git-merge.sh

   1 #!/bin/sh
   2 #
   3 # Copyright (c) 2005 Junio C Hamano
   4 #
   5
   6 USAGE='[-n] [--no-commit] [--squash] [-s <strategy>] [--reflog-action=<action>] [-m=<merge-message>] <commit>+'
   7
   8 . git-sh-setup
   9
  10 LF='
  11 '
  12
  13 all_strategies='recur recursive octopus resolve stupid ours'
  14 default_twohead_strategies='recursive'
  15 default_octopus_strategies='octopus'
  16 no_trivial_merge_strategies='ours'
  17 use_strategies=
  18
  19 index_merge=t
  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_up_to_date () {
  42         case "$squash" in
  43         t)
  44                 echo "$1 (nothing to squash)" ;;
  45         '')
  46                 echo "$1" ;;
  47         esac
  48         dropsave
  49 }
  50
  51 squash_message () {
  52         echo Squashed commit of the following:
  53         echo
  54         git-log --no-merges ^"$head" $remote
  55 }
  56
  57 finish () {
  58         if test '' = "$2"
  59         then
  60                 rlogm="$rloga"
  61         else
  62                 echo "$2"
  63                 rlogm="$rloga: $2"
  64         fi
  65         case "$squash" in
  66         t)
  67                 echo "Squash commit -- not updating HEAD"
  68                 squash_message >"$GIT_DIR/SQUASH_MSG"
  69                 ;;
  70         '')
  71                 case "$merge_msg" in
  72                 '')
  73                         echo "No merge message -- not updating HEAD"
  74                         ;;
  75                 *)
  76                         git-update-ref -m "$rlogm" HEAD "$1" "$head" || exit 1
  77                         ;;
  78                 esac
  79                 ;;
  80         esac
  81         case "$1" in
  82         '')
  83                 ;;
  84         ?*)
  85                 case "$no_summary" in
  86                 '')
  87                         git-diff-tree --stat --summary -M "$head" "$1"
  88                         ;;
  89                 esac
  90                 ;;
  91         esac
  92 }
  93
  94 case "$#" in 0) usage ;; esac
  95
  96 rloga= have_message=
  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         -m=*|--m=*|--me=*|--mes=*|--mess=*|--messa=*|--messag=*|--message=*)
 130                 merge_msg=`expr "z$1" : 'z-[^=]*=\(.*\)'`
 131                 have_message=t
 132                 ;;
 133         -m|--m|--me|--mes|--mess|--messa|--messag|--message)
 134                 shift
 135                 case "$#" in
 136                 1)      usage ;;
 137                 esac
 138                 merge_msg="$1"
 139                 have_message=t
 140                 ;;
 141         -*)     usage ;;
 142         *)      break ;;
 143         esac
 144         shift
 145 done
 146
 147 # This could be traditional "merge <msg> HEAD <commit>..."  and the
 148 # way we can tell it is to see if the second token is HEAD, but some
 149 # people might have misused the interface and used a committish that
 150 # is the same as HEAD there instead.  Traditional format never would
 151 # have "-m" so it is an additional safety measure to check for it.
 152
 153 if test -z "$have_message" &&
 154         second_token=$(git-rev-parse --verify "$2^0" 2>/dev/null) &&
 155         head_commit=$(git-rev-parse --verify "HEAD" 2>/dev/null) &&
 156         test "$second_token" = "$head_commit"
 157 then
 158         merge_msg="$1"
 159         shift
 160         head_arg="$1"
 161         shift
 162 elif ! git-rev-parse --verify HEAD >/dev/null 2>&1
 163 then
 164         # If the merged head is a valid one there is no reason to
 165         # forbid "git merge" into a branch yet to be born.  We do
 166         # the same for "git pull".
 167         if test 1 -ne $#
 168         then
 169                 echo >&2 "Can merge only exactly one commit into empty head"
 170                 exit 1
 171         fi
 172
 173         rh=$(git rev-parse --verify "$1^0") ||
 174                 die "$1 - not something we can merge"
 175
 176         git-update-ref -m "initial pull" HEAD "$rh" "" &&
 177         git-read-tree --reset -u HEAD
 178         exit
 179
 180 else
 181         # We are invoked directly as the first-class UI.
 182         head_arg=HEAD
 183
 184         # All the rest are the commits being merged; prepare
 185         # the standard merge summary message to be appended to
 186         # the given message.  If remote is invalid we will die
 187         # later in the common codepath so we discard the error
 188         # in this loop.
