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 if test $# -eq 0
   8 then
   9         set -- -h
  10 fi
  11 OPTS_SPEC="\
  12 git subtree add   --prefix=<prefix> <commit>
  13 git subtree add   --prefix=<prefix> <repository> <ref>
  14 git subtree merge --prefix=<prefix> <commit>
  15 git subtree pull  --prefix=<prefix> <repository> <ref>
  16 git subtree push  --prefix=<prefix> <repository> <ref>
  17 git subtree split --prefix=<prefix> <commit...>
  18 --
  19 h,help        show the help
  20 q             quiet
  21 d             show debug messages
  22 P,prefix=     the name of the subdir to split out
  23 m,message=    use the given message as the commit message for the merge commit
  24  options for 'split'
  25 annotate=     add a prefix to commit message of new commits
  26 b,branch=     create a new branch from the split subtree
  27 ignore-joins  ignore prior --rejoin commits
  28 onto=         try connecting new tree to an existing one
  29 rejoin        merge the new branch back into HEAD
  30  options for 'add', 'merge', and 'pull'
  31 squash        merge subtree changes as a single commit
  32 "
  33 eval "$(echo "$OPTS_SPEC" | git rev-parse --parseopt -- "$@" || echo exit $?)"
  34
  35 PATH=$PATH:$(git --exec-path)
  36 . git-sh-setup
  37
  38 require_work_tree
  39
  40 quiet=
  41 branch=
  42 debug=
  43 command=
  44 onto=
  45 rejoin=
  46 ignore_joins=
  47 annotate=
  48 squash=
  49 message=
  50 prefix=
  51
  52 debug () {
  53         if test -n "$debug"
  54         then
  55                 printf "%s\n" "$*" >&2
  56         fi
  57 }
  58
  59 say () {
  60         if test -z "$quiet"
  61         then
  62                 printf "%s\n" "$*" >&2
  63         fi
  64 }
  65
  66 progress () {
  67         if test -z "$quiet"
  68         then
  69                 printf "%s\r" "$*" >&2
  70         fi
  71 }
  72
  73 assert () {
  74         if ! "$@"
  75         then
  76                 die "assertion failed: " "$@"
  77         fi
  78 }
  79
  80
  81 while test $# -gt 0
  82 do
  83         opt="$1"
  84         shift
  85
  86         case "$opt" in
  87         -q)
  88                 quiet=1
  89                 ;;
  90         -d)
  91                 debug=1
  92                 ;;
  93         --annotate)
  94                 annotate="$1"
  95                 shift
  96                 ;;
  97         --no-annotate)
  98                 annotate=
  99                 ;;
 100         -b)
 101                 branch="$1"
 102                 shift
 103                 ;;
 104         -P)
 105                 prefix="${1%/}"
 106                 shift
 107                 ;;
 108         -m)
 109                 message="$1"
 110                 shift
 111                 ;;
 112         --no-prefix)
 113                 prefix=
 114                 ;;
 115         --onto)
 116                 onto="$1"
 117                 shift
 118                 ;;
 119         --no-onto)
 120                 onto=
 121                 ;;
 122         --rejoin)
 123                 rejoin=1
 124                 ;;
 125         --no-rejoin)
 126                 rejoin=
 127                 ;;
 128         --ignore-joins)
 129                 ignore_joins=1
 130                 ;;
 131         --no-ignore-joins)
 132                 ignore_joins=
 133                 ;;
 134         --squash)
 135                 squash=1
 136                 ;;
 137         --no-squash)
 138                 squash=
 139                 ;;
 140         --)
 141                 break
 142                 ;;
 143         *)
 144                 die "Unexpected option: $opt"
 145                 ;;
 146         esac
 147 done
 148
 149 command="$1"
 150 shift
 151
 152 case "$command" in
 153 add|merge|pull)
 154         default=
 155         ;;
 156 split|push)
 157         default="--default HEAD"
 158         ;;
 159 *)
 160         die "Unknown command '$command'"
 161         ;;
 162 esac
 163
 164 if test -z "$prefix"
 165 then
 166         die "You must provide the --prefix option."
 167 fi
 168
 169 case "$command" in
 170 add)
 171         test -e "$prefix" &&
 172                 die "prefix '$prefix' already exists."
 173         ;;
 174 *)
 175         test -e "$prefix" ||
 176                 die "'$prefix' does not exist; use 'git subtree add'"
 177         ;;
 178 esac
 179
 180 dir="$(dirname "$prefix/.")"
