Andrew's git / gitweb.git / git-merge.sh
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git-merge.shon commit Merge branch 'maint' (12d6697)
   1#!/bin/sh
   2#
   3# Copyright (c) 2005 Junio C Hamano
   4#
   5
   6USAGE='[-n] [--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 "$(git ls-files -u)" ||
  14        die "You are in the middle of a conflicted merge."
  15
  16LF='
  17'
  18
  19all_strategies='recur recursive octopus resolve stupid ours'
  20default_twohead_strategies='recursive'
  21default_octopus_strategies='octopus'
  22no_trivial_merge_strategies='ours'
  23use_strategies=
  24
  25index_merge=t
  26
  27dropsave() {
  28        rm -f -- "$GIT_DIR/MERGE_HEAD" "$GIT_DIR/MERGE_MSG" \
  29                 "$GIT_DIR/MERGE_SAVE" || exit 1
  30}
  31
  32savestate() {
  33        # Stash away any local modifications.
  34        git-diff-index -z --name-only $head |
  35        cpio -0 -o >"$GIT_DIR/MERGE_SAVE"
  36}
  37
  38restorestate() {
  39        if test -f "$GIT_DIR/MERGE_SAVE"
  40        then
  41                git reset --hard $head >/dev/null
  42                cpio -iuv <"$GIT_DIR/MERGE_SAVE"
  43                git-update-index --refresh >/dev/null
  44        fi
  45}
  46
  47finish_up_to_date () {
  48        case "$squash" in
  49        t)
  50                echo "$1 (nothing to squash)" ;;
  51        '')
  52                echo "$1" ;;
  53        esac
  54        dropsave
  55}
  56
  57squash_message () {
  58        echo Squashed commit of the following:
  59        echo
  60        git-log --no-merges ^"$head" $remote
  61}
  62
  63finish () {
  64        if test '' = "$2"
  65        then
  66                rlogm="$GIT_REFLOG_ACTION"
  67        else
  68                echo "$2"
  69                rlogm="$GIT_REFLOG_ACTION: $2"
  70        fi
  71        case "$squash" in
  72        t)
  73                echo "Squash commit -- not updating HEAD"
  74                squash_message >"$GIT_DIR/SQUASH_MSG"
  75                ;;
  76        '')
  77                case "$merge_msg" in
  78                '')
  79                        echo "No merge message -- not updating HEAD"
  80                        ;;
  81                *)
  82                        git-update-ref -m "$rlogm" HEAD "$1" "$head" || exit 1
  83                        ;;
  84                esac
  85                ;;
  86        esac
  87        case "$1" in
  88        '')
  89                ;;
  90        ?*)
  91                case "$no_summary" in
  92                '')
  93                        git-diff-tree --stat --summary -M "$head" "$1"
  94                        ;;
  95                esac
  96                ;;
  97        esac
  98}
  99
 100merge_name () {
 101        remote="$1"
 102        rh=$(git-rev-parse --verify "$remote^0" 2>/dev/null) || return
 103        bh=$(git-show-ref -s --verify "refs/heads/$remote" 2>/dev/null)
 104        if test "$rh" = "$bh"
 105        then
 106                echo "$rh               branch '$remote' of ."
 107        elif truname=$(expr "$remote" : '\(.*\)~[1-9][0-9]*$') &&
 108                git-show-ref -q --verify "refs/heads/$truname" 2>/dev/null
 109        then
 110                echo "$rh               branch '$truname' (early part) of ."
