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