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_strategies='recursive'
  15 use_strategies=
  16
  17 dropsave() {
  18         rm -f -- "$GIT_DIR/MERGE_HEAD" "$GIT_DIR/MERGE_MSG" \
  19                  "$GIT_DIR/MERGE_SAVE" || exit 1
  20 }
  21
  22 savestate() {
  23         # Stash away any local modifications.
  24         git-diff-index -z --name-only $head |
  25         cpio -0 -o >"$GIT_DIR/MERGE_SAVE"
  26 }
  27
  28 restorestate() {
  29         if test -f "$GIT_DIR/MERGE_SAVE"
  30         then
  31                 git reset --hard $head
  32                 cpio -iuv <"$GIT_DIR/MERGE_SAVE"
  33                 git-update-index --refresh >/dev/null
  34         fi
  35 }
  36
  37 finish () {
  38         test '' = "$2" || echo "$2"
  39         case "$merge_msg" in
  40         '')
  41                 echo "No merge message -- not updating HEAD"
  42                 ;;
  43         *)
  44                 git-update-ref HEAD "$1" "$head" || exit 1
  45                 ;;
  46         esac
  47
  48         case "$no_summary" in
  49         '')
  50                 git-diff-tree -p -M "$head" "$1" |
  51                 git-apply --stat --summary
  52                 ;;
  53         esac
  54 }
  55
  56 while case "$#" in 0) break ;; esac
  57 do
  58         case "$1" in
  59         -n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
  60                 --no-summa|--no-summar|--no-summary)
  61                 no_summary=t ;;
  62         --no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
  63                 no_commit=t ;;
  64         -s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
  65                 --strateg=*|--strategy=*|\
  66         -s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
  67                 case "$#,$1" in
  68                 *,*=*)
  69                         strategy=`expr "$1" : '-[^=]*=\(.*\)'` ;;
  70                 1,*)
  71                         usage ;;
  72                 *)
  73                         strategy="$2"
  74                         shift ;;
  75                 esac
  76                 case " $all_strategies " in
  77                 *" $strategy "*)
  78                         use_strategies="$use_strategies$strategy " ;;
  79                 *)
  80                         die "available strategies are: $all_strategies" ;;
  81                 esac
  82                 ;;
  83         -*)     usage ;;
  84         *)      break ;;
  85         esac
  86         shift
  87 done
  88
  89 test "$#" -le 2 && usage ;# we need at least two heads.
  90
  91 merge_msg="$1"
  92 shift
  93 head_arg="$1"
  94 head=$(git-rev-parse --verify "$1"^0) || usage
  95 shift
  96
  97 # All the rest are remote heads
  98 remoteheads=
  99 for remote
 100 do
 101         remotehead=$(git-rev-parse --verify "$remote"^0) ||
 102             die "$remote - not something we can merge"
 103         remoteheads="${remoteheads}$remotehead "
 104 done
 105 set x $remoteheads ; shift
 106
 107 case "$#" in
 108 1)
 109         common=$(git-merge-base --all $head "$@")
 110         ;;
 111 *)
 112         common=$(git-show-branch --merge-base $head "$@")
 113         ;;
 114 esac
 115 echo "$head" >"$GIT_DIR/ORIG_HEAD"
 116
 117 case "$#,$common,$no_commit" in
 118 *,'',*)
 119         # No common ancestors found. We need a real merge.
 120         ;;
 121 1,"$1",*)
 122         # If head can reach all the merge then we are up to date.
 123         # but first the most common case of merging one remote
 124         echo "Already up-to-date."
 125         dropsave
 126         exit 0
 127         ;;
 128 1,"$head",*)
 129         # Again the most common case of merging one remote.
 130         echo "Updating from $head to $1."
 131         git-update-index --refresh 2>/dev/null
 132         new_head=$(git-rev-parse --verify "$1^0") &&
 133         git-read-tree -u -m $head "$new_head" &&
 134         finish "$new_head" "Fast forward"
 135         dropsave
 136         exit 0
 137         ;;
 138 1,?*"$LF"?*,*)
 139         # We are not doing octopus and not fast forward.  Need a
 140         # real merge.
 141         ;;
 142 1,*,)
 143         # We are not doing octopus, not fast forward, and have only
 144         # one common.  See if it is really trivial.
 145         echo "Trying really trivial in-index merge..."
 146         git-update-index --refresh 2>/dev/null
 147         if git-read-tree --trivial -m -u $common $head "$1" &&
 148            result_tree=$(git-write-tree)
 149         then
 150             echo "Wonderful."
