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