 181
 182 if test "$command" != "pull" &&
 183                 test "$command" != "add" &&
 184                 test "$command" != "push"
 185 then
 186         revs=$(git rev-parse $default --revs-only "$@") || exit $?
 187         dirs=$(git rev-parse --no-revs --no-flags "$@") || exit $?
 188         if test -n "$dirs"
 189         then
 190                 die "Error: Use --prefix instead of bare filenames."
 191         fi
 192 fi
 193
 194 debug "command: {$command}"
 195 debug "quiet: {$quiet}"
 196 debug "revs: {$revs}"
 197 debug "dir: {$dir}"
 198 debug "opts: {$*}"
 199 debug
 200
 201 cache_setup () {
 202         cachedir="$GIT_DIR/subtree-cache/$$"
 203         rm -rf "$cachedir" ||
 204                 die "Can't delete old cachedir: $cachedir"
 205         mkdir -p "$cachedir" ||
 206                 die "Can't create new cachedir: $cachedir"
 207         mkdir -p "$cachedir/notree" ||
 208                 die "Can't create new cachedir: $cachedir/notree"
 209         debug "Using cachedir: $cachedir" >&2
 210 }
 211
 212 cache_get () {
 213         for oldrev in "$@"
 214         do
 215                 if test -r "$cachedir/$oldrev"
 216                 then
 217                         read newrev <"$cachedir/$oldrev"
 218                         echo $newrev
 219                 fi
 220         done
 221 }
 222
 223 cache_miss () {
 224         for oldrev in "$@"
 225         do
 226                 if ! test -r "$cachedir/$oldrev"
 227                 then
 228                         echo $oldrev
 229                 fi
 230         done
 231 }
 232
 233 check_parents () {
 234         missed=$(cache_miss "$@")
 235         for miss in $missed
 236         do
 237                 if ! test -r "$cachedir/notree/$miss"
 238                 then
 239                         debug "  incorrect order: $miss"
 240                 fi
 241         done
 242 }
 243
 244 set_notree () {
 245         echo "1" > "$cachedir/notree/$1"
 246 }
 247
 248 cache_set () {
 249         oldrev="$1"
 250         newrev="$2"
 251         if test "$oldrev" != "latest_old" &&
 252                 test "$oldrev" != "latest_new" &&
 253                 test -e "$cachedir/$oldrev"
 254         then
 255                 die "cache for $oldrev already exists!"
 256         fi
 257         echo "$newrev" >"$cachedir/$oldrev"
 258 }
 259
 260 rev_exists () {
 261         if git rev-parse "$1" >/dev/null 2>&1
 262         then
 263                 return 0
 264         else
 265                 return 1
 266         fi
 267 }
 268
 269 rev_is_descendant_of_branch () {
 270         newrev="$1"
 271         branch="$2"
 272         branch_hash=$(git rev-parse "$branch")
 273         match=$(git rev-list -1 "$branch_hash" "^$newrev")
 274
 275         if test -z "$match"
 276         then
 277                 return 0
 278         else
 279                 return 1
 280         fi
 281 }
 282
 283 # if a commit doesn't have a parent, this might not work.  But we only want
 284 # to remove the parent from the rev-list, and since it doesn't exist, it won't
 285 # be there anyway, so do nothing in that case.
 286 try_remove_previous () {
 287         if rev_exists "$1^"
 288         then
 289                 echo "^$1^"
 290         fi
 291 }
 292
 293 find_latest_squash () {
 294         debug "Looking for latest squash ($dir)..."
 295         dir="$1"
 296         sq=
 297         main=
 298         sub=
 299         git log --grep="^git-subtree-dir: $dir/*\$" \
 300                 --no-show-signature --pretty=format:'START %H%n%s%n%n%b%nEND%n' HEAD |
 301         while read a b junk
 302         do
 303                 debug "$a $b $junk"
 304                 debug "{{$sq/$main/$sub}}"
 305                 case "$a" in
 306                 START)
 307                         sq="$b"
 308                         ;;
 309                 git-subtree-mainline:)
 310                         main="$b"
 311                         ;;
 312                 git-subtree-split:)
 313                         sub="$(git rev-parse "$b^0")" ||
 314                         die "could not rev-parse split hash $b from commit $sq"
 315                         ;;
 316                 END)
 317                         if test -n "$sub"
 318                         then
 319                                 if test -n "$main"
 320                                 then
 321                                         # a rejoin commit?
