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 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         local grep_format="^git-subtree-dir: $dir/*\$"
 344         if test -n "$ignore_joins"
 345         then
 346                 grep_format="^Add '$dir/' from commit '"
 347         fi
 348         git log --grep="$grep_format" \
 349                 --no-show-signature --pretty=format:'START %H%n%s%n%n%b%nEND%n' $revs |
 350         while read a b junk
 351         do
 352                 case "$a" in
 353                 START)
 354                         sq="$b"
 355                         ;;
 356                 git-subtree-mainline:)
 357                         main="$b"
 358                         ;;
 359                 git-subtree-split:)
 360                         sub="$(git rev-parse "$b^0")" ||
 361                         die "could not rev-parse split hash $b from commit $sq"
 362                         ;;
 363                 END)
 364                         debug "  Main is: '$main'"
 365                         if test -z "$main" -a -n "$sub"
 366                         then
 367                                 # squash commits refer to a subtree
 368                                 debug "  Squash: $sq from $sub"
 369                                 cache_set "$sq" "$sub"
 370                         fi
 371                         if test -n "$main" -a -n "$sub"
 372                         then
 373                                 debug "  Prior: $main -> $sub"
 374                                 cache_set $main $sub
 375                                 cache_set $sub $sub
 376                                 try_remove_previous "$main"
 377                                 try_remove_previous "$sub"
 378                         fi
 379                         main=
 380                         sub=
 381                         ;;
 382                 esac
 383         done
 384 }
 385
 386 copy_commit () {
 387         # We're going to set some environment vars here, so
 388         # do it in a subshell to get rid of them safely later
 389         debug copy_commit "{$1}" "{$2}" "{$3}"
 390         git log -1 --no-show-signature --pretty=format:'%an%n%ae%n%aD%n%cn%n%ce%n%cD%n%B' "$1" |
 391         (
 392                 read GIT_AUTHOR_NAME
 393                 read GIT_AUTHOR_EMAIL
 394                 read GIT_AUTHOR_DATE
 395                 read GIT_COMMITTER_NAME
 396                 read GIT_COMMITTER_EMAIL
 397                 read GIT_COMMITTER_DATE
 398                 export  GIT_AUTHOR_NAME \
 399                         GIT_AUTHOR_EMAIL \
 400                         GIT_AUTHOR_DATE \
 401                         GIT_COMMITTER_NAME \
 402                         GIT_COMMITTER_EMAIL \
 403                         GIT_COMMITTER_DATE
 404                 (
 405                         printf "%s" "$annotate"
 406                         cat
 407                 ) |
 408                 git commit-tree "$2" $3  # reads the rest of stdin
 409         ) || die "Can't copy commit $1"
 410 }
 411
 412 add_msg () {
 413         dir="$1"
 414         latest_old="$2"
 415         latest_new="$3"
 416         if test -n "$message"
 417         then
 418                 commit_message="$message"
 419         else
 420                 commit_message="Add '$dir/' from commit '$latest_new'"
 421         fi
 422         cat <<-EOF
 423                 $commit_message
 424
 425                 git-subtree-dir: $dir
 426                 git-subtree-mainline: $latest_old
 427                 git-subtree-split: $latest_new
 428         EOF
 429 }
 430
 431 add_squashed_msg () {
 432         if test -n "$message"
 433         then
 434                 echo "$message"
 435         else
 436                 echo "Merge commit '$1' as '$2'"
 437         fi
 438 }
 439
 440 rejoin_msg () {
 441         dir="$1"
 442         latest_old="$2"
 443         latest_new="$3"
 444         if test -n "$message"
 445         then
 446                 commit_message="$message"
 447         else
 448                 commit_message="Split '$dir/' into commit '$latest_new'"
 449         fi
 450         cat <<-EOF
 451                 $commit_message
 452
 453                 git-subtree-dir: $dir
 454                 git-subtree-mainline: $latest_old
 455                 git-subtree-split: $latest_new
 456         EOF
 457 }
 458
 459 squash_msg () {
 460         dir="$1"
 461         oldsub="$2"
 462         newsub="$3"
 463         newsub_short=$(git rev-parse --short "$newsub")
 464
 465         if test -n "$oldsub"
 466         then
 467                 oldsub_short=$(git rev-parse --short "$oldsub")
 468                 echo "Squashed '$dir/' changes from $oldsub_short..$newsub_short"
 469                 echo
 470                 git log --no-show-signature --pretty=tformat:'%h %s' "$oldsub..$newsub"
 471                 git log --no-show-signature --pretty=tformat:'REVERT: %h %s' "$newsub..$oldsub"
 472         else
 473                 echo "Squashed '$dir/' content from commit $newsub_short"
 474         fi
 475
 476         echo
 477         echo "git-subtree-dir: $dir"
 478         echo "git-subtree-split: $newsub"
 479 }
 480
 481 toptree_for_commit () {
 482         commit="$1"
 483         git rev-parse --verify "$commit^{tree}" || exit $?
