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         if test '' = "$2"
  62         then
  63                 rlogm="$rloga"
  64         else
  65                 echo "$2"
  66                 rlogm="$rloga: $2"
  67         fi
  68         case "$squash" in
  69         t)
  70                 echo "Squash commit -- not updating HEAD"
  71                 squash_message >"$GIT_DIR/SQUASH_MSG"
  72                 ;;
  73         '')
  74                 case "$merge_msg" in
  75                 '')
  76                         echo "No merge message -- not updating HEAD"
  77                         ;;
  78                 *)
  79                         git-update-ref -m "$rlogm" HEAD "$1" "$head" || exit 1
  80                         ;;
  81                 esac
  82                 ;;
  83         esac
  84         case "$1" in
  85         '')
  86                 ;;
  87         ?*)
  88                 case "$no_summary" in
  89                 '')
  90                         git-diff-tree --stat --summary -M "$head" "$1"
  91                         ;;
  92                 esac
  93                 ;;
  94         esac
  95 }
  96
  97 rloga=
  98 while case "$#" in 0) break ;; esac
  99 do
 100         case "$1" in
 101         -n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
 102                 --no-summa|--no-summar|--no-summary)
 103                 no_summary=t ;;
 104         --sq|--squ|--squa|--squas|--squash)
 105                 squash=t no_commit=t ;;
 106         --no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
 107                 no_commit=t ;;
 108         -s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
 109                 --strateg=*|--strategy=*|\
 110         -s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
 111                 case "$#,$1" in
 112                 *,*=*)
 113                         strategy=`expr "z$1" : 'z-[^=]*=\(.*\)'` ;;
 114                 1,*)
 115                         usage ;;
 116                 *)
 117                         strategy="$2"
 118                         shift ;;
 119                 esac
 120                 case " $all_strategies " in
 121                 *" $strategy "*)
 122                         use_strategies="$use_strategies$strategy " ;;
 123                 *)
 124                         die "available strategies are: $all_strategies" ;;
 125                 esac
 126                 ;;
 127         --reflog-action=*)
 128                 rloga=`expr "z$1" : 'z-[^=]*=\(.*\)'`
 129                 ;;
 130         -*)     usage ;;
 131         *)      break ;;
 132         esac
 133         shift
 134 done
 135
 136 merge_msg="$1"
 137 shift
 138 head_arg="$1"
 139 head=$(git-rev-parse --verify "$1"^0) || usage
 140 shift
 141
 142 # All the rest are remote heads
 143 test "$#" = 0 && usage ;# we need at least one remote head.
 144 test "$rloga" = '' && rloga="merge: $@"
 145
 146 remoteheads=
 147 for remote
 148 do
 149         remotehead=$(git-rev-parse --verify "$remote"^0) ||
 150             die "$remote - not something we can merge"
 151         remoteheads="${remoteheads}$remotehead "
 152 done
 153 set x $remoteheads ; shift
 154
 155 case "$use_strategies" in
 156 '')
 157         case "$#" in
 158         1)
 159                 use_strategies="$default_twohead_strategies" ;;
 160         *)
 161                 use_strategies="$default_octopus_strategies" ;;
 162         esac
 163         ;;
 164 esac
 165
 166 for s in $use_strategies
 167 do
 168         case " $s " in
 169         *" $no_trivial_merge_strategies "*)
 170                 index_merge=f
 171                 break
 172                 ;;
 173         esac
 174 done
 175
 176 case "$#" in
 177 1)
 178         common=$(git-merge-base --all $head "$@")
 179         ;;
 180 *)
 181         common=$(git-show-branch --merge-base $head "$@")
 182         ;;
 183 esac
 184 echo "$head" >"$GIT_DIR/ORIG_HEAD"
 185
 186 case "$index_merge,$#,$common,$no_commit" in
 187 f,*)
 188         # We've been told not to try anything clever.  Skip to real merge.
 189         ;;
 190 ?,*,'',*)
 191         # No common ancestors found. We need a real merge.
 192         ;;
 193 ?,1,"$1",*)
 194         # If head can reach all the merge then we are up to date.
 195         # but first the most common case of merging one remote.
 196         finish_up_to_date "Already up-to-date."
 197         exit 0
 198         ;;
 199 ?,1,"$head",*)
 200         # Again the most common case of merging one remote.
 201         echo "Updating from $head to $1"
 202         git-update-index --refresh 2>/dev/null
 203         new_head=$(git-rev-parse --verify "$1^0") &&
 204         git-read-tree -u -v -m $head "$new_head" &&
 205         finish "$new_head" "Fast forward"
 206         dropsave
 207         exit 0
 208         ;;
 209 ?,1,?*"$LF"?*,*)
 210         # We are not doing octopus and not fast forward.  Need a
 211         # real merge.
 212         ;;
 213 ?,1,*,)
 214         # We are not doing octopus, not fast forward, and have only
 215         # one common.  See if it is really trivial.
 216         git var GIT_COMMITTER_IDENT >/dev/null || exit
 217
 218         echo "Trying really trivial in-index merge..."
 219         git-update-index --refresh 2>/dev/null
 220         if git-read-tree --trivial -m -u -v $common $head "$1" &&
 221            result_tree=$(git-write-tree)
 222         then
 223             echo "Wonderful."
