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