 484 }
 485
 486 subtree_for_commit () {
 487         commit="$1"
 488         dir="$2"
 489         git ls-tree "$commit" -- "$dir" |
 490         while read mode type tree name
 491         do
 492                 assert test "$name" = "$dir"
 493                 assert test "$type" = "tree" -o "$type" = "commit"
 494                 test "$type" = "commit" && continue  # ignore submodules
 495                 echo $tree
 496                 break
 497         done
 498 }
 499
 500 tree_changed () {
 501         tree=$1
 502         shift
 503         if test $# -ne 1
 504         then
 505                 return 0   # weird parents, consider it changed
 506         else
 507                 ptree=$(toptree_for_commit $1)
 508                 if test "$ptree" != "$tree"
 509                 then
 510                         return 0   # changed
 511                 else
 512                         return 1   # not changed
 513                 fi
 514         fi
 515 }
 516
 517 new_squash_commit () {
 518         old="$1"
 519         oldsub="$2"
 520         newsub="$3"
 521         tree=$(toptree_for_commit $newsub) || exit $?
 522         if test -n "$old"
 523         then
 524                 squash_msg "$dir" "$oldsub" "$newsub" |
 525                 git commit-tree "$tree" -p "$old" || exit $?
 526         else
 527                 squash_msg "$dir" "" "$newsub" |
 528                 git commit-tree "$tree" || exit $?
 529         fi
 530 }
 531
 532 copy_or_skip () {
 533         rev="$1"
 534         tree="$2"
 535         newparents="$3"
 536         assert test -n "$tree"
 537
 538         identical=
 539         nonidentical=
 540         p=
 541         gotparents=
 542         for parent in $newparents
 543         do
 544                 ptree=$(toptree_for_commit $parent) || exit $?
 545                 test -z "$ptree" && continue
 546                 if test "$ptree" = "$tree"
 547                 then
 548                         # an identical parent could be used in place of this rev.
 549                         identical="$parent"
 550                 else
 551                         nonidentical="$parent"
 552                 fi
 553
 554                 # sometimes both old parents map to the same newparent;
 555                 # eliminate duplicates
 556                 is_new=1
 557                 for gp in $gotparents
 558                 do
 559                         if test "$gp" = "$parent"
 560                         then
 561                                 is_new=
 562                                 break
 563                         fi
 564                 done
 565                 if test -n "$is_new"
 566                 then
 567                         gotparents="$gotparents $parent"
 568                         p="$p -p $parent"
 569                 fi
 570         done
 571
 572         copycommit=
 573         if test -n "$identical" && test -n "$nonidentical"
 574         then
 575                 extras=$(git rev-list --count $identical..$nonidentical)
 576                 if test "$extras" -ne 0
 577                 then
 578                         # we need to preserve history along the other branch
 579                         copycommit=1
 580                 fi
 581         fi
 582         if test -n "$identical" && test -z "$copycommit"
 583         then
 584                 echo $identical
 585         else
 586                 copy_commit "$rev" "$tree" "$p" || exit $?
 587         fi
 588 }
 589
 590 ensure_clean () {
 591         if ! git diff-index HEAD --exit-code --quiet 2>&1
 592         then
 593                 die "Working tree has modifications.  Cannot add."
 594         fi
 595         if ! git diff-index --cached HEAD --exit-code --quiet 2>&1
 596         then
 597                 die "Index has modifications.  Cannot add."
