Andrew's git / gitweb.git / git-merge.sh
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git-merge.shon commit Use the asyncronous function infrastructure in builtin-fetch-pack.c. (088fab5)
   1#!/bin/sh
   2#
   3# Copyright (c) 2005 Junio C Hamano
   4#
   5
   6USAGE='[-n] [--summary] [--[no-]commit] [--[no-]squash] [--[no-]ff] [-s <strategy>] [-m=<merge-message>] <commit>+'
   7
   8SUBDIRECTORY_OK=Yes
   9. git-sh-setup
  10require_work_tree
  11cd_to_toplevel
  12
  13test -z "$(git ls-files -u)" ||
  14        die "You are in the middle of a conflicted merge."
  15
  16LF='
  17'
  18
  19all_strategies='recur recursive octopus resolve stupid ours subtree'
  20default_twohead_strategies='recursive'
  21default_octopus_strategies='octopus'
  22no_fast_forward_strategies='subtree ours'
  23no_trivial_strategies='recursive recur subtree ours'
  24use_strategies=
  25
  26allow_fast_forward=t
  27allow_trivial_merge=t
  28
  29dropsave() {
  30        rm -f -- "$GIT_DIR/MERGE_HEAD" "$GIT_DIR/MERGE_MSG" \
  31                 "$GIT_DIR/MERGE_SAVE" || exit 1
  32}
  33
  34savestate() {
  35        # Stash away any local modifications.
  36        git diff-index -z --name-only $head |
  37        cpio -0 -o >"$GIT_DIR/MERGE_SAVE"
  38}
  39
  40restorestate() {
  41        if test -f "$GIT_DIR/MERGE_SAVE"
  42        then
  43                git reset --hard $head >/dev/null
  44                cpio -iuv <"$GIT_DIR/MERGE_SAVE"
  45                git update-index --refresh >/dev/null
  46        fi
  47}
  48
  49finish_up_to_date () {
  50        case "$squash" in
  51        t)
  52                echo "$1 (nothing to squash)" ;;
  53        '')
  54                echo "$1" ;;
  55        esac
  56        dropsave
  57}
  58
  59squash_message () {
  60        echo Squashed commit of the following:
  61        echo
  62        git log --no-merges ^"$head" $remoteheads
  63}
  64
  65finish () {
  66        if test '' = "$2"
  67        then
  68                rlogm="$GIT_REFLOG_ACTION"
  69        else
  70                echo "$2"
  71                rlogm="$GIT_REFLOG_ACTION: $2"
  72        fi
  73        case "$squash" in
  74        t)
  75                echo "Squash commit -- not updating HEAD"
  76                squash_message >"$GIT_DIR/SQUASH_MSG"
  77                ;;
  78        '')
  79                case "$merge_msg" in
  80                '')
  81                        echo "No merge message -- not updating HEAD"
  82                        ;;
  83                *)
  84                        git update-ref -m "$rlogm" HEAD "$1" "$head" || exit 1
  85                        git gc --auto
  86                        ;;
  87                esac
  88                ;;
  89        esac
  90        case "$1" in
  91        '')
  92                ;;
  93        ?*)
  94                if test "$show_diffstat" = t
  95                then
  96                        # We want color (if set), but no pager
  97                        GIT_PAGER='' git diff --stat --summary -M "$head" "$1"
  98                fi
  99                ;;
 100        esac
 101
 102        # Run a post-merge hook
 103        if test -x "$GIT_DIR"/hooks/post-merge
 104        then
 105            case "$squash" in
 106            t)
 107                "$GIT_DIR"/hooks/post-merge 1
 108                ;;
 109            '')
 110                "$GIT_DIR"/hooks/post-merge 0
 111                ;;
 112            esac
 113        fi
 114}
 115
 116merge_name () {
 117        remote="$1"
 118        rh=$(git rev-parse --verify "$remote^0" 2>/dev/null) || return
 119        bh=$(git show-ref -s --verify "refs/heads/$remote" 2>/dev/null)
 120        if test "$rh" = "$bh"
 121        then
 122                echo "$rh               branch '$remote' of ."
 123        elif truname=$(expr "$remote" : '\(.*\)~[1-9][0-9]*$') &&
 124                git show-ref -q --verify "refs/heads/$truname" 2>/dev/null
 125        then
 126                echo "$rh               branch '$truname' (early part) of ."
