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