git-merge.sh

   1 #!/bin/sh
   2 #
   3 # Copyright (c) 2005 Junio C Hamano
   4 #
   5
   6 USAGE='[-n] [--no-commit] [--squash] [-s <strategy>] [-m=<merge-message>] <commit>+'
   7
   8 SUBDIRECTORY_OK=Yes
   9 . git-sh-setup
  10 require_work_tree
  11 cd_to_toplevel
  12
  13 test -z "$(git ls-files -u)" ||
  14         die "You are in the middle of a conflicted merge."
  15
  16 LF='
  17 '
  18
  19 all_strategies='recur recursive octopus resolve stupid ours'
  20 default_twohead_strategies='recursive'
  21 default_octopus_strategies='octopus'
  22 no_trivial_merge_strategies='ours'
  23 use_strategies=
  24
  25 index_merge=t
  26
  27 dropsave() {
  28         rm -f -- "$GIT_DIR/MERGE_HEAD" "$GIT_DIR/MERGE_MSG" \
  29                  "$GIT_DIR/MERGE_SAVE" || exit 1
  30 }
  31
  32 savestate() {
  33         # Stash away any local modifications.
  34         git-diff-index -z --name-only $head |
  35         cpio -0 -o >"$GIT_DIR/MERGE_SAVE"
  36 }
  37
  38 restorestate() {
  39         if test -f "$GIT_DIR/MERGE_SAVE"
  40         then
  41                 git reset --hard $head >/dev/null
  42                 cpio -iuv <"$GIT_DIR/MERGE_SAVE"
  43                 git-update-index --refresh >/dev/null
  44         fi
  45 }
  46
  47 finish_up_to_date () {
  48         case "$squash" in
  49         t)
  50                 echo "$1 (nothing to squash)" ;;
  51         '')
  52                 echo "$1" ;;
  53         esac
  54         dropsave
  55 }
  56
  57 squash_message () {
  58         echo Squashed commit of the following:
  59         echo
  60         git-log --no-merges ^"$head" $remote
  61 }
  62
  63 finish () {
  64         if test '' = "$2"
  65         then
  66                 rlogm="$GIT_REFLOG_ACTION"
  67         else
  68                 echo "$2"
  69                 rlogm="$GIT_REFLOG_ACTION: $2"
  70         fi
  71         case "$squash" in
  72         t)
  73                 echo "Squash commit -- not updating HEAD"
  74                 squash_message >"$GIT_DIR/SQUASH_MSG"
  75                 ;;
  76         '')
  77                 case "$merge_msg" in
  78                 '')
  79                         echo "No merge message -- not updating HEAD"
  80                         ;;
  81                 *)
  82                         git-update-ref -m "$rlogm" HEAD "$1" "$head" || exit 1
  83                         ;;
  84                 esac
  85                 ;;
  86         esac
  87         case "$1" in
  88         '')
  89                 ;;
  90         ?*)
  91                 case "$no_summary" in
  92                 '')
  93                         git-diff-tree --stat --summary -M "$head" "$1"
  94                         ;;
  95                 esac
  96                 ;;
  97         esac
  98 }
  99
 100 merge_local_changes () {
 101         merge_error=$(git-read-tree -m -u --exclude-per-directory=.gitignore $1 $2 2>&1) || (
 102
 103                 # First stash away the local changes
 104                 git diff-index --binary -p HEAD >"$GIT_DIR"/LOCAL_DIFF
 105
 106                 # Match the index to the working tree, and do a three-way.
 107                 git diff-files --name-only |
 108                 git update-index --remove --stdin &&
 109                 work=`git write-tree` &&
 110                 git read-tree --reset -u $2 &&
 111                 git read-tree -m -u --aggressive --exclude-per-directory=.gitignore $1 $2 $work || exit
 112
 113                 echo >&2 "Carrying local changes forward."
 114                 if result=`git write-tree 2>/dev/null`
 115                 then
 116                         echo >&2 "Trivially automerged."
 117                 else
 118                         git merge-index -o git-merge-one-file -a
 119                 fi
 120
 121                 # Do not register the cleanly merged paths in the index
 122                 # yet; this is not a real merge before committing, but
 123                 # just carrying the working tree changes along.
