Andrew's git / gitweb.git / git-merge.sh
?
git-merge.shon commit Merge branch 'js/rebase-i' (9b0185c)
   1#!/bin/sh
   2#
   3# Copyright (c) 2005 Junio C Hamano
   4#
   5
   6USAGE='[-n] [--summary] [--no-commit] [--squash] [-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" $remote
  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 '$remote'"
 133        fi
 134}
 135
 136case "$#" in 0) usage ;; esac
 137
 138have_message=
 139while test $# != 0
 140do
 141        case "$1" in
 142        -n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
 143                --no-summa|--no-summar|--no-summary)
 144                show_diffstat=false ;;
 145        --summary)
 146                show_diffstat=t ;;
 147        --sq|--squ|--squa|--squas|--squash)
 148                squash=t no_commit=t ;;
 149        --no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
 150                no_commit=t ;;
 151        -s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
 152                --strateg=*|--strategy=*|\
 153        -s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
 154                case "$#,$1" in
 155                *,*=*)
 156                        strategy=`expr "z$1" : 'z-[^=]*=\(.*\)'` ;;
 157                1,*)
 158                        usage ;;
 159                *)
 160                        strategy="$2"
 161                        shift ;;
 162                esac
 163                case " $all_strategies " in
 164                *" $strategy "*)
 165                        use_strategies="$use_strategies$strategy " ;;
 166                *)
 167                        die "available strategies are: $all_strategies" ;;
 168                esac
 169                ;;
 170        -m=*|--m=*|--me=*|--mes=*|--mess=*|--messa=*|--messag=*|--message=*)
 171                merge_msg=`expr "z$1" : 'z-[^=]*=\(.*\)'`
 172                have_message=t
 173                ;;
 174        -m|--m|--me|--mes|--mess|--messa|--messag|--message)
 175                shift
 176                case "$#" in
 177                1)      usage ;;
 178                esac
 179                merge_msg="$1"
 180                have_message=t
 181                ;;
 182        -*)     usage ;;
 183        *)      break ;;
 184        esac
 185        shift
 186done
 187
 188if test -z "$show_diffstat"; then
 189    test "$(git config --bool merge.diffstat)" = false && show_diffstat=false
 190    test -z "$show_diffstat" && show_diffstat=t
 191fi
 192
 193# This could be traditional "merge <msg> HEAD <commit>..."  and the
 194# way we can tell it is to see if the second token is HEAD, but some
 195# people might have misused the interface and used a committish that
 196# is the same as HEAD there instead.  Traditional format never would
 197# have "-m" so it is an additional safety measure to check for it.
 198
 199if test -z "$have_message" &&
 200        second_token=$(git rev-parse --verify "$2^0" 2>/dev/null) &&
 201        head_commit=$(git rev-parse --verify "HEAD" 2>/dev/null) &&
 202        test "$second_token" = "$head_commit"
 203then
 204        merge_msg="$1"
 205        shift
 206        head_arg="$1"
 207        shift
 208elif ! git rev-parse --verify HEAD >/dev/null 2>&1
 209then
 210        # If the merged head is a valid one there is no reason to
 211        # forbid "git merge" into a branch yet to be born.  We do
 212        # the same for "git pull".
 213        if test 1 -ne $#
 214        then
 215                echo >&2 "Can merge only exactly one commit into empty head"
 216                exit 1
 217        fi
 218
 219        rh=$(git rev-parse --verify "$1^0") ||
 220                die "$1 - not something we can merge"
 221
 222        git update-ref -m "initial pull" HEAD "$rh" "" &&
 223        git read-tree --reset -u HEAD
 224        exit
 225
 226else
 227        # We are invoked directly as the first-class UI.
 228        head_arg=HEAD
 229
 230        # All the rest are the commits being merged; prepare
 231        # the standard merge summary message to be appended to
 232        # the given message.  If remote is invalid we will die
 233        # later in the common codepath so we discard the error
 234        # in this loop.
 235        merge_name=$(for remote
 236                do
 237                        merge_name "$remote"
 238                done | git fmt-merge-msg
 239        )
 240        merge_msg="${merge_msg:+$merge_msg$LF$LF}$merge_name"
 241fi
 242head=$(git rev-parse --verify "$head_arg"^0) || usage
 243
 244# All the rest are remote heads
 245test "$#" = 0 && usage ;# we need at least one remote head.
