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='recur recursive recursive-old 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='recur recursive resolve octopus stupid ours'
  21 fi
  22
  23 dropsave() {
  24         rm -f -- "$GIT_DIR/MERGE_HEAD" "$GIT_DIR/MERGE_MSG" \
  25                  "$GIT_DIR/MERGE_SAVE" || exit 1
  26 }
  27
  28 savestate() {
  29         # Stash away any local modifications.
  30         git-diff-index -z --name-only $head |
  31         cpio -0 -o >"$GIT_DIR/MERGE_SAVE"
  32 }
  33
  34 restorestate() {
  35         if test -f "$GIT_DIR/MERGE_SAVE"
  36         then
  37                 git reset --hard $head
  38                 cpio -iuv <"$GIT_DIR/MERGE_SAVE"
  39                 git-update-index --refresh >/dev/null
  40         fi
  41 }
  42
  43 finish_up_to_date () {
  44         case "$squash" in
  45         t)
  46                 echo "$1 (nothing to squash)" ;;
  47         '')
  48                 echo "$1" ;;
  49         esac
  50         dropsave
  51 }
  52
  53 squash_message () {
  54         echo Squashed commit of the following:
  55         echo
  56         git-log --no-merges ^"$head" $remote
  57 }
  58
  59 finish () {
  60         if test '' = "$2"
  61         then
  62                 rlogm="$rloga"
  63         else
  64                 echo "$2"
  65                 rlogm="$rloga: $2"
  66         fi
  67         case "$squash" in
  68         t)
  69                 echo "Squash commit -- not updating HEAD"
  70                 squash_message >"$GIT_DIR/SQUASH_MSG"
  71                 ;;
  72         '')
  73                 case "$merge_msg" in
  74                 '')
  75                         echo "No merge message -- not updating HEAD"
  76                         ;;
  77                 *)
  78                         git-update-ref -m "$rlogm" HEAD "$1" "$head" || exit 1
  79                         ;;
  80                 esac
  81                 ;;
  82         esac
  83         case "$1" in
  84         '')
  85                 ;;
  86         ?*)
  87                 case "$no_summary" in
  88                 '')
  89                         git-diff-tree --stat --summary -M "$head" "$1"
  90                         ;;
  91                 esac
  92                 ;;
  93         esac
  94 }
  95
  96 rloga=
  97 while case "$#" in 0) break ;; esac
  98 do
  99         case "$1" in
 100         -n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
 101                 --no-summa|--no-summar|--no-summary)
 102                 no_summary=t ;;
 103         --sq|--squ|--squa|--squas|--squash)
 104                 squash=t no_commit=t ;;
 105         --no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
 106                 no_commit=t ;;
 107         -s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
 108                 --strateg=*|--strategy=*|\
 109         -s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
 110                 case "$#,$1" in
 111                 *,*=*)
 112                         strategy=`expr "z$1" : 'z-[^=]*=\(.*\)'` ;;
 113                 1,*)
 114                         usage ;;
 115                 *)
 116                         strategy="$2"
 117                         shift ;;
 118                 esac
 119                 case " $all_strategies " in
 120                 *" $strategy "*)
 121                         use_strategies="$use_strategies$strategy " ;;
 122                 *)
 123                         die "available strategies are: $all_strategies" ;;
 124                 esac
 125                 ;;
 126         --reflog-action=*)
 127                 rloga=`expr "z$1" : 'z-[^=]*=\(.*\)'`
 128                 ;;
 129         -*)     usage ;;
 130         *)      break ;;
 131         esac
 132         shift
 133 done
 134
 135 merge_msg="$1"
 136 shift
 137 head_arg="$1"
 138 head=$(git-rev-parse --verify "$1"^0) || usage
 139 shift
 140
 141 # All the rest are remote heads
 142 test "$#" = 0 && usage ;# we need at least one remote head.
