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 if test "@@NO_PYTHON@@"; then
  17         all_strategies='resolve octopus stupid ours'
  18         default_strategies='resolve'
  19 fi
  20
  21 dropsave() {
  22         rm -f -- "$GIT_DIR/MERGE_HEAD" "$GIT_DIR/MERGE_MSG" \
  23                  "$GIT_DIR/MERGE_SAVE" || exit 1
  24 }
  25
  26 savestate() {
  27         # Stash away any local modifications.
  28         git-diff-index -z --name-only $head |
  29         cpio -0 -o >"$GIT_DIR/MERGE_SAVE"
  30 }
  31
  32 restorestate() {
  33         if test -f "$GIT_DIR/MERGE_SAVE"
  34         then
  35                 git reset --hard $head
  36                 cpio -iuv <"$GIT_DIR/MERGE_SAVE"
  37                 git-update-index --refresh >/dev/null
  38         fi
  39 }
  40
  41 finish () {
  42         test '' = "$2" || echo "$2"
  43         case "$merge_msg" in
  44         '')
  45                 echo "No merge message -- not updating HEAD"
  46                 ;;
  47         *)
  48                 git-update-ref HEAD "$1" "$head" || exit 1
  49                 ;;
  50         esac
  51
  52         case "$no_summary" in
  53         '')
  54                 git-diff-tree -p -M "$head" "$1" |
  55                 git-apply --stat --summary
  56                 ;;
  57         esac
  58 }
  59
  60 while case "$#" in 0) break ;; esac
  61 do
  62         case "$1" in
  63         -n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
  64                 --no-summa|--no-summar|--no-summary)
  65                 no_summary=t ;;
  66         --no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
  67                 no_commit=t ;;
  68         -s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
  69                 --strateg=*|--strategy=*|\
  70         -s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
  71                 case "$#,$1" in
  72                 *,*=*)
  73                         strategy=`expr "$1" : '-[^=]*=\(.*\)'` ;;
  74                 1,*)
  75                         usage ;;
  76                 *)
  77                         strategy="$2"
  78                         shift ;;
  79                 esac
  80                 case " $all_strategies " in
  81                 *" $strategy "*)
  82                         use_strategies="$use_strategies$strategy " ;;
  83                 *)
  84                         die "available strategies are: $all_strategies" ;;
  85                 esac
  86                 ;;
  87         -*)     usage ;;
  88         *)      break ;;
  89         esac
  90         shift
  91 done
  92
  93 test "$#" -le 2 && usage ;# we need at least two heads.
  94
  95 merge_msg="$1"
  96 shift
  97 head_arg="$1"
  98 head=$(git-rev-parse --verify "$1"^0) || usage
  99 shift
 100
 101 # All the rest are remote heads
 102 remoteheads=
 103 for remote
 104 do
 105         remotehead=$(git-rev-parse --verify "$remote"^0) ||
 106             die "$remote - not something we can merge"
 107         remoteheads="${remoteheads}$remotehead "
 108 done
 109 set x $remoteheads ; shift
 110
 111 case "$#" in
 112 1)
 113         common=$(git-merge-base --all $head "$@")
 114         ;;
 115 *)
 116         common=$(git-show-branch --merge-base $head "$@")
 117         ;;
 118 esac
 119 echo "$head" >"$GIT_DIR/ORIG_HEAD"
 120
 121 case "$#,$common,$no_commit" in
 122 *,'',*)
 123         # No common ancestors found. We need a real merge.
 124         ;;
 125 1,"$1",*)
 126         # If head can reach all the merge then we are up to date.
 127         # but first the most common case of merging one remote
 128         echo "Already up-to-date."
 129         dropsave
 130         exit 0
 131         ;;
 132 1,"$head",*)
 133         # Again the most common case of merging one remote.
 134         echo "Updating from $head to $1."
 135         git-update-index --refresh 2>/dev/null
 136         new_head=$(git-rev-parse --verify "$1^0") &&
 137         git-read-tree -u -m $head "$new_head" &&
 138         finish "$new_head" "Fast forward"
 139         dropsave
 140         exit 0
 141         ;;
 142 1,?*"$LF"?*,*)
 143         # We are not doing octopus and not fast forward.  Need a
 144         # real merge.
 145         ;;
 146 1,*,)
 147         # We are not doing octopus, not fast forward, and have only
 148         # one common.  See if it is really trivial.
 149         echo "Trying really trivial in-index merge..."
 150         git-update-index --refresh 2>/dev/null
 151         if git-read-tree --trivial -m -u $common $head "$1" &&
 152            result_tree=$(git-write-tree)
 153         then
 154             echo "Wonderful."
 155             result_commit=$(
 156                 echo "$merge_msg" |
 157                 git-commit-tree $result_tree -p HEAD -p "$1"
 158             ) || exit
 159             finish "$result_commit" "In-index merge"
 160             dropsave
 161             exit 0
 162         fi
 163         echo "Nope."