 127        elif test "$remote" = "FETCH_HEAD" -a -r "$GIT_DIR/FETCH_HEAD"
 128        then
 129                sed -e 's/      not-for-merge   /               /' -e 1q \
 130                        "$GIT_DIR/FETCH_HEAD"
 131        else
 132                echo "$rh               commit '$remote'"
 133        fi
 134}
 135
 136parse_option () {
 137        case "$1" in
 138        -n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
 139                --no-summa|--no-summar|--no-summary)
 140                show_diffstat=false ;;
 141        --summary)
 142                show_diffstat=t ;;
 143        --sq|--squ|--squa|--squas|--squash)
 144                allow_fast_forward=t squash=t no_commit=t ;;
 145        --no-sq|--no-squ|--no-squa|--no-squas|--no-squash)
 146                allow_fast_forward=t squash= no_commit= ;;
 147        --c|--co|--com|--comm|--commi|--commit)
 148                allow_fast_forward=t squash= no_commit= ;;
 149        --no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
 150                allow_fast_forward=t squash= no_commit=t ;;
 151        --ff)
 152                allow_fast_forward=t squash= no_commit= ;;
 153        --no-ff)
 154                allow_fast_forward=false squash= no_commit= ;;
 155        -s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
 156                --strateg=*|--strategy=*|\
 157        -s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
 158                case "$#,$1" in
 159                *,*=*)
 160                        strategy=`expr "z$1" : 'z-[^=]*=\(.*\)'` ;;
 161                1,*)
 162                        usage ;;
 163                *)
 164                        strategy="$2"
 165                        shift ;;
 166                esac
 167                case " $all_strategies " in
 168                *" $strategy "*)
 169                        use_strategies="$use_strategies$strategy " ;;
 170                *)
 171                        die "available strategies are: $all_strategies" ;;
 172                esac
 173                ;;
 174        -m=*|--m=*|--me=*|--mes=*|--mess=*|--messa=*|--messag=*|--message=*)
 175                merge_msg=`expr "z$1" : 'z-[^=]*=\(.*\)'`
 176                have_message=t
 177                ;;
 178        -m|--m|--me|--mes|--mess|--messa|--messag|--message)
 179                shift
 180                case "$#" in
 181                1)      usage ;;
 182                esac
 183                merge_msg="$1"
 184                have_message=t
 185                ;;
 186        -*)     usage ;;
 187        *)      return 1 ;;
 188        esac
 189        shift
 190        args_left=$#
 191}
 192
 193parse_config () {
 194        while test $# -gt 0
 195        do
 196                parse_option "$@" || usage
 197                while test $args_left -lt $#
 198                do
 199                        shift
 200                done
 201        done
 202}
 203
 204test $# != 0 || usage
 205
 206have_message=
 207
 208if branch=$(git-symbolic-ref -q HEAD)
 209then
 210        mergeopts=$(git config "branch.${branch#refs/heads/}.mergeoptions")
 211        if test -n "$mergeopts"
 212        then
 213                parse_config $mergeopts
 214        fi
 215fi
 216
 217while parse_option "$@"
 218do
 219        while test $args_left -lt $#
 220        do
 221                shift
 222        done
 223done
 224
 225if test -z "$show_diffstat"; then
 226    test "$(git config --bool merge.diffstat)" = false && show_diffstat=false
 227    test -z "$show_diffstat" && show_diffstat=t
 228fi
 229
 230# This could be traditional "merge <msg> HEAD <commit>..."  and the
 231# way we can tell it is to see if the second token is HEAD, but some
 232# people might have misused the interface and used a committish that
 233# is the same as HEAD there instead.  Traditional format never would
 234# have "-m" so it is an additional safety measure to check for it.
 235
 236if test -z "$have_message" &&
 237        second_token=$(git rev-parse --verify "$2^0" 2>/dev/null) &&
 238        head_commit=$(git rev-parse --verify "HEAD" 2>/dev/null) &&
 239        test "$second_token" = "$head_commit"
 240then
 241        merge_msg="$1"
 242        shift
 243        head_arg="$1"
 244        shift
 245elif ! git rev-parse --verify HEAD >/dev/null 2>&1
 246then
 247        # If the merged head is a valid one there is no reason to
 248        # forbid "git merge" into a branch yet to be born.  We do
 249        # the same for "git pull".
 250        if test 1 -ne $#
 251        then
 252                echo >&2 "Can merge only exactly one commit into empty head"
 253                exit 1
 254        fi
 255
 256        rh=$(git rev-parse --verify "$1^0") ||
 257                die "$1 - not something we can merge"
 258
 259        git update-ref -m "initial pull" HEAD "$rh" "" &&
 260        git read-tree --reset -u HEAD
 261        exit
 262
 263else
 264        # We are invoked directly as the first-class UI.
 265        head_arg=HEAD
 266
 267        # All the rest are the commits being merged; prepare
 268        # the standard merge summary message to be appended to
 269        # the given message.  If remote is invalid we will die
 270        # later in the common codepath so we discard the error
 271        # in this loop.