 143 test "$rloga" = '' && rloga="merge: $@"
 144
 145 remoteheads=
 146 for remote
 147 do
 148         remotehead=$(git-rev-parse --verify "$remote"^0) ||
 149             die "$remote - not something we can merge"
 150         remoteheads="${remoteheads}$remotehead "
 151 done
 152 set x $remoteheads ; shift
 153
 154 case "$use_strategies" in
 155 '')
 156         case "$#" in
 157         1)
 158                 use_strategies="$default_twohead_strategies" ;;
 159         *)
 160                 use_strategies="$default_octopus_strategies" ;;
 161         esac
 162         ;;
 163 esac
 164
 165 for s in $use_strategies
 166 do
 167         case " $s " in
 168         *" $no_trivial_merge_strategies "*)
 169                 index_merge=f
 170                 break
 171                 ;;
 172         esac
 173 done
 174
 175 case "$#" in
 176 1)
 177         common=$(git-merge-base --all $head "$@")
 178         ;;
 179 *)
 180         common=$(git-show-branch --merge-base $head "$@")
 181         ;;
 182 esac
 183 echo "$head" >"$GIT_DIR/ORIG_HEAD"
 184
 185 case "$index_merge,$#,$common,$no_commit" in
 186 f,*)
 187         # We've been told not to try anything clever.  Skip to real merge.
 188         ;;
 189 ?,*,'',*)
 190         # No common ancestors found. We need a real merge.
 191         ;;
 192 ?,1,"$1",*)
 193         # If head can reach all the merge then we are up to date.
 194         # but first the most common case of merging one remote.
 195         finish_up_to_date "Already up-to-date."
 196         exit 0
 197         ;;
 198 ?,1,"$head",*)
 199         # Again the most common case of merging one remote.
 200         echo "Updating $(git-rev-parse --short $head)..$(git-rev-parse --short $1)"
 201         git-update-index --refresh 2>/dev/null
 202         new_head=$(git-rev-parse --verify "$1^0") &&
 203         git-read-tree -u -v -m $head "$new_head" &&
 204         finish "$new_head" "Fast forward"
 205         dropsave
 206         exit 0
 207         ;;
 208 ?,1,?*"$LF"?*,*)
 209         # We are not doing octopus and not fast forward.  Need a
 210         # real merge.
 211         ;;
 212 ?,1,*,)
 213         # We are not doing octopus, not fast forward, and have only
 214         # one common.  See if it is really trivial.
 215         git var GIT_COMMITTER_IDENT >/dev/null || exit
 216
 217         echo "Trying really trivial in-index merge..."
 218         git-update-index --refresh 2>/dev/null
 219         if git-read-tree --trivial -m -u -v $common $head "$1" &&
 220            result_tree=$(git-write-tree)
 221         then
 222             echo "Wonderful."
 223             result_commit=$(
 224                 echo "$merge_msg" |
 225                 git-commit-tree $result_tree -p HEAD -p "$1"
 226             ) || exit
 227             finish "$result_commit" "In-index merge"
 228             dropsave
 229             exit 0
 230         fi
 231         echo "Nope."
 232         ;;
 233 *)
 234         # An octopus.  If we can reach all the remote we are up to date.
 235         up_to_date=t
 236         for remote
 237         do
 238                 common_one=$(git-merge-base --all $head $remote)
 239                 if test "$common_one" != "$remote"
 240                 then
 241                         up_to_date=f
 242                         break
 243                 fi
 244         done
 245         if test "$up_to_date" = t
 246         then
 247                 finish_up_to_date "Already up-to-date. Yeeah!"
 248                 exit 0
 249         fi
 250         ;;
 251 esac
 252
 253 # We are going to make a new commit.
 254 git var GIT_COMMITTER_IDENT >/dev/null || exit
 255
 256 # At this point, we need a real merge.  No matter what strategy
 257 # we use, it would operate on the index, possibly affecting the
 258 # working tree, and when resolved cleanly, have the desired tree
 259 # in the index -- this means that the index must be in sync with
 260 # the $head commit.  The strategies are responsible to ensure this.