 164         ;;
 165 *)
 166         # An octopus.  If we can reach all the remote we are up to date.
 167         up_to_date=t
 168         for remote
 169         do
 170                 common_one=$(git-merge-base --all $head $remote)
 171                 if test "$common_one" != "$remote"
 172                 then
 173                         up_to_date=f
 174                         break
 175                 fi
 176         done
 177         if test "$up_to_date" = t
 178         then
 179                 echo "Already up-to-date. Yeeah!"
 180                 dropsave
 181                 exit 0
 182         fi
 183         ;;
 184 esac
 185
 186 case "$use_strategies" in
 187 '')
 188         case "$#" in
 189         1)
 190                 use_strategies="$default_strategies" ;;
 191         *)
 192                 use_strategies=octopus ;;
 193         esac
 194         ;;
 195 esac
 196
 197 # At this point, we need a real merge.  No matter what strategy
 198 # we use, it would operate on the index, possibly affecting the
 199 # working tree, and when resolved cleanly, have the desired tree
 200 # in the index -- this means that the index must be in sync with
 201 # the $head commit.  The strategies are responsible to ensure this.
 202
 203 case "$use_strategies" in
 204 ?*' '?*)
 205     # Stash away the local changes so that we can try more than one.
 206     savestate
 207     single_strategy=no
 208     ;;
 209 *)
 210     rm -f "$GIT_DIR/MERGE_SAVE"
 211     single_strategy=yes
 212     ;;
 213 esac
 214
 215 result_tree= best_cnt=-1 best_strategy= wt_strategy=
 216 merge_was_ok=
 217 for strategy in $use_strategies
 218 do
 219     test "$wt_strategy" = '' || {
 220         echo "Rewinding the tree to pristine..."
 221         restorestate
 222     }
 223     case "$single_strategy" in
 224     no)
 225         echo "Trying merge strategy $strategy..."
 226         ;;
 227     esac
 228
 229     # Remember which strategy left the state in the working tree
 230     wt_strategy=$strategy
 231
 232     git-merge-$strategy $common -- "$head_arg" "$@"
 233     exit=$?
 234     if test "$no_commit" = t && test "$exit" = 0
 235     then
 236         merge_was_ok=t
 237         exit=1 ;# pretend it left conflicts.
 238     fi
 239
 240     test "$exit" = 0 || {
 241
 242         # The backend exits with 1 when conflicts are left to be resolved,
 243         # with 2 when it does not handle the given merge at all.
 244
 245         if test "$exit" -eq 1
 246         then
 247             cnt=`{
 248                 git-diff-files --name-only
 249                 git-ls-files --unmerged
 250             } | wc -l`
 251             if test $best_cnt -le 0 -o $cnt -le $best_cnt
 252             then
 253                 best_strategy=$strategy
 254                 best_cnt=$cnt
 255             fi
 256         fi
 257         continue
 258     }
 259
 260     # Automerge succeeded.
 261     result_tree=$(git-write-tree) && break
 262 done
 263
 264 # If we have a resulting tree, that means the strategy module
 265 # auto resolved the merge cleanly.
 266 if test '' != "$result_tree"
 267 then
 268     parents="-p $head"
 269     for remote
 270     do
 271         parents="$parents -p $remote"
 272     done
 273     result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents) || exit
 274     finish "$result_commit" "Merge $result_commit, made by $wt_strategy."
 275     dropsave
 276     exit 0
 277 fi
 278
 279 # Pick the result from the best strategy and have the user fix it up.
 280 case "$best_strategy" in
 281 '')
 282         restorestate
 283         echo >&2 "No merge strategy handled the merge."
 284         exit 2
 285         ;;
 286 "$wt_strategy")
 287         # We already have its result in the working tree.
 288         ;;
 289 *)
 290         echo "Rewinding the tree to pristine..."
 291         restorestate
 292         echo "Using the $best_strategy to prepare resolving by hand."
 293         git-merge-$best_strategy $common -- "$head_arg" "$@"
 294         ;;
 295 esac
 296 for remote
 297 do
 298         echo $remote
 299 done >"$GIT_DIR/MERGE_HEAD"
 300 echo "$merge_msg" >"$GIT_DIR/MERGE_MSG"
 301
 302 if test "$merge_was_ok" = t
 303 then
 304         echo >&2 \
 305         "Automatic merge went well; stopped before committing as requested"
 306         exit 0
 307 else
 308         {
 309             echo '
 310 Conflicts:
 311 '
 312                 git ls-files --unmerged |
 313                 sed -e 's/^[^   ]*      /       /' |
 314                 uniq
 315         } >>"$GIT_DIR/MERGE_MSG"
 316         if test -d "$GIT_DIR/rr-cache"
 317         then
 318                 git-rerere
 319         fi
 320         die "Automatic merge failed; fix up by hand"
 321 fi