 111        elif test "$remote" = "FETCH_HEAD" -a -r "$GIT_DIR/FETCH_HEAD"
 112        then
 113                sed -e 's/      not-for-merge   /               /' -e 1q \
 114                        "$GIT_DIR/FETCH_HEAD"
 115        else
 116                echo "$rh               commit '$remote'"
 117        fi
 118}
 119
 120case "$#" in 0) usage ;; esac
 121
 122have_message=
 123while case "$#" in 0) break ;; esac
 124do
 125        case "$1" in
 126        -n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
 127                --no-summa|--no-summar|--no-summary)
 128                no_summary=t ;;
 129        --sq|--squ|--squa|--squas|--squash)
 130                squash=t no_commit=t ;;
 131        --no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
 132                no_commit=t ;;
 133        -s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
 134                --strateg=*|--strategy=*|\
 135        -s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
 136                case "$#,$1" in
 137                *,*=*)
 138                        strategy=`expr "z$1" : 'z-[^=]*=\(.*\)'` ;;
 139                1,*)
 140                        usage ;;
 141                *)
 142                        strategy="$2"
 143                        shift ;;
 144                esac
 145                case " $all_strategies " in
 146                *" $strategy "*)
 147                        use_strategies="$use_strategies$strategy " ;;
 148                *)
 149                        die "available strategies are: $all_strategies" ;;
 150                esac
 151                ;;
 152        -m=*|--m=*|--me=*|--mes=*|--mess=*|--messa=*|--messag=*|--message=*)
 153                merge_msg=`expr "z$1" : 'z-[^=]*=\(.*\)'`
 154                have_message=t
 155                ;;
 156        -m|--m|--me|--mes|--mess|--messa|--messag|--message)
 157                shift
 158                case "$#" in
 159                1)      usage ;;
 160                esac
 161                merge_msg="$1"
 162                have_message=t
 163                ;;
 164        -*)     usage ;;
 165        *)      break ;;
 166        esac
 167        shift
 168done
 169
 170# This could be traditional "merge <msg> HEAD <commit>..."  and the
 171# way we can tell it is to see if the second token is HEAD, but some
 172# people might have misused the interface and used a committish that
 173# is the same as HEAD there instead.  Traditional format never would
 174# have "-m" so it is an additional safety measure to check for it.
 175
 176if test -z "$have_message" &&
 177        second_token=$(git-rev-parse --verify "$2^0" 2>/dev/null) &&
 178        head_commit=$(git-rev-parse --verify "HEAD" 2>/dev/null) &&
 179        test "$second_token" = "$head_commit"
 180then
 181        merge_msg="$1"
 182        shift
 183        head_arg="$1"
 184        shift
 185elif ! git-rev-parse --verify HEAD >/dev/null 2>&1
 186then
 187        # If the merged head is a valid one there is no reason to
 188        # forbid "git merge" into a branch yet to be born.  We do
 189        # the same for "git pull".
 190        if test 1 -ne $#
 191        then
 192                echo >&2 "Can merge only exactly one commit into empty head"
 193                exit 1
 194        fi
 195
 196        rh=$(git rev-parse --verify "$1^0") ||
 197                die "$1 - not something we can merge"
 198
 199        git-update-ref -m "initial pull" HEAD "$rh" "" &&
 200        git-read-tree --reset -u HEAD
 201        exit
 202
 203else
 204        # We are invoked directly as the first-class UI.
 205        head_arg=HEAD
 206
 207        # All the rest are the commits being merged; prepare
 208        # the standard merge summary message to be appended to
 209        # the given message.  If remote is invalid we will die
 210        # later in the common codepath so we discard the error
 211        # in this loop.
 212        merge_name=$(for remote
 213                do
 214                        merge_name "$remote"
 215                done | git-fmt-merge-msg
 216        )
 217        merge_msg="${merge_msg:+$merge_msg$LF$LF}$merge_name"
 218fi
 219head=$(git-rev-parse --verify "$head_arg"^0) || usage
 220
 221# All the rest are remote heads
 222test "$#" = 0 && usage ;# we need at least one remote head.
