Andrew's git / gitweb.git / git-merge.sh
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git-merge.shon commit for-each-ref: implement missing tag values (87412ec)
   1#!/bin/sh
   2#
   3# Copyright (c) 2005 Junio C Hamano
   4#
   5
   6OPTIONS_KEEPDASHDASH=
   7OPTIONS_SPEC="\
   8git-merge [options] <remote>...
   9git-merge [options] <msg> HEAD <remote>
  10--
  11stat                 show a diffstat at the end of the merge
  12n                    don't show a diffstat at the end of the merge
  13summary              (synonym to --stat)
  14log                  add list of one-line log to merge commit message
  15squash               create a single commit instead of doing a merge
  16commit               perform a commit if the merge succeeds (default)
  17ff                   allow fast forward (default)
  18s,strategy=          merge strategy to use
  19m,message=           message to be used for the merge commit (if any)
  20"
  21
  22SUBDIRECTORY_OK=Yes
  23. git-sh-setup
  24require_work_tree
  25cd_to_toplevel
  26
  27test -z "$(git ls-files -u)" ||
  28        die "You are in the middle of a conflicted merge."
  29
  30LF='
  31'
  32
  33all_strategies='recur recursive octopus resolve stupid ours subtree'
  34default_twohead_strategies='recursive'
  35default_octopus_strategies='octopus'
  36no_fast_forward_strategies='subtree ours'
  37no_trivial_strategies='recursive recur subtree ours'
  38use_strategies=
  39
  40allow_fast_forward=t
  41allow_trivial_merge=t
  42squash= no_commit= log_arg=
  43
  44dropsave() {
  45        rm -f -- "$GIT_DIR/MERGE_HEAD" "$GIT_DIR/MERGE_MSG" \
  46                 "$GIT_DIR/MERGE_STASH" || exit 1
  47}
  48
  49savestate() {
  50        # Stash away any local modifications.
  51        git stash create >"$GIT_DIR/MERGE_STASH"
  52}
  53
  54restorestate() {
  55        if test -f "$GIT_DIR/MERGE_STASH"
  56        then
  57                git reset --hard $head >/dev/null
  58                git stash apply $(cat "$GIT_DIR/MERGE_STASH")
  59                git update-index --refresh >/dev/null
  60        fi
  61}
  62
  63finish_up_to_date () {
  64        case "$squash" in
  65        t)
  66                echo "$1 (nothing to squash)" ;;
  67        '')
  68                echo "$1" ;;
  69        esac
  70        dropsave
  71}
  72
  73squash_message () {
  74        echo Squashed commit of the following:
  75        echo
  76        git log --no-merges --pretty=medium ^"$head" $remoteheads
  77}
  78
  79finish () {
  80        if test '' = "$2"
  81        then
  82                rlogm="$GIT_REFLOG_ACTION"
  83        else
  84                echo "$2"
  85                rlogm="$GIT_REFLOG_ACTION: $2"
  86        fi
  87        case "$squash" in
  88        t)
  89                echo "Squash commit -- not updating HEAD"
  90                squash_message >"$GIT_DIR/SQUASH_MSG"
  91                ;;
  92        '')
  93                case "$merge_msg" in
  94                '')
  95                        echo "No merge message -- not updating HEAD"
  96                        ;;
  97                *)
  98                        git update-ref -m "$rlogm" HEAD "$1" "$head" || exit 1
  99                        git gc --auto
 100                        ;;
 101                esac
 102                ;;
 103        esac
 104        case "$1" in
 105        '')
 106                ;;
 107        ?*)
 108                if test "$show_diffstat" = t
 109                then
 110                        # We want color (if set), but no pager
 111                        GIT_PAGER='' git diff --stat --summary -M "$head" "$1"
 112                fi
 113                ;;
 114        esac
 115
 116        # Run a post-merge hook
 117        if test -x "$GIT_DIR"/hooks/post-merge
 118        then
 119            case "$squash" in
 120            t)
 121                "$GIT_DIR"/hooks/post-merge 1
 122                ;;
 123            '')
 124                "$GIT_DIR"/hooks/post-merge 0
 125                ;;
 126            esac
 127        fi
 128}
 129
 130merge_name () {
 131        remote="$1"
 132        rh=$(git rev-parse --verify "$remote^0" 2>/dev/null) || return
 133        bh=$(git show-ref -s --verify "refs/heads/$remote" 2>/dev/null)
 134        if test "$rh" = "$bh"
 135        then
 136                echo "$rh               branch '$remote' of ."
