git-merge.sh

   1 #!/bin/sh
   2 #
   3 # Copyright (c) 2005 Junio C Hamano
   4 #
   5
   6 USAGE='[-n] [--no-commit] [--squash] [-s <strategy>] [-m=<merge-message>] <commit>+'
   7
   8 SUBDIRECTORY_OK=Yes
   9 . git-sh-setup
  10 set_reflog_action "merge $*"
  11 require_work_tree
  12 cd_to_toplevel
  13
  14 test -z "$(git ls-files -u)" ||
  15         die "You are in the middle of a conflicted merge."
  16
  17 LF='
  18 '
  19
  20 all_strategies='recur recursive octopus resolve stupid ours'
  21 default_twohead_strategies='recursive'
  22 default_octopus_strategies='octopus'
  23 no_trivial_merge_strategies='ours'
  24 use_strategies=
  25
  26 index_merge=t
  27
  28 dropsave() {
  29         rm -f -- "$GIT_DIR/MERGE_HEAD" "$GIT_DIR/MERGE_MSG" \
  30                  "$GIT_DIR/MERGE_SAVE" || exit 1
  31 }
  32
  33 savestate() {
  34         # Stash away any local modifications.
  35         git-diff-index -z --name-only $head |
  36         cpio -0 -o >"$GIT_DIR/MERGE_SAVE"
  37 }
  38
  39 restorestate() {
  40         if test -f "$GIT_DIR/MERGE_SAVE"
  41         then
  42                 git reset --hard $head >/dev/null
  43                 cpio -iuv <"$GIT_DIR/MERGE_SAVE"
  44                 git-update-index --refresh >/dev/null
  45         fi
  46 }
  47
  48 finish_up_to_date () {
  49         case "$squash" in
  50         t)
  51                 echo "$1 (nothing to squash)" ;;
  52         '')
  53                 echo "$1" ;;
  54         esac
  55         dropsave
  56 }
  57
  58 squash_message () {
  59         echo Squashed commit of the following:
  60         echo
  61         git-log --no-merges ^"$head" $remote
  62 }
  63
  64 finish () {
  65         if test '' = "$2"
  66         then
  67                 rlogm="$GIT_REFLOG_ACTION"
  68         else
  69                 echo "$2"
  70                 rlogm="$GIT_REFLOG_ACTION: $2"
  71         fi
  72         case "$squash" in
  73         t)
  74                 echo "Squash commit -- not updating HEAD"
  75                 squash_message >"$GIT_DIR/SQUASH_MSG"
  76                 ;;
  77         '')
  78                 case "$merge_msg" in
  79                 '')
  80                         echo "No merge message -- not updating HEAD"
  81                         ;;
  82                 *)
  83                         git-update-ref -m "$rlogm" HEAD "$1" "$head" || exit 1
  84                         ;;
  85                 esac
  86                 ;;
  87         esac
  88         case "$1" in
  89         '')
  90                 ;;
  91         ?*)
  92                 case "$no_summary" in
  93                 '')
  94                         git-diff-tree --stat --summary -M "$head" "$1"
  95                         ;;
  96                 esac
  97                 ;;
  98         esac
  99 }
 100
 101 merge_local_changes () {
 102         merge_error=$(git-read-tree -m -u --exclude-per-directory=.gitignore $1 $2 2>&1) || (
 103
 104                 # First stash away the local changes
 105                 git diff-index --binary -p HEAD >"$GIT_DIR"/LOCAL_DIFF
 106
 107                 # Match the index to the working tree, and do a three-way.
 108                 git diff-files --name-only |
 109                 git update-index --remove --stdin &&
 110                 work=`git write-tree` &&
 111                 git read-tree --reset -u $2 &&
 112                 git read-tree -m -u --aggressive --exclude-per-directory=.gitignore $1 $2 $work || exit
 113
 114                 echo >&2 "Carrying local changes forward."
 115                 if result=`git write-tree 2>/dev/null`
 116                 then
 117                         echo >&2 "Trivially automerged."
 118                 else
 119                         git merge-index -o git-merge-one-file -a
 120                 fi
 121
 122                 # Do not register the cleanly merged paths in the index
 123                 # yet; this is not a real merge before committing, but
 124                 # just carrying the working tree changes along.
