Andrew's git / gitweb.git / git-merge.sh
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git-merge.shon commit git-merge: add --ff and --no-ff options (d66424c)
   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                        ;;
  86                esac
  87                ;;
  88        esac
  89        case "$1" in
  90        '')
  91                ;;
  92        ?*)
  93                if test "$show_diffstat" = t
  94                then
  95                        # We want color (if set), but no pager
  96                        GIT_PAGER='' git diff --stat --summary -M "$head" "$1"
  97                fi
  98                ;;
  99        esac
 100}
 101
 102merge_name () {
 103        remote="$1"
 104        rh=$(git rev-parse --verify "$remote^0" 2>/dev/null) || return
 105        bh=$(git show-ref -s --verify "refs/heads/$remote" 2>/dev/null)
 106        if test "$rh" = "$bh"
 107        then
 108                echo "$rh               branch '$remote' of ."
 109        elif truname=$(expr "$remote" : '\(.*\)~[1-9][0-9]*$') &&
 110                git show-ref -q --verify "refs/heads/$truname" 2>/dev/null
 111        then
 112                echo "$rh               branch '$truname' (early part) of ."
 113        elif test "$remote" = "FETCH_HEAD" -a -r "$GIT_DIR/FETCH_HEAD"
 114        then
 115                sed -e 's/      not-for-merge   /               /' -e 1q \
 116                        "$GIT_DIR/FETCH_HEAD"
 117        else
 118                echo "$rh               commit '$remote'"
 119        fi
 120}
 121
 122parse_option () {
 123        case "$1" in
 124        -n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
 125                --no-summa|--no-summar|--no-summary)
 126                show_diffstat=false ;;
 127        --summary)
 128                show_diffstat=t ;;
 129        --sq|--squ|--squa|--squas|--squash)
 130                allow_fast_forward=t squash=t no_commit=t ;;
 131        --no-sq|--no-squ|--no-squa|--no-squas|--no-squash)
 132                allow_fast_forward=t squash= no_commit= ;;
 133        --c|--co|--com|--comm|--commi|--commit)
 134                allow_fast_forward=t squash= no_commit= ;;
 135        --no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
 136                allow_fast_forward=t squash= no_commit=t ;;
 137        --ff)
 138                allow_fast_forward=t squash= no_commit= ;;
 139        --no-ff)
 140                allow_fast_forward=false squash= no_commit= ;;
 141        -s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
 142                --strateg=*|--strategy=*|\
 143        -s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
 144                case "$#,$1" in
 145                *,*=*)
 146                        strategy=`expr "z$1" : 'z-[^=]*=\(.*\)'` ;;
 147                1,*)
 148                        usage ;;
 149                *)
 150                        strategy="$2"
 151                        shift ;;
 152                esac
 153                case " $all_strategies " in
 154                *" $strategy "*)
 155                        use_strategies="$use_strategies$strategy " ;;
 156                *)
 157                        die "available strategies are: $all_strategies" ;;
 158                esac
 159                ;;
 160        -m=*|--m=*|--me=*|--mes=*|--mess=*|--messa=*|--messag=*|--message=*)
 161                merge_msg=`expr "z$1" : 'z-[^=]*=\(.*\)'`
 162                have_message=t
 163                ;;
 164        -m|--m|--me|--mes|--mess|--messa|--messag|--message)
 165                shift
 166                case "$#" in
 167                1)      usage ;;
 168                esac
 169                merge_msg="$1"
 170                have_message=t
 171                ;;
 172        -*)     usage ;;
 173        *)      return 1 ;;
 174        esac
 175        shift
 176        args_left=$#
 177}
 178
 179parse_config () {
 180        while test $# -gt 0
 181        do
 182                parse_option "$@" || usage
 183                while test $args_left -lt $#
 184                do
 185                        shift
 186                done
 187        done
 188}
 189
 190test $# != 0 || usage
 191
 192have_message=
 193
 194if branch=$(git-symbolic-ref -q HEAD)
 195then
 196        mergeopts=$(git config "branch.${branch#refs/heads/}.mergeoptions")
 197        if test -n "$mergeopts"
 198        then
 199                parse_config $mergeopts
 200        fi
 201fi
 202
 203while parse_option "$@"
 204do
 205        while test $args_left -lt $#
 206        do
 207                shift
 208        done
 209done
 210
 211if test -z "$show_diffstat"; then
 212    test "$(git config --bool merge.diffstat)" = false && show_diffstat=false
 213    test -z "$show_diffstat" && show_diffstat=t
 214fi
 215
 216# This could be traditional "merge <msg> HEAD <commit>..."  and the
 217# way we can tell it is to see if the second token is HEAD, but some
 218# people might have misused the interface and used a committish that
 219# is the same as HEAD there instead.  Traditional format never would
 220# have "-m" so it is an additional safety measure to check for it.
