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 "$1")
 235         local indent=$(($2 + 1))
 236         for miss in $missed
 237         do
 238                 if ! test -r "$cachedir/notree/$miss"
 239                 then
 240                         debug "  incorrect order: $miss"
 241                         process_split_commit "$miss" "" "$indent"
 242                 fi
 243         done
 244 }
 245
 246 set_notree () {
 247         echo "1" > "$cachedir/notree/$1"
 248 }
 249
 250 cache_set () {
 251         oldrev="$1"
 252         newrev="$2"
 253         if test "$oldrev" != "latest_old" &&
 254                 test "$oldrev" != "latest_new" &&
 255                 test -e "$cachedir/$oldrev"
 256         then
 257                 die "cache for $oldrev already exists!"
 258         fi
 259         echo "$newrev" >"$cachedir/$oldrev"
 260 }
 261
 262 rev_exists () {
 263         if git rev-parse "$1" >/dev/null 2>&1
 264         then
 265                 return 0
 266         else
 267                 return 1
 268         fi
 269 }
 270
 271 rev_is_descendant_of_branch () {
 272         newrev="$1"
 273         branch="$2"
 274         branch_hash=$(git rev-parse "$branch")
 275         match=$(git rev-list -1 "$branch_hash" "^$newrev")
 276
 277         if test -z "$match"
 278         then
 279                 return 0
 280         else
 281                 return 1
 282         fi
 283 }
 284
 285 # if a commit doesn't have a parent, this might not work.  But we only want
 286 # to remove the parent from the rev-list, and since it doesn't exist, it won't
 287 # be there anyway, so do nothing in that case.
 288 try_remove_previous () {
 289         if rev_exists "$1^"
 290         then
 291                 echo "^$1^"
 292         fi
 293 }
 294
 295 find_latest_squash () {
 296         debug "Looking for latest squash ($dir)..."
 297         dir="$1"
 298         sq=
 299         main=
 300         sub=
 301         git log --grep="^git-subtree-dir: $dir/*\$" \
 302                 --no-show-signature --pretty=format:'START %H%n%s%n%n%b%nEND%n' HEAD |
 303         while read a b junk
 304         do
 305                 debug "$a $b $junk"
 306                 debug "{{$sq/$main/$sub}}"
 307                 case "$a" in
 308                 START)
 309                         sq="$b"
 310                         ;;
 311                 git-subtree-mainline:)
 312                         main="$b"
 313                         ;;
 314                 git-subtree-split:)
 315                         sub="$(git rev-parse "$b^0")" ||
 316                         die "could not rev-parse split hash $b from commit $sq"
 317                         ;;
 318                 END)
 319                         if test -n "$sub"
 320                         then
 321                                 if test -n "$main"
 322                                 then
 323                                         # a rejoin commit?
 324                                         # Pretend its sub was a squash.
 325                                         sq="$sub"
 326                                 fi
 327                                 debug "Squash found: $sq $sub"
 328                                 echo "$sq" "$sub"
 329                                 break
 330                         fi
 331                         sq=
 332                         main=
 333                         sub=
 334                         ;;
 335                 esac
 336         done
 337 }
 338
 339 find_existing_splits () {
 340         debug "Looking for prior splits..."