 246set_reflog_action "merge $*"
 247
 248remoteheads=
 249for remote
 250do
 251        remotehead=$(git rev-parse --verify "$remote"^0 2>/dev/null) ||
 252            die "$remote - not something we can merge"
 253        remoteheads="${remoteheads}$remotehead "
 254        eval GITHEAD_$remotehead='"$remote"'
 255        export GITHEAD_$remotehead
 256done
 257set x $remoteheads ; shift
 258
 259case "$use_strategies" in
 260'')
 261        case "$#" in
 262        1)
 263                var="`git config --get pull.twohead`"
 264                if test -n "$var"
 265                then
 266                        use_strategies="$var"
 267                else
 268                        use_strategies="$default_twohead_strategies"
 269                fi ;;
 270        *)
 271                var="`git config --get pull.octopus`"
 272                if test -n "$var"
 273                then
 274                        use_strategies="$var"
 275                else
 276                        use_strategies="$default_octopus_strategies"
 277                fi ;;
 278        esac
 279        ;;
 280esac
 281
 282for s in $use_strategies
 283do
 284        for ss in $no_fast_forward_strategies
 285        do
 286                case " $s " in
 287                *" $ss "*)
 288                        allow_fast_forward=f
 289                        break
 290                        ;;
 291                esac
 292        done
 293        for ss in $no_trivial_strategies
 294        do
 295                case " $s " in
 296                *" $ss "*)
 297                        allow_trivial_merge=f
 298                        break
 299                        ;;
 300                esac
 301        done
 302done
 303
 304case "$#" in
 3051)
 306        common=$(git merge-base --all $head "$@")
 307        ;;
 308*)
 309        common=$(git show-branch --merge-base $head "$@")
 310        ;;
 311esac
 312echo "$head" >"$GIT_DIR/ORIG_HEAD"
 313
 314case "$allow_fast_forward,$#,$common,$no_commit" in
 315?,*,'',*)
 316        # No common ancestors found. We need a real merge.
 317        ;;
 318?,1,"$1",*)
 319        # If head can reach all the merge then we are up to date.
 320        # but first the most common case of merging one remote.
 321        finish_up_to_date "Already up-to-date."
 322        exit 0
 323        ;;
 324t,1,"$head",*)
 325        # Again the most common case of merging one remote.
 326        echo "Updating $(git rev-parse --short $head)..$(git rev-parse --short $1)"
 327        git update-index --refresh 2>/dev/null
 328        msg="Fast forward"
 329        if test -n "$have_message"
 330        then
 331                msg="$msg (no commit created; -m option ignored)"
 332        fi
 333        new_head=$(git rev-parse --verify "$1^0") &&
 334        git read-tree -v -m -u --exclude-per-directory=.gitignore $head "$new_head" &&
 335        finish "$new_head" "$msg" || exit
 336        dropsave
 337        exit 0
 338        ;;
 339?,1,?*"$LF"?*,*)
 340        # We are not doing octopus and not fast forward.  Need a
 341        # real merge.
 342        ;;
 343?,1,*,)
 344        # We are not doing octopus, not fast forward, and have only
 345        # one common.
 346        git update-index --refresh 2>/dev/null
 347        case "$allow_trivial_merge" in
 348        t)
 349                # See if it is really trivial.
 350                git var GIT_COMMITTER_IDENT >/dev/null || exit
 351                echo "Trying really trivial in-index merge..."
 352                if git read-tree --trivial -m -u -v $common $head "$1" &&
 353                   result_tree=$(git write-tree)
 354                then
 355                        echo "Wonderful."
 356                        result_commit=$(
 357                                printf '%s\n' "$merge_msg" |
 358                                git commit-tree $result_tree -p HEAD -p "$1"
 359                        ) || exit
 360                        finish "$result_commit" "In-index merge"
 361                        dropsave
 362                        exit 0
 363                fi
 364                echo "Nope."
 365        esac
 366        ;;
 367*)
 368        # An octopus.  If we can reach all the remote we are up to date.
 369        up_to_date=t
 370        for remote
 371        do
 372                common_one=$(git merge-base --all $head $remote)
 373                if test "$common_one" != "$remote"
 374                then
 375                        up_to_date=f
 376                        break
 377                fi
 378        done
 379        if test "$up_to_date" = t
 380        then
 381                finish_up_to_date "Already up-to-date. Yeeah!"
