git-merge.sh

   1 #!/bin/sh
   2 #
   3 # Copyright (c) 2005 Junio C Hamano
   4 #
   5
   6 USAGE='[-n] [--no-commit] [--squash] [-s <strategy>] [--reflog-action=<action>] [-m=<merge-message>] <commit>+'
   7
   8 . git-sh-setup
   9
  10 LF='
  11 '
  12
  13 all_strategies='recur recursive octopus resolve stupid ours'
  14 default_twohead_strategies='recursive'
  15 default_octopus_strategies='octopus'
  16 no_trivial_merge_strategies='ours'
  17 use_strategies=
  18
  19 index_merge=t
  20
  21 dropsave() {
  22         rm -f -- "$GIT_DIR/MERGE_HEAD" "$GIT_DIR/MERGE_MSG" \
  23                  "$GIT_DIR/MERGE_SAVE" || exit 1
  24 }
  25
  26 savestate() {
  27         # Stash away any local modifications.
  28         git-diff-index -z --name-only $head |
  29         cpio -0 -o >"$GIT_DIR/MERGE_SAVE"
  30 }
  31
  32 restorestate() {
  33         if test -f "$GIT_DIR/MERGE_SAVE"
  34         then
  35                 git reset --hard $head >/dev/null
  36                 cpio -iuv <"$GIT_DIR/MERGE_SAVE"
  37                 git-update-index --refresh >/dev/null
  38         fi
  39 }
  40
  41 finish_up_to_date () {
  42         case "$squash" in
  43         t)
  44                 echo "$1 (nothing to squash)" ;;
  45         '')
  46                 echo "$1" ;;
  47         esac
  48         dropsave
  49 }
  50
  51 squash_message () {
  52         echo Squashed commit of the following:
  53         echo
  54         git-log --no-merges ^"$head" $remote
  55 }
  56
  57 finish () {
  58         if test '' = "$2"
  59         then
  60                 rlogm="$rloga"
  61         else
  62                 echo "$2"
  63                 rlogm="$rloga: $2"
  64         fi
  65         case "$squash" in
  66         t)
  67                 echo "Squash commit -- not updating HEAD"
  68                 squash_message >"$GIT_DIR/SQUASH_MSG"
  69                 ;;
  70         '')
  71                 case "$merge_msg" in
  72                 '')
  73                         echo "No merge message -- not updating HEAD"
  74                         ;;
  75                 *)
  76                         git-update-ref -m "$rlogm" HEAD "$1" "$head" || exit 1
  77                         ;;
  78                 esac
  79                 ;;
  80         esac
  81         case "$1" in
  82         '')
  83                 ;;
  84         ?*)
  85                 case "$no_summary" in
  86                 '')
  87                         git-diff-tree --stat --summary -M "$head" "$1"
  88                         ;;
  89                 esac
  90                 ;;
  91         esac
  92 }
  93
  94 merge_name () {
  95         remote="$1"
  96         rh=$(git-rev-parse --verify "$remote^0" 2>/dev/null) || return
  97         bh=$(git-show-ref -s --verify "refs/heads/$remote" 2>/dev/null)
  98         if test "$rh" = "$bh"
  99         then
 100                 echo "$rh               branch '$remote' of ."
 101         elif truname=$(expr "$remote" : '\(.*\)~[1-9][0-9]*$') &&
 102                 git-show-ref -q --verify "refs/heads/$truname" 2>/dev/null
 103         then
 104                 echo "$rh               branch '$truname' (early part) of ."
 105         else
 106                 echo "$rh               commit '$remote'"
 107         fi
 108 }
 109
 110 case "$#" in 0) usage ;; esac
 111
 112 rloga= have_message=
 113 while case "$#" in 0) break ;; esac
 114 do
 115         case "$1" in
 116         -n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
 117                 --no-summa|--no-summar|--no-summary)
 118                 no_summary=t ;;
 119         --sq|--squ|--squa|--squas|--squash)
 120                 squash=t no_commit=t ;;
 121         --no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
 122                 no_commit=t ;;
 123         -s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
 124                 --strateg=*|--strategy=*|\
 125         -s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
 126                 case "$#,$1" in
 127                 *,*=*)
 128                         strategy=`expr "z$1" : 'z-[^=]*=\(.*\)'` ;;
 129                 1,*)
 130                         usage ;;
 131                 *)
 132                         strategy="$2"
 133                         shift ;;
 134                 esac
 135                 case " $all_strategies " in
 136                 *" $strategy "*)
 137                         use_strategies="$use_strategies$strategy " ;;
 138                 *)
 139                         die "available strategies are: $all_strategies" ;;
 140                 esac
 141                 ;;
 142         --reflog-action=*)
 143                 rloga=`expr "z$1" : 'z-[^=]*=\(.*\)'`
 144                 ;;
 145         -m=*|--m=*|--me=*|--mes=*|--mess=*|--messa=*|--messag=*|--message=*)
 146                 merge_msg=`expr "z$1" : 'z-[^=]*=\(.*\)'`
 147                 have_message=t
 148                 ;;
 149         -m|--m|--me|--mes|--mess|--messa|--messag|--message)
 150                 shift
 151                 case "$#" in
 152                 1)      usage ;;
 153                 esac
 154                 merge_msg="$1"
 155                 have_message=t
 156                 ;;
 157         -*)     usage ;;
 158         *)      break ;;
 159         esac
 160         shift
 161 done
 162
 163 # This could be traditional "merge <msg> HEAD <commit>..."  and the
 164 # way we can tell it is to see if the second token is HEAD, but some
 165 # people might have misused the interface and used a committish that
 166 # is the same as HEAD there instead.  Traditional format never would
 167 # have "-m" so it is an additional safety measure to check for it.
