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