 189         merge_name=$(for remote
 190                 do
 191                         rh=$(git-rev-parse --verify "$remote"^0 2>/dev/null) &&
 192                         bh=$(git show-ref -s --verify "refs/heads/$remote" 2>/dev/null) &&
 193                         if test "$rh" = "$bh"
 194                         then
 195                                 echo "$rh               branch '$remote' of ."
 196                         else
 197                                 echo "$rh               commit '$remote'"
 198                         fi
 199                 done | git-fmt-merge-msg
 200         )
 201         merge_msg="${merge_msg:+$merge_msg$LF$LF}$merge_name"
 202 fi
 203 head=$(git-rev-parse --verify "$head_arg"^0) || usage
 204
 205 # All the rest are remote heads
 206 test "$#" = 0 && usage ;# we need at least one remote head.
 207 test "$rloga" = '' && rloga="merge: $@"
 208
 209 remoteheads=
 210 for remote
 211 do
 212         remotehead=$(git-rev-parse --verify "$remote"^0 2>/dev/null) ||
 213             die "$remote - not something we can merge"
 214         remoteheads="${remoteheads}$remotehead "
 215 done
 216 set x $remoteheads ; shift
 217
 218 case "$use_strategies" in
 219 '')
 220         case "$#" in
 221         1)
 222                 use_strategies="$default_twohead_strategies" ;;
 223         *)
 224                 use_strategies="$default_octopus_strategies" ;;
 225         esac
 226         ;;
 227 esac
 228
 229 for s in $use_strategies
 230 do
 231         case " $s " in
 232         *" $no_trivial_merge_strategies "*)
 233                 index_merge=f
 234                 break
 235                 ;;
 236         esac
 237 done
 238
 239 case "$#" in
 240 1)
 241         common=$(git-merge-base --all $head "$@")
 242         ;;
 243 *)
 244         common=$(git-show-branch --merge-base $head "$@")
 245         ;;
 246 esac
 247 echo "$head" >"$GIT_DIR/ORIG_HEAD"
 248
 249 case "$index_merge,$#,$common,$no_commit" in
 250 f,*)
 251         # We've been told not to try anything clever.  Skip to real merge.
 252         ;;
 253 ?,*,'',*)
 254         # No common ancestors found. We need a real merge.
 255         ;;
 256 ?,1,"$1",*)
 257         # If head can reach all the merge then we are up to date.
 258         # but first the most common case of merging one remote.
 259         finish_up_to_date "Already up-to-date."
 260         exit 0
 261         ;;
 262 ?,1,"$head",*)
 263         # Again the most common case of merging one remote.
 264         echo "Updating $(git-rev-parse --short $head)..$(git-rev-parse --short $1)"
 265         git-update-index --refresh 2>/dev/null
 266         new_head=$(git-rev-parse --verify "$1^0") &&
 267         git-read-tree -u -v -m $head "$new_head" &&
 268         finish "$new_head" "Fast forward"
 269         dropsave
 270         exit 0
 271         ;;
 272 ?,1,?*"$LF"?*,*)
 273         # We are not doing octopus and not fast forward.  Need a
 274         # real merge.
 275         ;;
 276 ?,1,*,)
 277         # We are not doing octopus, not fast forward, and have only
 278         # one common.  See if it is really trivial.
 279         git var GIT_COMMITTER_IDENT >/dev/null || exit
 280
 281         echo "Trying really trivial in-index merge..."
 282         git-update-index --refresh 2>/dev/null
 283         if git-read-tree --trivial -m -u -v $common $head "$1" &&
 284            result_tree=$(git-write-tree)
 285         then
 286             echo "Wonderful."
 287             result_commit=$(
 288                 echo "$merge_msg" |
 289                 git-commit-tree $result_tree -p HEAD -p "$1"
 290             ) || exit
 291             finish "$result_commit" "In-index merge"
 292             dropsave
 293             exit 0
 294         fi
 295         echo "Nope."
 296         ;;
 297 *)
 298         # An octopus.  If we can reach all the remote we are up to date.
 299         up_to_date=t
 300         for remote
 301         do
 302                 common_one=$(git-merge-base --all $head $remote)
 303                 if test "$common_one" != "$remote"
 304                 then
 305                         up_to_date=f
 306                         break
 307                 fi
 308         done
 309         if test "$up_to_date" = t
 310         then
 311                 finish_up_to_date "Already up-to-date. Yeeah!"
