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