 224             result_commit=$(
 225                 echo "$merge_msg" |
 226                 git-commit-tree $result_tree -p HEAD -p "$1"
 227             ) || exit
 228             finish "$result_commit" "In-index merge"
 229             dropsave
 230             exit 0
 231         fi
 232         echo "Nope."
 233         ;;
 234 *)
 235         # An octopus.  If we can reach all the remote we are up to date.
 236         up_to_date=t
 237         for remote
 238         do
 239                 common_one=$(git-merge-base --all $head $remote)
 240                 if test "$common_one" != "$remote"
 241                 then
 242                         up_to_date=f
 243                         break
 244                 fi
 245         done
 246         if test "$up_to_date" = t
 247         then
 248                 finish_up_to_date "Already up-to-date. Yeeah!"
 249                 exit 0
 250         fi
 251         ;;
 252 esac
 253
 254 # We are going to make a new commit.
 255 git var GIT_COMMITTER_IDENT >/dev/null || exit
 256
 257 # At this point, we need a real merge.  No matter what strategy
 258 # we use, it would operate on the index, possibly affecting the
 259 # working tree, and when resolved cleanly, have the desired tree
 260 # in the index -- this means that the index must be in sync with
 261 # the $head commit.  The strategies are responsible to ensure this.
 262
 263 case "$use_strategies" in
 264 ?*' '?*)
 265     # Stash away the local changes so that we can try more than one.
 266     savestate
 267     single_strategy=no
 268     ;;
 269 *)
 270     rm -f "$GIT_DIR/MERGE_SAVE"
 271     single_strategy=yes
 272     ;;
 273 esac
 274
 275 result_tree= best_cnt=-1 best_strategy= wt_strategy=
 276 merge_was_ok=
 277 for strategy in $use_strategies
 278 do
 279     test "$wt_strategy" = '' || {
 280         echo "Rewinding the tree to pristine..."
 281         restorestate
 282     }
 283     case "$single_strategy" in
 284     no)
 285         echo "Trying merge strategy $strategy..."
 286         ;;
 287     esac
 288
 289     # Remember which strategy left the state in the working tree
 290     wt_strategy=$strategy
 291
 292     git-merge-$strategy $common -- "$head_arg" "$@"
 293     exit=$?
 294     if test "$no_commit" = t && test "$exit" = 0
 295     then
 296         merge_was_ok=t
 297         exit=1 ;# pretend it left conflicts.
 298     fi
 299
 300     test "$exit" = 0 || {
 301
 302         # The backend exits with 1 when conflicts are left to be resolved,
 303         # with 2 when it does not handle the given merge at all.
 304
 305         if test "$exit" -eq 1
 306         then
 307             cnt=`{
 308                 git-diff-files --name-only
 309                 git-ls-files --unmerged
 310             } | wc -l`
 311             if test $best_cnt -le 0 -o $cnt -le $best_cnt
 312             then
 313                 best_strategy=$strategy
 314                 best_cnt=$cnt
 315             fi
 316         fi
 317         continue
 318     }
 319
 320     # Automerge succeeded.
 321     result_tree=$(git-write-tree) && break
 322 done
 323
 324 # If we have a resulting tree, that means the strategy module
 325 # auto resolved the merge cleanly.
 326 if test '' != "$result_tree"
 327 then
 328     parents=$(git-show-branch --independent "$head" "$@" | sed -e 's/^/-p /')
 329     result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents) || exit
 330     finish "$result_commit" "Merge made by $wt_strategy."
 331     dropsave
 332     exit 0
 333 fi
 334
 335 # Pick the result from the best strategy and have the user fix it up.
 336 case "$best_strategy" in
 337 '')
 338         restorestate
 339         echo >&2 "No merge strategy handled the merge."
 340         exit 2
 341         ;;
 342 "$wt_strategy")
 343         # We already have its result in the working tree.
 344         ;;
 345 *)
 346         echo "Rewinding the tree to pristine..."
 347         restorestate
 348         echo "Using the $best_strategy to prepare resolving by hand."
 349         git-merge-$best_strategy $common -- "$head_arg" "$@"
 350         ;;
 351 esac
 352
 353 if test "$squash" = t
 354 then
 355         finish
 356 else
 357         for remote
 358         do
 359                 echo $remote
 360         done >"$GIT_DIR/MERGE_HEAD"
 361         echo "$merge_msg" >"$GIT_DIR/MERGE_MSG"
 362 fi
 363
 364 if test "$merge_was_ok" = t
 365 then
 366         echo >&2 \
 367         "Automatic merge went well; stopped before committing as requested"
 368         exit 0
 369 else
 370         {
 371             echo '
 372 Conflicts:
 373 '
 374                 git ls-files --unmerged |
 375                 sed -e 's/^[^   ]*      /       /' |
 376                 uniq
 377         } >>"$GIT_DIR/MERGE_MSG"
 378         if test -d "$GIT_DIR/rr-cache"
 379         then
 380                 git-rerere
 381         fi
 382         die "Automatic merge failed; fix conflicts and then commit the result."
 383 fi