contrib/examples/git-merge.sh

   1 #!/bin/sh
   2 #
   3 # Copyright (c) 2005 Junio C Hamano
   4 #
   5
   6 OPTIONS_KEEPDASHDASH=
   7 OPTIONS_SPEC="\
   8 git merge [options] <remote>...
   9 git merge [options] <msg> HEAD <remote>
  10 --
  11 stat                 show a diffstat at the end of the merge
  12 n                    don't show a diffstat at the end of the merge
  13 summary              (synonym to --stat)
  14 log                  add list of one-line log to merge commit message
  15 squash               create a single commit instead of doing a merge
  16 commit               perform a commit if the merge succeeds (default)
  17 ff                   allow fast-forward (default)
  18 ff-only              abort if fast-forward is not possible
  19 rerere-autoupdate    update index with any reused conflict resolution
  20 s,strategy=          merge strategy to use
  21 X=                   option for selected merge strategy
  22 m,message=           message to be used for the merge commit (if any)
  23 "
  24
  25 SUBDIRECTORY_OK=Yes
  26 . git-sh-setup
  27 require_work_tree
  28 cd_to_toplevel
  29
  30 test -z "$(git ls-files -u)" ||
  31         die "Merge is not possible because you have unmerged files."
  32
  33 ! test -e "$GIT_DIR/MERGE_HEAD" ||
  34         die 'You have not concluded your merge (MERGE_HEAD exists).'
  35
  36 LF='
  37 '
  38
  39 all_strategies='recur recursive octopus resolve stupid ours subtree'
  40 all_strategies="$all_strategies recursive-ours recursive-theirs"
  41 not_strategies='base file index tree'
  42 default_twohead_strategies='recursive'
  43 default_octopus_strategies='octopus'
  44 no_fast_forward_strategies='subtree ours'
  45 no_trivial_strategies='recursive recur subtree ours recursive-ours recursive-theirs'
  46 use_strategies=
  47 xopt=
  48
  49 allow_fast_forward=t
  50 fast_forward_only=
  51 allow_trivial_merge=t
  52 squash= no_commit= log_arg= rr_arg=
  53
  54 dropsave() {
  55         rm -f -- "$GIT_DIR/MERGE_HEAD" "$GIT_DIR/MERGE_MSG" \
  56                  "$GIT_DIR/MERGE_STASH" "$GIT_DIR/MERGE_MODE" || exit 1
  57 }
  58
  59 savestate() {
  60         # Stash away any local modifications.
  61         git stash create >"$GIT_DIR/MERGE_STASH"
  62 }
  63
  64 restorestate() {
  65         if test -f "$GIT_DIR/MERGE_STASH"
  66         then
  67                 git reset --hard $head >/dev/null
  68                 git stash apply $(cat "$GIT_DIR/MERGE_STASH")
  69                 git update-index --refresh >/dev/null
  70         fi
  71 }
  72
  73 finish_up_to_date () {
  74         case "$squash" in
  75         t)
  76                 echo "$1 (nothing to squash)" ;;
  77         '')
  78                 echo "$1" ;;
  79         esac
  80         dropsave
  81 }
  82
  83 squash_message () {
  84         echo Squashed commit of the following:
  85         echo
  86         git log --no-merges --pretty=medium ^"$head" $remoteheads
  87 }
  88
  89 finish () {
  90         if test '' = "$2"
  91         then
  92                 rlogm="$GIT_REFLOG_ACTION"
  93         else
  94                 echo "$2"
  95                 rlogm="$GIT_REFLOG_ACTION: $2"
  96         fi
  97         case "$squash" in
  98         t)
  99                 echo "Squash commit -- not updating HEAD"
 100                 squash_message >"$GIT_DIR/SQUASH_MSG"
 101                 ;;
 102         '')
 103                 case "$merge_msg" in
 104                 '')
 105                         echo "No merge message -- not updating HEAD"
 106                         ;;
 107                 *)
 108                         git update-ref -m "$rlogm" HEAD "$1" "$head" || exit 1
 109                         git gc --auto
 110                         ;;
 111                 esac
 112                 ;;
 113         esac
 114         case "$1" in
 115         '')
 116                 ;;
 117         ?*)
 118                 if test "$show_diffstat" = t
 119                 then
 120                         # We want color (if set), but no pager
 121                         GIT_PAGER='' git diff --stat --summary -M "$head" "$1"
 122                 fi
 123                 ;;
 124         esac
 125
 126         # Run a post-merge hook
 127         if test -x "$GIT_DIR"/hooks/post-merge
 128         then
 129             case "$squash" in
 130             t)
 131                 "$GIT_DIR"/hooks/post-merge 1
 132                 ;;
 133             '')
 134                 "$GIT_DIR"/hooks/post-merge 0
 135                 ;;
 136             esac
 137         fi
 138 }
 139
 140 merge_name () {
 141         remote="$1"
 142         rh=$(git rev-parse --verify "$remote^0" 2>/dev/null) || return
 143         if truname=$(expr "$remote" : '\(.*\)~[0-9]*$') &&
 144                 git show-ref -q --verify "refs/heads/$truname" 2>/dev/null
 145         then
 146                 echo "$rh               branch '$truname' (early part) of ."