 312                 exit 0
 313         fi
 314         ;;
 315 esac
 316
 317 # We are going to make a new commit.
 318 git var GIT_COMMITTER_IDENT >/dev/null || exit
 319
 320 # At this point, we need a real merge.  No matter what strategy
 321 # we use, it would operate on the index, possibly affecting the
 322 # working tree, and when resolved cleanly, have the desired tree
 323 # in the index -- this means that the index must be in sync with
 324 # the $head commit.  The strategies are responsible to ensure this.
 325
 326 case "$use_strategies" in
 327 ?*' '?*)
 328     # Stash away the local changes so that we can try more than one.
 329     savestate
 330     single_strategy=no
 331     ;;
 332 *)
 333     rm -f "$GIT_DIR/MERGE_SAVE"
 334     single_strategy=yes
 335     ;;
 336 esac
 337
 338 result_tree= best_cnt=-1 best_strategy= wt_strategy=
 339 merge_was_ok=
 340 for strategy in $use_strategies
 341 do
 342     test "$wt_strategy" = '' || {
 343         echo "Rewinding the tree to pristine..."
 344         restorestate
 345     }
 346     case "$single_strategy" in
 347     no)
 348         echo "Trying merge strategy $strategy..."
 349         ;;
 350     esac
 351
 352     # Remember which strategy left the state in the working tree
 353     wt_strategy=$strategy
 354
 355     git-merge-$strategy $common -- "$head_arg" "$@"
 356     exit=$?
 357     if test "$no_commit" = t && test "$exit" = 0
 358     then
 359         merge_was_ok=t
 360         exit=1 ;# pretend it left conflicts.
 361     fi
 362
 363     test "$exit" = 0 || {
 364
 365         # The backend exits with 1 when conflicts are left to be resolved,
 366         # with 2 when it does not handle the given merge at all.
 367
 368         if test "$exit" -eq 1
 369         then
 370             cnt=`{
 371                 git-diff-files --name-only
 372                 git-ls-files --unmerged
 373             } | wc -l`
 374             if test $best_cnt -le 0 -o $cnt -le $best_cnt
 375             then
 376                 best_strategy=$strategy
 377                 best_cnt=$cnt
 378             fi
 379         fi
 380         continue
 381     }
 382
 383     # Automerge succeeded.
 384     result_tree=$(git-write-tree) && break
 385 done
 386
 387 # If we have a resulting tree, that means the strategy module
 388 # auto resolved the merge cleanly.
 389 if test '' != "$result_tree"
 390 then
 391     parents=$(git-show-branch --independent "$head" "$@" | sed -e 's/^/-p /')
 392     result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents) || exit
 393     finish "$result_commit" "Merge made by $wt_strategy."
 394     dropsave
 395     exit 0
 396 fi
 397
 398 # Pick the result from the best strategy and have the user fix it up.
 399 case "$best_strategy" in
 400 '')
 401         restorestate
 402         echo >&2 "No merge strategy handled the merge."
 403         exit 2
 404         ;;
 405 "$wt_strategy")
 406         # We already have its result in the working tree.
 407         ;;
 408 *)
 409         echo "Rewinding the tree to pristine..."
 410         restorestate
 411         echo "Using the $best_strategy to prepare resolving by hand."
 412         git-merge-$best_strategy $common -- "$head_arg" "$@"
 413         ;;
 414 esac
 415
 416 if test "$squash" = t
 417 then
 418         finish
 419 else
 420         for remote
 421         do
 422                 echo $remote
 423         done >"$GIT_DIR/MERGE_HEAD"
 424         echo "$merge_msg" >"$GIT_DIR/MERGE_MSG"
 425 fi
 426
 427 if test "$merge_was_ok" = t
 428 then
 429         echo >&2 \
 430         "Automatic merge went well; stopped before committing as requested"
 431         exit 0
 432 else
 433         {
 434             echo '
 435 Conflicts:
 436 '
 437                 git ls-files --unmerged |
 438                 sed -e 's/^[^   ]*      /       /' |
 439                 uniq
 440         } >>"$GIT_DIR/MERGE_MSG"
 441         if test -d "$GIT_DIR/rr-cache"
 442         then
 443                 git-rerere
 444         fi
 445         die "Automatic merge failed; fix conflicts and then commit the result."
 446 fi