 124                 unmerged=`git ls-files -u`
 125                 git read-tree --reset $2
 126                 case "$unmerged" in
 127                 '')     ;;
 128                 *)
 129                         (
 130                                 z40=0000000000000000000000000000000000000000
 131                                 echo "$unmerged" |
 132                                 sed -e 's/^[0-7]* [0-9a-f]* /'"0 $z40 /"
 133                                 echo "$unmerged"
 134                         ) | git update-index --index-info
 135
 136                         echo >&2 "Conflicts in locally modified files:"
 137                         git diff --name-only --diff-filter=U >&2
 138                         echo >&2 "Your local changes are found in $GIT_DIR/LOCAL_DIFF"
 139                         ;;
 140                 esac
 141                 exit 0
 142         )
 143 }
 144
 145 merge_name () {
 146         remote="$1"
 147         rh=$(git-rev-parse --verify "$remote^0" 2>/dev/null) || return
 148         bh=$(git-show-ref -s --verify "refs/heads/$remote" 2>/dev/null)
 149         if test "$rh" = "$bh"
 150         then
 151                 echo "$rh               branch '$remote' of ."
 152         elif truname=$(expr "$remote" : '\(.*\)~[1-9][0-9]*$') &&
 153                 git-show-ref -q --verify "refs/heads/$truname" 2>/dev/null
 154         then
 155                 echo "$rh               branch '$truname' (early part) of ."
 156         elif test "$remote" = "FETCH_HEAD" -a -r "$GIT_DIR/FETCH_HEAD"
 157         then
 158                 sed -e 's/      not-for-merge   /               /' -e 1q \
 159                         "$GIT_DIR/FETCH_HEAD"
 160         else
 161                 echo "$rh               commit '$remote'"
 162         fi
 163 }
 164
 165 case "$#" in 0) usage ;; esac
 166
 167 have_message=
 168 while case "$#" in 0) break ;; esac
 169 do
 170         case "$1" in
 171         -n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
 172                 --no-summa|--no-summar|--no-summary)
 173                 no_summary=t ;;
 174         --sq|--squ|--squa|--squas|--squash)
 175                 squash=t no_commit=t ;;
 176         --no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
 177                 no_commit=t ;;
 178         -s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
 179                 --strateg=*|--strategy=*|\
 180         -s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
 181                 case "$#,$1" in
 182                 *,*=*)
 183                         strategy=`expr "z$1" : 'z-[^=]*=\(.*\)'` ;;
 184                 1,*)
 185                         usage ;;
 186                 *)
 187                         strategy="$2"
 188                         shift ;;
 189                 esac
 190                 case " $all_strategies " in
 191                 *" $strategy "*)
 192                         use_strategies="$use_strategies$strategy " ;;
 193                 *)
 194                         die "available strategies are: $all_strategies" ;;
 195                 esac
 196                 ;;
 197         -m=*|--m=*|--me=*|--mes=*|--mess=*|--messa=*|--messag=*|--message=*)
 198                 merge_msg=`expr "z$1" : 'z-[^=]*=\(.*\)'`
 199                 have_message=t
 200                 ;;
 201         -m|--m|--me|--mes|--mess|--messa|--messag|--message)
 202                 shift
 203                 case "$#" in
 204                 1)      usage ;;
 205                 esac
 206                 merge_msg="$1"
 207                 have_message=t
 208                 ;;
 209         -*)     usage ;;
 210         *)      break ;;
 211         esac
 212         shift
 213 done
 214
 215 # This could be traditional "merge <msg> HEAD <commit>..."  and the
 216 # way we can tell it is to see if the second token is HEAD, but some
 217 # people might have misused the interface and used a committish that
 218 # is the same as HEAD there instead.  Traditional format never would
 219 # have "-m" so it is an additional safety measure to check for it.
 220
 221 if test -z "$have_message" &&
 222         second_token=$(git-rev-parse --verify "$2^0" 2>/dev/null) &&
 223         head_commit=$(git-rev-parse --verify "HEAD" 2>/dev/null) &&
 224         test "$second_token" = "$head_commit"
 225 then
 226         merge_msg="$1"
 227         shift
 228         head_arg="$1"
 229         shift
 230 elif ! git-rev-parse --verify HEAD >/dev/null 2>&1
 231 then
 232         # If the merged head is a valid one there is no reason to
 233         # forbid "git merge" into a branch yet to be born.  We do
 234         # the same for "git pull".
 235         if test 1 -ne $#
 236         then
 237                 echo >&2 "Can merge only exactly one commit into empty head"
 238                 exit 1
 239         fi
 240
 241         rh=$(git rev-parse --verify "$1^0") ||
 242                 die "$1 - not something we can merge"
 243
 244         git-update-ref -m "initial pull" HEAD "$rh" "" &&
 245         git-read-tree --reset -u HEAD
 246         exit
 247
 248 else
 249         # We are invoked directly as the first-class UI.
 250         head_arg=HEAD
 251
 252         # All the rest are the commits being merged; prepare
 253         # the standard merge summary message to be appended to
 254         # the given message.  If remote is invalid we will die
 255         # later in the common codepath so we discard the error
 256         # in this loop.
