Andrew's git - gitweb.git/blob

   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,no-stat            don't show a diffstat at the end of the merge
  13summary              (synonym to --stat)
  14no-summary           (synonym to --no-stat)
  15log                  add list of one-line log to merge commit message
  16no-log               don't add list of one-line log to merge commit message
  17squash               create a single commit instead of doing a merge
  18commit               perform a commit if the merge sucesses (default)
  19ff                   allow fast forward (default)
  20s,strategy=          merge strategy to use
  21m,message=           message to be used for the merge commit (if any)
  22"
  23
  24SUBDIRECTORY_OK=Yes
  25. git-sh-setup
  26require_work_tree
  27cd_to_toplevel
  28
  29test -z "$(git ls-files -u)" ||
  30        die "You are in the middle of a conflicted merge."
  31
  32LF='
  33'
  34
  35all_strategies='recur recursive octopus resolve stupid ours subtree'
  36default_twohead_strategies='recursive'
  37default_octopus_strategies='octopus'
  38no_fast_forward_strategies='subtree ours'
  39no_trivial_strategies='recursive recur subtree ours'
  40use_strategies=
  41
  42allow_fast_forward=t
  43allow_trivial_merge=t
  44squash= no_commit= log_arg=
  45
  46dropsave() {
  47        rm -f -- "$GIT_DIR/MERGE_HEAD" "$GIT_DIR/MERGE_MSG" \
  48                 "$GIT_DIR/MERGE_STASH" || exit 1
  49}
  50
  51savestate() {
  52        # Stash away any local modifications.
  53        git stash create >"$GIT_DIR/MERGE_STASH"
  54}
  55
  56restorestate() {
  57        if test -f "$GIT_DIR/MERGE_STASH"
  58        then
  59                git reset --hard $head >/dev/null
  60                git stash apply $(cat "$GIT_DIR/MERGE_STASH")
  61                git update-index --refresh >/dev/null
  62        fi
  63}
  64
  65finish_up_to_date () {
  66        case "$squash" in
  67        t)
  68                echo "$1 (nothing to squash)" ;;
  69        '')
  70                echo "$1" ;;
  71        esac
  72        dropsave
  73}
  74
  75squash_message () {
  76        echo Squashed commit of the following:
  77        echo
  78        git log --no-merges --pretty=medium ^"$head" $remoteheads
  79}
  80
  81finish () {
  82        if test '' = "$2"
  83        then
  84                rlogm="$GIT_REFLOG_ACTION"
  85        else
  86                echo "$2"
  87                rlogm="$GIT_REFLOG_ACTION: $2"
  88        fi
  89        case "$squash" in
  90        t)
  91                echo "Squash commit -- not updating HEAD"
  92                squash_message >"$GIT_DIR/SQUASH_MSG"
  93                ;;
  94        '')
  95                case "$merge_msg" in
  96                '')
  97                        echo "No merge message -- not updating HEAD"
  98                        ;;
  99                *)
 100                        git update-ref -m "$rlogm" HEAD "$1" "$head" || exit 1
 101                        git gc --auto
 102                        ;;
 103                esac
 104                ;;
 105        esac
 106        case "$1" in
 107        '')
 108                ;;
 109        ?*)
 110                if test "$show_diffstat" = t
 111                then
 112                        # We want color (if set), but no pager
 113                        GIT_PAGER='' git diff --stat --summary -M "$head" "$1"
 114                fi
 115                ;;
 116        esac
 117
 118        # Run a post-merge hook
 119        if test -x "$GIT_DIR"/hooks/post-merge
 120        then
 121            case "$squash" in
 122            t)
 123                "$GIT_DIR"/hooks/post-merge 1
 124                ;;
 125            '')
 126                "$GIT_DIR"/hooks/post-merge 0
 127                ;;
 128            esac
 129        fi
 130}
 131
 132merge_name () {
 133        remote="$1"
 134        rh=$(git rev-parse --verify "$remote^0" 2>/dev/null) || return
 135        bh=$(git show-ref -s --verify "refs/heads/$remote" 2>/dev/null)
 136        if test "$rh" = "$bh"
 137        then
 138                echo "$rh               branch '$remote' of ."
 139        elif truname=$(expr "$remote" : '\(.*\)~[1-9][0-9]*$') &&
 140                git show-ref -q --verify "refs/heads/$truname" 2>/dev/null
 141        then
 142                echo "$rh               branch '$truname' (early part) of ."
