git-merge.sh

   1 #!/bin/sh
   2 #
   3 # Copyright (c) 2005 Junio C Hamano
   4 #
   5
   6 USAGE='[-n] [--no-commit] [--squash] [-s <strategy>]... <merge-message> <head> <remote>+'
   7 . git-sh-setup
   8
   9 LF='
  10 '
  11
  12 all_strategies='recursive octopus resolve stupid ours'
  13 default_twohead_strategies='recursive'
  14 default_octopus_strategies='octopus'
  15 no_trivial_merge_strategies='ours'
  16 use_strategies=
  17
  18 index_merge=t
  19 if test "@@NO_PYTHON@@"; then
  20         all_strategies='resolve octopus stupid ours'
  21         default_twohead_strategies='resolve'
  22 fi
  23
  24 dropsave() {
  25         rm -f -- "$GIT_DIR/MERGE_HEAD" "$GIT_DIR/MERGE_MSG" \
  26                  "$GIT_DIR/MERGE_SAVE" || exit 1
  27 }
  28
  29 savestate() {
  30         # Stash away any local modifications.
  31         git-diff-index -z --name-only $head |
  32         cpio -0 -o >"$GIT_DIR/MERGE_SAVE"
  33 }
  34
  35 restorestate() {
  36         if test -f "$GIT_DIR/MERGE_SAVE"
  37         then
  38                 git reset --hard $head
  39                 cpio -iuv <"$GIT_DIR/MERGE_SAVE"
  40                 git-update-index --refresh >/dev/null
  41         fi
  42 }
  43
  44 finish_up_to_date () {
  45         case "$squash" in
  46         t)
  47                 echo "$1 (nothing to squash)" ;;
  48         '')
  49                 echo "$1" ;;
  50         esac
  51         dropsave
  52 }
  53
  54 squash_message () {
  55         echo Squashed commit of the following:
  56         echo
  57         git-log --no-merges ^"$head" $remote
  58 }
  59
  60 finish () {
  61         test '' = "$2" || echo "$2"
  62         case "$squash" in
  63         t)
  64                 echo "Squash commit -- not updating HEAD"
  65                 squash_message >"$GIT_DIR/SQUASH_MSG"
  66                 ;;
  67         '')
  68                 case "$merge_msg" in
  69                 '')
  70                         echo "No merge message -- not updating HEAD"
  71                         ;;
  72                 *)
  73                         git-update-ref HEAD "$1" "$head" || exit 1
  74                         ;;
  75                 esac
  76                 ;;
  77         esac
  78         case "$1" in
  79         '')
  80                 ;;
  81         ?*)
  82                 case "$no_summary" in
  83                 '')
  84                         git-diff-tree --stat --summary -M "$head" "$1"
  85                         ;;
  86                 esac
  87                 ;;
  88         esac
  89 }
  90
  91 while case "$#" in 0) break ;; esac
  92 do
  93         case "$1" in
  94         -n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
  95                 --no-summa|--no-summar|--no-summary)
  96                 no_summary=t ;;
  97         --sq|--squ|--squa|--squas|--squash)
  98                 squash=t no_commit=t ;;
  99         --no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
 100                 no_commit=t ;;
 101         -s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
 102                 --strateg=*|--strategy=*|\
 103         -s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
 104                 case "$#,$1" in
 105                 *,*=*)
 106                         strategy=`expr "z$1" : 'z-[^=]*=\(.*\)'` ;;
 107                 1,*)
 108                         usage ;;
 109                 *)
 110                         strategy="$2"
 111                         shift ;;
 112                 esac
 113                 case " $all_strategies " in
 114                 *" $strategy "*)
 115                         use_strategies="$use_strategies$strategy " ;;
 116                 *)
 117                         die "available strategies are: $all_strategies" ;;
 118                 esac
 119                 ;;
 120         -*)     usage ;;
 121         *)      break ;;
 122         esac
 123         shift
 124 done
 125
 126 merge_msg="$1"
 127 shift
 128 head_arg="$1"
 129 head=$(git-rev-parse --verify "$1"^0) || usage
 130 shift
 131
 132 # All the rest are remote heads
 133 test "$#" = 0 && usage ;# we need at least one remote head.
