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 recur octopus resolve stupid ours'
  13 case "${GIT_USE_RECUR_FOR_RECURSIVE}" in
  14 '')
  15         default_twohead_strategies=recursive ;;
  16 ?*)
  17         default_twohead_strategies=recur ;;
  18 esac
  19 default_octopus_strategies='octopus'
  20 no_trivial_merge_strategies='ours'
  21 use_strategies=
  22
  23 index_merge=t
  24 if test "@@NO_PYTHON@@"; then
  25         all_strategies='recur resolve octopus stupid ours'
  26         default_twohead_strategies='resolve'
  27 fi
  28
  29 dropsave() {
  30         rm -f -- "$GIT_DIR/MERGE_HEAD" "$GIT_DIR/MERGE_MSG" \
  31                  "$GIT_DIR/MERGE_SAVE" || exit 1
  32 }
  33
  34 savestate() {
  35         # Stash away any local modifications.
  36         git-diff-index -z --name-only $head |
  37         cpio -0 -o >"$GIT_DIR/MERGE_SAVE"
  38 }
  39
  40 restorestate() {
  41         if test -f "$GIT_DIR/MERGE_SAVE"
  42         then
  43                 git reset --hard $head
  44                 cpio -iuv <"$GIT_DIR/MERGE_SAVE"
  45                 git-update-index --refresh >/dev/null
  46         fi
  47 }
  48
  49 finish_up_to_date () {
  50         case "$squash" in
  51         t)
  52                 echo "$1 (nothing to squash)" ;;
  53         '')
  54                 echo "$1" ;;
  55         esac
  56         dropsave
  57 }
  58
  59 squash_message () {
  60         echo Squashed commit of the following:
  61         echo
  62         git-log --no-merges ^"$head" $remote
  63 }
  64
  65 finish () {
  66         test '' = "$2" || echo "$2"
  67         case "$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 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" "$1"
  90                         ;;
  91                 esac
  92                 ;;
  93         esac
  94 }
  95
  96 while case "$#" in 0) break ;; esac
  97 do
  98         case "$1" in
  99         -n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
 100                 --no-summa|--no-summar|--no-summary)
 101                 no_summary=t ;;
 102         --sq|--squ|--squa|--squas|--squash)
 103                 squash=t no_commit=t ;;
 104         --no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
 105                 no_commit=t ;;
 106         -s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
 107                 --strateg=*|--strategy=*|\
 108         -s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
 109                 case "$#,$1" in
 110                 *,*=*)
 111                         strategy=`expr "z$1" : 'z-[^=]*=\(.*\)'` ;;
 112                 1,*)
 113                         usage ;;
 114                 *)
 115                         strategy="$2"
 116                         shift ;;
 117                 esac
 118                 case "$strategy,${GIT_USE_RECUR_FOR_RECURSIVE}" in
 119                 recursive,?*)
 120                         strategy=recur ;;
 121                 esac
 122                 case " $all_strategies " in
 123                 *" $strategy "*)
 124                         use_strategies="$use_strategies$strategy " ;;
 125                 *)
 126                         die "available strategies are: $all_strategies" ;;
 127                 esac
 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
 144 remoteheads=
 145 for remote
 146 do
 147         remotehead=$(git-rev-parse --verify "$remote"^0) ||
 148             die "$remote - not something we can merge"
 149         remoteheads="${remoteheads}$remotehead "
 150 done
 151 set x $remoteheads ; shift
 152
 153 case "$use_strategies" in
 154 '')
 155         case "$#" in
 156         1)
 157                 use_strategies="$default_twohead_strategies" ;;
 158         *)
 159                 use_strategies="$default_octopus_strategies" ;;
 160         esac
 161         ;;
 162 esac
 163
 164 for s in $use_strategies
 165 do
 166         case " $s " in
 167         *" $no_trivial_merge_strategies "*)
 168                 index_merge=f
 169                 break
 170                 ;;
 171         esac
 172 done
 173
 174 case "$#" in
 175 1)
 176         common=$(git-merge-base --all $head "$@")
 177         ;;
 178 *)
 179         common=$(git-show-branch --merge-base $head "$@")
 180         ;;
 181 esac
 182 echo "$head" >"$GIT_DIR/ORIG_HEAD"
 183
 184 case "$index_merge,$#,$common,$no_commit" in
 185 f,*)
 186         # We've been told not to try anything clever.  Skip to real merge.
 187         ;;
 188 ?,*,'',*)
 189         # No common ancestors found. We need a real merge.
 190         ;;
 191 ?,1,"$1",*)
 192         # If head can reach all the merge then we are up to date.
 193         # but first the most common case of merging one remote.
 194         finish_up_to_date "Already up-to-date."
 195         exit 0
 196         ;;
 197 ?,1,"$head",*)
 198         # Again the most common case of merging one remote.
 199         echo "Updating from $head to $1"
 200         git-update-index --refresh 2>/dev/null
 201         new_head=$(git-rev-parse --verify "$1^0") &&
 202         git-read-tree -u -v -m $head "$new_head" &&
 203         finish "$new_head" "Fast forward"
 204         dropsave
 205         exit 0
 206         ;;
 207 ?,1,?*"$LF"?*,*)
 208         # We are not doing octopus and not fast forward.  Need a
 209         # real merge.
 210         ;;
 211 ?,1,*,)
 212         # We are not doing octopus, not fast forward, and have only
 213         # one common.  See if it is really trivial.
