Andrew's git - gitweb.git/blob

   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
   8. git-sh-setup
   9set_reflog_action "merge $*"
  10require_work_tree
  11
  12test -z "$(git ls-files -u)" ||
  13        die "You are in a middle of conflicted merge."
  14
  15LF='
  16'
  17
  18all_strategies='recur recursive octopus resolve stupid ours'
  19default_twohead_strategies='recursive'
  20default_octopus_strategies='octopus'
  21no_trivial_merge_strategies='ours'
  22use_strategies=
  23
  24index_merge=t
  25
  26dropsave() {
  27        rm -f -- "$GIT_DIR/MERGE_HEAD" "$GIT_DIR/MERGE_MSG" \
  28                 "$GIT_DIR/MERGE_SAVE" || exit 1
  29}
  30
  31savestate() {
  32        # Stash away any local modifications.
  33        git-diff-index -z --name-only $head |
  34        cpio -0 -o >"$GIT_DIR/MERGE_SAVE"
  35}
  36
  37restorestate() {
  38        if test -f "$GIT_DIR/MERGE_SAVE"
  39        then
  40                git reset --hard $head >/dev/null
  41                cpio -iuv <"$GIT_DIR/MERGE_SAVE"
  42                git-update-index --refresh >/dev/null
  43        fi
  44}
  45
  46finish_up_to_date () {
  47        case "$squash" in
  48        t)
  49                echo "$1 (nothing to squash)" ;;
  50        '')
  51                echo "$1" ;;
  52        esac
  53        dropsave
  54}
  55
  56squash_message () {
  57        echo Squashed commit of the following:
  58        echo
  59        git-log --no-merges ^"$head" $remote
  60}
  61
  62finish () {
  63        if test '' = "$2"
  64        then
  65                rlogm="$GIT_REFLOG_ACTION"
  66        else
  67                echo "$2"
  68                rlogm="$GIT_REFLOG_ACTION: $2"
  69        fi
  70        case "$squash" in
  71        t)
  72                echo "Squash commit -- not updating HEAD"
  73                squash_message >"$GIT_DIR/SQUASH_MSG"
  74                ;;
  75        '')
  76                case "$merge_msg" in
  77                '')
  78                        echo "No merge message -- not updating HEAD"
  79                        ;;
  80                *)
  81                        git-update-ref -m "$rlogm" HEAD "$1" "$head" || exit 1
  82                        ;;
  83                esac
  84                ;;
  85        esac
  86        case "$1" in
  87        '')
  88                ;;
  89        ?*)
  90                case "$no_summary" in
  91                '')
  92                        git-diff-tree --stat --summary -M "$head" "$1"
  93                        ;;
  94                esac
  95                ;;
  96        esac
  97}
  98
  99merge_name () {
 100        remote="$1"
 101        rh=$(git-rev-parse --verify "$remote^0" 2>/dev/null) || return
 102        bh=$(git-show-ref -s --verify "refs/heads/$remote" 2>/dev/null)
 103        if test "$rh" = "$bh"
 104        then
 105                echo "$rh               branch '$remote' of ."
 106        elif truname=$(expr "$remote" : '\(.*\)~[1-9][0-9]*$') &&
 107                git-show-ref -q --verify "refs/heads/$truname" 2>/dev/null
 108        then
 109                echo "$rh               branch '$truname' (early part) of ."