 134
 135 remoteheads=
 136 for remote
 137 do
 138         remotehead=$(git-rev-parse --verify "$remote"^0) ||
 139             die "$remote - not something we can merge"
 140         remoteheads="${remoteheads}$remotehead "
 141 done
 142 set x $remoteheads ; shift
 143
 144 case "$use_strategies" in
 145 '')
 146         case "$#" in
 147         1)
 148                 use_strategies="$default_twohead_strategies" ;;
 149         *)
 150                 use_strategies="$default_octopus_strategies" ;;
 151         esac
 152         ;;
 153 esac
 154
 155 for s in $use_strategies
 156 do
 157         case " $s " in
 158         *" $no_trivial_merge_strategies "*)
 159                 index_merge=f
 160                 break
 161                 ;;
 162         esac
 163 done
 164
 165 case "$#" in
 166 1)
 167         common=$(git-merge-base --all $head "$@")
 168         ;;
 169 *)
 170         common=$(git-show-branch --merge-base $head "$@")
 171         ;;
 172 esac
 173 echo "$head" >"$GIT_DIR/ORIG_HEAD"
 174
 175 case "$index_merge,$#,$common,$no_commit" in
 176 f,*)
 177         # We've been told not to try anything clever.  Skip to real merge.
 178         ;;
 179 ?,*,'',*)
 180         # No common ancestors found. We need a real merge.
 181         ;;
 182 ?,1,"$1",*)
 183         # If head can reach all the merge then we are up to date.
 184         # but first the most common case of merging one remote.
 185         finish_up_to_date "Already up-to-date."
 186         exit 0
 187         ;;
 188 ?,1,"$head",*)
 189         # Again the most common case of merging one remote.
 190         echo "Updating from $head to $1"
 191         git-update-index --refresh 2>/dev/null
 192         new_head=$(git-rev-parse --verify "$1^0") &&
 193         git-read-tree -u -v -m $head "$new_head" &&
 194         finish "$new_head" "Fast forward"
 195         dropsave
 196         exit 0
 197         ;;
 198 ?,1,?*"$LF"?*,*)
 199         # We are not doing octopus and not fast forward.  Need a
 200         # real merge.
 201         ;;
 202 ?,1,*,)
 203         # We are not doing octopus, not fast forward, and have only
 204         # one common.  See if it is really trivial.
 205         git var GIT_COMMITTER_IDENT >/dev/null || exit
 206
 207         echo "Trying really trivial in-index merge..."
 208         git-update-index --refresh 2>/dev/null
 209         if git-read-tree --trivial -m -u -v $common $head "$1" &&
 210            result_tree=$(git-write-tree)
 211         then
 212             echo "Wonderful."
 213             result_commit=$(
 214                 echo "$merge_msg" |
 215                 git-commit-tree $result_tree -p HEAD -p "$1"
 216             ) || exit
 217             finish "$result_commit" "In-index merge"
 218             dropsave
 219             exit 0
 220         fi
 221         echo "Nope."
 222         ;;
 223 *)
 224         # An octopus.  If we can reach all the remote we are up to date.
 225         up_to_date=t
 226         for remote
 227         do
 228                 common_one=$(git-merge-base --all $head $remote)
 229                 if test "$common_one" != "$remote"
 230                 then
 231                         up_to_date=f
 232                         break
 233                 fi
 234         done
 235         if test "$up_to_date" = t
 236         then
 237                 finish_up_to_date "Already up-to-date. Yeeah!"
 238                 exit 0
 239         fi
 240         ;;
 241 esac
 242
 243 # We are going to make a new commit.
 244 git var GIT_COMMITTER_IDENT >/dev/null || exit
 245
 246 # At this point, we need a real merge.  No matter what strategy
 247 # we use, it would operate on the index, possibly affecting the
 248 # working tree, and when resolved cleanly, have the desired tree
 249 # in the index -- this means that the index must be in sync with
 250 # the $head commit.  The strategies are responsible to ensure this.