 598         fi
 599 }
 600
 601 ensure_valid_ref_format () {
 602         git check-ref-format "refs/heads/$1" ||
 603                 die "'$1' does not look like a ref"
 604 }
 605
 606 process_split_commit () {
 607         local rev="$1"
 608         local parents="$2"
 609         revcount=$(($revcount + 1))
 610         progress "$revcount/$revmax ($createcount)"
 611         debug "Processing commit: $rev"
 612         exists=$(cache_get "$rev")
 613         if test -n "$exists"
 614         then
 615                 debug "  prior: $exists"
 616                 return
 617         fi
 618         createcount=$(($createcount + 1))
 619         debug "  parents: $parents"
 620         newparents=$(cache_get $parents)
 621         debug "  newparents: $newparents"
 622
 623         tree=$(subtree_for_commit "$rev" "$dir")
 624         debug "  tree is: $tree"
 625
 626         check_parents $parents
 627
 628         # ugly.  is there no better way to tell if this is a subtree
 629         # vs. a mainline commit?  Does it matter?
 630         if test -z "$tree"
 631         then
 632                 set_notree "$rev"
 633                 if test -n "$newparents"
 634                 then
 635                         cache_set "$rev" "$rev"
 636                 fi
 637                 return
 638         fi
 639
 640         newrev=$(copy_or_skip "$rev" "$tree" "$newparents") || exit $?
 641         debug "  newrev is: $newrev"
 642         cache_set "$rev" "$newrev"
 643         cache_set latest_new "$newrev"
 644         cache_set latest_old "$rev"
 645 }
 646
 647 cmd_add () {
 648         if test -e "$dir"
 649         then
 650                 die "'$dir' already exists.  Cannot add."
 651         fi
 652
 653         ensure_clean
 654
 655         if test $# -eq 1
 656         then
 657                 git rev-parse -q --verify "$1^{commit}" >/dev/null ||
 658                         die "'$1' does not refer to a commit"
 659
 660                 cmd_add_commit "$@"
 661
 662         elif test $# -eq 2
 663         then
 664                 # Technically we could accept a refspec here but we're
 665                 # just going to turn around and add FETCH_HEAD under the
 666                 # specified directory.  Allowing a refspec might be
 667                 # misleading because we won't do anything with any other
 668                 # branches fetched via the refspec.
 669                 ensure_valid_ref_format "$2"
 670
 671                 cmd_add_repository "$@"
 672         else
 673                 say "error: parameters were '$@'"
 674                 die "Provide either a commit or a repository and commit."
 675         fi
 676 }
 677
 678 cmd_add_repository () {
 679         echo "git fetch" "$@"
 680         repository=$1
 681         refspec=$2
 682         git fetch "$@" || exit $?
 683         revs=FETCH_HEAD
 684         set -- $revs
 685         cmd_add_commit "$@"
 686 }
 687
 688 cmd_add_commit () {
 689         revs=$(git rev-parse $default --revs-only "$@") || exit $?
 690         set -- $revs
 691         rev="$1"
 692
 693         debug "Adding $dir as '$rev'..."
 694         git read-tree --prefix="$dir" $rev || exit $?
 695         git checkout -- "$dir" || exit $?
 696         tree=$(git write-tree) || exit $?
 697
 698         headrev=$(git rev-parse HEAD) || exit $?
 699         if test -n "$headrev" && test "$headrev" != "$rev"
 700         then
 701                 headp="-p $headrev"
 702         else
 703                 headp=
 704         fi
 705
 706         if test -n "$squash"
 707         then
 708                 rev=$(new_squash_commit "" "" "$rev") || exit $?
 709                 commit=$(add_squashed_msg "$rev" "$dir" |
 710                         git commit-tree "$tree" $headp -p "$rev") || exit $?
 711         else
 712                 revp=$(peel_committish "$rev") &&
 713                 commit=$(add_msg "$dir" $headrev "$rev" |
 714                         git commit-tree "$tree" $headp -p "$revp") || exit $?
 715         fi
 716         git reset "$commit" || exit $?
 717
 718         say "Added dir '$dir'"
 719 }
 720
 721 cmd_split () {
 722         debug "Splitting $dir..."
 723         cache_setup || exit $?
 724
 725         if test -n "$onto"
 726         then
 727                 debug "Reading history for --onto=$onto..."
 728                 git rev-list $onto |
 729                 while read rev
 730                 do
 731                         # the 'onto' history is already just the subdir, so
 732                         # any parent we find there can be used verbatim
 733                         debug "  cache: $rev"
 734                         cache_set "$rev" "$rev"
 735                 done
 736         fi
 737
 738         unrevs="$(find_existing_splits "$dir" "$revs")"
 739
 740         # We can't restrict rev-list to only $dir here, because some of our
 741         # parents have the $dir contents the root, and those won't match.
