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