 137        elif truname=$(expr "$remote" : '\(.*\)~[1-9][0-9]*$') &&
 138                git show-ref -q --verify "refs/heads/$truname" 2>/dev/null
 139        then
 140                echo "$rh               branch '$truname' (early part) of ."
 141        elif test "$remote" = "FETCH_HEAD" -a -r "$GIT_DIR/FETCH_HEAD"
 142        then
 143                sed -e 's/      not-for-merge   /               /' -e 1q \
 144                        "$GIT_DIR/FETCH_HEAD"
 145        else
 146                echo "$rh               commit '$remote'"
 147        fi
 148}
 149
 150parse_config () {
 151        while test $# != 0; do
 152                case "$1" in
 153                -n|--no-stat|--no-summary)
 154                        show_diffstat=false ;;
 155                --stat|--summary)
 156                        show_diffstat=t ;;
 157                --log|--no-log)
 158                        log_arg=$1 ;;
 159                --squash)
 160                        test "$allow_fast_forward" = t ||
 161                                die "You cannot combine --squash with --no-ff."
 162                        squash=t no_commit=t ;;
 163                --no-squash)
 164                        squash= no_commit= ;;
 165                --commit)
 166                        no_commit= ;;
 167                --no-commit)
 168                        no_commit=t ;;
 169                --ff)
 170                        allow_fast_forward=t ;;
 171                --no-ff)
 172                        test "$squash" != t ||
 173                                die "You cannot combine --squash with --no-ff."
 174                        allow_fast_forward=f ;;
 175                -s|--strategy)
 176                        shift
 177                        case " $all_strategies " in
 178                        *" $1 "*)
 179                                use_strategies="$use_strategies$1 " ;;
 180                        *)
 181                                die "available strategies are: $all_strategies" ;;
 182                        esac
 183                        ;;
 184                -m|--message)
 185                        shift
 186                        merge_msg="$1"
 187                        have_message=t
 188                        ;;
 189                --)
 190                        shift
 191                        break ;;
 192                *)      usage ;;
 193                esac
 194                shift
 195        done
 196        args_left=$#
 197}
 198
 199test $# != 0 || usage
 200
 201have_message=
 202
 203if branch=$(git-symbolic-ref -q HEAD)
 204then
 205        mergeopts=$(git config "branch.${branch#refs/heads/}.mergeoptions")
 206        if test -n "$mergeopts"
 207        then
 208                parse_config $mergeopts --
 209        fi
 210fi
 211
 212parse_config "$@"
 213while test $args_left -lt $#; do shift; done
 214
 215if test -z "$show_diffstat"; then
 216    test "$(git config --bool merge.diffstat)" = false && show_diffstat=false
 217    test "$(git config --bool merge.stat)" = false && show_diffstat=false
 218    test -z "$show_diffstat" && show_diffstat=t
 219fi
 220
 221# This could be traditional "merge <msg> HEAD <commit>..."  and the
 222# way we can tell it is to see if the second token is HEAD, but some
 223# people might have misused the interface and used a committish that
 224# is the same as HEAD there instead.  Traditional format never would
 225# have "-m" so it is an additional safety measure to check for it.
 226
 227if test -z "$have_message" &&
 228        second_token=$(git rev-parse --verify "$2^0" 2>/dev/null) &&
 229        head_commit=$(git rev-parse --verify "HEAD" 2>/dev/null) &&
 230        test "$second_token" = "$head_commit"
 231then
 232        merge_msg="$1"
 233        shift
 234        head_arg="$1"
 235        shift
 236elif ! git rev-parse --verify HEAD >/dev/null 2>&1
 237then
 238        # If the merged head is a valid one there is no reason to
 239        # forbid "git merge" into a branch yet to be born.  We do
 240        # the same for "git pull".
 241        if test 1 -ne $#
 242        then
 243                echo >&2 "Can merge only exactly one commit into empty head"
 244                exit 1
 245        fi
 246
 247        rh=$(git rev-parse --verify "$1^0") ||
 248                die "$1 - not something we can merge"
 249
 250        git update-ref -m "initial pull" HEAD "$rh" "" &&
 251        git read-tree --reset -u HEAD
 252        exit
 253
 254else
 255        # We are invoked directly as the first-class UI.
 256        head_arg=HEAD
 257
 258        # All the rest are the commits being merged; prepare
 259        # the standard merge summary message to be appended to
 260        # the given message.  If remote is invalid we will die
 261        # later in the common codepath so we discard the error
 262        # in this loop.
