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