 147                 return
 148         fi
 149         if found_ref=$(git rev-parse --symbolic-full-name --verify \
 150                                                         "$remote" 2>/dev/null)
 151         then
 152                 expanded=$(git check-ref-format --branch "$remote") ||
 153                         exit
 154                 if test "${found_ref#refs/heads/}" != "$found_ref"
 155                 then
 156                         echo "$rh               branch '$expanded' of ."
 157                         return
 158                 elif test "${found_ref#refs/remotes/}" != "$found_ref"
 159                 then
 160                         echo "$rh               remote branch '$expanded' of ."
 161                         return
 162                 fi
 163         fi
 164         if test "$remote" = "FETCH_HEAD" && test -r "$GIT_DIR/FETCH_HEAD"
 165         then
 166                 sed -e 's/      not-for-merge   /               /' -e 1q \
 167                         "$GIT_DIR/FETCH_HEAD"
 168                 return
 169         fi
 170         echo "$rh               commit '$remote'"
 171 }
 172
 173 parse_config () {
 174         while test $# != 0; do
 175                 case "$1" in
 176                 -n|--no-stat|--no-summary)
 177                         show_diffstat=false ;;
 178                 --stat|--summary)
 179                         show_diffstat=t ;;
 180                 --log|--no-log)
 181                         log_arg=$1 ;;
 182                 --squash)
 183                         test "$allow_fast_forward" = t ||
 184                                 die "You cannot combine --squash with --no-ff."
 185                         squash=t no_commit=t ;;
 186                 --no-squash)
 187                         squash= no_commit= ;;
 188                 --commit)
 189                         no_commit= ;;
 190                 --no-commit)
 191                         no_commit=t ;;
 192                 --ff)
 193                         allow_fast_forward=t ;;
 194                 --no-ff)
 195                         test "$squash" != t ||
 196                                 die "You cannot combine --squash with --no-ff."
 197                         test "$fast_forward_only" != t ||
 198                                 die "You cannot combine --ff-only with --no-ff."
 199                         allow_fast_forward=f ;;
 200                 --ff-only)
 201                         test "$allow_fast_forward" != f ||
 202                                 die "You cannot combine --ff-only with --no-ff."
 203                         fast_forward_only=t ;;
 204                 --rerere-autoupdate|--no-rerere-autoupdate)
 205                         rr_arg=$1 ;;
 206                 -s|--strategy)
 207                         shift
 208                         case " $all_strategies " in
 209                         *" $1 "*)
 210                                 use_strategies="$use_strategies$1 "
 211                                 ;;
 212                         *)
 213                                 case " $not_strategies " in
 214                                 *" $1 "*)
 215                                         false
 216                                 esac &&
 217                                 type "git-merge-$1" >/dev/null 2>&1 ||
 218                                         die "available strategies are: $all_strategies"
 219                                 use_strategies="$use_strategies$1 "
 220                                 ;;
 221                         esac
 222                         ;;
 223                 -X)
 224                         shift
 225                         xopt="${xopt:+$xopt }$(git rev-parse --sq-quote "--$1")"
 226                         ;;
 227                 -m|--message)
 228                         shift
 229                         merge_msg="$1"
 230                         have_message=t
 231                         ;;
 232                 --)
 233                         shift
 234                         break ;;
 235                 *)      usage ;;
 236                 esac
 237                 shift
 238         done
 239         args_left=$#
 240 }
 241
 242 test $# != 0 || usage
 243
 244 have_message=
 245
 246 if branch=$(git-symbolic-ref -q HEAD)
 247 then
 248         mergeopts=$(git config "branch.${branch#refs/heads/}.mergeoptions")
 249         if test -n "$mergeopts"
 250         then
 251                 parse_config $mergeopts --
 252         fi
 253 fi
 254
 255 parse_config "$@"
 256 while test $args_left -lt $#; do shift; done
 257
 258 if test -z "$show_diffstat"; then
 259     test "$(git config --bool merge.diffstat)" = false && show_diffstat=false
 260     test "$(git config --bool merge.stat)" = false && show_diffstat=false
 261     test -z "$show_diffstat" && show_diffstat=t
 262 fi
 263
 264 # This could be traditional "merge <msg> HEAD <commit>..."  and the
 265 # way we can tell it is to see if the second token is HEAD, but some
 266 # people might have misused the interface and used a commit-ish that
 267 # is the same as HEAD there instead.  Traditional format never would
 268 # have "-m" so it is an additional safety measure to check for it.