 272        merge_name=$(for remote
 273                do
 274                        merge_name "$remote"
 275                done | git fmt-merge-msg
 276        )
 277        merge_msg="${merge_msg:+$merge_msg$LF$LF}$merge_name"
 278fi
 279head=$(git rev-parse --verify "$head_arg"^0) || usage
 280
 281# All the rest are remote heads
 282test "$#" = 0 && usage ;# we need at least one remote head.
 283set_reflog_action "merge $*"
 284
 285remoteheads=
 286for remote
 287do
 288        remotehead=$(git rev-parse --verify "$remote"^0 2>/dev/null) ||
 289            die "$remote - not something we can merge"
 290        remoteheads="${remoteheads}$remotehead "
 291        eval GITHEAD_$remotehead='"$remote"'
 292        export GITHEAD_$remotehead
 293done
 294set x $remoteheads ; shift
 295
 296case "$use_strategies" in
 297'')
 298        case "$#" in
 299        1)
 300                var="`git config --get pull.twohead`"
 301                if test -n "$var"
 302                then
 303                        use_strategies="$var"
 304                else
 305                        use_strategies="$default_twohead_strategies"
 306                fi ;;
 307        *)
 308                var="`git config --get pull.octopus`"
 309                if test -n "$var"
 310                then
 311                        use_strategies="$var"
 312                else
 313                        use_strategies="$default_octopus_strategies"
 314                fi ;;
 315        esac
 316        ;;
 317esac
 318
 319for s in $use_strategies
 320do
 321        for ss in $no_fast_forward_strategies
 322        do
 323                case " $s " in
 324                *" $ss "*)
 325                        allow_fast_forward=f
 326                        break
 327                        ;;
 328                esac
 329        done
 330        for ss in $no_trivial_strategies
 331        do
 332                case " $s " in
 333                *" $ss "*)
 334                        allow_trivial_merge=f
 335                        break
 336                        ;;
 337                esac
 338        done
 339done
 340
 341case "$#" in
 3421)
 343        common=$(git merge-base --all $head "$@")
 344        ;;
 345*)
 346        common=$(git show-branch --merge-base $head "$@")
 347        ;;
 348esac
 349echo "$head" >"$GIT_DIR/ORIG_HEAD"
 350
 351case "$allow_fast_forward,$#,$common,$no_commit" in
 352?,*,'',*)
 353        # No common ancestors found. We need a real merge.
 354        ;;
 355?,1,"$1",*)
 356        # If head can reach all the merge then we are up to date.
 357        # but first the most common case of merging one remote.
 358        finish_up_to_date "Already up-to-date."
 359        exit 0
 360        ;;
 361t,1,"$head",*)
 362        # Again the most common case of merging one remote.
 363        echo "Updating $(git rev-parse --short $head)..$(git rev-parse --short $1)"
 364        git update-index --refresh 2>/dev/null
 365        msg="Fast forward"
 366        if test -n "$have_message"
 367        then
 368                msg="$msg (no commit created; -m option ignored)"
 369        fi
 370        new_head=$(git rev-parse --verify "$1^0") &&
 371        git read-tree -v -m -u --exclude-per-directory=.gitignore $head "$new_head" &&
 372        finish "$new_head" "$msg" || exit
 373        dropsave
 374        exit 0
 375        ;;
 376?,1,?*"$LF"?*,*)
 377        # We are not doing octopus and not fast forward.  Need a
 378        # real merge.
 379        ;;
 380?,1,*,)
 381        # We are not doing octopus, not fast forward, and have only
 382        # one common.
 383        git update-index --refresh 2>/dev/null
 384        case "$allow_trivial_merge" in
 385        t)
 386                # See if it is really trivial.
 387                git var GIT_COMMITTER_IDENT >/dev/null || exit
 388                echo "Trying really trivial in-index merge..."
 389                if git read-tree --trivial -m -u -v $common $head "$1" &&
 390                   result_tree=$(git write-tree)
 391                then
 392                        echo "Wonderful."
 393                        result_commit=$(
 394                                printf '%s\n' "$merge_msg" |
 395                                git commit-tree $result_tree -p HEAD -p "$1"
 396                        ) || exit
 397                        finish "$result_commit" "In-index merge"
 398                        dropsave
 399                        exit 0
 400                fi
 401                echo "Nope."
 402        esac
 403        ;;
 404*)
 405        # An octopus.  If we can reach all the remote we are up to date.
 406        up_to_date=t
 407        for remote
 408        do
 409                common_one=$(git merge-base --all $head $remote)
 410                if test "$common_one" != "$remote"
 411                then
 412                        up_to_date=f
 413                        break
 414                fi
 415        done
 416        if test "$up_to_date" = t
 417        then
 418                finish_up_to_date "Already up-to-date. Yeeah!"
