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