 263        merge_name=$(for remote
 264                do
 265                        merge_name "$remote"
 266                done | git fmt-merge-msg $log_arg
 267        )
 268        merge_msg="${merge_msg:+$merge_msg$LF$LF}$merge_name"
 269fi
 270head=$(git rev-parse --verify "$head_arg"^0) || usage
 271
 272# All the rest are remote heads
 273test "$#" = 0 && usage ;# we need at least one remote head.
 274set_reflog_action "merge $*"
 275
 276remoteheads=
 277for remote
 278do
 279        remotehead=$(git rev-parse --verify "$remote"^0 2>/dev/null) ||
 280            die "$remote - not something we can merge"
 281        remoteheads="${remoteheads}$remotehead "
 282        eval GITHEAD_$remotehead='"$remote"'
 283        export GITHEAD_$remotehead
 284done
 285set x $remoteheads ; shift
 286
 287case "$use_strategies" in
 288'')
 289        case "$#" in
 290        1)
 291                var="`git config --get pull.twohead`"
 292                if test -n "$var"
 293                then
 294                        use_strategies="$var"
 295                else
 296                        use_strategies="$default_twohead_strategies"
 297                fi ;;
 298        *)
 299                var="`git config --get pull.octopus`"
 300                if test -n "$var"
 301                then
 302                        use_strategies="$var"
 303                else
 304                        use_strategies="$default_octopus_strategies"
 305                fi ;;
 306        esac
 307        ;;
 308esac
 309
 310for s in $use_strategies
 311do
 312        for ss in $no_fast_forward_strategies
 313        do
 314                case " $s " in
 315                *" $ss "*)
 316                        allow_fast_forward=f
 317                        break
 318                        ;;
 319                esac
 320        done
 321        for ss in $no_trivial_strategies
 322        do
 323                case " $s " in
 324                *" $ss "*)
 325                        allow_trivial_merge=f
 326                        break
 327                        ;;
 328                esac
 329        done
 330done
 331
 332case "$#" in
 3331)
 334        common=$(git merge-base --all $head "$@")
 335        ;;
 336*)
 337        common=$(git show-branch --merge-base $head "$@")
 338        ;;
 339esac
 340echo "$head" >"$GIT_DIR/ORIG_HEAD"
 341
 342case "$allow_fast_forward,$#,$common,$no_commit" in
 343?,*,'',*)
 344        # No common ancestors found. We need a real merge.
 345        ;;
 346?,1,"$1",*)
 347        # If head can reach all the merge then we are up to date.
 348        # but first the most common case of merging one remote.
 349        finish_up_to_date "Already up-to-date."
 350        exit 0
 351        ;;
 352t,1,"$head",*)
 353        # Again the most common case of merging one remote.
 354        echo "Updating $(git rev-parse --short $head)..$(git rev-parse --short $1)"
 355        git update-index --refresh 2>/dev/null
 356        msg="Fast forward"
 357        if test -n "$have_message"
 358        then
 359                msg="$msg (no commit created; -m option ignored)"
 360        fi
 361        new_head=$(git rev-parse --verify "$1^0") &&
 362        git read-tree -v -m -u --exclude-per-directory=.gitignore $head "$new_head" &&
 363        finish "$new_head" "$msg" || exit
 364        dropsave
 365        exit 0
 366        ;;
 367?,1,?*"$LF"?*,*)
 368        # We are not doing octopus and not fast forward.  Need a
 369        # real merge.
 370        ;;
 371?,1,*,)
 372        # We are not doing octopus, not fast forward, and have only
 373        # one common.
 374        git update-index --refresh 2>/dev/null
 375        case "$allow_trivial_merge" in
 376        t)
 377                # See if it is really trivial.
 378                git var GIT_COMMITTER_IDENT >/dev/null || exit
 379                echo "Trying really trivial in-index merge..."
 380                if git read-tree --trivial -m -u -v $common $head "$1" &&
 381                   result_tree=$(git write-tree)
 382                then
 383                        echo "Wonderful."
 384                        result_commit=$(
 385                                printf '%s\n' "$merge_msg" |
 386                                git commit-tree $result_tree -p HEAD -p "$1"
 387                        ) || exit
 388                        finish "$result_commit" "In-index merge"
 389                        dropsave
 390                        exit 0
 391                fi
 392                echo "Nope."
 393        esac
 394        ;;
 395*)
 396        # An octopus.  If we can reach all the remote we are up to date.
 397        up_to_date=t
 398        for remote
 399        do
 400                common_one=$(git merge-base --all $head $remote)
 401                if test "$common_one" != "$remote"
 402                then
 403                        up_to_date=f
 404                        break
 405                fi
 406        done
 407        if test "$up_to_date" = t
 408        then
 409                finish_up_to_date "Already up-to-date. Yeeah!"
