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