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