 322                                         # Pretend its sub was a squash.
 323                                         sq="$sub"
 324                                 fi
 325                                 debug "Squash found: $sq $sub"
 326                                 echo "$sq" "$sub"
 327                                 break
 328                         fi
 329                         sq=
 330                         main=
 331                         sub=
 332                         ;;
 333                 esac
 334         done
 335 }
 336
 337 find_existing_splits () {
 338         debug "Looking for prior splits..."
 339         dir="$1"
 340         revs="$2"
 341         main=
 342         sub=
 343         git log --grep="^git-subtree-dir: $dir/*\$" \
 344                 --no-show-signature --pretty=format:'START %H%n%s%n%n%b%nEND%n' $revs |
 345         while read a b junk
 346         do
 347                 case "$a" in
 348                 START)
 349                         sq="$b"
 350                         ;;
 351                 git-subtree-mainline:)
 352                         main="$b"
 353                         ;;
 354                 git-subtree-split:)
 355                         sub="$(git rev-parse "$b^0")" ||
 356                         die "could not rev-parse split hash $b from commit $sq"
 357                         ;;
 358                 END)
 359                         debug "  Main is: '$main'"
 360                         if test -z "$main" -a -n "$sub"
 361                         then
 362                                 # squash commits refer to a subtree
 363                                 debug "  Squash: $sq from $sub"
 364                                 cache_set "$sq" "$sub"
 365                         fi
 366                         if test -n "$main" -a -n "$sub"
 367                         then
 368                                 debug "  Prior: $main -> $sub"
 369                                 cache_set $main $sub
 370                                 cache_set $sub $sub
 371                                 try_remove_previous "$main"
 372                                 try_remove_previous "$sub"
 373                         fi
 374                         main=
 375                         sub=
 376                         ;;
 377                 esac
 378         done
 379 }
 380
 381 copy_commit () {
 382         # We're going to set some environment vars here, so
 383         # do it in a subshell to get rid of them safely later
 384         debug copy_commit "{$1}" "{$2}" "{$3}"
 385         git log -1 --no-show-signature --pretty=format:'%an%n%ae%n%aD%n%cn%n%ce%n%cD%n%B' "$1" |
 386         (
 387                 read GIT_AUTHOR_NAME
 388                 read GIT_AUTHOR_EMAIL
 389                 read GIT_AUTHOR_DATE
 390                 read GIT_COMMITTER_NAME
 391                 read GIT_COMMITTER_EMAIL
 392                 read GIT_COMMITTER_DATE
 393                 export  GIT_AUTHOR_NAME \
 394                         GIT_AUTHOR_EMAIL \
 395                         GIT_AUTHOR_DATE \
 396                         GIT_COMMITTER_NAME \
 397                         GIT_COMMITTER_EMAIL \
 398                         GIT_COMMITTER_DATE
 399                 (
 400                         printf "%s" "$annotate"
 401                         cat
 402                 ) |
 403                 git commit-tree "$2" $3  # reads the rest of stdin
 404         ) || die "Can't copy commit $1"
 405 }
 406
 407 add_msg () {
 408         dir="$1"
 409         latest_old="$2"
 410         latest_new="$3"
 411         if test -n "$message"
 412         then
 413                 commit_message="$message"
 414         else
 415                 commit_message="Add '$dir/' from commit '$latest_new'"
 416         fi
 417         cat <<-EOF
 418                 $commit_message
 419
 420                 git-subtree-dir: $dir
 421                 git-subtree-mainline: $latest_old
 422                 git-subtree-split: $latest_new
 423         EOF
 424 }
 425
 426 add_squashed_msg () {
 427         if test -n "$message"
 428         then
 429                 echo "$message"
 430         else
 431                 echo "Merge commit '$1' as '$2'"
 432         fi
 433 }
 434
 435 rejoin_msg () {
 436         dir="$1"
 437         latest_old="$2"
 438         latest_new="$3"
 439         if test -n "$message"
 440         then
 441                 commit_message="$message"
 442         else
 443                 commit_message="Split '$dir/' into commit '$latest_new'"
 444         fi
 445         cat <<-EOF
 446                 $commit_message
 447
 448                 git-subtree-dir: $dir
 449                 git-subtree-mainline: $latest_old
 450                 git-subtree-split: $latest_new
 451         EOF
 452 }
 453
 454 squash_msg () {
 455         dir="$1"
 456         oldsub="$2"
 457         newsub="$3"
 458         newsub_short=$(git rev-parse --short "$newsub")
 459
 460         if test -n "$oldsub"
 461         then
 462                 oldsub_short=$(git rev-parse --short "$oldsub")
 463                 echo "Squashed '$dir/' changes from $oldsub_short..$newsub_short"
 464                 echo
 465                 git log --no-show-signature --pretty=tformat:'%h %s' "$oldsub..$newsub"
 466                 git log --no-show-signature --pretty=tformat:'REVERT: %h %s' "$newsub..$oldsub"
 467         else
 468                 echo "Squashed '$dir/' content from commit $newsub_short"
 469         fi
 470
 471         echo
 472         echo "git-subtree-dir: $dir"
 473         echo "git-subtree-split: $newsub"
 474 }
 475
 476 toptree_for_commit () {
 477         commit="$1"
 478         git rev-parse --verify "$commit^{tree}" || exit $?
