git-merge.sh

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