 151             result_commit=$(
 152                 echo "$merge_msg" |
 153                 git-commit-tree $result_tree -p HEAD -p "$1"
 154             ) || exit
 155             finish "$result_commit" "In-index merge"
 156             dropsave
 157             exit 0
 158         fi
 159         echo "Nope."
 160         ;;
 161 *)
 162         # An octopus.  If we can reach all the remote we are up to date.
 163         up_to_date=t
 164         for remote
 165         do
 166                 common_one=$(git-merge-base --all $head $remote)
 167                 if test "$common_one" != "$remote"
 168                 then
 169                         up_to_date=f
 170                         break
 171                 fi
 172         done
 173         if test "$up_to_date" = t
 174         then
 175                 echo "Already up-to-date. Yeeah!"
 176                 dropsave
 177                 exit 0
 178         fi
 179         ;;
 180 esac
 181
 182 case "$use_strategies" in
 183 '')
 184         case "$#" in
 185         1)
 186                 use_strategies="$default_strategies" ;;
 187         *)
 188                 use_strategies=octopus ;;
 189         esac
 190         ;;
 191 esac
 192
 193 # At this point, we need a real merge.  No matter what strategy
 194 # we use, it would operate on the index, possibly affecting the
 195 # working tree, and when resolved cleanly, have the desired tree
 196 # in the index -- this means that the index must be in sync with
 197 # the $head commit.  The strategies are responsible to ensure this.
 198
 199 case "$use_strategies" in
 200 ?*' '?*)
 201     # Stash away the local changes so that we can try more than one.
 202     savestate
 203     single_strategy=no
 204     ;;
 205 *)
 206     rm -f "$GIT_DIR/MERGE_SAVE"
 207     single_strategy=yes
 208     ;;
 209 esac
 210
 211 result_tree= best_cnt=-1 best_strategy= wt_strategy=
 212 for strategy in $use_strategies
 213 do
 214     test "$wt_strategy" = '' || {
 215         echo "Rewinding the tree to pristine..."
 216         restorestate
 217     }
 218     case "$single_strategy" in
 219     no)
 220         echo "Trying merge strategy $strategy..."
 221         ;;
 222     esac
 223
 224     # Remember which strategy left the state in the working tree
 225     wt_strategy=$strategy
 226
 227     git-merge-$strategy $common -- "$head_arg" "$@"
 228     exit=$?
 229     if test "$no_commit" = t && test "$exit" = 0
 230     then
 231         exit=1 ;# pretend it left conflicts.
 232     fi
 233
 234     test "$exit" = 0 || {
 235
 236         # The backend exits with 1 when conflicts are left to be resolved,
 237         # with 2 when it does not handle the given merge at all.
 238
 239         if test "$exit" -eq 1
 240         then
 241             cnt=`{
 242                 git-diff-files --name-only
 243                 git-ls-files --unmerged
 244             } | wc -l`
 245             if test $best_cnt -le 0 -o $cnt -le $best_cnt
 246             then
 247                 best_strategy=$strategy
 248                 best_cnt=$cnt
 249             fi
 250         fi
 251         continue
 252     }
 253
 254     # Automerge succeeded.
 255     result_tree=$(git-write-tree) && break
 256 done
 257
 258 # If we have a resulting tree, that means the strategy module
 259 # auto resolved the merge cleanly.
 260 if test '' != "$result_tree"
 261 then
 262     parents="-p $head"
 263     for remote
 264     do
 265         parents="$parents -p $remote"
 266     done
 267     result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents) || exit
 268     finish "$result_commit" "Merge $result_commit, made by $wt_strategy."
 269     dropsave
 270     exit 0
 271 fi
 272
 273 # Pick the result from the best strategy and have the user fix it up.
 274 case "$best_strategy" in
 275 '')
 276         restorestate
 277         echo >&2 "No merge strategy handled the merge."
 278         exit 2
 279         ;;
 280 "$wt_strategy")
 281         # We already have its result in the working tree.
 282         ;;
 283 *)
 284         echo "Rewinding the tree to pristine..."
 285         restorestate
 286         echo "Using the $best_strategy to prepare resolving by hand."
 287         git-merge-$best_strategy $common -- "$head_arg" "$@"
 288         ;;
 289 esac
 290 for remote
 291 do
 292         echo $remote
 293 done >"$GIT_DIR/MERGE_HEAD"
 294 echo $merge_msg >"$GIT_DIR/MERGE_MSG"
 295
 296 die "Automatic merge failed/prevented; fix up by hand"