 341         dir="$1"
 342         revs="$2"
 343         main=
 344         sub=
 345         local grep_format="^git-subtree-dir: $dir/*\$"
 346         if test -n "$ignore_joins"
 347         then
 348                 grep_format="^Add '$dir/' from commit '"
 349         fi
 350         git log --grep="$grep_format" \
 351                 --no-show-signature --pretty=format:'START %H%n%s%n%n%b%nEND%n' $revs |
 352         while read a b junk
 353         do
 354                 case "$a" in
 355                 START)
 356                         sq="$b"
 357                         ;;
 358                 git-subtree-mainline:)
 359                         main="$b"
 360                         ;;
 361                 git-subtree-split:)
 362                         sub="$(git rev-parse "$b^0")" ||
 363                         die "could not rev-parse split hash $b from commit $sq"
 364                         ;;
 365                 END)
 366                         debug "  Main is: '$main'"
 367                         if test -z "$main" -a -n "$sub"
 368                         then
 369                                 # squash commits refer to a subtree
 370                                 debug "  Squash: $sq from $sub"
 371                                 cache_set "$sq" "$sub"
 372                         fi
 373                         if test -n "$main" -a -n "$sub"
 374                         then
 375                                 debug "  Prior: $main -> $sub"
 376                                 cache_set $main $sub
 377                                 cache_set $sub $sub
 378                                 try_remove_previous "$main"
 379                                 try_remove_previous "$sub"
 380                         fi
 381                         main=
 382                         sub=
 383                         ;;
 384                 esac
 385         done
 386 }
 387
 388 copy_commit () {
 389         # We're going to set some environment vars here, so
 390         # do it in a subshell to get rid of them safely later
 391         debug copy_commit "{$1}" "{$2}" "{$3}"
 392         git log -1 --no-show-signature --pretty=format:'%an%n%ae%n%aD%n%cn%n%ce%n%cD%n%B' "$1" |
 393         (
 394                 read GIT_AUTHOR_NAME
 395                 read GIT_AUTHOR_EMAIL
 396                 read GIT_AUTHOR_DATE
 397                 read GIT_COMMITTER_NAME
 398                 read GIT_COMMITTER_EMAIL
 399                 read GIT_COMMITTER_DATE
 400                 export  GIT_AUTHOR_NAME \
 401                         GIT_AUTHOR_EMAIL \
 402                         GIT_AUTHOR_DATE \
 403                         GIT_COMMITTER_NAME \
 404                         GIT_COMMITTER_EMAIL \
 405                         GIT_COMMITTER_DATE
 406                 (
 407                         printf "%s" "$annotate"
 408                         cat
 409                 ) |
 410                 git commit-tree "$2" $3  # reads the rest of stdin
 411         ) || die "Can't copy commit $1"
 412 }
 413
 414 add_msg () {
 415         dir="$1"
 416         latest_old="$2"
 417         latest_new="$3"
 418         if test -n "$message"
 419         then
 420                 commit_message="$message"
 421         else
 422                 commit_message="Add '$dir/' from commit '$latest_new'"
 423         fi
 424         cat <<-EOF
 425                 $commit_message
 426
 427                 git-subtree-dir: $dir
 428                 git-subtree-mainline: $latest_old
 429                 git-subtree-split: $latest_new
 430         EOF
 431 }
 432
 433 add_squashed_msg () {
 434         if test -n "$message"
 435         then
 436                 echo "$message"
 437         else
 438                 echo "Merge commit '$1' as '$2'"
 439         fi
 440 }
 441
 442 rejoin_msg () {
 443         dir="$1"
 444         latest_old="$2"
 445         latest_new="$3"
 446         if test -n "$message"
 447         then
 448                 commit_message="$message"
 449         else
 450                 commit_message="Split '$dir/' into commit '$latest_new'"
 451         fi
 452         cat <<-EOF
 453                 $commit_message
 454
 455                 git-subtree-dir: $dir
 456                 git-subtree-mainline: $latest_old
 457                 git-subtree-split: $latest_new
 458         EOF
 459 }
 460
 461 squash_msg () {
 462         dir="$1"
 463         oldsub="$2"
 464         newsub="$3"
 465         newsub_short=$(git rev-parse --short "$newsub")
 466
 467         if test -n "$oldsub"
 468         then
 469                 oldsub_short=$(git rev-parse --short "$oldsub")
 470                 echo "Squashed '$dir/' changes from $oldsub_short..$newsub_short"
 471                 echo
 472                 git log --no-show-signature --pretty=tformat:'%h %s' "$oldsub..$newsub"
 473                 git log --no-show-signature --pretty=tformat:'REVERT: %h %s' "$newsub..$oldsub"
 474         else
 475                 echo "Squashed '$dir/' content from commit $newsub_short"
 476         fi
 477
 478         echo
 479         echo "git-subtree-dir: $dir"
 480         echo "git-subtree-split: $newsub"
 481 }
 482
 483 toptree_for_commit () {
 484         commit="$1"
 485         git rev-parse --verify "$commit^{tree}" || exit $?