 261
 262 case "$use_strategies" in
 263 ?*' '?*)
 264     # Stash away the local changes so that we can try more than one.
 265     savestate
 266     single_strategy=no
 267     ;;
 268 *)
 269     rm -f "$GIT_DIR/MERGE_SAVE"
 270     single_strategy=yes
 271     ;;
 272 esac
 273
 274 result_tree= best_cnt=-1 best_strategy= wt_strategy=
 275 merge_was_ok=
 276 for strategy in $use_strategies
 277 do
 278     test "$wt_strategy" = '' || {
 279         echo "Rewinding the tree to pristine..."
 280         restorestate
 281     }
 282     case "$single_strategy" in
 283     no)
 284         echo "Trying merge strategy $strategy..."
 285         ;;
 286     esac
 287
 288     # Remember which strategy left the state in the working tree
 289     wt_strategy=$strategy
 290
 291     git-merge-$strategy $common -- "$head_arg" "$@"
 292     exit=$?
 293     if test "$no_commit" = t && test "$exit" = 0
 294     then
 295         merge_was_ok=t
 296         exit=1 ;# pretend it left conflicts.
 297     fi
 298
 299     test "$exit" = 0 || {
 300
 301         # The backend exits with 1 when conflicts are left to be resolved,
 302         # with 2 when it does not handle the given merge at all.
 303
 304         if test "$exit" -eq 1
 305         then
 306             cnt=`{
 307                 git-diff-files --name-only
 308                 git-ls-files --unmerged
 309             } | wc -l`
 310             if test $best_cnt -le 0 -o $cnt -le $best_cnt
 311             then
 312                 best_strategy=$strategy
 313                 best_cnt=$cnt
 314             fi
 315         fi
 316         continue
 317     }
 318
 319     # Automerge succeeded.
 320     result_tree=$(git-write-tree) && break
 321 done
 322
 323 # If we have a resulting tree, that means the strategy module
 324 # auto resolved the merge cleanly.
 325 if test '' != "$result_tree"
 326 then
 327     parents=$(git-show-branch --independent "$head" "$@" | sed -e 's/^/-p /')
 328     result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents) || exit
 329     finish "$result_commit" "Merge made by $wt_strategy."
 330     dropsave
 331     exit 0
 332 fi
 333
 334 # Pick the result from the best strategy and have the user fix it up.
 335 case "$best_strategy" in
 336 '')
 337         restorestate
 338         echo >&2 "No merge strategy handled the merge."
 339         exit 2
 340         ;;
 341 "$wt_strategy")
 342         # We already have its result in the working tree.
 343         ;;
 344 *)
 345         echo "Rewinding the tree to pristine..."
 346         restorestate
 347         echo "Using the $best_strategy to prepare resolving by hand."
 348         git-merge-$best_strategy $common -- "$head_arg" "$@"
 349         ;;
 350 esac
 351
 352 if test "$squash" = t
 353 then
 354         finish
 355 else
 356         for remote
 357         do
 358                 echo $remote
 359         done >"$GIT_DIR/MERGE_HEAD"
 360         echo "$merge_msg" >"$GIT_DIR/MERGE_MSG"
 361 fi
 362
 363 if test "$merge_was_ok" = t
 364 then
 365         echo >&2 \
 366         "Automatic merge went well; stopped before committing as requested"
 367         exit 0
 368 else
 369         {
 370             echo '
 371 Conflicts:
 372 '
 373                 git ls-files --unmerged |
 374                 sed -e 's/^[^   ]*      /       /' |
 375                 uniq
 376         } >>"$GIT_DIR/MERGE_MSG"
 377         if test -d "$GIT_DIR/rr-cache"
 378         then
 379                 git-rerere
 380         fi
 381         die "Automatic merge failed; fix conflicts and then commit the result."
 382 fi