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