 251
 252 case "$use_strategies" in
 253 ?*' '?*)
 254     # Stash away the local changes so that we can try more than one.
 255     savestate
 256     single_strategy=no
 257     ;;
 258 *)
 259     rm -f "$GIT_DIR/MERGE_SAVE"
 260     single_strategy=yes
 261     ;;
 262 esac
 263
 264 result_tree= best_cnt=-1 best_strategy= wt_strategy=
 265 merge_was_ok=
 266 for strategy in $use_strategies
 267 do
 268     test "$wt_strategy" = '' || {
 269         echo "Rewinding the tree to pristine..."
 270         restorestate
 271     }
 272     case "$single_strategy" in
 273     no)
 274         echo "Trying merge strategy $strategy..."
 275         ;;
 276     esac
 277
 278     # Remember which strategy left the state in the working tree
 279     wt_strategy=$strategy
 280
 281     git-merge-$strategy $common -- "$head_arg" "$@"
 282     exit=$?
 283     if test "$no_commit" = t && test "$exit" = 0
 284     then
 285         merge_was_ok=t
 286         exit=1 ;# pretend it left conflicts.
 287     fi
 288
 289     test "$exit" = 0 || {
 290
 291         # The backend exits with 1 when conflicts are left to be resolved,
 292         # with 2 when it does not handle the given merge at all.
 293
 294         if test "$exit" -eq 1
 295         then
 296             cnt=`{
 297                 git-diff-files --name-only
 298                 git-ls-files --unmerged
 299             } | wc -l`
 300             if test $best_cnt -le 0 -o $cnt -le $best_cnt
 301             then
 302                 best_strategy=$strategy
 303                 best_cnt=$cnt
 304             fi
 305         fi
 306         continue
 307     }
 308
 309     # Automerge succeeded.
 310     result_tree=$(git-write-tree) && break
 311 done
 312
 313 # If we have a resulting tree, that means the strategy module
 314 # auto resolved the merge cleanly.
 315 if test '' != "$result_tree"
 316 then
 317     parents=$(git-show-branch --independent "$head" "$@" | sed -e 's/^/-p /')
 318     result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents) || exit
 319     finish "$result_commit" "Merge $result_commit, made by $wt_strategy."
 320     dropsave
 321     exit 0
 322 fi
 323
 324 # Pick the result from the best strategy and have the user fix it up.
 325 case "$best_strategy" in
 326 '')
 327         restorestate
 328         echo >&2 "No merge strategy handled the merge."
 329         exit 2
 330         ;;
 331 "$wt_strategy")
 332         # We already have its result in the working tree.
 333         ;;
 334 *)
 335         echo "Rewinding the tree to pristine..."
 336         restorestate
 337         echo "Using the $best_strategy to prepare resolving by hand."
 338         git-merge-$best_strategy $common -- "$head_arg" "$@"
 339         ;;
 340 esac
 341
 342 if test "$squash" = t
 343 then
 344         finish
 345 else
 346         for remote
 347         do
 348                 echo $remote
 349         done >"$GIT_DIR/MERGE_HEAD"
 350         echo "$merge_msg" >"$GIT_DIR/MERGE_MSG"
 351 fi
 352
 353 if test "$merge_was_ok" = t
 354 then
 355         echo >&2 \
 356         "Automatic merge went well; stopped before committing as requested"
 357         exit 0
 358 else
 359         {
 360             echo '
 361 Conflicts:
 362 '
 363                 git ls-files --unmerged |
 364                 sed -e 's/^[^   ]*      /       /' |
 365                 uniq
 366         } >>"$GIT_DIR/MERGE_MSG"
 367         if test -d "$GIT_DIR/rr-cache"
 368         then
 369                 git-rerere
 370         fi
 371         die "Automatic merge failed; fix conflicts and then commit the result."
 372 fi