 143        elif test "$remote" = "FETCH_HEAD" -a -r "$GIT_DIR/FETCH_HEAD"
 144        then
 145                sed -e 's/      not-for-merge   /               /' -e 1q \
 146                        "$GIT_DIR/FETCH_HEAD"
 147        else
 148                echo "$rh               commit '$remote'"
 149        fi
 150}
 151
 152parse_config () {
 153        while test $# != 0; do
 154                case "$1" in
 155                -n|--no-stat|--no-summary)
 156                        show_diffstat=false ;;
 157                --stat|--summary)
 158                        show_diffstat=t ;;
 159                --log|--no-log)
 160                        log_arg=$1 ;;
 161                --squash)
 162                        test "$allow_fast_forward" = t ||
 163                                die "You cannot combine --squash with --no-ff."
 164                        squash=t no_commit=t ;;
 165                --no-squash)
 166                        squash= no_commit= ;;
 167                --commit)
 168                        no_commit= ;;
 169                --no-commit)
 170                        no_commit=t ;;
 171                --ff)
 172                        allow_fast_forward=t ;;
 173                --no-ff)
 174                        test "$squash" != t ||
 175                                die "You cannot combine --squash with --no-ff."
 176                        allow_fast_forward=f ;;
 177                -s|--strategy)
 178                        shift
 179                        case " $all_strategies " in
 180                        *" $1 "*)
 181                                use_strategies="$use_strategies$1 " ;;
 182                        *)
 183                                die "available strategies are: $all_strategies" ;;
 184                        esac
 185                        ;;
 186                -m|--message)
 187                        shift
 188                        merge_msg="$1"
 189                        have_message=t
 190                        ;;
 191                --)
 192                        shift
 193                        break ;;
 194                *)      usage ;;
 195                esac
 196                shift
 197        done
 198        args_left=$#
 199}
 200
 201test $# != 0 || usage
 202
 203have_message=
 204
 205if branch=$(git-symbolic-ref -q HEAD)
 206then
 207        mergeopts=$(git config "branch.${branch#refs/heads/}.mergeoptions")
 208        if test -n "$mergeopts"
 209        then
 210                parse_config $mergeopts --
 211        fi
 212fi
 213
 214parse_config "$@"
 215while test $args_left -lt $#; do shift; done
 216
 217if test -z "$show_diffstat"; then
 218    test "$(git config --bool merge.diffstat)" = false && show_diffstat=false
 219    test "$(git config --bool merge.stat)" = false && show_diffstat=false
 220    test -z "$show_diffstat" && show_diffstat=t
 221fi
 222
 223# This could be traditional "merge <msg> HEAD <commit>..."  and the
 224# way we can tell it is to see if the second token is HEAD, but some
 225# people might have misused the interface and used a committish that
 226# is the same as HEAD there instead.  Traditional format never would
 227# have "-m" so it is an additional safety measure to check for it.
 228
 229if test -z "$have_message" &&
 230        second_token=$(git rev-parse --verify "$2^0" 2>/dev/null) &&
 231        head_commit=$(git rev-parse --verify "HEAD" 2>/dev/null) &&
 232        test "$second_token" = "$head_commit"
 233then
 234        merge_msg="$1"
 235        shift
 236        head_arg="$1"
 237        shift
 238elif ! git rev-parse --verify HEAD >/dev/null 2>&1
 239then
 240        # If the merged head is a valid one there is no reason to
 241        # forbid "git merge" into a branch yet to be born.  We do
 242        # the same for "git pull".
 243        if test 1 -ne $#
 244        then
 245                echo >&2 "Can merge only exactly one commit into empty head"
 246                exit 1
 247        fi
 248
 249        rh=$(git rev-parse --verify "$1^0") ||
 250                die "$1 - not something we can merge"
 251
 252        git update-ref -m "initial pull" HEAD "$rh" "" &&
 253        git read-tree --reset -u HEAD
 254        exit
 255
 256else
 257        # We are invoked directly as the first-class UI.
 258        head_arg=HEAD
 259
 260        # All the rest are the commits being merged; prepare
 261        # the standard merge summary message to be appended to
 262        # the given message.  If remote is invalid we will die
 263        # later in the common codepath so we discard the error
 264        # in this loop.
 265        merge_name=$(for remote
 266                do
 267                        merge_name "$remote"
 268                done | git fmt-merge-msg $log_arg
 269        )
 270        merge_msg="${merge_msg:+$merge_msg$LF$LF}$merge_name"
 271fi
 272head=$(git rev-parse --verify "$head_arg"^0) || usage
 273
 274# All the rest are remote heads
 275test "$#" = 0 && usage ;# we need at least one remote head.
