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 "$#" in
 229         1)
 230                 use_strategies="$default_twohead_strategies" ;;
 231         *)
 232                 use_strategies="$default_octopus_strategies" ;;
 233         esac
 234         ;;
 235 esac
 236
 237 for s in $use_strategies
 238 do
 239         case " $s " in
 240         *" $no_trivial_merge_strategies "*)
 241                 index_merge=f
 242                 break
 243                 ;;
 244         esac
 245 done
 246
 247 case "$#" in
 248 1)
 249         common=$(git-merge-base --all $head "$@")
 250         ;;
 251 *)
 252         common=$(git-show-branch --merge-base $head "$@")
 253         ;;
 254 esac
 255 echo "$head" >"$GIT_DIR/ORIG_HEAD"
 256
 257 case "$index_merge,$#,$common,$no_commit" in
 258 f,*)
 259         # We've been told not to try anything clever.  Skip to real merge.
 260         ;;
 261 ?,*,'',*)
 262         # No common ancestors found. We need a real merge.
 263         ;;
 264 ?,1,"$1",*)
 265         # If head can reach all the merge then we are up to date.
 266         # but first the most common case of merging one remote.
 267         finish_up_to_date "Already up-to-date."
 268         exit 0
 269         ;;
 270 ?,1,"$head",*)
 271         # Again the most common case of merging one remote.
 272         echo "Updating $(git-rev-parse --short $head)..$(git-rev-parse --short $1)"
 273         git-update-index --refresh 2>/dev/null
 274         new_head=$(git-rev-parse --verify "$1^0") &&
 275         git-read-tree -v -m -u --exclude-per-directory=.gitignore $head "$new_head" &&
 276         finish "$new_head" "Fast forward"
 277         dropsave
 278         exit 0
 279         ;;
 280 ?,1,?*"$LF"?*,*)
 281         # We are not doing octopus and not fast forward.  Need a
 282         # real merge.
 283         ;;
 284 ?,1,*,)
 285         # We are not doing octopus, not fast forward, and have only
 286         # one common.  See if it is really trivial.
 287         git var GIT_COMMITTER_IDENT >/dev/null || exit
 288
 289         echo "Trying really trivial in-index merge..."
 290         git-update-index --refresh 2>/dev/null
 291         if git-read-tree --trivial -m -u -v $common $head "$1" &&
 292            result_tree=$(git-write-tree)
 293         then
 294             echo "Wonderful."
 295             result_commit=$(
 296                 echo "$merge_msg" |
 297                 git-commit-tree $result_tree -p HEAD -p "$1"
 298             ) || exit
 299             finish "$result_commit" "In-index merge"
 300             dropsave
 301             exit 0
 302         fi
 303         echo "Nope."
 304         ;;
 305 *)
 306         # An octopus.  If we can reach all the remote we are up to date.
 307         up_to_date=t
 308         for remote
 309         do
 310                 common_one=$(git-merge-base --all $head $remote)
 311                 if test "$common_one" != "$remote"
 312                 then
 313                         up_to_date=f
 314                         break
 315                 fi
 316         done
 317         if test "$up_to_date" = t
 318         then
 319                 finish_up_to_date "Already up-to-date. Yeeah!"
 320                 exit 0
 321         fi
 322         ;;
 323 esac
 324
 325 # We are going to make a new commit.
 326 git var GIT_COMMITTER_IDENT >/dev/null || exit
 327
 328 # At this point, we need a real merge.  No matter what strategy
 329 # we use, it would operate on the index, possibly affecting the
 330 # working tree, and when resolved cleanly, have the desired tree
 331 # in the index -- this means that the index must be in sync with
 332 # the $head commit.  The strategies are responsible to ensure this.
 333
 334 case "$use_strategies" in
 335 ?*' '?*)
 336     # Stash away the local changes so that we can try more than one.
 337     savestate
 338     single_strategy=no
 339     ;;
 340 *)
 341     rm -f "$GIT_DIR/MERGE_SAVE"
 342     single_strategy=yes
 343     ;;
 344 esac
 345
 346 result_tree= best_cnt=-1 best_strategy= wt_strategy=
 347 merge_was_ok=
 348 for strategy in $use_strategies
 349 do
 350     test "$wt_strategy" = '' || {
 351         echo "Rewinding the tree to pristine..."
 352         restorestate
 353     }
 354     case "$single_strategy" in
 355     no)
 356         echo "Trying merge strategy $strategy..."
 357         ;;
 358     esac
 359
 360     # Remember which strategy left the state in the working tree
 361     wt_strategy=$strategy
 362
 363     git-merge-$strategy $common -- "$head_arg" "$@"
 364     exit=$?
 365     if test "$no_commit" = t && test "$exit" = 0
 366     then
 367         merge_was_ok=t
 368         exit=1 ;# pretend it left conflicts.
 369     fi
 370
 371     test "$exit" = 0 || {
 372
 373         # The backend exits with 1 when conflicts are left to be resolved,
 374         # with 2 when it does not handle the given merge at all.
 375
 376         if test "$exit" -eq 1
 377         then
 378             cnt=`{
 379                 git-diff-files --name-only
 380                 git-ls-files --unmerged
 381             } | wc -l`
 382             if test $best_cnt -le 0 -o $cnt -le $best_cnt
 383             then
 384                 best_strategy=$strategy
 385                 best_cnt=$cnt
 386             fi
 387         fi
 388         continue
 389     }
 390
 391     # Automerge succeeded.
 392     result_tree=$(git-write-tree) && break
 393 done
 394
 395 # If we have a resulting tree, that means the strategy module
 396 # auto resolved the merge cleanly.
 397 if test '' != "$result_tree"
 398 then
 399     parents=$(git-show-branch --independent "$head" "$@" | sed -e 's/^/-p /')
 400     result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents) || exit
 401     finish "$result_commit" "Merge made by $wt_strategy."
 402     dropsave
 403     exit 0
 404 fi
 405
 406 # Pick the result from the best strategy and have the user fix it up.
 407 case "$best_strategy" in
 408 '')
 409         restorestate
 410         case "$use_strategies" in
 411         ?*' '?*)
 412                 echo >&2 "No merge strategy handled the merge."
 413                 ;;
 414         *)
 415                 echo >&2 "Merge with strategy $use_strategies failed."
 416                 ;;
 417         esac
 418         exit 2
 419         ;;
 420 "$wt_strategy")
 421         # We already have its result in the working tree.
 422         ;;
 423 *)
 424         echo "Rewinding the tree to pristine..."
 425         restorestate
 426         echo "Using the $best_strategy to prepare resolving by hand."
 427         git-merge-$best_strategy $common -- "$head_arg" "$@"
 428         ;;
 429 esac
 430
 431 if test "$squash" = t
 432 then
 433         finish
 434 else
 435         for remote
 436         do
 437                 echo $remote
 438         done >"$GIT_DIR/MERGE_HEAD"
 439         echo "$merge_msg" >"$GIT_DIR/MERGE_MSG"
 440 fi
 441
 442 if test "$merge_was_ok" = t
 443 then
 444         echo >&2 \
 445         "Automatic merge went well; stopped before committing as requested"
 446         exit 0
 447 else
 448         {
 449             echo '
 450 Conflicts:
 451 '
 452                 git ls-files --unmerged |
 453                 sed -e 's/^[^   ]*      /       /' |
 454                 uniq
 455         } >>"$GIT_DIR/MERGE_MSG"
 456         if test -d "$GIT_DIR/rr-cache"
 457         then
 458                 git-rerere
 459         fi
 460         die "Automatic merge failed; fix conflicts and then commit the result."
 461 fi