 257         merge_name=$(for remote
 258                 do
 259                         merge_name "$remote"
 260                 done | git-fmt-merge-msg
 261         )
 262         merge_msg="${merge_msg:+$merge_msg$LF$LF}$merge_name"
 263 fi
 264 head=$(git-rev-parse --verify "$head_arg"^0) || usage
 265
 266 # All the rest are remote heads
 267 test "$#" = 0 && usage ;# we need at least one remote head.
 268 set_reflog_action "merge $*"
 269
 270 remoteheads=
 271 for remote
 272 do
 273         remotehead=$(git-rev-parse --verify "$remote"^0 2>/dev/null) ||
 274             die "$remote - not something we can merge"
 275         remoteheads="${remoteheads}$remotehead "
 276         eval GITHEAD_$remotehead='"$remote"'
 277         export GITHEAD_$remotehead
 278 done
 279 set x $remoteheads ; shift
 280
 281 case "$use_strategies" in
 282 '')
 283         case "$#" in
 284         1)
 285                 var="`git-config --get pull.twohead`"
 286                 if test -n "$var"
 287                 then
 288                         use_strategies="$var"
 289                 else
 290                         use_strategies="$default_twohead_strategies"
 291                 fi ;;
 292         *)
 293                 var="`git-config --get pull.octopus`"
 294                 if test -n "$var"
 295                 then
 296                         use_strategies="$var"
 297                 else
 298                         use_strategies="$default_octopus_strategies"
 299                 fi ;;
 300         esac
 301         ;;
 302 esac
 303
 304 for s in $use_strategies
 305 do
 306         for nt in $no_trivial_merge_strategies
 307         do
 308                 case " $s " in
 309                 *" $nt "*)
 310                         index_merge=f
 311                         break
 312                         ;;
 313                 esac
 314         done
 315 done
 316
 317 case "$#" in
 318 1)
 319         common=$(git-merge-base --all $head "$@")
 320         ;;
 321 *)
 322         common=$(git-show-branch --merge-base $head "$@")
 323         ;;
 324 esac
 325 echo "$head" >"$GIT_DIR/ORIG_HEAD"
 326
 327 case "$index_merge,$#,$common,$no_commit" in
 328 f,*)
 329         # We've been told not to try anything clever.  Skip to real merge.
 330         ;;
 331 ?,*,'',*)
 332         # No common ancestors found. We need a real merge.
 333         ;;
 334 ?,1,"$1",*)
 335         # If head can reach all the merge then we are up to date.
 336         # but first the most common case of merging one remote.
 337         finish_up_to_date "Already up-to-date."
 338         exit 0
 339         ;;
 340 ?,1,"$head",*)
 341         # Again the most common case of merging one remote.
 342         echo "Updating $(git-rev-parse --short $head)..$(git-rev-parse --short $1)"
 343         git-update-index --refresh 2>/dev/null
 344         msg="Fast forward"
 345         if test -n "$have_message"
 346         then
 347                 msg="$msg (no commit created; -m option ignored)"
 348         fi
 349         new_head=$(git-rev-parse --verify "$1^0") &&
 350         merge_local_changes $head $new_head &&
 351         finish "$new_head" "$msg" || exit
 352         dropsave
 353         exit 0
 354         ;;
 355 ?,1,?*"$LF"?*,*)
 356         # We are not doing octopus and not fast forward.  Need a
 357         # real merge.
 358         ;;
 359 ?,1,*,)
 360         # We are not doing octopus, not fast forward, and have only
 361         # one common.
 362         git-update-index --refresh 2>/dev/null
 363         case " $use_strategies " in
 364         *' recursive '*|*' recur '*)
 365                 : run merge later
 366                 ;;
 367         *)
 368                 # See if it is really trivial.
 369                 git var GIT_COMMITTER_IDENT >/dev/null || exit
 370                 echo "Trying really trivial in-index merge..."
 371                 if git-read-tree --trivial -m -u -v $common $head "$1" &&
 372                    result_tree=$(git-write-tree)
 373                 then
 374                         echo "Wonderful."
 375                         result_commit=$(
 376                                 echo "$merge_msg" |
 377                                 git-commit-tree $result_tree -p HEAD -p "$1"
 378                         ) || exit
 379                         finish "$result_commit" "In-index merge"
 380                         dropsave
 381                         exit 0
 382                 fi
 383                 echo "Nope."
 384         esac
 385         ;;
 386 *)
 387         # An octopus.  If we can reach all the remote we are up to date.
 388         up_to_date=t
 389         for remote
 390         do
 391                 common_one=$(git-merge-base --all $head $remote)
 392                 if test "$common_one" != "$remote"
 393                 then
 394                         up_to_date=f
 395                         break
 396                 fi
 397         done
 398         if test "$up_to_date" = t
 399         then
 400                 finish_up_to_date "Already up-to-date. Yeeah!"