 486 }
 487
 488 subtree_for_commit () {
 489         commit="$1"
 490         dir="$2"
 491         git ls-tree "$commit" -- "$dir" |
 492         while read mode type tree name
 493         do
 494                 assert test "$name" = "$dir"
 495                 assert test "$type" = "tree" -o "$type" = "commit"
 496                 test "$type" = "commit" && continue  # ignore submodules
 497                 echo $tree
 498                 break
 499         done
 500 }
 501
 502 tree_changed () {
 503         tree=$1
 504         shift
 505         if test $# -ne 1
 506         then
 507                 return 0   # weird parents, consider it changed
 508         else
 509                 ptree=$(toptree_for_commit $1)
 510                 if test "$ptree" != "$tree"
 511                 then
 512                         return 0   # changed
 513                 else
 514                         return 1   # not changed
 515                 fi
 516         fi
 517 }
 518
 519 new_squash_commit () {
 520         old="$1"
 521         oldsub="$2"
 522         newsub="$3"
 523         tree=$(toptree_for_commit $newsub) || exit $?
 524         if test -n "$old"
 525         then
 526                 squash_msg "$dir" "$oldsub" "$newsub" |
 527                 git commit-tree "$tree" -p "$old" || exit $?
 528         else
 529                 squash_msg "$dir" "" "$newsub" |
 530                 git commit-tree "$tree" || exit $?
 531         fi
 532 }
 533
 534 copy_or_skip () {
 535         rev="$1"
 536         tree="$2"
 537         newparents="$3"
 538         assert test -n "$tree"
 539
 540         identical=
 541         nonidentical=
 542         p=
 543         gotparents=
 544         copycommit=
 545         for parent in $newparents
 546         do
 547                 ptree=$(toptree_for_commit $parent) || exit $?
 548                 test -z "$ptree" && continue
 549                 if test "$ptree" = "$tree"
 550                 then
 551                         # an identical parent could be used in place of this rev.
 552                         if test -n "$identical"
 553                         then
 554                                 # if a previous identical parent was found, check whether
 555                                 # one is already an ancestor of the other
 556                                 mergebase=$(git merge-base $identical $parent)
 557                                 if test "$identical" = "$mergebase"
 558                                 then
 559                                         # current identical commit is an ancestor of parent
 560                                         identical="$parent"
 561                                 elif test "$parent" != "$mergebase"
 562                                 then
 563                                         # no common history; commit must be copied
 564                                         copycommit=1
 565                                 fi
 566                         else
 567                                 # first identical parent detected
 568                                 identical="$parent"
 569                         fi
 570                 else
 571                         nonidentical="$parent"
 572                 fi
 573
 574                 # sometimes both old parents map to the same newparent;
 575                 # eliminate duplicates
 576                 is_new=1
 577                 for gp in $gotparents
 578                 do
 579                         if test "$gp" = "$parent"
 580                         then
 581                                 is_new=
 582                                 break
 583                         fi
 584                 done
 585                 if test -n "$is_new"
 586                 then
 587                         gotparents="$gotparents $parent"
 588                         p="$p -p $parent"
 589                 fi
 590         done
 591
 592         if test -n "$identical" && test -n "$nonidentical"
 593         then
 594                 extras=$(git rev-list --count $identical..$nonidentical)
 595                 if test "$extras" -ne 0
 596                 then
 597                         # we need to preserve history along the other branch
 598                         copycommit=1
 599                 fi
 600         fi
 601         if test -n "$identical" && test -z "$copycommit"
 602         then
 603                 echo $identical
 604         else
 605                 copy_commit "$rev" "$tree" "$p" || exit $?
 606         fi
 607 }
 608
 609 ensure_clean () {
 610         if ! git diff-index HEAD --exit-code --quiet 2>&1
 611         then
 612                 die "Working tree has modifications.  Cannot add."
 613         fi
 614         if ! git diff-index --cached HEAD --exit-code --quiet 2>&1
 615         then
 616                 die "Index has modifications.  Cannot add."
 617         fi
 618 }
 619
 620 ensure_valid_ref_format () {
 621         git check-ref-format "refs/heads/$1" ||
 622                 die "'$1' does not look like a ref"
 623 }
 624
 625 process_split_commit () {
 626         local rev="$1"
 627         local parents="$2"
 628         local indent=$3
 629
 630         if test $indent -eq 0
 631         then
 632                 revcount=$(($revcount + 1))
 633         else
 634                 # processing commit without normal parent information;
 635                 # fetch from repo
 636                 parents=$(git rev-parse "$rev^@")
 637                 extracount=$(($extracount + 1))
 638         fi
 639
 640         progress "$revcount/$revmax ($createcount) [$extracount]"
 641
 642         debug "Processing commit: $rev"
 643         exists=$(cache_get "$rev")
 644         if test -n "$exists"
 645         then
 646                 debug "  prior: $exists"
 647                 return
 648         fi
 649         createcount=$(($createcount + 1))
 650         debug "  parents: $parents"
 651         check_parents "$parents" "$indent"
 652         newparents=$(cache_get $parents)
 653         debug "  newparents: $newparents"
 654
 655         tree=$(subtree_for_commit "$rev" "$dir")
 656         debug "  tree is: $tree"
 657
 658         # ugly.  is there no better way to tell if this is a subtree
 659         # vs. a mainline commit?  Does it matter?