 479 }
 480
 481 subtree_for_commit () {
 482         commit="$1"
 483         dir="$2"
 484         git ls-tree "$commit" -- "$dir" |
 485         while read mode type tree name
 486         do
 487                 assert test "$name" = "$dir"
 488                 assert test "$type" = "tree" -o "$type" = "commit"
 489                 test "$type" = "commit" && continue  # ignore submodules
 490                 echo $tree
 491                 break
 492         done
 493 }
 494
 495 tree_changed () {
 496         tree=$1
 497         shift
 498         if test $# -ne 1
 499         then
 500                 return 0   # weird parents, consider it changed
 501         else
 502                 ptree=$(toptree_for_commit $1)
 503                 if test "$ptree" != "$tree"
 504                 then
 505                         return 0   # changed
 506                 else
 507                         return 1   # not changed
 508                 fi
 509         fi
 510 }
 511
 512 new_squash_commit () {
 513         old="$1"
 514         oldsub="$2"
 515         newsub="$3"
 516         tree=$(toptree_for_commit $newsub) || exit $?
 517         if test -n "$old"
 518         then
 519                 squash_msg "$dir" "$oldsub" "$newsub" |
 520                 git commit-tree "$tree" -p "$old" || exit $?
 521         else
 522                 squash_msg "$dir" "" "$newsub" |
 523                 git commit-tree "$tree" || exit $?
 524         fi
 525 }
 526
 527 copy_or_skip () {
 528         rev="$1"
 529         tree="$2"
 530         newparents="$3"
 531         assert test -n "$tree"
 532
 533         identical=
 534         nonidentical=
 535         p=
 536         gotparents=
 537         for parent in $newparents
 538         do
 539                 ptree=$(toptree_for_commit $parent) || exit $?
 540                 test -z "$ptree" && continue
 541                 if test "$ptree" = "$tree"
 542                 then
 543                         # an identical parent could be used in place of this rev.
 544                         identical="$parent"
 545                 else
 546                         nonidentical="$parent"
 547                 fi
 548
 549                 # sometimes both old parents map to the same newparent;
 550                 # eliminate duplicates
 551                 is_new=1
 552                 for gp in $gotparents
 553                 do
 554                         if test "$gp" = "$parent"
 555                         then
 556                                 is_new=
 557                                 break
 558                         fi
 559                 done
 560                 if test -n "$is_new"
 561                 then
 562                         gotparents="$gotparents $parent"
 563                         p="$p -p $parent"
 564                 fi
 565         done
 566
 567         copycommit=
 568         if test -n "$identical" && test -n "$nonidentical"
 569         then
 570                 extras=$(git rev-list --count $identical..$nonidentical)
 571                 if test "$extras" -ne 0
 572                 then
 573                         # we need to preserve history along the other branch
 574                         copycommit=1
 575                 fi
 576         fi
 577         if test -n "$identical" && test -z "$copycommit"
 578         then
 579                 echo $identical
 580         else
 581                 copy_commit "$rev" "$tree" "$p" || exit $?
 582         fi
 583 }
 584
 585 ensure_clean () {
 586         if ! git diff-index HEAD --exit-code --quiet 2>&1
 587         then
 588                 die "Working tree has modifications.  Cannot add."
 589         fi
 590         if ! git diff-index --cached HEAD --exit-code --quiet 2>&1
 591         then
 592                 die "Index has modifications.  Cannot add."
