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 "$remote"^0 2>/dev/null) ||
 192                         continue ;# not something we can merge
 193                         bh=$(git show-ref -s --verify "refs/heads/$remote" 2>/dev/null)
 194                         if test "$rh" = "$bh"
 195                         then
 196                                 echo "$rh               branch '$remote' of ."
 197                         else
 198                                 echo "$rh               commit '$remote'"
 199                         fi
 200                 done | git-fmt-merge-msg
 201         )
 202         merge_msg="${merge_msg:+$merge_msg$LF$LF}$merge_name"
 203 fi
 204 head=$(git-rev-parse --verify "$head_arg"^0) || usage
 205
 206 # All the rest are remote heads
 207 test "$#" = 0 && usage ;# we need at least one remote head.
 208 test "$rloga" = '' && rloga="merge: $@"
 209
 210 remoteheads=
 211 for remote
 212 do
 213         remotehead=$(git-rev-parse --verify "$remote"^0 2>/dev/null) ||
 214             die "$remote - not something we can merge"
 215         remoteheads="${remoteheads}$remotehead "
 216 done
 217 set x $remoteheads ; shift
 218
 219 case "$use_strategies" in
 220 '')
 221         case "$#" in
 222         1)
 223                 use_strategies="$default_twohead_strategies" ;;
 224         *)
 225                 use_strategies="$default_octopus_strategies" ;;
 226         esac
 227         ;;
 228 esac
 229
 230 for s in $use_strategies
 231 do
 232         case " $s " in
 233         *" $no_trivial_merge_strategies "*)
 234                 index_merge=f
 235                 break
 236                 ;;
 237         esac
 238 done
 239
 240 case "$#" in
 241 1)
 242         common=$(git-merge-base --all $head "$@")
 243         ;;
 244 *)
 245         common=$(git-show-branch --merge-base $head "$@")
 246         ;;
 247 esac
 248 echo "$head" >"$GIT_DIR/ORIG_HEAD"
 249
 250 case "$index_merge,$#,$common,$no_commit" in
 251 f,*)
 252         # We've been told not to try anything clever.  Skip to real merge.
 253         ;;
 254 ?,*,'',*)
 255         # No common ancestors found. We need a real merge.
 256         ;;
 257 ?,1,"$1",*)
 258         # If head can reach all the merge then we are up to date.
 259         # but first the most common case of merging one remote.
 260         finish_up_to_date "Already up-to-date."
 261         exit 0
 262         ;;
 263 ?,1,"$head",*)
 264         # Again the most common case of merging one remote.
 265         echo "Updating $(git-rev-parse --short $head)..$(git-rev-parse --short $1)"
 266         git-update-index --refresh 2>/dev/null
 267         new_head=$(git-rev-parse --verify "$1^0") &&
 268         git-read-tree -u -v -m $head "$new_head" &&
 269         finish "$new_head" "Fast forward"
 270         dropsave
 271         exit 0
 272         ;;
 273 ?,1,?*"$LF"?*,*)
 274         # We are not doing octopus and not fast forward.  Need a
 275         # real merge.
 276         ;;
 277 ?,1,*,)
 278         # We are not doing octopus, not fast forward, and have only
 279         # one common.  See if it is really trivial.
 280         git var GIT_COMMITTER_IDENT >/dev/null || exit
 281
 282         echo "Trying really trivial in-index merge..."
 283         git-update-index --refresh 2>/dev/null
 284         if git-read-tree --trivial -m -u -v $common $head "$1" &&
 285            result_tree=$(git-write-tree)
 286         then
 287             echo "Wonderful."
 288             result_commit=$(
 289                 echo "$merge_msg" |
 290                 git-commit-tree $result_tree -p HEAD -p "$1"
 291             ) || exit
 292             finish "$result_commit" "In-index merge"
 293             dropsave
 294             exit 0
 295         fi
 296         echo "Nope."
 297         ;;
 298 *)
 299         # An octopus.  If we can reach all the remote we are up to date.
 300         up_to_date=t
 301         for remote
 302         do
 303                 common_one=$(git-merge-base --all $head $remote)
 304                 if test "$common_one" != "$remote"
 305                 then
 306                         up_to_date=f
 307                         break
 308                 fi
 309         done
 310         if test "$up_to_date" = t
 311         then
 312                 finish_up_to_date "Already up-to-date. Yeeah!"
 313                 exit 0
 314         fi
 315         ;;
 316 esac
 317
 318 # We are going to make a new commit.