 214         git var GIT_COMMITTER_IDENT >/dev/null || exit
 215
 216         echo "Trying really trivial in-index merge..."
 217         git-update-index --refresh 2>/dev/null
 218         if git-read-tree --trivial -m -u -v $common $head "$1" &&
 219            result_tree=$(git-write-tree)
 220         then
 221             echo "Wonderful."
 222             result_commit=$(
 223                 echo "$merge_msg" |
 224                 git-commit-tree $result_tree -p HEAD -p "$1"
 225             ) || exit
 226             finish "$result_commit" "In-index merge"
 227             dropsave
 228             exit 0
 229         fi
 230         echo "Nope."
 231         ;;
 232 *)
 233         # An octopus.  If we can reach all the remote we are up to date.
 234         up_to_date=t
 235         for remote
 236         do
 237                 common_one=$(git-merge-base --all $head $remote)
 238                 if test "$common_one" != "$remote"
 239                 then
 240                         up_to_date=f
 241                         break
 242                 fi
 243         done
 244         if test "$up_to_date" = t
 245         then
 246                 finish_up_to_date "Already up-to-date. Yeeah!"
 247                 exit 0
 248         fi
 249         ;;
 250 esac
 251
 252 # We are going to make a new commit.
 253 git var GIT_COMMITTER_IDENT >/dev/null || exit
 254
 255 # At this point, we need a real merge.  No matter what strategy
 256 # we use, it would operate on the index, possibly affecting the
 257 # working tree, and when resolved cleanly, have the desired tree
 258 # in the index -- this means that the index must be in sync with
 259 # the $head commit.  The strategies are responsible to ensure this.
 260
 261 case "$use_strategies" in
 262 ?*' '?*)
 263     # Stash away the local changes so that we can try more than one.
 264     savestate
 265     single_strategy=no
 266     ;;
 267 *)
 268     rm -f "$GIT_DIR/MERGE_SAVE"
 269     single_strategy=yes
 270     ;;
 271 esac
 272
 273 result_tree= best_cnt=-1 best_strategy= wt_strategy=
 274 merge_was_ok=
 275 for strategy in $use_strategies
 276 do
 277     test "$wt_strategy" = '' || {
 278         echo "Rewinding the tree to pristine..."
 279         restorestate
 280     }
 281     case "$single_strategy" in
 282     no)
 283         echo "Trying merge strategy $strategy..."
 284         ;;
 285     esac
 286
 287     # Remember which strategy left the state in the working tree
 288     wt_strategy=$strategy
 289
 290     git-merge-$strategy $common -- "$head_arg" "$@"
 291     exit=$?
 292     if test "$no_commit" = t && test "$exit" = 0
 293     then
 294         merge_was_ok=t
 295         exit=1 ;# pretend it left conflicts.
 296     fi
 297
 298     test "$exit" = 0 || {
 299
 300         # The backend exits with 1 when conflicts are left to be resolved,
 301         # with 2 when it does not handle the given merge at all.
 302
 303         if test "$exit" -eq 1
 304         then
 305             cnt=`{
 306                 git-diff-files --name-only
 307                 git-ls-files --unmerged
 308             } | wc -l`
 309             if test $best_cnt -le 0 -o $cnt -le $best_cnt
 310             then
 311                 best_strategy=$strategy
 312                 best_cnt=$cnt
 313             fi
 314         fi
 315         continue
 316     }
 317
 318     # Automerge succeeded.
 319     result_tree=$(git-write-tree) && break
 320 done
 321
 322 # If we have a resulting tree, that means the strategy module
 323 # auto resolved the merge cleanly.
 324 if test '' != "$result_tree"
 325 then
 326     parents=$(git-show-branch --independent "$head" "$@" | sed -e 's/^/-p /')
 327     result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents) || exit
 328     finish "$result_commit" "Merge $result_commit, made by $wt_strategy."
 329     dropsave
 330     exit 0
 331 fi
 332
 333 # Pick the result from the best strategy and have the user fix it up.
 334 case "$best_strategy" in
 335 '')
 336         restorestate
 337         echo >&2 "No merge strategy handled the merge."
 338         exit 2
 339         ;;
 340 "$wt_strategy")
 341         # We already have its result in the working tree.
 342         ;;
 343 *)
 344         echo "Rewinding the tree to pristine..."
 345         restorestate
 346         echo "Using the $best_strategy to prepare resolving by hand."
 347         git-merge-$best_strategy $common -- "$head_arg" "$@"
 348         ;;
 349 esac
 350
 351 if test "$squash" = t
 352 then
 353         finish
 354 else
 355         for remote
 356         do
 357                 echo $remote
 358         done >"$GIT_DIR/MERGE_HEAD"
 359         echo "$merge_msg" >"$GIT_DIR/MERGE_MSG"
 360 fi
 361
 362 if test "$merge_was_ok" = t
 363 then
 364         echo >&2 \
 365         "Automatic merge went well; stopped before committing as requested"
 366         exit 0
 367 else
 368         {
 369             echo '
 370 Conflicts:
 371 '
 372                 git ls-files --unmerged |
 373                 sed -e 's/^[^   ]*      /       /' |
 374                 uniq
 375         } >>"$GIT_DIR/MERGE_MSG"
 376         if test -d "$GIT_DIR/rr-cache"
 377         then
 378                 git-rerere
 379         fi
 380         die "Automatic merge failed; fix conflicts and then commit the result."
 381 fi