 223set_reflog_action "merge $*"
 224
 225remoteheads=
 226for remote
 227do
 228        remotehead=$(git-rev-parse --verify "$remote"^0 2>/dev/null) ||
 229            die "$remote - not something we can merge"
 230        remoteheads="${remoteheads}$remotehead "
 231        eval GITHEAD_$remotehead='"$remote"'
 232        export GITHEAD_$remotehead
 233done
 234set x $remoteheads ; shift
 235
 236case "$use_strategies" in
 237'')
 238        case "$#" in
 239        1)
 240                var="`git-config --get pull.twohead`"
 241                if test -n "$var"
 242                then
 243                        use_strategies="$var"
 244                else
 245                        use_strategies="$default_twohead_strategies"
 246                fi ;;
 247        *)
 248                var="`git-config --get pull.octopus`"
 249                if test -n "$var"
 250                then
 251                        use_strategies="$var"
 252                else
 253                        use_strategies="$default_octopus_strategies"
 254                fi ;;
 255        esac
 256        ;;
 257esac
 258
 259for s in $use_strategies
 260do
 261        for nt in $no_trivial_merge_strategies
 262        do
 263                case " $s " in
 264                *" $nt "*)
 265                        index_merge=f
 266                        break
 267                        ;;
 268                esac
 269        done
 270done
 271
 272case "$#" in
 2731)
 274        common=$(git-merge-base --all $head "$@")
 275        ;;
 276*)
 277        common=$(git-show-branch --merge-base $head "$@")
 278        ;;
 279esac
 280echo "$head" >"$GIT_DIR/ORIG_HEAD"
 281
 282case "$index_merge,$#,$common,$no_commit" in
 283f,*)
 284        # We've been told not to try anything clever.  Skip to real merge.
 285        ;;
 286?,*,'',*)
 287        # No common ancestors found. We need a real merge.
 288        ;;
 289?,1,"$1",*)
 290        # If head can reach all the merge then we are up to date.
 291        # but first the most common case of merging one remote.
 292        finish_up_to_date "Already up-to-date."
 293        exit 0
 294        ;;
 295?,1,"$head",*)
 296        # Again the most common case of merging one remote.
 297        echo "Updating $(git-rev-parse --short $head)..$(git-rev-parse --short $1)"
 298        git-update-index --refresh 2>/dev/null
 299        msg="Fast forward"
 300        if test -n "$have_message"
 301        then
 302                msg="$msg (no commit created; -m option ignored)"
 303        fi
 304        new_head=$(git-rev-parse --verify "$1^0") &&
 305        git-read-tree -v -m -u --exclude-per-directory=.gitignore $head "$new_head" &&
 306        finish "$new_head" "$msg" || exit
 307        dropsave
 308        exit 0
 309        ;;
 310?,1,?*"$LF"?*,*)
 311        # We are not doing octopus and not fast forward.  Need a
 312        # real merge.
 313        ;;
 314?,1,*,)
 315        # We are not doing octopus, not fast forward, and have only
 316        # one common.
 317        git-update-index --refresh 2>/dev/null
 318        case " $use_strategies " in
 319        *' recursive '*|*' recur '*)
 320                : run merge later
 321                ;;
 322        *)
 323                # See if it is really trivial.
 324                git var GIT_COMMITTER_IDENT >/dev/null || exit
 325                echo "Trying really trivial in-index merge..."
 326                if git-read-tree --trivial -m -u -v $common $head "$1" &&
 327                   result_tree=$(git-write-tree)
 328                then
 329                        echo "Wonderful."
 330                        result_commit=$(
 331                                echo "$merge_msg" |
 332                                git-commit-tree $result_tree -p HEAD -p "$1"
 333                        ) || exit
 334                        finish "$result_commit" "In-index merge"
 335                        dropsave
 336                        exit 0
 337                fi
 338                echo "Nope."
 339        esac
 340        ;;
 341*)
 342        # An octopus.  If we can reach all the remote we are up to date.
 343        up_to_date=t
 344        for remote
 345        do
 346                common_one=$(git-merge-base --all $head $remote)
 347                if test "$common_one" != "$remote"
 348                then
 349                        up_to_date=f
 350                        break
 351                fi
 352        done
 353        if test "$up_to_date" = t
 354        then
 355                finish_up_to_date "Already up-to-date. Yeeah!"
 356                exit 0
 357        fi
 358        ;;
 359esac
 360
 361# We are going to make a new commit.
 362git var GIT_COMMITTER_IDENT >/dev/null || exit
 363
 364# At this point, we need a real merge.  No matter what strategy
 365# we use, it would operate on the index, possibly affecting the
 366# working tree, and when resolved cleanly, have the desired tree
 367# in the index -- this means that the index must be in sync with
 368# the $head commit.  The strategies are responsible to ensure this.
