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