 168
 169 if test -z "$have_message" &&
 170         second_token=$(git-rev-parse --verify "$2^0" 2>/dev/null) &&
 171         head_commit=$(git-rev-parse --verify "HEAD" 2>/dev/null) &&
 172         test "$second_token" = "$head_commit"
 173 then
 174         merge_msg="$1"
 175         shift
 176         head_arg="$1"
 177         shift
 178 elif ! git-rev-parse --verify HEAD >/dev/null 2>&1
 179 then
 180         # If the merged head is a valid one there is no reason to
 181         # forbid "git merge" into a branch yet to be born.  We do
 182         # the same for "git pull".
 183         if test 1 -ne $#
 184         then
 185                 echo >&2 "Can merge only exactly one commit into empty head"
 186                 exit 1
 187         fi
 188
 189         rh=$(git rev-parse --verify "$1^0") ||
 190                 die "$1 - not something we can merge"
 191
 192         git-update-ref -m "initial pull" HEAD "$rh" "" &&
 193         git-read-tree --reset -u HEAD
 194         exit
 195
 196 else
 197         # We are invoked directly as the first-class UI.
 198         head_arg=HEAD
 199
 200         # All the rest are the commits being merged; prepare
 201         # the standard merge summary message to be appended to
 202         # the given message.  If remote is invalid we will die
 203         # later in the common codepath so we discard the error
 204         # in this loop.
 205         merge_name=$(for remote
 206                 do
 207                         merge_name "$remote"
 208                 done | git-fmt-merge-msg
 209         )
 210         merge_msg="${merge_msg:+$merge_msg$LF$LF}$merge_name"
 211 fi
 212 head=$(git-rev-parse --verify "$head_arg"^0) || usage
 213
 214 # All the rest are remote heads
 215 test "$#" = 0 && usage ;# we need at least one remote head.
 216 test "$rloga" = '' && rloga="merge: $@"
 217
 218 remoteheads=
 219 for remote
 220 do
 221         remotehead=$(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 "$#" in
 232         1)
 233                 use_strategies="$default_twohead_strategies" ;;
 234         *)
 235                 use_strategies="$default_octopus_strategies" ;;
 236         esac
 237         ;;
 238 esac
 239
 240 for s in $use_strategies
 241 do
 242         case " $s " in
 243         *" $no_trivial_merge_strategies "*)
 244                 index_merge=f
 245                 break
 246                 ;;
 247         esac
 248 done
 249
 250 case "$#" in
 251 1)
 252         common=$(git-merge-base --all $head "$@")
 253         ;;
 254 *)
 255         common=$(git-show-branch --merge-base $head "$@")
 256         ;;
 257 esac
 258 echo "$head" >"$GIT_DIR/ORIG_HEAD"
 259
 260 case "$index_merge,$#,$common,$no_commit" in
 261 f,*)
 262         # We've been told not to try anything clever.  Skip to real merge.
 263         ;;
 264 ?,*,'',*)
 265         # No common ancestors found. We need a real merge.
 266         ;;
 267 ?,1,"$1",*)
 268         # If head can reach all the merge then we are up to date.
 269         # but first the most common case of merging one remote.
 270         finish_up_to_date "Already up-to-date."
 271         exit 0
 272         ;;
 273 ?,1,"$head",*)
 274         # Again the most common case of merging one remote.
 275         echo "Updating $(git-rev-parse --short $head)..$(git-rev-parse --short $1)"
 276         git-update-index --refresh 2>/dev/null
 277         new_head=$(git-rev-parse --verify "$1^0") &&
 278         git-read-tree -v -m -u --exclude-per-directory=.gitignore $head "$new_head" &&
 279         finish "$new_head" "Fast forward"
 280         dropsave
 281         exit 0
 282         ;;
 283 ?,1,?*"$LF"?*,*)
 284         # We are not doing octopus and not fast forward.  Need a
 285         # real merge.
 286         ;;
 287 ?,1,*,)
 288         # We are not doing octopus, not fast forward, and have only
 289         # one common.  See if it is really trivial.
 290         git var GIT_COMMITTER_IDENT >/dev/null || exit
 291
 292         echo "Trying really trivial in-index merge..."
 293         git-update-index --refresh 2>/dev/null
 294         if git-read-tree --trivial -m -u -v $common $head "$1" &&
 295            result_tree=$(git-write-tree)
 296         then
 297             echo "Wonderful."
