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