 269
 270 if test -z "$have_message" &&
 271         second_token=$(git rev-parse --verify "$2^0" 2>/dev/null) &&
 272         head_commit=$(git rev-parse --verify "HEAD" 2>/dev/null) &&
 273         test "$second_token" = "$head_commit"
 274 then
 275         merge_msg="$1"
 276         shift
 277         head_arg="$1"
 278         shift
 279 elif ! git rev-parse --verify HEAD >/dev/null 2>&1
 280 then
 281         # If the merged head is a valid one there is no reason to
 282         # forbid "git merge" into a branch yet to be born.  We do
 283         # the same for "git pull".
 284         if test 1 -ne $#
 285         then
 286                 echo >&2 "Can merge only exactly one commit into empty head"
 287                 exit 1
 288         fi
 289
 290         test "$squash" != t ||
 291                 die "Squash commit into empty head not supported yet"
 292         test "$allow_fast_forward" = t ||
 293                 die "Non-fast-forward into an empty head does not make sense"
 294         rh=$(git rev-parse --verify "$1^0") ||
 295                 die "$1 - not something we can merge"
 296
 297         git update-ref -m "initial pull" HEAD "$rh" "" &&
 298         git read-tree --reset -u HEAD
 299         exit
 300
 301 else
 302         # We are invoked directly as the first-class UI.
 303         head_arg=HEAD
 304
 305         # All the rest are the commits being merged; prepare
 306         # the standard merge summary message to be appended to
 307         # the given message.  If remote is invalid we will die
 308         # later in the common codepath so we discard the error
 309         # in this loop.
 310         merge_msg="$(
 311                 for remote
 312                 do
 313                         merge_name "$remote"
 314                 done |
 315                 if test "$have_message" = t
 316                 then
 317                         git fmt-merge-msg -m "$merge_msg" $log_arg
 318                 else
 319                         git fmt-merge-msg $log_arg
 320                 fi
 321         )"
 322 fi
 323 head=$(git rev-parse --verify "$head_arg"^0) || usage
 324
 325 # All the rest are remote heads
 326 test "$#" = 0 && usage ;# we need at least one remote head.
 327 set_reflog_action "merge $*"
 328
 329 remoteheads=
 330 for remote
 331 do
 332         remotehead=$(git rev-parse --verify "$remote"^0 2>/dev/null) ||
 333             die "$remote - not something we can merge"
 334         remoteheads="${remoteheads}$remotehead "
 335         eval GITHEAD_$remotehead='"$remote"'
 336         export GITHEAD_$remotehead
 337 done
 338 set x $remoteheads ; shift
 339
 340 case "$use_strategies" in
 341 '')
 342         case "$#" in
 343         1)
 344                 var="$(git config --get pull.twohead)"
 345                 if test -n "$var"
 346                 then
 347                         use_strategies="$var"
 348                 else
 349                         use_strategies="$default_twohead_strategies"
 350                 fi ;;
 351         *)
 352                 var="$(git config --get pull.octopus)"
 353                 if test -n "$var"
 354                 then
 355                         use_strategies="$var"
 356                 else
 357                         use_strategies="$default_octopus_strategies"
 358                 fi ;;
 359         esac
 360         ;;
 361 esac
 362
 363 for s in $use_strategies
 364 do
 365         for ss in $no_fast_forward_strategies
 366         do
 367                 case " $s " in
 368                 *" $ss "*)
 369                         allow_fast_forward=f
 370                         break
 371                         ;;
 372                 esac
 373         done
 374         for ss in $no_trivial_strategies
 375         do
 376                 case " $s " in
 377                 *" $ss "*)
 378                         allow_trivial_merge=f
 379                         break
 380                         ;;
 381                 esac
 382         done
 383 done
 384
 385 case "$#" in
 386 1)
 387         common=$(git merge-base --all $head "$@")
 388         ;;
 389 *)
 390         common=$(git merge-base --all --octopus $head "$@")
 391         ;;
 392 esac
 393 echo "$head" >"$GIT_DIR/ORIG_HEAD"
 394
 395 case "$allow_fast_forward,$#,$common,$no_commit" in
 396 ?,*,'',*)
 397         # No common ancestors found. We need a real merge.