 298             result_commit=$(
 299                 echo "$merge_msg" |
 300                 git-commit-tree $result_tree -p HEAD -p "$1"
 301             ) || exit
 302             finish "$result_commit" "In-index merge"
 303             dropsave
 304             exit 0
 305         fi
 306         echo "Nope."
 307         ;;
 308 *)
 309         # An octopus.  If we can reach all the remote we are up to date.
 310         up_to_date=t
 311         for remote
 312         do
 313                 common_one=$(git-merge-base --all $head $remote)
 314                 if test "$common_one" != "$remote"
 315                 then
 316                         up_to_date=f
 317                         break
 318                 fi
 319         done
 320         if test "$up_to_date" = t
 321         then
 322                 finish_up_to_date "Already up-to-date. Yeeah!"
 323                 exit 0
 324         fi
 325         ;;
 326 esac
 327
 328 # We are going to make a new commit.
 329 git var GIT_COMMITTER_IDENT >/dev/null || exit
 330
 331 # At this point, we need a real merge.  No matter what strategy
 332 # we use, it would operate on the index, possibly affecting the
 333 # working tree, and when resolved cleanly, have the desired tree
 334 # in the index -- this means that the index must be in sync with
 335 # the $head commit.  The strategies are responsible to ensure this.
 336
 337 case "$use_strategies" in
 338 ?*' '?*)
 339     # Stash away the local changes so that we can try more than one.
 340     savestate
 341     single_strategy=no
 342     ;;
 343 *)
 344     rm -f "$GIT_DIR/MERGE_SAVE"
 345     single_strategy=yes
 346     ;;
 347 esac
 348
 349 result_tree= best_cnt=-1 best_strategy= wt_strategy=
 350 merge_was_ok=
 351 for strategy in $use_strategies
 352 do
 353     test "$wt_strategy" = '' || {
 354         echo "Rewinding the tree to pristine..."
 355         restorestate
 356     }
 357     case "$single_strategy" in
 358     no)
 359         echo "Trying merge strategy $strategy..."
 360         ;;
 361     esac
 362
 363     # Remember which strategy left the state in the working tree
 364     wt_strategy=$strategy
 365
 366     git-merge-$strategy $common -- "$head_arg" "$@"
 367     exit=$?
 368     if test "$no_commit" = t && test "$exit" = 0
 369     then
 370         merge_was_ok=t
 371         exit=1 ;# pretend it left conflicts.
 372     fi
 373
 374     test "$exit" = 0 || {
 375
 376         # The backend exits with 1 when conflicts are left to be resolved,
 377         # with 2 when it does not handle the given merge at all.
 378
 379         if test "$exit" -eq 1
 380         then
 381             cnt=`{
 382                 git-diff-files --name-only
 383                 git-ls-files --unmerged
 384             } | wc -l`
 385             if test $best_cnt -le 0 -o $cnt -le $best_cnt
 386             then
 387                 best_strategy=$strategy
 388                 best_cnt=$cnt
 389             fi
 390         fi
 391         continue
 392     }
 393
 394     # Automerge succeeded.
 395     result_tree=$(git-write-tree) && break
 396 done
 397
 398 # If we have a resulting tree, that means the strategy module
 399 # auto resolved the merge cleanly.
 400 if test '' != "$result_tree"
 401 then
 402     parents=$(git-show-branch --independent "$head" "$@" | sed -e 's/^/-p /')
 403     result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents) || exit
 404     finish "$result_commit" "Merge made by $wt_strategy."
 405     dropsave
 406     exit 0
 407 fi
 408
 409 # Pick the result from the best strategy and have the user fix it up.
 410 case "$best_strategy" in
 411 '')
 412         restorestate
 413         case "$use_strategies" in
 414         ?*' '?*)
 415                 echo >&2 "No merge strategy handled the merge."
 416                 ;;
 417         *)
 418                 echo >&2 "Merge with strategy $use_strategies failed."
 419                 ;;
 420         esac
 421         exit 2
 422         ;;
 423 "$wt_strategy")
 424         # We already have its result in the working tree.
 425         ;;
 426 *)
 427         echo "Rewinding the tree to pristine..."
 428         restorestate
 429         echo "Using the $best_strategy to prepare resolving by hand."
 430         git-merge-$best_strategy $common -- "$head_arg" "$@"
 431         ;;
 432 esac
 433
 434 if test "$squash" = t
 435 then
 436         finish
 437 else
 438         for remote
 439         do
 440                 echo $remote
 441         done >"$GIT_DIR/MERGE_HEAD"
 442         echo "$merge_msg" >"$GIT_DIR/MERGE_MSG"
 443 fi
 444
 445 if test "$merge_was_ok" = t
 446 then
 447         echo >&2 \
 448         "Automatic merge went well; stopped before committing as requested"
 449         exit 0
 450 else
 451         {
 452             echo '
 453 Conflicts:
 454 '
 455                 git ls-files --unmerged |
 456                 sed -e 's/^[^   ]*      /       /' |
 457                 uniq
 458         } >>"$GIT_DIR/MERGE_MSG"
 459         if test -d "$GIT_DIR/rr-cache"
 460         then
 461                 git-rerere
 462         fi
 463         die "Automatic merge failed; fix conflicts and then commit the result."
 464 fi