 419                exit 0
 420        fi
 421        ;;
 422esac
 423
 424# We are going to make a new commit.
 425git var GIT_COMMITTER_IDENT >/dev/null || exit
 426
 427# At this point, we need a real merge.  No matter what strategy
 428# we use, it would operate on the index, possibly affecting the
 429# working tree, and when resolved cleanly, have the desired tree
 430# in the index -- this means that the index must be in sync with
 431# the $head commit.  The strategies are responsible to ensure this.
 432
 433case "$use_strategies" in
 434?*' '?*)
 435    # Stash away the local changes so that we can try more than one.
 436    savestate
 437    single_strategy=no
 438    ;;
 439*)
 440    rm -f "$GIT_DIR/MERGE_SAVE"
 441    single_strategy=yes
 442    ;;
 443esac
 444
 445result_tree= best_cnt=-1 best_strategy= wt_strategy=
 446merge_was_ok=
 447for strategy in $use_strategies
 448do
 449    test "$wt_strategy" = '' || {
 450        echo "Rewinding the tree to pristine..."
 451        restorestate
 452    }
 453    case "$single_strategy" in
 454    no)
 455        echo "Trying merge strategy $strategy..."
 456        ;;
 457    esac
 458
 459    # Remember which strategy left the state in the working tree
 460    wt_strategy=$strategy
 461
 462    git-merge-$strategy $common -- "$head_arg" "$@"
 463    exit=$?
 464    if test "$no_commit" = t && test "$exit" = 0
 465    then
 466        merge_was_ok=t
 467        exit=1 ;# pretend it left conflicts.
 468    fi
 469
 470    test "$exit" = 0 || {
 471
 472        # The backend exits with 1 when conflicts are left to be resolved,
 473        # with 2 when it does not handle the given merge at all.
 474
 475        if test "$exit" -eq 1
 476        then
 477            cnt=`{
 478                git diff-files --name-only
 479                git ls-files --unmerged
 480            } | wc -l`
 481            if test $best_cnt -le 0 -o $cnt -le $best_cnt
 482            then
 483                best_strategy=$strategy
 484                best_cnt=$cnt
 485            fi
 486        fi
 487        continue
 488    }
 489
 490    # Automerge succeeded.
 491    result_tree=$(git write-tree) && break
 492done
 493
 494# If we have a resulting tree, that means the strategy module
 495# auto resolved the merge cleanly.
 496if test '' != "$result_tree"
 497then
 498    if test "$allow_fast_forward" = "t"
 499    then
 500        parents=$(git show-branch --independent "$head" "$@")
 501    else
 502        parents=$(git rev-parse "$head" "$@")
 503    fi
 504    parents=$(echo "$parents" | sed -e 's/^/-p /')
 505    result_commit=$(printf '%s\n' "$merge_msg" | git commit-tree $result_tree $parents) || exit
 506    finish "$result_commit" "Merge made by $wt_strategy."
 507    dropsave
 508    exit 0
 509fi
 510
 511# Pick the result from the best strategy and have the user fix it up.
 512case "$best_strategy" in
 513'')
 514        restorestate
 515        case "$use_strategies" in
 516        ?*' '?*)
 517                echo >&2 "No merge strategy handled the merge."
 518                ;;
 519        *)
 520                echo >&2 "Merge with strategy $use_strategies failed."
 521                ;;
 522        esac
 523        exit 2
 524        ;;
 525"$wt_strategy")
 526        # We already have its result in the working tree.
 527        ;;
 528*)
 529        echo "Rewinding the tree to pristine..."
 530        restorestate
 531        echo "Using the $best_strategy to prepare resolving by hand."
 532        git-merge-$best_strategy $common -- "$head_arg" "$@"
 533        ;;
 534esac
 535
 536if test "$squash" = t
 537then
 538        finish
 539else
 540        for remote
 541        do
 542                echo $remote
 543        done >"$GIT_DIR/MERGE_HEAD"
 544        printf '%s\n' "$merge_msg" >"$GIT_DIR/MERGE_MSG"
 545fi
 546
 547if test "$merge_was_ok" = t
 548then
 549        echo >&2 \
 550        "Automatic merge went well; stopped before committing as requested"
 551        exit 0
 552else
 553        {
 554            echo '
 555Conflicts:
 556'
 557                git ls-files --unmerged |
 558                sed -e 's/^[^   ]*      /       /' |
 559                uniq
 560        } >>"$GIT_DIR/MERGE_MSG"
 561        git rerere
 562        die "Automatic merge failed; fix conflicts and then commit the result."
 563fi