 221
 222if test -z "$have_message" &&
 223        second_token=$(git rev-parse --verify "$2^0" 2>/dev/null) &&
 224        head_commit=$(git rev-parse --verify "HEAD" 2>/dev/null) &&
 225        test "$second_token" = "$head_commit"
 226then
 227        merge_msg="$1"
 228        shift
 229        head_arg="$1"
 230        shift
 231elif ! git rev-parse --verify HEAD >/dev/null 2>&1
 232then
 233        # If the merged head is a valid one there is no reason to
 234        # forbid "git merge" into a branch yet to be born.  We do
 235        # the same for "git pull".
 236        if test 1 -ne $#
 237        then
 238                echo >&2 "Can merge only exactly one commit into empty head"
 239                exit 1
 240        fi
 241
 242        rh=$(git rev-parse --verify "$1^0") ||
 243                die "$1 - not something we can merge"
 244
 245        git update-ref -m "initial pull" HEAD "$rh" "" &&
 246        git read-tree --reset -u HEAD
 247        exit
 248
 249else
 250        # We are invoked directly as the first-class UI.
 251        head_arg=HEAD
 252
 253        # All the rest are the commits being merged; prepare
 254        # the standard merge summary message to be appended to
 255        # the given message.  If remote is invalid we will die
 256        # later in the common codepath so we discard the error
 257        # in this loop.
 258        merge_name=$(for remote
 259                do
 260                        merge_name "$remote"
 261                done | git fmt-merge-msg
 262        )
 263        merge_msg="${merge_msg:+$merge_msg$LF$LF}$merge_name"
 264fi
 265head=$(git rev-parse --verify "$head_arg"^0) || usage
 266
 267# All the rest are remote heads
 268test "$#" = 0 && usage ;# we need at least one remote head.
 269set_reflog_action "merge $*"
 270
 271remoteheads=
 272for remote
 273do
 274        remotehead=$(git rev-parse --verify "$remote"^0 2>/dev/null) ||
 275            die "$remote - not something we can merge"
 276        remoteheads="${remoteheads}$remotehead "
 277        eval GITHEAD_$remotehead='"$remote"'
 278        export GITHEAD_$remotehead
 279done
 280set x $remoteheads ; shift
 281
 282case "$use_strategies" in
 283'')
 284        case "$#" in
 285        1)
 286                var="`git config --get pull.twohead`"
 287                if test -n "$var"
 288                then
 289                        use_strategies="$var"
 290                else
 291                        use_strategies="$default_twohead_strategies"
 292                fi ;;
 293        *)
 294                var="`git config --get pull.octopus`"
 295                if test -n "$var"
 296                then
 297                        use_strategies="$var"
 298                else
 299                        use_strategies="$default_octopus_strategies"
 300                fi ;;
 301        esac
 302        ;;
 303esac
 304
 305for s in $use_strategies
 306do
 307        for ss in $no_fast_forward_strategies
 308        do
 309                case " $s " in
 310                *" $ss "*)
 311                        allow_fast_forward=f
 312                        break
 313                        ;;
 314                esac
 315        done
 316        for ss in $no_trivial_strategies
 317        do
 318                case " $s " in
 319                *" $ss "*)
 320                        allow_trivial_merge=f
 321                        break
 322                        ;;
 323                esac
 324        done
 325done
 326
 327case "$#" in
 3281)
 329        common=$(git merge-base --all $head "$@")
 330        ;;
 331*)
 332        common=$(git show-branch --merge-base $head "$@")
 333        ;;
 334esac
 335echo "$head" >"$GIT_DIR/ORIG_HEAD"
 336
 337case "$allow_fast_forward,$#,$common,$no_commit" in
 338?,*,'',*)
 339        # No common ancestors found. We need a real merge.
