addmerge_message="$(rejoin_msg "$dir" "$latest_old" "$latest_new")" || exit $?
 980                 if test -z "$(find_latest_squash "$dir")"
 981                 then
 982                         cmd_add "$latest_new" >&2 || exit $?
 983                 else
 984                         cmd_merge "$latest_new" >&2 || exit $?
 985                 fi
 986         fi
 987         if test -n "$arg_split_branch"
 988         then
 989                 if rev_exists "refs/heads/$arg_split_branch"
 990                 then
 991                         if ! git merge-base --is-ancestor "$arg_split_branch" "$latest_new"
 992                         then
 993                                 die "fatal: branch '$arg_split_branch' is not an ancestor of commit '$latest_new'."
 994                         fi
 995                         action='Updated'
 996                 else
 997                         action='Created'
 998                 fi
 999                 git update-ref -m 'subtree split' \
1000                         "refs/heads/$arg_split_branch" "$latest_new" || exit $?
1001                 say >&2 "$action branch '$arg_split_branch'"
1002         fi
1003         echo "$latest_new"
1004         exit 0
1005 }
1006
1007 # Usage: cmd_merge REV [REPOSITORY]
1008 cmd_merge () {
1009         test $# -eq 1 -o $# -eq 2 ||
1010                 die "fatal: you must provide exactly one revision, and optionally a repository. Got: '$*'"
1011         rev=$(git rev-parse -q --verify "$1^{commit}") ||
1012                 die "fatal: '$1' does not refer to a commit"
1013         repository=""
1014         if test "$#" = 2
1015         then
1016                 repository="$2"
1017         fi
1018         ensure_clean
1019
1020         if test -n "$arg_addmerge_squash"
1021         then
1022                 first_split="$(find_latest_squash "$dir" "$repository")" || exit $?
1023                 if test -z "$first_split"
1024                 then
1025                         die "fatal: can't squash-merge: '$dir' was never added."
1026                 fi
1027                 set $first_split
1028                 old=$1
1029                 sub=$2
1030                 if test "$sub" = "$rev"
1031                 then
1032                         say >&2 "Subtree is already at commit $rev."
1033                         exit 0
1034                 fi
1035                 new=$(new_squash_commit "$old" "$sub" "$rev") || exit $?
1036                 debug "New squash commit: $new"
1037                 rev="$new"
1038         fi
1039
1040         if test -n "$arg_addmerge_message"
1041         then
1042                 git merge --no-ff -Xsubtree="$arg_prefix" \
1043                         --message="$arg_addmerge_message" "$rev"
1044         else
1045                 git merge --no-ff -Xsubtree="$arg_prefix" $rev
1046         fi
1047 }
1048
1049 # Usage: cmd_pull REPOSITORY REMOTEREF
1050 cmd_pull () {
1051         if test $# -ne 2
1052         then
1053                 die "fatal: you must provide <repository> <ref>"
1054         fi
1055         repository="$1"
1056         ref="$2"
1057         ensure_clean
1058         ensure_valid_ref_format "$ref"
1059         git fetch "$repository" "$ref" || exit $?
1060         cmd_merge FETCH_HEAD "$repository"
1061 }
1062
1063 # Usage: cmd_push REPOSITORY [+][LOCALREV:]REMOTEREF
1064 cmd_push () {
1065         if test $# -ne 2
1066         then
1067                 die "fatal: you must provide <repository> <refspec>"
1068         fi
1069         if test -e "$dir"
1070         then
1071                 repository=$1
1072                 refspec=${2#+}
1073                 remoteref=${refspec#*:}
1074                 if test "$remoteref" = "$refspec"
1075                 then
1076                         localrevname_presplit=HEAD
1077                 else
1078                         localrevname_presplit=${refspec%%:*}
1079                 fi
1080                 ensure_valid_ref_format "$remoteref"
1081                 localrev_presplit=$(git rev-parse -q --verify "$localrevname_presplit^{commit}") ||
1082                         die "fatal: '$localrevname_presplit' does not refer to a commit"
1083
1084                 echo "git push using: " "$repository" "$refspec"
1085                 localrev=$(cmd_split "$localrev_presplit" "$repository") || die
1086                 git push "$repository" "$localrev":"refs/heads/$remoteref"
1087         else
1088                 die "fatal: '$dir' must already exist. Try 'git subtree add'."
1089         fi
1090 }
1091
1092 main "$@"