 593         fi
 594 }
 595
 596 ensure_valid_ref_format () {
 597         git check-ref-format "refs/heads/$1" ||
 598                 die "'$1' does not look like a ref"
 599 }
 600
 601 cmd_add () {
 602         if test -e "$dir"
 603         then
 604                 die "'$dir' already exists.  Cannot add."
 605         fi
 606
 607         ensure_clean
 608
 609         if test $# -eq 1
 610         then
 611                 git rev-parse -q --verify "$1^{commit}" >/dev/null ||
 612                         die "'$1' does not refer to a commit"
 613
 614                 cmd_add_commit "$@"
 615
 616         elif test $# -eq 2
 617         then
 618                 # Technically we could accept a refspec here but we're
 619                 # just going to turn around and add FETCH_HEAD under the
 620                 # specified directory.  Allowing a refspec might be
 621                 # misleading because we won't do anything with any other
 622                 # branches fetched via the refspec.
 623                 ensure_valid_ref_format "$2"
 624
 625                 cmd_add_repository "$@"
 626         else
 627                 say "error: parameters were '$@'"
 628                 die "Provide either a commit or a repository and commit."
 629         fi
 630 }
 631
 632 cmd_add_repository () {
 633         echo "git fetch" "$@"
 634         repository=$1
 635         refspec=$2
 636         git fetch "$@" || exit $?
 637         revs=FETCH_HEAD
 638         set -- $revs
 639         cmd_add_commit "$@"
 640 }
 641
 642 cmd_add_commit () {
 643         revs=$(git rev-parse $default --revs-only "$@") || exit $?
 644         set -- $revs
 645         rev="$1"
 646
 647         debug "Adding $dir as '$rev'..."
 648         git read-tree --prefix="$dir" $rev || exit $?
 649         git checkout -- "$dir" || exit $?
 650         tree=$(git write-tree) || exit $?
 651
 652         headrev=$(git rev-parse HEAD) || exit $?
 653         if test -n "$headrev" && test "$headrev" != "$rev"
 654         then
 655                 headp="-p $headrev"
 656         else
 657                 headp=
 658         fi
 659
 660         if test -n "$squash"
 661         then
 662                 rev=$(new_squash_commit "" "" "$rev") || exit $?
 663                 commit=$(add_squashed_msg "$rev" "$dir" |
 664                         git commit-tree "$tree" $headp -p "$rev") || exit $?
 665         else
 666                 revp=$(peel_committish "$rev") &&
 667                 commit=$(add_msg "$dir" $headrev "$rev" |
 668                         git commit-tree "$tree" $headp -p "$revp") || exit $?
 669         fi
 670         git reset "$commit" || exit $?
 671
 672         say "Added dir '$dir'"
 673 }
 674
 675 cmd_split () {
 676         debug "Splitting $dir..."
 677         cache_setup || exit $?
 678
 679         if test -n "$onto"
 680         then
 681                 debug "Reading history for --onto=$onto..."
 682                 git rev-list $onto |
 683                 while read rev
 684                 do
 685                         # the 'onto' history is already just the subdir, so
 686                         # any parent we find there can be used verbatim
 687                         debug "  cache: $rev"
 688                         cache_set "$rev" "$rev"
 689                 done
 690         fi
 691
 692         if test -n "$ignore_joins"
 693         then
 694                 unrevs=
 695         else
 696                 unrevs="$(find_existing_splits "$dir" "$revs")"
 697         fi
 698
 699         # We can't restrict rev-list to only $dir here, because some of our
 700         # parents have the $dir contents the root, and those won't match.
 701         # (and rev-list --follow doesn't seem to solve this)
 702         grl='git rev-list --topo-order --reverse --parents $revs $unrevs'
 703         revmax=$(eval "$grl" | wc -l)
 704         revcount=0
 705         createcount=0
 706         eval "$grl" |
 707         while read rev parents
 708         do
 709                 revcount=$(($revcount + 1))
 710                 progress "$revcount/$revmax ($createcount)"
 711                 debug "Processing commit: $rev"
 712                 exists=$(cache_get "$rev")
 713                 if test -n "$exists"
 714                 then
 715                         debug "  prior: $exists"
 716                         continue
 717                 fi
 718                 createcount=$(($createcount + 1))
 719                 debug "  parents: $parents"
 720                 newparents=$(cache_get $parents)
 721                 debug "  newparents: $newparents"
 722
 723                 tree=$(subtree_for_commit "$rev" "$dir")
 724                 debug "  tree is: $tree"
 725
 726                 check_parents $parents
 727
 728                 # ugly.  is there no better way to tell if this is a subtree
 729                 # vs. a mainline commit?  Does it matter?