 340        ;;
 341?,1,"$1",*)
 342        # If head can reach all the merge then we are up to date.
 343        # but first the most common case of merging one remote.
 344        finish_up_to_date "Already up-to-date."
 345        exit 0
 346        ;;
 347t,1,"$head",*)
 348        # Again the most common case of merging one remote.
 349        echo "Updating $(git rev-parse --short $head)..$(git rev-parse --short $1)"
 350        git update-index --refresh 2>/dev/null
 351        msg="Fast forward"
 352        if test -n "$have_message"
 353        then
 354                msg="$msg (no commit created; -m option ignored)"
 355        fi
 356        new_head=$(git rev-parse --verify "$1^0") &&
 357        git read-tree -v -m -u --exclude-per-directory=.gitignore $head "$new_head" &&
 358        finish "$new_head" "$msg" || exit
 359        dropsave
 360        exit 0
 361        ;;
 362?,1,?*"$LF"?*,*)
 363        # We are not doing octopus and not fast forward.  Need a
 364        # real merge.
 365        ;;
 366?,1,*,)
 367        # We are not doing octopus, not fast forward, and have only
 368        # one common.
 369        git update-index --refresh 2>/dev/null
 370        case "$allow_trivial_merge" in
 371        t)
 372                # See if it is really trivial.
 373                git var GIT_COMMITTER_IDENT >/dev/null || exit
 374                echo "Trying really trivial in-index merge..."
 375                if git read-tree --trivial -m -u -v $common $head "$1" &&
 376                   result_tree=$(git write-tree)
 377                then
 378                        echo "Wonderful."
 379                        result_commit=$(
 380                                printf '%s\n' "$merge_msg" |
 381                                git commit-tree $result_tree -p HEAD -p "$1"
 382                        ) || exit
 383                        finish "$result_commit" "In-index merge"
 384                        dropsave
 385                        exit 0
 386                fi
 387                echo "Nope."
 388        esac
 389        ;;
 390*)
 391        # An octopus.  If we can reach all the remote we are up to date.
 392        up_to_date=t
 393        for remote
 394        do
 395                common_one=$(git merge-base --all $head $remote)
 396                if test "$common_one" != "$remote"
 397                then
 398                        up_to_date=f
 399                        break
 400                fi
 401        done
 402        if test "$up_to_date" = t
 403        then
 404                finish_up_to_date "Already up-to-date. Yeeah!"
 405                exit 0
 406        fi
 407        ;;
 408esac
 409
 410# We are going to make a new commit.
 411git var GIT_COMMITTER_IDENT >/dev/null || exit
 412
 413# At this point, we need a real merge.  No matter what strategy
 414# we use, it would operate on the index, possibly affecting the
 415# working tree, and when resolved cleanly, have the desired tree
 416# in the index -- this means that the index must be in sync with
 417# the $head commit.  The strategies are responsible to ensure this.
 418
 419case "$use_strategies" in
 420?*' '?*)
 421    # Stash away the local changes so that we can try more than one.