 125                 unmerged=`git ls-files -u`
 126                 git read-tree --reset $2
 127                 case "$unmerged" in
 128                 '')     ;;
 129                 *)
 130                         (
 131                                 z40=0000000000000000000000000000000000000000
 132                                 echo "$unmerged" |
 133                                 sed -e 's/^[0-7]* [0-9a-f]* /'"0 $z40 /"
 134                                 echo "$unmerged"
 135                         ) | git update-index --index-info
 136
 137                         echo >&2 "Conflicts in locally modified files:"
 138                         git diff --name-only --diff-filter=U >&2
 139                         echo >&2 "Your local changes are found in $GIT_DIR/LOCAL_DIFF"
 140                         ;;
 141                 esac
 142                 exit 0
 143         )
 144 }
 145
 146 merge_name () {
 147         remote="$1"
 148         rh=$(git-rev-parse --verify "$remote^0" 2>/dev/null) || return
 149         bh=$(git-show-ref -s --verify "refs/heads/$remote" 2>/dev/null)
 150         if test "$rh" = "$bh"
 151         then
 152                 echo "$rh               branch '$remote' of ."
 153         elif truname=$(expr "$remote" : '\(.*\)~[1-9][0-9]*$') &&
 154                 git-show-ref -q --verify "refs/heads/$truname" 2>/dev/null
 155         then
 156                 echo "$rh               branch '$truname' (early part) of ."
 157         else
 158                 echo "$rh               commit '$remote'"
 159         fi
 160 }
 161
 162 case "$#" in 0) usage ;; esac
 163
 164 have_message=
 165 while case "$#" in 0) break ;; esac
 166 do
 167         case "$1" in
 168         -n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
 169                 --no-summa|--no-summar|--no-summary)
 170                 no_summary=t ;;
 171         --sq|--squ|--squa|--squas|--squash)
 172                 squash=t no_commit=t ;;
 173         --no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
 174                 no_commit=t ;;
 175         -s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
 176                 --strateg=*|--strategy=*|\
 177         -s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
 178                 case "$#,$1" in
 179                 *,*=*)
 180                         strategy=`expr "z$1" : 'z-[^=]*=\(.*\)'` ;;
 181                 1,*)
 182                         usage ;;
 183                 *)
 184                         strategy="$2"
 185                         shift ;;
 186                 esac
 187                 case " $all_strategies " in
 188                 *" $strategy "*)
 189                         use_strategies="$use_strategies$strategy " ;;
 190                 *)
 191                         die "available strategies are: $all_strategies" ;;
 192                 esac
 193                 ;;
 194         -m=*|--m=*|--me=*|--mes=*|--mess=*|--messa=*|--messag=*|--message=*)
 195                 merge_msg=`expr "z$1" : 'z-[^=]*=\(.*\)'`
 196                 have_message=t
 197                 ;;
 198         -m|--m|--me|--mes|--mess|--messa|--messag|--message)
 199                 shift
 200                 case "$#" in
 201                 1)      usage ;;
 202                 esac
 203                 merge_msg="$1"
 204                 have_message=t
 205                 ;;
 206         -*)     usage ;;
 207         *)      break ;;
 208         esac
 209         shift
 210 done
 211
 212 # This could be traditional "merge <msg> HEAD <commit>..."  and the
 213 # way we can tell it is to see if the second token is HEAD, but some
 214 # people might have misused the interface and used a committish that
 215 # is the same as HEAD there instead.  Traditional format never would
 216 # have "-m" so it is an additional safety measure to check for it.
 217
 218 if test -z "$have_message" &&
 219         second_token=$(git-rev-parse --verify "$2^0" 2>/dev/null) &&
 220         head_commit=$(git-rev-parse --verify "HEAD" 2>/dev/null) &&
 221         test "$second_token" = "$head_commit"
 222 then
 223         merge_msg="$1"
 224         shift
 225         head_arg="$1"
 226         shift
 227 elif ! git-rev-parse --verify HEAD >/dev/null 2>&1
 228 then
 229         # If the merged head is a valid one there is no reason to
 230         # forbid "git merge" into a branch yet to be born.  We do
 231         # the same for "git pull".
 232         if test 1 -ne $#
 233         then
 234                 echo >&2 "Can merge only exactly one commit into empty head"
 235                 exit 1
 236         fi
 237
 238         rh=$(git rev-parse --verify "$1^0") ||
 239                 die "$1 - not something we can merge"
 240
 241         git-update-ref -m "initial pull" HEAD "$rh" "" &&
 242         git-read-tree --reset -u HEAD
 243         exit
 244
 245 else
 246         # We are invoked directly as the first-class UI.
 247         head_arg=HEAD
 248
 249         # All the rest are the commits being merged; prepare
 250         # the standard merge summary message to be appended to
 251         # the given message.  If remote is invalid we will die
 252         # later in the common codepath so we discard the error
 253         # in this loop.