 730                 if test -z "$tree"
 731                 then
 732                         set_notree "$rev"
 733                         if test -n "$newparents"
 734                         then
 735                                 cache_set "$rev" "$rev"
 736                         fi
 737                         continue
 738                 fi
 739
 740                 newrev=$(copy_or_skip "$rev" "$tree" "$newparents") || exit $?
 741                 debug "  newrev is: $newrev"
 742                 cache_set "$rev" "$newrev"
 743                 cache_set latest_new "$newrev"
 744                 cache_set latest_old "$rev"
 745         done || exit $?
 746
 747         latest_new=$(cache_get latest_new)
 748         if test -z "$latest_new"
 749         then
 750                 die "No new revisions were found"
 751         fi
 752
 753         if test -n "$rejoin"
 754         then
 755                 debug "Merging split branch into HEAD..."
 756                 latest_old=$(cache_get latest_old)
 757                 git merge -s ours \
 758                         --allow-unrelated-histories \
 759                         -m "$(rejoin_msg "$dir" "$latest_old" "$latest_new")" \
 760                         "$latest_new" >&2 || exit $?
 761         fi
 762         if test -n "$branch"
 763         then
 764                 if rev_exists "refs/heads/$branch"
 765                 then
 766                         if ! rev_is_descendant_of_branch "$latest_new" "$branch"
 767                         then
 768                                 die "Branch '$branch' is not an ancestor of commit '$latest_new'."
 769                         fi
 770                         action='Updated'
 771                 else
 772                         action='Created'
 773                 fi
 774                 git update-ref -m 'subtree split' \
 775                         "refs/heads/$branch" "$latest_new" || exit $?
 776                 say "$action branch '$branch'"
 777         fi
 778         echo "$latest_new"
 779         exit 0
 780 }
 781
 782 cmd_merge () {
 783         revs=$(git rev-parse $default --revs-only "$@") || exit $?
 784         ensure_clean
 785
 786         set -- $revs
 787         if test $# -ne 1
 788         then
 789                 die "You must provide exactly one revision.  Got: '$revs'"
 790         fi
 791         rev="$1"
 792
 793         if test -n "$squash"
 794         then
 795                 first_split="$(find_latest_squash "$dir")"
 796                 if test -z "$first_split"
 797                 then
 798                         die "Can't squash-merge: '$dir' was never added."
 799                 fi
 800                 set $first_split
 801                 old=$1
 802                 sub=$2
 803                 if test "$sub" = "$rev"
 804                 then
 805                         say "Subtree is already at commit $rev."
 806                         exit 0
 807                 fi
 808                 new=$(new_squash_commit "$old" "$sub" "$rev") || exit $?
 809                 debug "New squash commit: $new"
 810                 rev="$new"
 811         fi
 812
 813         version=$(git version)
 814         if test "$version" \< "git version 1.7"
 815         then
 816                 if test -n "$message"
 817                 then
 818                         git merge -s subtree --message="$message" "$rev"
 819                 else
 820                         git merge -s subtree "$rev"
 821                 fi
 822         else
 823                 if test -n "$message"
 824                 then
 825                         git merge -Xsubtree="$prefix" \
 826                                 --message="$message" "$rev"
 827                 else
 828                         git merge -Xsubtree="$prefix" $rev
 829                 fi
 830         fi
 831 }
 832
 833 cmd_pull () {
 834         if test $# -ne 2
 835         then
 836                 die "You must provide <repository> <ref>"
 837         fi
 838         ensure_clean
 839         ensure_valid_ref_format "$2"
 840         git fetch "$@" || exit $?
 841         revs=FETCH_HEAD
 842         set -- $revs
 843         cmd_merge "$@"
 844 }
 845
 846 cmd_push () {
 847         if test $# -ne 2
 848         then
 849                 die "You must provide <repository> <ref>"
 850         fi
 851         ensure_valid_ref_format "$2"
 852         if test -e "$dir"
 853         then
 854                 repository=$1
 855                 refspec=$2
 856                 echo "git push using: " "$repository" "$refspec"
 857                 localrev=$(git subtree split --prefix="$prefix") || die
 858                 git push "$repository" "$localrev":"refs/heads/$refspec"
 859         else
 860                 die "'$dir' must already exist. Try 'git subtree add'."
 861         fi
 862 }
 863
 864 "cmd_$command" "$@"