git-merge.sh

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