 382                exit 0
 383        fi
 384        ;;
 385esac
 386
 387# We are going to make a new commit.
 388git var GIT_COMMITTER_IDENT >/dev/null || exit
 389
 390# At this point, we need a real merge.  No matter what strategy
 391# we use, it would operate on the index, possibly affecting the
 392# working tree, and when resolved cleanly, have the desired tree
 393# in the index -- this means that the index must be in sync with
 394# the $head commit.  The strategies are responsible to ensure this.
 395
 396case "$use_strategies" in
 397?*' '?*)
 398    # Stash away the local changes so that we can try more than one.
 399    savestate
 400    single_strategy=no
 401    ;;
 402*)
 403    rm -f "$GIT_DIR/MERGE_SAVE"
 404    single_strategy=yes
 405    ;;
 406esac
 407
 408result_tree= best_cnt=-1 best_strategy= wt_strategy=
 409merge_was_ok=
 410for strategy in $use_strategies
 411do
 412    test "$wt_strategy" = '' || {
 413        echo "Rewinding the tree to pristine..."
 414        restorestate
 415    }
 416    case "$single_strategy" in
 417    no)
 418        echo "Trying merge strategy $strategy..."
 419        ;;
 420    esac
 421
 422    # Remember which strategy left the state in the working tree
 423    wt_strategy=$strategy
 424
 425    git-merge-$strategy $common -- "$head_arg" "$@"
 426    exit=$?
 427    if test "$no_commit" = t && test "$exit" = 0
 428    then
 429        merge_was_ok=t
 430        exit=1 ;# pretend it left conflicts.
 431    fi
 432
 433    test "$exit" = 0 || {
 434
 435        # The backend exits with 1 when conflicts are left to be resolved,
 436        # with 2 when it does not handle the given merge at all.
 437
 438        if test "$exit" -eq 1
 439        then
 440            cnt=`{
 441                git diff-files --name-only
 442                git ls-files --unmerged
 443            } | wc -l`
 444            if test $best_cnt -le 0 -o $cnt -le $best_cnt
 445            then
 446                best_strategy=$strategy
 447                best_cnt=$cnt
 448            fi
 449        fi
 450        continue
 451    }
 452
 453    # Automerge succeeded.
 454    result_tree=$(git write-tree) && break
 455done
 456
 457# If we have a resulting tree, that means the strategy module
 458# auto resolved the merge cleanly.
 459if test '' != "$result_tree"
 460then
 461    parents=$(git show-branch --independent "$head" "$@" | sed -e 's/^/-p /')
 462    result_commit=$(printf '%s\n' "$merge_msg" | git commit-tree $result_tree $parents) || exit
 463    finish "$result_commit" "Merge made by $wt_strategy."
 464    dropsave
 465    exit 0
 466fi
 467
 468# Pick the result from the best strategy and have the user fix it up.
 469case "$best_strategy" in
 470'')
 471        restorestate
 472        case "$use_strategies" in
 473        ?*' '?*)
 474                echo >&2 "No merge strategy handled the merge."
 475                ;;
 476        *)
 477                echo >&2 "Merge with strategy $use_strategies failed."
 478                ;;
 479        esac
 480        exit 2
 481        ;;
 482"$wt_strategy")
 483        # We already have its result in the working tree.
 484        ;;
 485*)
 486        echo "Rewinding the tree to pristine..."
 487        restorestate
 488        echo "Using the $best_strategy to prepare resolving by hand."
 489        git-merge-$best_strategy $common -- "$head_arg" "$@"
 490        ;;
 491esac
 492
 493if test "$squash" = t
 494then
 495        finish
 496else
 497        for remote
 498        do
 499                echo $remote
 500        done >"$GIT_DIR/MERGE_HEAD"
 501        printf '%s\n' "$merge_msg" >"$GIT_DIR/MERGE_MSG"
 502fi
 503
 504if test "$merge_was_ok" = t
 505then
 506        echo >&2 \
 507        "Automatic merge went well; stopped before committing as requested"
 508        exit 0
 509else
 510        {
 511            echo '
 512Conflicts:
 513'
 514                git ls-files --unmerged |
 515                sed -e 's/^[^   ]*      /       /' |
 516                uniq
 517        } >>"$GIT_DIR/MERGE_MSG"
 518        git rerere
 519        die "Automatic merge failed; fix conflicts and then commit the result."
 520fi