 276set_reflog_action "merge $*"
 277
 278remoteheads=
 279for remote
 280do
 281        remotehead=$(git rev-parse --verify "$remote"^0 2>/dev/null) ||
 282            die "$remote - not something we can merge"
 283        remoteheads="${remoteheads}$remotehead "
 284        eval GITHEAD_$remotehead='"$remote"'
 285        export GITHEAD_$remotehead
 286done
 287set x $remoteheads ; shift
 288
 289case "$use_strategies" in
 290'')
 291        case "$#" in
 292        1)
 293                var="`git config --get pull.twohead`"
 294                if test -n "$var"
 295                then
 296                        use_strategies="$var"
 297                else
 298                        use_strategies="$default_twohead_strategies"
 299                fi ;;
 300        *)
 301                var="`git config --get pull.octopus`"
 302                if test -n "$var"
 303                then
 304                        use_strategies="$var"
 305                else
 306                        use_strategies="$default_octopus_strategies"
 307                fi ;;
 308        esac
 309        ;;
 310esac
 311
 312for s in $use_strategies
 313do
 314        for ss in $no_fast_forward_strategies
 315        do
 316                case " $s " in
 317                *" $ss "*)
 318                        allow_fast_forward=f
 319                        break
 320                        ;;
 321                esac
 322        done
 323        for ss in $no_trivial_strategies
 324        do
 325                case " $s " in
 326                *" $ss "*)
 327                        allow_trivial_merge=f
 328                        break
 329                        ;;
 330                esac
 331        done
 332done
 333
 334case "$#" in
 3351)
 336        common=$(git merge-base --all $head "$@")
 337        ;;
 338*)
 339        common=$(git show-branch --merge-base $head "$@")
 340        ;;
 341esac
 342echo "$head" >"$GIT_DIR/ORIG_HEAD"
 343
 344case "$allow_fast_forward,$#,$common,$no_commit" in
 345?,*,'',*)
 346        # No common ancestors found. We need a real merge.
 347        ;;
 348?,1,"$1",*)
 349        # If head can reach all the merge then we are up to date.
 350        # but first the most common case of merging one remote.
 351        finish_up_to_date "Already up-to-date."
 352        exit 0
 353        ;;
 354t,1,"$head",*)
 355        # Again the most common case of merging one remote.
 356        echo "Updating $(git rev-parse --short $head)..$(git rev-parse --short $1)"
 357        git update-index --refresh 2>/dev/null
 358        msg="Fast forward"
 359        if test -n "$have_message"
 360        then
 361                msg="$msg (no commit created; -m option ignored)"
 362        fi
 363        new_head=$(git rev-parse --verify "$1^0") &&
 364        git read-tree -v -m -u --exclude-per-directory=.gitignore $head "$new_head" &&
 365        finish "$new_head" "$msg" || exit
 366        dropsave
 367        exit 0
 368        ;;
 369?,1,?*"$LF"?*,*)
 370        # We are not doing octopus and not fast forward.  Need a
 371        # real merge.
 372        ;;
 373?,1,*,)
 374        # We are not doing octopus, not fast forward, and have only
 375        # one common.
 376        git update-index --refresh 2>/dev/null
 377        case "$allow_trivial_merge" in
 378        t)
 379                # See if it is really trivial.
 380                git var GIT_COMMITTER_IDENT >/dev/null || exit
 381                echo "Trying really trivial in-index merge..."
 382                if git read-tree --trivial -m -u -v $common $head "$1" &&
 383                   result_tree=$(git write-tree)
 384                then
 385                        echo "Wonderful."
 386                        result_commit=$(
 387                                printf '%s\n' "$merge_msg" |
 388                                git commit-tree $result_tree -p HEAD -p "$1"
 389                        ) || exit
 390                        finish "$result_commit" "In-index merge"
 391                        dropsave
 392                        exit 0
 393                fi
 394                echo "Nope."
 395        esac
 396        ;;
 397*)
 398        # An octopus.  If we can reach all the remote we are up to date.
 399        up_to_date=t
 400        for remote
 401        do
 402                common_one=$(git merge-base --all $head $remote)
 403                if test "$common_one" != "$remote"
 404                then
 405                        up_to_date=f
 406                        break
 407                fi
 408        done
 409        if test "$up_to_date" = t
 410        then
 411                finish_up_to_date "Already up-to-date. Yeeah!"