 401                 exit 0
 402         fi
 403         ;;
 404 esac
 405
 406 # We are going to make a new commit.
 407 git var GIT_COMMITTER_IDENT >/dev/null || exit
 408
 409 # At this point, we need a real merge.  No matter what strategy
 410 # we use, it would operate on the index, possibly affecting the
 411 # working tree, and when resolved cleanly, have the desired tree
 412 # in the index -- this means that the index must be in sync with
 413 # the $head commit.  The strategies are responsible to ensure this.
 414
 415 case "$use_strategies" in
 416 ?*' '?*)
 417     # Stash away the local changes so that we can try more than one.
 418     savestate
 419     single_strategy=no
 420     ;;
 421 *)
 422     rm -f "$GIT_DIR/MERGE_SAVE"
 423     single_strategy=yes
 424     ;;
 425 esac
 426
 427 result_tree= best_cnt=-1 best_strategy= wt_strategy=
 428 merge_was_ok=
 429 for strategy in $use_strategies
 430 do
 431     test "$wt_strategy" = '' || {
 432         echo "Rewinding the tree to pristine..."
 433         restorestate
 434     }
 435     case "$single_strategy" in
 436     no)
 437         echo "Trying merge strategy $strategy..."
 438         ;;
 439     esac
 440
 441     # Remember which strategy left the state in the working tree
 442     wt_strategy=$strategy
 443
 444     git-merge-$strategy $common -- "$head_arg" "$@"
 445     exit=$?
 446     if test "$no_commit" = t && test "$exit" = 0
 447     then
 448         merge_was_ok=t
 449         exit=1 ;# pretend it left conflicts.
 450     fi
 451
 452     test "$exit" = 0 || {
 453
 454         # The backend exits with 1 when conflicts are left to be resolved,
 455         # with 2 when it does not handle the given merge at all.
 456
 457         if test "$exit" -eq 1
 458         then
 459             cnt=`{
 460                 git-diff-files --name-only
 461                 git-ls-files --unmerged
 462             } | wc -l`
 463             if test $best_cnt -le 0 -o $cnt -le $best_cnt
 464             then
 465                 best_strategy=$strategy
 466                 best_cnt=$cnt
 467             fi
 468         fi
 469         continue
 470     }
 471
 472     # Automerge succeeded.
 473     result_tree=$(git-write-tree) && break
 474 done
 475
 476 # If we have a resulting tree, that means the strategy module
 477 # auto resolved the merge cleanly.
 478 if test '' != "$result_tree"
 479 then
 480     parents=$(git-show-branch --independent "$head" "$@" | sed -e 's/^/-p /')
 481     result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents) || exit
 482     finish "$result_commit" "Merge made by $wt_strategy."
 483     dropsave
 484     exit 0
 485 fi
 486
 487 # Pick the result from the best strategy and have the user fix it up.
 488 case "$best_strategy" in
 489 '')
 490         restorestate
 491         case "$use_strategies" in
 492         ?*' '?*)
 493                 echo >&2 "No merge strategy handled the merge."
 494                 ;;
 495         *)
 496                 echo >&2 "Merge with strategy $use_strategies failed."
 497                 ;;
 498         esac
 499         exit 2
 500         ;;
 501 "$wt_strategy")
 502         # We already have its result in the working tree.
 503         ;;
 504 *)
 505         echo "Rewinding the tree to pristine..."
 506         restorestate
 507         echo "Using the $best_strategy to prepare resolving by hand."
 508         git-merge-$best_strategy $common -- "$head_arg" "$@"
 509         ;;
 510 esac
 511
 512 if test "$squash" = t
 513 then
 514         finish
 515 else
 516         for remote
 517         do
 518                 echo $remote
 519         done >"$GIT_DIR/MERGE_HEAD"
 520         echo "$merge_msg" >"$GIT_DIR/MERGE_MSG"
 521 fi
 522
 523 if test "$merge_was_ok" = t
 524 then
 525         echo >&2 \
 526         "Automatic merge went well; stopped before committing as requested"
 527         exit 0
 528 else
 529         {
 530             echo '
 531 Conflicts:
 532 '
 533                 git ls-files --unmerged |
 534                 sed -e 's/^[^   ]*      /       /' |
 535                 uniq
 536         } >>"$GIT_DIR/MERGE_MSG"
 537         if test -d "$GIT_DIR/rr-cache"
 538         then
 539                 git-rerere
 540         fi
 541         die "Automatic merge failed; fix conflicts and then commit the result."
 542 fi