 319 git var GIT_COMMITTER_IDENT >/dev/null || exit
 320
 321 # At this point, we need a real merge.  No matter what strategy
 322 # we use, it would operate on the index, possibly affecting the
 323 # working tree, and when resolved cleanly, have the desired tree
 324 # in the index -- this means that the index must be in sync with
 325 # the $head commit.  The strategies are responsible to ensure this.
 326
 327 case "$use_strategies" in
 328 ?*' '?*)
 329     # Stash away the local changes so that we can try more than one.
 330     savestate
 331     single_strategy=no
 332     ;;
 333 *)
 334     rm -f "$GIT_DIR/MERGE_SAVE"
 335     single_strategy=yes
 336     ;;
 337 esac
 338
 339 result_tree= best_cnt=-1 best_strategy= wt_strategy=
 340 merge_was_ok=
 341 for strategy in $use_strategies
 342 do
 343     test "$wt_strategy" = '' || {
 344         echo "Rewinding the tree to pristine..."
 345         restorestate
 346     }
 347     case "$single_strategy" in
 348     no)
 349         echo "Trying merge strategy $strategy..."
 350         ;;
 351     esac
 352
 353     # Remember which strategy left the state in the working tree
 354     wt_strategy=$strategy
 355
 356     git-merge-$strategy $common -- "$head_arg" "$@"
 357     exit=$?
 358     if test "$no_commit" = t && test "$exit" = 0
 359     then
 360         merge_was_ok=t
 361         exit=1 ;# pretend it left conflicts.
 362     fi
 363
 364     test "$exit" = 0 || {
 365
 366         # The backend exits with 1 when conflicts are left to be resolved,
 367         # with 2 when it does not handle the given merge at all.
 368
 369         if test "$exit" -eq 1
 370         then
 371             cnt=`{
 372                 git-diff-files --name-only
 373                 git-ls-files --unmerged
 374             } | wc -l`
 375             if test $best_cnt -le 0 -o $cnt -le $best_cnt
 376             then
 377                 best_strategy=$strategy
 378                 best_cnt=$cnt
 379             fi
 380         fi
 381         continue
 382     }
 383
 384     # Automerge succeeded.
 385     result_tree=$(git-write-tree) && break
 386 done
 387
 388 # If we have a resulting tree, that means the strategy module
 389 # auto resolved the merge cleanly.
 390 if test '' != "$result_tree"
 391 then
 392     parents=$(git-show-branch --independent "$head" "$@" | sed -e 's/^/-p /')
 393     result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents) || exit
 394     finish "$result_commit" "Merge made by $wt_strategy."
 395     dropsave
 396     exit 0
 397 fi
 398
 399 # Pick the result from the best strategy and have the user fix it up.
 400 case "$best_strategy" in
 401 '')
 402         restorestate
 403         case "$use_strategies" in
 404         ?*' '?*)
 405                 echo >&2 "No merge strategy handled the merge."
 406                 ;;
 407         *)
 408                 echo >&2 "Merge with strategy $use_strategies failed."
 409                 ;;
 410         esac
 411         exit 2
 412         ;;
 413 "$wt_strategy")
 414         # We already have its result in the working tree.
 415         ;;
 416 *)
 417         echo "Rewinding the tree to pristine..."
 418         restorestate
 419         echo "Using the $best_strategy to prepare resolving by hand."
 420         git-merge-$best_strategy $common -- "$head_arg" "$@"
 421         ;;
 422 esac
 423
 424 if test "$squash" = t
 425 then
 426         finish
 427 else
 428         for remote
 429         do
 430                 echo $remote
 431         done >"$GIT_DIR/MERGE_HEAD"
 432         echo "$merge_msg" >"$GIT_DIR/MERGE_MSG"
 433 fi
 434
 435 if test "$merge_was_ok" = t
 436 then
 437         echo >&2 \
 438         "Automatic merge went well; stopped before committing as requested"
 439         exit 0
 440 else
 441         {
 442             echo '
 443 Conflicts:
 444 '
 445                 git ls-files --unmerged |
 446                 sed -e 's/^[^   ]*      /       /' |
 447                 uniq
 448         } >>"$GIT_DIR/MERGE_MSG"
 449         if test -d "$GIT_DIR/rr-cache"
 450         then
 451                 git-rerere
 452         fi
 453         die "Automatic merge failed; fix conflicts and then commit the result."
 454 fi