 660         if test -z "$tree"
 661         then
 662                 set_notree "$rev"
 663                 if test -n "$newparents"
 664                 then
 665                         cache_set "$rev" "$rev"
 666                 fi
 667                 return
 668         fi
 669
 670         newrev=$(copy_or_skip "$rev" "$tree" "$newparents") || exit $?
 671         debug "  newrev is: $newrev"
 672         cache_set "$rev" "$newrev"
 673         cache_set latest_new "$newrev"
 674         cache_set latest_old "$rev"
 675 }
 676
 677 cmd_add () {
 678         if test -e "$dir"
 679         then
 680                 die "'$dir' already exists.  Cannot add."
 681         fi
 682
 683         ensure_clean
 684
 685         if test $# -eq 1
 686         then
 687                 git rev-parse -q --verify "$1^{commit}" >/dev/null ||
 688                         die "'$1' does not refer to a commit"
 689
 690                 cmd_add_commit "$@"
 691
 692         elif test $# -eq 2
 693         then
 694                 # Technically we could accept a refspec here but we're
 695                 # just going to turn around and add FETCH_HEAD under the
 696                 # specified directory.  Allowing a refspec might be
 697                 # misleading because we won't do anything with any other
 698                 # branches fetched via the refspec.
 699                 ensure_valid_ref_format "$2"
 700
 701                 cmd_add_repository "$@"
 702         else
 703                 say "error: parameters were '$@'"
 704                 die "Provide either a commit or a repository and commit."
 705         fi
 706 }
 707
 708 cmd_add_repository () {
 709         echo "git fetch" "$@"
 710         repository=$1
 711         refspec=$2
 712         git fetch "$@" || exit $?
 713         revs=FETCH_HEAD
 714         set -- $revs
 715         cmd_add_commit "$@"
 716 }
 717
 718 cmd_add_commit () {
 719         revs=$(git rev-parse $default --revs-only "$@") || exit $?
 720         set -- $revs
 721         rev="$1"
 722
 723         debug "Adding $dir as '$rev'..."
 724         git read-tree --prefix="$dir" $rev || exit $?
 725         git checkout -- "$dir" || exit $?
 726         tree=$(git write-tree) || exit $?
 727
 728         headrev=$(git rev-parse HEAD) || exit $?
 729         if test -n "$headrev" && test "$headrev" != "$rev"
 730         then
 731                 headp="-p $headrev"
 732         else
 733                 headp=
 734         fi
 735
 736         if test -n "$squash"
 737         then
 738                 rev=$(new_squash_commit "" "" "$rev") || exit $?
 739                 commit=$(add_squashed_msg "$rev" "$dir" |
 740                         git commit-tree "$tree" $headp -p "$rev") || exit $?
 741         else
 742                 revp=$(peel_committish "$rev") &&
 743                 commit=$(add_msg "$dir" $headrev "$rev" |
 744                         git commit-tree "$tree" $headp -p "$revp") || exit $?
 745         fi
 746         git reset "$commit" || exit $?
 747
 748         say "Added dir '$dir'"
 749 }
 750
 751 cmd_split () {
 752         debug "Splitting $dir..."
 753         cache_setup || exit $?
 754
 755         if test -n "$onto"
 756         then
 757                 debug "Reading history for --onto=$onto..."
 758                 git rev-list $onto |
 759                 while read rev
 760                 do
 761                         # the 'onto' history is already just the subdir, so
 762                         # any parent we find there can be used verbatim
 763                         debug "  cache: $rev"
 764                         cache_set "$rev" "$rev"
 765                 done
 766         fi
 767
 768         unrevs="$(find_existing_splits "$dir" "$revs")"
 769
 770         # We can't restrict rev-list to only $dir here, because some of our
 771         # parents have the $dir contents the root, and those won't match.