 410                exit 0
 411        fi
 412        ;;
 413esac
 414
 415# We are going to make a new commit.
 416git var GIT_COMMITTER_IDENT >/dev/null || exit
 417
 418# At this point, we need a real merge.  No matter what strategy
 419# we use, it would operate on the index, possibly affecting the
 420# working tree, and when resolved cleanly, have the desired tree
 421# in the index -- this means that the index must be in sync with
 422# the $head commit.  The strategies are responsible to ensure this.
 423
 424case "$use_strategies" in
 425?*' '?*)
 426    # Stash away the local changes so that we can try more than one.
 427    savestate
 428    single_strategy=no
 429    ;;
 430*)
 431    rm -f "$GIT_DIR/MERGE_STASH"
 432    single_strategy=yes
 433    ;;
 434esac
 435
 436result_tree= best_cnt=-1 best_strategy= wt_strategy=
 437merge_was_ok=
 438for strategy in $use_strategies
 439do
 440    test "$wt_strategy" = '' || {
 441        echo "Rewinding the tree to pristine..."
 442        restorestate
 443    }
 444    case "$single_strategy" in
 445    no)
 446        echo "Trying merge strategy $strategy..."
 447        ;;
 448    esac
 449
 450    # Remember which strategy left the state in the working tree
 451    wt_strategy=$strategy
 452
 453    git-merge-$strategy $common -- "$head_arg" "$@"
 454    exit=$?
 455    if test "$no_commit" = t && test "$exit" = 0
 456    then
 457        merge_was_ok=t
 458        exit=1 ;# pretend it left conflicts.
 459    fi
 460
 461    test "$exit" = 0 || {
 462
 463        # The backend exits with 1 when conflicts are left to be resolved,
 464        # with 2 when it does not handle the given merge at all.
 465
 466        if test "$exit" -eq 1
 467        then
 468            cnt=`{
 469                git diff-files --name-only
 470                git ls-files --unmerged
 471            } | wc -l`
 472            if test $best_cnt -le 0 -o $cnt -le $best_cnt
 473            then
 474                best_strategy=$strategy
 475                best_cnt=$cnt
 476            fi
 477        fi
 478        continue
 479    }
 480
 481    # Automerge succeeded.
 482    result_tree=$(git write-tree) && break
 483done
 484
 485# If we have a resulting tree, that means the strategy module
 486# auto resolved the merge cleanly.
 487if test '' != "$result_tree"
 488then
 489    if test "$allow_fast_forward" = "t"
 490    then
 491        parents=$(git show-branch --independent "$head" "$@")
 492    else
 493        parents=$(git rev-parse "$head" "$@")
 494    fi
 495    parents=$(echo "$parents" | sed -e 's/^/-p /')
 496    result_commit=$(printf '%s\n' "$merge_msg" | git commit-tree $result_tree $parents) || exit
 497    finish "$result_commit" "Merge made by $wt_strategy."
 498    dropsave
 499    exit 0
 500fi
 501
 502# Pick the result from the best strategy and have the user fix it up.
 503case "$best_strategy" in
 504'')
 505        restorestate
 506        case "$use_strategies" in
 507        ?*' '?*)
 508                echo >&2 "No merge strategy handled the merge."
 509                ;;
 510        *)
 511                echo >&2 "Merge with strategy $use_strategies failed."
 512                ;;
 513        esac
 514        exit 2
 515        ;;
 516"$wt_strategy")
 517        # We already have its result in the working tree.
 518        ;;
 519*)
 520        echo "Rewinding the tree to pristine..."
 521        restorestate
 522        echo "Using the $best_strategy to prepare resolving by hand."
 523        git-merge-$best_strategy $common -- "$head_arg" "$@"
 524        ;;
 525esac
 526
 527if test "$squash" = t
 528then
 529        finish
 530else
 531        for remote
 532        do
 533                echo $remote
 534        done >"$GIT_DIR/MERGE_HEAD"
 535        printf '%s\n' "$merge_msg" >"$GIT_DIR/MERGE_MSG"
 536fi
 537
 538if test "$merge_was_ok" = t
 539then
 540        echo >&2 \
 541        "Automatic merge went well; stopped before committing as requested"
 542        exit 0
 543else
 544        {
 545            echo '
 546Conflicts:
 547'
 548                git ls-files --unmerged |
 549                sed -e 's/^[^   ]*      /       /' |
 550                uniq
 551        } >>"$GIT_DIR/MERGE_MSG"
 552        git rerere
 553        die "Automatic merge failed; fix conflicts and then commit the result."
 554fi