 412                exit 0
 413        fi
 414        ;;
 415esac
 416
 417# We are going to make a new commit.
 418git var GIT_COMMITTER_IDENT >/dev/null || exit
 419
 420# At this point, we need a real merge.  No matter what strategy
 421# we use, it would operate on the index, possibly affecting the
 422# working tree, and when resolved cleanly, have the desired tree
 423# in the index -- this means that the index must be in sync with
 424# the $head commit.  The strategies are responsible to ensure this.
 425
 426case "$use_strategies" in
 427?*' '?*)
 428    # Stash away the local changes so that we can try more than one.
 429    savestate
 430    single_strategy=no
 431    ;;
 432*)
 433    rm -f "$GIT_DIR/MERGE_STASH"
 434    single_strategy=yes
 435    ;;
 436esac
 437
 438result_tree= best_cnt=-1 best_strategy= wt_strategy=
 439merge_was_ok=
 440for strategy in $use_strategies
 441do
 442    test "$wt_strategy" = '' || {
 443        echo "Rewinding the tree to pristine..."
 444        restorestate
 445    }
 446    case "$single_strategy" in
 447    no)
 448        echo "Trying merge strategy $strategy..."
 449        ;;
 450    esac
 451
 452    # Remember which strategy left the state in the working tree
 453    wt_strategy=$strategy
 454
 455    git-merge-$strategy $common -- "$head_arg" "$@"
 456    exit=$?
 457    if test "$no_commit" = t && test "$exit" = 0
 458    then
 459        merge_was_ok=t
 460        exit=1 ;# pretend it left conflicts.
 461    fi
 462
 463    test "$exit" = 0 || {
 464
 465        # The backend exits with 1 when conflicts are left to be resolved,
 466        # with 2 when it does not handle the given merge at all.
 467
 468        if test "$exit" -eq 1
 469        then
 470            cnt=`{
 471                git diff-files --name-only
 472                git ls-files --unmerged
 473            } | wc -l`
 474            if test $best_cnt -le 0 -o $cnt -le $best_cnt
 475            then
 476                best_strategy=$strategy
 477                best_cnt=$cnt
 478            fi
 479        fi
 480        continue
 481    }
 482
 483    # Automerge succeeded.
 484    result_tree=$(git write-tree) && break
 485done
 486
 487# If we have a resulting tree, that means the strategy module
 488# auto resolved the merge cleanly.
 489if test '' != "$result_tree"
 490then
 491    if test "$allow_fast_forward" = "t"
 492    then
 493        parents=$(git show-branch --independent "$head" "$@")
 494    else
 495        parents=$(git rev-parse "$head" "$@")
 496    fi
 497    parents=$(echo "$parents" | sed -e 's/^/-p /')
 498    result_commit=$(printf '%s\n' "$merge_msg" | git commit-tree $result_tree $parents) || exit
 499    finish "$result_commit" "Merge made by $wt_strategy."
 500    dropsave
 501    exit 0
 502fi
 503
 504# Pick the result from the best strategy and have the user fix it up.
 505case "$best_strategy" in
 506'')
 507        restorestate
 508        case "$use_strategies" in
 509        ?*' '?*)
 510                echo >&2 "No merge strategy handled the merge."
 511                ;;
 512        *)
 513                echo >&2 "Merge with strategy $use_strategies failed."
 514                ;;
 515        esac
 516        exit 2
 517        ;;
 518"$wt_strategy")
 519        # We already have its result in the working tree.
 520        ;;
 521*)
 522        echo "Rewinding the tree to pristine..."
 523        restorestate
 524        echo "Using the $best_strategy to prepare resolving by hand."
 525        git-merge-$best_strategy $common -- "$head_arg" "$@"
 526        ;;
 527esac
 528
 529if test "$squash" = t
 530then
 531        finish
 532else
 533        for remote
 534        do
 535                echo $remote
 536        done >"$GIT_DIR/MERGE_HEAD"
 537        printf '%s\n' "$merge_msg" >"$GIT_DIR/MERGE_MSG"
 538fi
 539
 540if test "$merge_was_ok" = t
 541then
 542        echo >&2 \
 543        "Automatic merge went well; stopped before committing as requested"
 544        exit 0
 545else
 546        {
 547            echo '
 548Conflicts:
 549'
 550                git ls-files --unmerged |
 551                sed -e 's/^[^   ]*      /       /' |
 552                uniq
 553        } >>"$GIT_DIR/MERGE_MSG"
 554        git rerere
 555        die "Automatic merge failed; fix conflicts and then commit the result."
 556fi