 772         # (and rev-list --follow doesn't seem to solve this)
 773         grl='git rev-list --topo-order --reverse --parents $revs $unrevs'
 774         revmax=$(eval "$grl" | wc -l)
 775         revcount=0
 776         createcount=0
 777         extracount=0
 778         eval "$grl" |
 779         while read rev parents
 780         do
 781                 process_split_commit "$rev" "$parents" 0
 782         done || exit $?
 783
 784         latest_new=$(cache_get latest_new)
 785         if test -z "$latest_new"
 786         then
 787                 die "No new revisions were found"
 788         fi
 789
 790         if test -n "$rejoin"
 791         then
 792                 debug "Merging split branch into HEAD..."
 793                 latest_old=$(cache_get latest_old)
 794                 git merge -s ours \
 795                         --allow-unrelated-histories \
 796                         -m "$(rejoin_msg "$dir" "$latest_old" "$latest_new")" \
 797                         "$latest_new" >&2 || exit $?
 798         fi
 799         if test -n "$branch"
 800         then
 801                 if rev_exists "refs/heads/$branch"
 802                 then
 803                         if ! rev_is_descendant_of_branch "$latest_new" "$branch"
 804                         then
 805                                 die "Branch '$branch' is not an ancestor of commit '$latest_new'."
 806                         fi
 807                         action='Updated'
 808                 else
 809                         action='Created'
 810                 fi
 811                 git update-ref -m 'subtree split' \
 812                         "refs/heads/$branch" "$latest_new" || exit $?
 813                 say "$action branch '$branch'"
 814         fi
 815         echo "$latest_new"
 816         exit 0
 817 }
 818
 819 cmd_merge () {
 820         revs=$(git rev-parse $default --revs-only "$@") || exit $?
 821         ensure_clean
 822
 823         set -- $revs
 824         if test $# -ne 1
 825         then
 826                 die "You must provide exactly one revision.  Got: '$revs'"
 827         fi
 828         rev="$1"
 829
 830         if test -n "$squash"
 831         then
 832                 first_split="$(find_latest_squash "$dir")"
 833                 if test -z "$first_split"
 834                 then
 835                         die "Can't squash-merge: '$dir' was never added."
 836                 fi
 837                 set $first_split
 838                 old=$1
 839                 sub=$2
 840                 if test "$sub" = "$rev"
 841                 then
 842                         say "Subtree is already at commit $rev."
 843                         exit 0
 844                 fi
 845                 new=$(new_squash_commit "$old" "$sub" "$rev") || exit $?
 846                 debug "New squash commit: $new"
 847                 rev="$new"
 848         fi
 849
 850         version=$(git version)
 851         if test "$version" \< "git version 1.7"
 852         then
 853                 if test -n "$message"
 854                 then
 855                         git merge -s subtree --message="$message" "$rev"
 856                 else
 857                         git merge -s subtree "$rev"
 858                 fi
 859         else
 860                 if test -n "$message"
 861                 then
 862                         git merge -Xsubtree="$prefix" \
 863                                 --message="$message" "$rev"
 864                 else
 865                         git merge -Xsubtree="$prefix" $rev
 866                 fi
 867         fi
 868 }
 869
 870 cmd_pull () {
 871         if test $# -ne 2
 872         then
 873                 die "You must provide <repository> <ref>"
 874         fi
 875         ensure_clean
 876         ensure_valid_ref_format "$2"
 877         git fetch "$@" || exit $?
 878         revs=FETCH_HEAD
 879         set -- $revs
 880         cmd_merge "$@"
 881 }
 882
 883 cmd_push () {
 884         if test $# -ne 2
 885         then
 886                 die "You must provide <repository> <ref>"
 887         fi
 888         ensure_valid_ref_format "$2"
 889         if test -e "$dir"
 890         then
 891                 repository=$1
 892                 refspec=$2
 893                 echo "git push using: " "$repository" "$refspec"
 894                 localrev=$(git subtree split --prefix="$prefix") || die
 895                 git push "$repository" "$localrev":"refs/heads/$refspec"
 896         else
 897                 die "'$dir' must already exist. Try 'git subtree add'."
 898         fi
 899 }
 900
 901 "cmd_$command" "$@"