 398         ;;
 399 ?,1,"$1",*)
 400         # If head can reach all the merge then we are up to date.
 401         # but first the most common case of merging one remote.
 402         finish_up_to_date "Already up-to-date."
 403         exit 0
 404         ;;
 405 t,1,"$head",*)
 406         # Again the most common case of merging one remote.
 407         echo "Updating $(git rev-parse --short $head)..$(git rev-parse --short $1)"
 408         git update-index --refresh 2>/dev/null
 409         msg="Fast-forward"
 410         if test -n "$have_message"
 411         then
 412                 msg="$msg (no commit created; -m option ignored)"
 413         fi
 414         new_head=$(git rev-parse --verify "$1^0") &&
 415         git read-tree -v -m -u --exclude-per-directory=.gitignore $head "$new_head" &&
 416         finish "$new_head" "$msg" || exit
 417         dropsave
 418         exit 0
 419         ;;
 420 ?,1,?*"$LF"?*,*)
 421         # We are not doing octopus and not fast-forward.  Need a
 422         # real merge.
 423         ;;
 424 ?,1,*,)
 425         # We are not doing octopus, not fast-forward, and have only
 426         # one common.
 427         git update-index --refresh 2>/dev/null
 428         case "$allow_trivial_merge,$fast_forward_only" in
 429         t,)
 430                 # See if it is really trivial.
 431                 git var GIT_COMMITTER_IDENT >/dev/null || exit
 432                 echo "Trying really trivial in-index merge..."
 433                 if git read-tree --trivial -m -u -v $common $head "$1" &&
 434                    result_tree=$(git write-tree)
 435                 then
 436                         echo "Wonderful."
 437                         result_commit=$(
 438                                 printf '%s\n' "$merge_msg" |
 439                                 git commit-tree $result_tree -p HEAD -p "$1"
 440                         ) || exit
 441                         finish "$result_commit" "In-index merge"
 442                         dropsave
 443                         exit 0
 444                 fi
 445                 echo "Nope."
 446         esac
 447         ;;
 448 *)
 449         # An octopus.  If we can reach all the remote we are up to date.
 450         up_to_date=t
 451         for remote
 452         do
 453                 common_one=$(git merge-base --all $head $remote)
 454                 if test "$common_one" != "$remote"
 455                 then
 456                         up_to_date=f
 457                         break
 458                 fi
 459         done
 460         if test "$up_to_date" = t
 461         then
 462                 finish_up_to_date "Already up-to-date. Yeeah!"
 463                 exit 0
 464         fi
 465         ;;
 466 esac
 467
 468 if test "$fast_forward_only" = t
 469 then
 470         die "Not possible to fast-forward, aborting."
 471 fi
 472
 473 # We are going to make a new commit.
 474 git var GIT_COMMITTER_IDENT >/dev/null || exit
 475
 476 # At this point, we need a real merge.  No matter what strategy
 477 # we use, it would operate on the index, possibly affecting the
 478 # working tree, and when resolved cleanly, have the desired tree
 479 # in the index -- this means that the index must be in sync with
 480 # the $head commit.  The strategies are responsible to ensure this.
 481
 482 case "$use_strategies" in
 483 ?*' '?*)
 484     # Stash away the local changes so that we can try more than one.