 369
 370case "$use_strategies" in
 371?*' '?*)
 372    # Stash away the local changes so that we can try more than one.
 373    savestate
 374    single_strategy=no
 375    ;;
 376*)
 377    rm -f "$GIT_DIR/MERGE_SAVE"
 378    single_strategy=yes
 379    ;;
 380esac
 381
 382result_tree= best_cnt=-1 best_strategy= wt_strategy=
 383merge_was_ok=
 384for strategy in $use_strategies
 385do
 386    test "$wt_strategy" = '' || {
 387        echo "Rewinding the tree to pristine..."
 388        restorestate
 389    }
 390    case "$single_strategy" in
 391    no)
 392        echo "Trying merge strategy $strategy..."
 393        ;;
 394    esac
 395
 396    # Remember which strategy left the state in the working tree
 397    wt_strategy=$strategy
 398
 399    git-merge-$strategy $common -- "$head_arg" "$@"
 400    exit=$?
 401    if test "$no_commit" = t && test "$exit" = 0
 402    then
 403        merge_was_ok=t
 404        exit=1 ;# pretend it left conflicts.
 405    fi
 406
 407    test "$exit" = 0 || {
 408
 409        # The backend exits with 1 when conflicts are left to be resolved,
 410        # with 2 when it does not handle the given merge at all.
 411
 412        if test "$exit" -eq 1
 413        then
 414            cnt=`{
 415                git-diff-files --name-only
 416                git-ls-files --unmerged
 417            } | wc -l`
 418            if test $best_cnt -le 0 -o $cnt -le $best_cnt
 419            then
 420                best_strategy=$strategy
 421                best_cnt=$cnt
 422            fi
 423        fi
 424        continue
 425    }
 426
 427    # Automerge succeeded.
 428    result_tree=$(git-write-tree) && break
 429done
 430
 431# If we have a resulting tree, that means the strategy module
 432# auto resolved the merge cleanly.
 433if test '' != "$result_tree"
 434then
 435    parents=$(git-show-branch --independent "$head" "$@" | sed -e 's/^/-p /')
 436    result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents) || exit
 437    finish "$result_commit" "Merge made by $wt_strategy."
 438    dropsave
 439    exit 0
 440fi
 441
 442# Pick the result from the best strategy and have the user fix it up.
 443case "$best_strategy" in
 444'')
 445        restorestate
 446        case "$use_strategies" in
 447        ?*' '?*)
 448                echo >&2 "No merge strategy handled the merge."
 449                ;;
 450        *)
 451                echo >&2 "Merge with strategy $use_strategies failed."
 452                ;;
 453        esac
 454        exit 2
 455        ;;
 456"$wt_strategy")
 457        # We already have its result in the working tree.
 458        ;;
 459*)
 460        echo "Rewinding the tree to pristine..."
 461        restorestate
 462        echo "Using the $best_strategy to prepare resolving by hand."
 463        git-merge-$best_strategy $common -- "$head_arg" "$@"
 464        ;;
 465esac
 466
 467if test "$squash" = t
 468then
 469        finish
 470else
 471        for remote
 472        do
 473                echo $remote
 474        done >"$GIT_DIR/MERGE_HEAD"
 475        echo "$merge_msg" >"$GIT_DIR/MERGE_MSG"
 476fi
 477
 478if test "$merge_was_ok" = t
 479then
 480        echo >&2 \
 481        "Automatic merge went well; stopped before committing as requested"
 482        exit 0
 483else
 484        {
 485            echo '
 486Conflicts:
 487'
 488                git ls-files --unmerged |
 489                sed -e 's/^[^   ]*      /       /' |
 490                uniq
 491        } >>"$GIT_DIR/MERGE_MSG"
 492        if test -d "$GIT_DIR/rr-cache"
 493        then
 494                git-rerere
 495        fi
 496        die "Automatic merge failed; fix conflicts and then commit the result."
 497fi