 254         merge_name=$(for remote
 255                 do
 256                         merge_name "$remote"
 257                 done | git-fmt-merge-msg
 258         )
 259         merge_msg="${merge_msg:+$merge_msg$LF$LF}$merge_name"
 260 fi
 261 head=$(git-rev-parse --verify "$head_arg"^0) || usage
 262
 263 # All the rest are remote heads
 264 test "$#" = 0 && usage ;# we need at least one remote head.
 265
 266 remoteheads=
 267 for remote
 268 do
 269         remotehead=$(git-rev-parse --verify "$remote"^0 2>/dev/null) ||
 270             die "$remote - not something we can merge"
 271         remoteheads="${remoteheads}$remotehead "
 272         eval GITHEAD_$remotehead='"$remote"'
 273         export GITHEAD_$remotehead
 274 done
 275 set x $remoteheads ; shift
 276
 277 case "$use_strategies" in
 278 '')
 279         case "$#" in
 280         1)
 281                 var="`git-repo-config --get pull.twohead`"
 282                 if test -n "$var"
 283                 then
 284                         use_strategies="$var"
 285                 else
 286                         use_strategies="$default_twohead_strategies"
 287                 fi ;;
 288         *)
 289                 var="`git-repo-config --get pull.octopus`"
 290                 if test -n "$var"
 291                 then
 292                         use_strategies="$var"
 293                 else
 294                         use_strategies="$default_octopus_strategies"
 295                 fi ;;
 296         esac
 297         ;;
 298 esac
 299
 300 for s in $use_strategies
 301 do
 302         case " $s " in
 303         *" $no_trivial_merge_strategies "*)
 304                 index_merge=f
 305                 break
 306                 ;;
 307         esac
 308 done
 309
 310 case "$#" in
 311 1)
 312         common=$(git-merge-base --all $head "$@")
 313         ;;
 314 *)
 315         common=$(git-show-branch --merge-base $head "$@")
 316         ;;
 317 esac
 318 echo "$head" >"$GIT_DIR/ORIG_HEAD"
 319
 320 case "$index_merge,$#,$common,$no_commit" in
 321 f,*)
 322         # We've been told not to try anything clever.  Skip to real merge.
 323         ;;
 324 ?,*,'',*)
 325         # No common ancestors found. We need a real merge.
 326         ;;
 327 ?,1,"$1",*)
 328         # If head can reach all the merge then we are up to date.
 329         # but first the most common case of merging one remote.
 330         finish_up_to_date "Already up-to-date."
 331         exit 0
 332         ;;
 333 ?,1,"$head",*)
 334         # Again the most common case of merging one remote.
 335         echo "Updating $(git-rev-parse --short $head)..$(git-rev-parse --short $1)"
 336         git-update-index --refresh 2>/dev/null
 337         new_head=$(git-rev-parse --verify "$1^0") &&
 338         merge_local_changes $head $new_head &&
 339         finish "$new_head" "Fast forward"
 340         dropsave
 341         exit 0
 342         ;;
 343 ?,1,?*"$LF"?*,*)
 344         # We are not doing octopus and not fast forward.  Need a
 345         # real merge.
 346         ;;
 347 ?,1,*,)
 348         # We are not doing octopus, not fast forward, and have only
 349         # one common.
 350         git-update-index --refresh 2>/dev/null
 351         case " $use_strategies " in
 352         *' recursive '*|*' recur '*)
 353                 : run merge later
 354                 ;;
 355         *)
 356                 # See if it is really trivial.
 357                 git var GIT_COMMITTER_IDENT >/dev/null || exit
 358                 echo "Trying really trivial in-index merge..."
 359                 if git-read-tree --trivial -m -u -v $common $head "$1" &&
 360                    result_tree=$(git-write-tree)
 361                 then
 362                         echo "Wonderful."
 363                         result_commit=$(
 364                                 echo "$merge_msg" |
 365                                 git-commit-tree $result_tree -p HEAD -p "$1"
 366                         ) || exit
 367                         finish "$result_commit" "In-index merge"
 368                         dropsave
 369                         exit 0
 370                 fi
 371                 echo "Nope."
 372         esac
 373         ;;
 374 *)
 375         # An octopus.  If we can reach all the remote we are up to date.
 376         up_to_date=t
 377         for remote
 378         do
 379                 common_one=$(git-merge-base --all $head $remote)
 380                 if test "$common_one" != "$remote"
 381                 then
 382                         up_to_date=f
 383                         break
 384                 fi
 385         done
 386         if test "$up_to_date" = t
 387         then
 388                 finish_up_to_date "Already up-to-date. Yeeah!"