 485     savestate
 486     single_strategy=no
 487     ;;
 488 *)
 489     rm -f "$GIT_DIR/MERGE_STASH"
 490     single_strategy=yes
 491     ;;
 492 esac
 493
 494 result_tree= best_cnt=-1 best_strategy= wt_strategy=
 495 merge_was_ok=
 496 for strategy in $use_strategies
 497 do
 498     test "$wt_strategy" = '' || {
 499         echo "Rewinding the tree to pristine..."
 500         restorestate
 501     }
 502     case "$single_strategy" in
 503     no)
 504         echo "Trying merge strategy $strategy..."
 505         ;;
 506     esac
 507
 508     # Remember which strategy left the state in the working tree
 509     wt_strategy=$strategy
 510
 511     eval 'git-merge-$strategy '"$xopt"' $common -- "$head_arg" "$@"'
 512     exit=$?
 513     if test "$no_commit" = t && test "$exit" = 0
 514     then
 515         merge_was_ok=t
 516         exit=1 ;# pretend it left conflicts.
 517     fi
 518
 519     test "$exit" = 0 || {
 520
 521         # The backend exits with 1 when conflicts are left to be resolved,
 522         # with 2 when it does not handle the given merge at all.
 523
 524         if test "$exit" -eq 1
 525         then
 526             cnt=$({
 527                 git diff-files --name-only
 528                 git ls-files --unmerged
 529             } | wc -l)
 530             if test $best_cnt -le 0 || test $cnt -le $best_cnt
 531             then
 532                 best_strategy=$strategy
 533                 best_cnt=$cnt
 534             fi
 535         fi
 536         continue
 537     }
 538
 539     # Automerge succeeded.
 540     result_tree=$(git write-tree) && break
 541 done
 542
 543 # If we have a resulting tree, that means the strategy module
 544 # auto resolved the merge cleanly.
 545 if test '' != "$result_tree"
 546 then
 547     if test "$allow_fast_forward" = "t"
 548     then
 549         parents=$(git merge-base --independent "$head" "$@")
 550     else
 551         parents=$(git rev-parse "$head" "$@")
 552     fi
 553     parents=$(echo "$parents" | sed -e 's/^/-p /')
 554     result_commit=$(printf '%s\n' "$merge_msg" | git commit-tree $result_tree $parents) || exit
 555     finish "$result_commit" "Merge made by $wt_strategy."
 556     dropsave
 557     exit 0
 558 fi
 559
 560 # Pick the result from the best strategy and have the user fix it up.
 561 case "$best_strategy" in
 562 '')
 563         restorestate
 564         case "$use_strategies" in
 565         ?*' '?*)
 566                 echo >&2 "No merge strategy handled the merge."
 567                 ;;
 568         *)
 569                 echo >&2 "Merge with strategy $use_strategies failed."
 570                 ;;
 571         esac
 572         exit 2
 573         ;;
 574 "$wt_strategy")
 575         # We already have its result in the working tree.
 576         ;;
 577 *)
 578         echo "Rewinding the tree to pristine..."
 579         restorestate
 580         echo "Using the $best_strategy to prepare resolving by hand."
 581         git-merge-$best_strategy $common -- "$head_arg" "$@"
 582         ;;
 583 esac
 584
 585 if test "$squash" = t
 586 then
 587         finish
 588 else
 589         for remote
 590         do
 591                 echo $remote
 592         done >"$GIT_DIR/MERGE_HEAD"
 593         printf '%s\n' "$merge_msg" >"$GIT_DIR/MERGE_MSG" ||
 594                 die "Could not write to $GIT_DIR/MERGE_MSG"
 595         if test "$allow_fast_forward" != t
 596         then
 597                 printf "%s" no-ff
 598         else
 599                 :
 600         fi >"$GIT_DIR/MERGE_MODE" ||
 601                 die "Could not write to $GIT_DIR/MERGE_MODE"
 602 fi
 603
 604 if test "$merge_was_ok" = t
 605 then
 606         echo >&2 \
 607         "Automatic merge went well; stopped before committing as requested"
 608         exit 0
 609 else
 610         {
 611             echo '
 612 Conflicts:
 613 '
 614                 git ls-files --unmerged |
 615                 sed -e 's/^[^   ]*      /       /' |
 616                 uniq
 617         } >>"$GIT_DIR/MERGE_MSG"
 618         git rerere $rr_arg
 619         die "Automatic merge failed; fix conflicts and then commit the result."
 620 fi