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