 742         # (and rev-list --follow doesn't seem to solve this)
 743         grl='git rev-list --topo-order --reverse --parents $revs $unrevs'
 744         revmax=$(eval "$grl" | wc -l)
 745         revcount=0
 746         createcount=0
 747         eval "$grl" |
 748         while read rev parents
 749         do
 750                 process_split_commit "$rev" "$parents"
 751         done || exit $?
 752
 753         latest_new=$(cache_get latest_new)
 754         if test -z "$latest_new"
 755         then
 756                 die "No new revisions were found"
 757         fi
 758
 759         if test -n "$rejoin"
 760         then
 761                 debug "Merging split branch into HEAD..."
 762                 latest_old=$(cache_get latest_old)
 763                 git merge -s ours \
 764                         --allow-unrelated-histories \
 765                         -m "$(rejoin_msg "$dir" "$latest_old" "$latest_new")" \
 766                         "$latest_new" >&2 || exit $?
 767         fi
 768         if test -n "$branch"
 769         then
 770                 if rev_exists "refs/heads/$branch"
 771                 then
 772                         if ! rev_is_descendant_of_branch "$latest_new" "$branch"
 773                         then
 774                                 die "Branch '$branch' is not an ancestor of commit '$latest_new'."
 775                         fi
 776                         action='Updated'
 777                 else
 778                         action='Created'
 779                 fi
 780                 git update-ref -m 'subtree split' \
 781                         "refs/heads/$branch" "$latest_new" || exit $?
 782                 say "$action branch '$branch'"
 783         fi
 784         echo "$latest_new"
 785         exit 0
 786 }
 787
 788 cmd_merge () {
 789         revs=$(git rev-parse $default --revs-only "$@") || exit $?
 790         ensure_clean
 791
 792         set -- $revs
 793         if test $# -ne 1
 794         then
 795                 die "You must provide exactly one revision.  Got: '$revs'"
 796         fi
 797         rev="$1"
 798
 799         if test -n "$squash"
 800         then
 801                 first_split="$(find_latest_squash "$dir")"
 802                 if test -z "$first_split"
 803                 then
 804                         die "Can't squash-merge: '$dir' was never added."
 805                 fi
 806                 set $first_split
 807                 old=$1
 808                 sub=$2
 809                 if test "$sub" = "$rev"
 810                 then
 811                         say "Subtree is already at commit $rev."
 812                         exit 0
 813                 fi
 814                 new=$(new_squash_commit "$old" "$sub" "$rev") || exit $?
 815                 debug "New squash commit: $new"
 816                 rev="$new"
 817         fi
 818
 819         version=$(git version)
 820         if test "$version" \< "git version 1.7"
 821         then
 822                 if test -n "$message"
 823                 then
 824                         git merge -s subtree --message="$message" "$rev"
 825                 else
 826                         git merge -s subtree "$rev"
 827                 fi
 828         else
 829                 if test -n "$message"
 830                 then
 831                         git merge -Xsubtree="$prefix" \
 832                                 --message="$message" "$rev"
 833                 else
 834                         git merge -Xsubtree="$prefix" $rev
 835                 fi
 836         fi
 837 }
 838
 839 cmd_pull () {
 840         if test $# -ne 2
 841         then
 842                 die "You must provide <repository> <ref>"
 843         fi
 844         ensure_clean
 845         ensure_valid_ref_format "$2"
 846         git fetch "$@" || exit $?
 847         revs=FETCH_HEAD
 848         set -- $revs
 849         cmd_merge "$@"
 850 }
 851
 852 cmd_push () {
 853         if test $# -ne 2
 854         then
 855                 die "You must provide <repository> <ref>"
 856         fi
 857         ensure_valid_ref_format "$2"
 858         if test -e "$dir"
 859         then
 860                 repository=$1
 861                 refspec=$2
 862                 echo "git push using: " "$repository" "$refspec"
 863                 localrev=$(git subtree split --prefix="$prefix") || die
 864                 git push "$repository" "$localrev":"refs/heads/$refspec"
 865         else
 866                 die "'$dir' must already exist. Try 'git subtree add'."
 867         fi
 868 }
 869
 870 "cmd_$command" "$@"