 389                 exit 0
 390         fi
 391         ;;
 392 esac
 393
 394 # We are going to make a new commit.
 395 git var GIT_COMMITTER_IDENT >/dev/null || exit
 396
 397 # At this point, we need a real merge.  No matter what strategy
 398 # we use, it would operate on the index, possibly affecting the
 399 # working tree, and when resolved cleanly, have the desired tree
 400 # in the index -- this means that the index must be in sync with
 401 # the $head commit.  The strategies are responsible to ensure this.
 402
 403 case "$use_strategies" in
 404 ?*' '?*)
 405     # Stash away the local changes so that we can try more than one.
 406     savestate
 407     single_strategy=no
 408     ;;
 409 *)
 410     rm -f "$GIT_DIR/MERGE_SAVE"
 411     single_strategy=yes
 412     ;;
 413 esac
 414
 415 result_tree= best_cnt=-1 best_strategy= wt_strategy=
 416 merge_was_ok=
 417 for strategy in $use_strategies
 418 do
 419     test "$wt_strategy" = '' || {
 420         echo "Rewinding the tree to pristine..."
 421         restorestate
 422     }
 423     case "$single_strategy" in
 424     no)
 425         echo "Trying merge strategy $strategy..."
 426         ;;
 427     esac
 428
 429     # Remember which strategy left the state in the working tree
 430     wt_strategy=$strategy
 431
 432     git-merge-$strategy $common -- "$head_arg" "$@"
 433     exit=$?
 434     if test "$no_commit" = t && test "$exit" = 0
 435     then
 436         merge_was_ok=t
 437         exit=1 ;# pretend it left conflicts.
 438     fi
 439
 440     test "$exit" = 0 || {
 441
 442         # The backend exits with 1 when conflicts are left to be resolved,
 443         # with 2 when it does not handle the given merge at all.
 444
 445         if test "$exit" -eq 1
 446         then
 447             cnt=`{
 448                 git-diff-files --name-only
 449                 git-ls-files --unmerged
 450             } | wc -l`
 451             if test $best_cnt -le 0 -o $cnt -le $best_cnt
 452             then
 453                 best_strategy=$strategy
 454                 best_cnt=$cnt
 455             fi
 456         fi
 457         continue
 458     }
 459
 460     # Automerge succeeded.
 461     result_tree=$(git-write-tree) && break
 462 done
 463
 464 # If we have a resulting tree, that means the strategy module
 465 # auto resolved the merge cleanly.
 466 if test '' != "$result_tree"
 467 then
 468     parents=$(git-show-branch --independent "$head" "$@" | sed -e 's/^/-p /')
 469     result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents) || exit
 470     finish "$result_commit" "Merge made by $wt_strategy."
 471     dropsave
 472     exit 0
 473 fi
 474
 475 # Pick the result from the best strategy and have the user fix it up.
 476 case "$best_strategy" in
 477 '')
 478         restorestate
 479         case "$use_strategies" in
 480         ?*' '?*)
 481                 echo >&2 "No merge strategy handled the merge."
 482                 ;;
 483         *)
 484                 echo >&2 "Merge with strategy $use_strategies failed."
 485                 ;;
 486         esac
 487         exit 2
 488         ;;
 489 "$wt_strategy")
 490         # We already have its result in the working tree.
 491         ;;
 492 *)
 493         echo "Rewinding the tree to pristine..."
 494         restorestate
 495         echo "Using the $best_strategy to prepare resolving by hand."
 496         git-merge-$best_strategy $common -- "$head_arg" "$@"
 497         ;;
 498 esac
 499
 500 if test "$squash" = t
 501 then
 502         finish
 503 else
 504         for remote
 505         do
 506                 echo $remote
 507         done >"$GIT_DIR/MERGE_HEAD"
 508         echo "$merge_msg" >"$GIT_DIR/MERGE_MSG"
 509 fi
 510
 511 if test "$merge_was_ok" = t
 512 then
 513         echo >&2 \
 514         "Automatic merge went well; stopped before committing as requested"
 515         exit 0
 516 else
 517         {
 518             echo '
 519 Conflicts:
 520 '
 521                 git ls-files --unmerged |
 522                 sed -e 's/^[^   ]*      /       /' |
 523                 uniq
 524         } >>"$GIT_DIR/MERGE_MSG"
 525         if test -d "$GIT_DIR/rr-cache"
 526         then
 527                 git-rerere
 528         fi
 529         die "Automatic merge failed; fix conflicts and then commit the result."
 530 fi