 422    savestate
 423    single_strategy=no
 424    ;;
 425*)
 426    rm -f "$GIT_DIR/MERGE_SAVE"
 427    single_strategy=yes
 428    ;;
 429esac
 430
 431result_tree= best_cnt=-1 best_strategy= wt_strategy=
 432merge_was_ok=
 433for strategy in $use_strategies
 434do
 435    test "$wt_strategy" = '' || {
 436        echo "Rewinding the tree to pristine..."
 437        restorestate
 438    }
 439    case "$single_strategy" in
 440    no)
 441        echo "Trying merge strategy $strategy..."
 442        ;;
 443    esac
 444
 445    # Remember which strategy left the state in the working tree
 446    wt_strategy=$strategy
 447
 448    git-merge-$strategy $common -- "$head_arg" "$@"
 449    exit=$?
 450    if test "$no_commit" = t && test "$exit" = 0
 451    then
 452        merge_was_ok=t
 453        exit=1 ;# pretend it left conflicts.
 454    fi
 455
 456    test "$exit" = 0 || {
 457
 458        # The backend exits with 1 when conflicts are left to be resolved,
 459        # with 2 when it does not handle the given merge at all.
 460
 461        if test "$exit" -eq 1
 462        then
 463            cnt=`{
 464                git diff-files --name-only
 465                git ls-files --unmerged
 466            } | wc -l`
 467            if test $best_cnt -le 0 -o $cnt -le $best_cnt
 468            then
 469                best_strategy=$strategy
 470                best_cnt=$cnt
 471            fi
 472        fi
 473        continue
 474    }
 475
 476    # Automerge succeeded.
 477    result_tree=$(git write-tree) && break
 478done
 479
 480# If we have a resulting tree, that means the strategy module
 481# auto resolved the merge cleanly.
 482if test '' != "$result_tree"
 483then
 484    if test "$allow_fast_forward" = "t"
 485    then
 486        parents=$(git show-branch --independent "$head" "$@")
 487    else
 488        parents=$(git rev-parse "$head" "$@")
 489    fi
 490    parents=$(echo "$parents" | sed -e 's/^/-p /')
 491    result_commit=$(printf '%s\n' "$merge_msg" | git commit-tree $result_tree $parents) || exit
 492    finish "$result_commit" "Merge made by $wt_strategy."
 493    dropsave
 494    exit 0
 495fi
 496
 497# Pick the result from the best strategy and have the user fix it up.
 498case "$best_strategy" in
 499'')
 500        restorestate
 501        case "$use_strategies" in
 502        ?*' '?*)
 503                echo >&2 "No merge strategy handled the merge."
 504                ;;
 505        *)
 506                echo >&2 "Merge with strategy $use_strategies failed."
 507                ;;
 508        esac
 509        exit 2
 510        ;;
 511"$wt_strategy")
 512        # We already have its result in the working tree.
 513        ;;
 514*)
 515        echo "Rewinding the tree to pristine..."
 516        restorestate
 517        echo "Using the $best_strategy to prepare resolving by hand."
 518        git-merge-$best_strategy $common -- "$head_arg" "$@"
 519        ;;
 520esac
 521
 522if test "$squash" = t
 523then
 524        finish
 525else
 526        for remote
 527        do
 528                echo $remote
 529        done >"$GIT_DIR/MERGE_HEAD"
 530        printf '%s\n' "$merge_msg" >"$GIT_DIR/MERGE_MSG"
 531fi
 532
 533if test "$merge_was_ok" = t
 534then
 535        echo >&2 \
 536        "Automatic merge went well; stopped before committing as requested"
 537        exit 0
 538else
 539        {
 540            echo '
 541Conflicts:
 542'
 543                git ls-files --unmerged |
 544                sed -e 's/^[^   ]*      /       /' |
 545                uniq
 546        } >>"$GIT_DIR/MERGE_MSG"
 547        git rerere
 548        die "Automatic merge failed; fix conflicts and then commit the result."
 549fi