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.
 302         git-update-index --refresh 2>/dev/null
 303         case " $use_strategies " in
 304         *' recursive '*|*' recur '*)
 305                 : run merge later
 306                 ;;
 307         *)
 308                 # See if it is really trivial.
 309                 git var GIT_COMMITTER_IDENT >/dev/null || exit
 310                 echo "Trying really trivial in-index merge..."
 311                 if git-read-tree --trivial -m -u -v $common $head "$1" &&
 312                    result_tree=$(git-write-tree)
 313                 then
 314                         echo "Wonderful."
 315                         result_commit=$(
 316                                 echo "$merge_msg" |
 317                                 git-commit-tree $result_tree -p HEAD -p "$1"
 318                         ) || exit
 319                         finish "$result_commit" "In-index merge"
 320                         dropsave
 321                         exit 0
 322                 fi
 323                 echo "Nope."
 324         esac
 325         ;;
 326 *)
 327         # An octopus.  If we can reach all the remote we are up to date.
 328         up_to_date=t
 329         for remote
 330         do
 331                 common_one=$(git-merge-base --all $head $remote)
 332                 if test "$common_one" != "$remote"
 333                 then
 334                         up_to_date=f
 335                         break
 336                 fi
 337         done
 338         if test "$up_to_date" = t
 339         then
 340                 finish_up_to_date "Already up-to-date. Yeeah!"
 341                 exit 0
 342         fi
 343         ;;
 344 esac
 345
 346 # We are going to make a new commit.
 347 git var GIT_COMMITTER_IDENT >/dev/null || exit
 348
 349 # At this point, we need a real merge.  No matter what strategy
 350 # we use, it would operate on the index, possibly affecting the
 351 # working tree, and when resolved cleanly, have the desired tree
 352 # in the index -- this means that the index must be in sync with
 353 # the $head commit.  The strategies are responsible to ensure this.
 354
 355 case "$use_strategies" in
 356 ?*' '?*)
 357     # Stash away the local changes so that we can try more than one.
 358     savestate
 359     single_strategy=no
 360     ;;
 361 *)
 362     rm -f "$GIT_DIR/MERGE_SAVE"
 363     single_strategy=yes
 364     ;;
 365 esac
 366
 367 result_tree= best_cnt=-1 best_strategy= wt_strategy=
 368 merge_was_ok=
 369 for strategy in $use_strategies
 370 do
 371     test "$wt_strategy" = '' || {
 372         echo "Rewinding the tree to pristine..."
 373         restorestate
 374     }
 375     case "$single_strategy" in
 376     no)
 377         echo "Trying merge strategy $strategy..."
 378         ;;
 379     esac
 380
 381     # Remember which strategy left the state in the working tree
 382     wt_strategy=$strategy
 383
 384     git-merge-$strategy $common -- "$head_arg" "$@"
 385     exit=$?
 386     if test "$no_commit" = t && test "$exit" = 0
 387     then
 388         merge_was_ok=t
 389         exit=1 ;# pretend it left conflicts.
 390     fi
 391
 392     test "$exit" = 0 || {
 393
 394         # The backend exits with 1 when conflicts are left to be resolved,
 395         # with 2 when it does not handle the given merge at all.
 396
 397         if test "$exit" -eq 1
 398         then
 399             cnt=`{
 400                 git-diff-files --name-only
 401                 git-ls-files --unmerged
 402             } | wc -l`
 403             if test $best_cnt -le 0 -o $cnt -le $best_cnt
 404             then
 405                 best_strategy=$strategy
 406                 best_cnt=$cnt
 407             fi
 408         fi
 409         continue
 410     }
 411
 412     # Automerge succeeded.
 413     result_tree=$(git-write-tree) && break
 414 done
 415
 416 # If we have a resulting tree, that means the strategy module
 417 # auto resolved the merge cleanly.
 418 if test '' != "$result_tree"
 419 then
 420     parents=$(git-show-branch --independent "$head" "$@" | sed -e 's/^/-p /')
 421     result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents) || exit
 422     finish "$result_commit" "Merge made by $wt_strategy."
 423     dropsave
 424     exit 0
 425 fi
 426
 427 # Pick the result from the best strategy and have the user fix it up.
 428 case "$best_strategy" in
 429 '')
 430         restorestate
 431         case "$use_strategies" in
 432         ?*' '?*)
 433                 echo >&2 "No merge strategy handled the merge."
 434                 ;;
 435         *)
 436                 echo >&2 "Merge with strategy $use_strategies failed."
 437                 ;;
 438         esac
 439         exit 2
 440         ;;
 441 "$wt_strategy")
 442         # We already have its result in the working tree.
 443         ;;
 444 *)
 445         echo "Rewinding the tree to pristine..."
 446         restorestate
 447         echo "Using the $best_strategy to prepare resolving by hand."
 448         git-merge-$best_strategy $common -- "$head_arg" "$@"
 449         ;;
 450 esac
 451
 452 if test "$squash" = t
 453 then
 454         finish
 455 else
 456         for remote
 457         do
 458                 echo $remote
 459         done >"$GIT_DIR/MERGE_HEAD"
 460         echo "$merge_msg" >"$GIT_DIR/MERGE_MSG"
 461 fi
 462
 463 if test "$merge_was_ok" = t
 464 then
 465         echo >&2 \
 466         "Automatic merge went well; stopped before committing as requested"
 467         exit 0
 468 else
 469         {
 470             echo '
 471 Conflicts:
 472 '
 473                 git ls-files --unmerged |
 474                 sed -e 's/^[^   ]*      /       /' |
 475                 uniq
 476         } >>"$GIT_DIR/MERGE_MSG"
 477         if test -d "$GIT_DIR/rr-cache"
 478         then
 479                 git-rerere
 480         fi
 481         die "Automatic merge failed; fix conflicts and then commit the result."
 482 fi