 110        else
 111                echo "$rh               commit '$remote'"
 112        fi
 113}
 114
 115case "$#" in 0) usage ;; esac
 116
 117have_message=
 118while case "$#" in 0) break ;; esac
 119do
 120        case "$1" in
 121        -n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
 122                --no-summa|--no-summar|--no-summary)
 123                no_summary=t ;;
 124        --sq|--squ|--squa|--squas|--squash)
 125                squash=t no_commit=t ;;
 126        --no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
 127                no_commit=t ;;
 128        -s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
 129                --strateg=*|--strategy=*|\
 130        -s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
 131                case "$#,$1" in
 132                *,*=*)
 133                        strategy=`expr "z$1" : 'z-[^=]*=\(.*\)'` ;;
 134                1,*)
 135                        usage ;;
 136                *)
 137                        strategy="$2"
 138                        shift ;;
 139                esac
 140                case " $all_strategies " in
 141                *" $strategy "*)
 142                        use_strategies="$use_strategies$strategy " ;;
 143                *)
 144                        die "available strategies are: $all_strategies" ;;
 145                esac
 146                ;;
 147        -m=*|--m=*|--me=*|--mes=*|--mess=*|--messa=*|--messag=*|--message=*)
 148                merge_msg=`expr "z$1" : 'z-[^=]*=\(.*\)'`
 149                have_message=t
 150                ;;
 151        -m|--m|--me|--mes|--mess|--messa|--messag|--message)
 152                shift
 153                case "$#" in
 154                1)      usage ;;
 155                esac
 156                merge_msg="$1"
 157                have_message=t
 158                ;;
 159        -*)     usage ;;
 160        *)      break ;;
 161        esac
 162        shift
 163done
 164
 165# This could be traditional "merge <msg> HEAD <commit>..."  and the
 166# way we can tell it is to see if the second token is HEAD, but some
 167# people might have misused the interface and used a committish that
 168# is the same as HEAD there instead.  Traditional format never would
 169# have "-m" so it is an additional safety measure to check for it.
 170
 171if test -z "$have_message" &&
 172        second_token=$(git-rev-parse --verify "$2^0" 2>/dev/null) &&
 173        head_commit=$(git-rev-parse --verify "HEAD" 2>/dev/null) &&
 174        test "$second_token" = "$head_commit"
 175then
 176        merge_msg="$1"
 177        shift
 178        head_arg="$1"
 179        shift
 180elif ! git-rev-parse --verify HEAD >/dev/null 2>&1
 181then
 182        # If the merged head is a valid one there is no reason to
 183        # forbid "git merge" into a branch yet to be born.  We do
 184        # the same for "git pull".
 185        if test 1 -ne $#
 186        then
 187                echo >&2 "Can merge only exactly one commit into empty head"
 188                exit 1
 189        fi
 190
 191        rh=$(git rev-parse --verify "$1^0") ||
 192                die "$1 - not something we can merge"
 193
 194        git-update-ref -m "initial pull" HEAD "$rh" "" &&
 195        git-read-tree --reset -u HEAD
 196        exit
 197
 198else
 199        # We are invoked directly as the first-class UI.
 200        head_arg=HEAD
 201
 202        # All the rest are the commits being merged; prepare
 203        # the standard merge summary message to be appended to
 204        # the given message.  If remote is invalid we will die
 205        # later in the common codepath so we discard the error
 206        # in this loop.
 207        merge_name=$(for remote
 208                do
 209                        merge_name "$remote"
 210                done | git-fmt-merge-msg
 211        )
 212        merge_msg="${merge_msg:+$merge_msg$LF$LF}$merge_name"
 213fi
 214head=$(git-rev-parse --verify "$head_arg"^0) || usage
 215
 216# All the rest are remote heads
 217test "$#" = 0 && usage ;# we need at least one remote head.
 218
 219remoteheads=
 220for remote
 221do
 222        remotehead=$(git-rev-parse --verify "$remote"^0 2>/dev/null) ||
 223            die "$remote - not something we can merge"
 224        remoteheads="${remoteheads}$remotehead "
 225        eval GITHEAD_$remotehead='"$remote"'
 226        export GITHEAD_$remotehead
 227done
 228set x $remoteheads ; shift
 229
 230case "$use_strategies" in
 231'')
 232        case "$#" in
 233        1)
 234                var="`git-repo-config --get pull.twohead`"
 235                if test -n "$var"
 236                then
 237                        use_strategies="$var"
 238                else
 239                        use_strategies="$default_twohead_strategies"
 240                fi ;;
 241        *)
 242                var="`git-repo-config --get pull.octopus`"
 243                if test -n "$var"
 244                then
 245                        use_strategies="$var"
 246                else
 247                        use_strategies="$default_octopus_strategies"
 248                fi ;;
 249        esac
 250        ;;
 251esac
 252
 253for s in $use_strategies
 254do
 255        case " $s " in
 256        *" $no_trivial_merge_strategies "*)
 257                index_merge=f
 258                break
 259                ;;
 260        esac
 261done
 262
 263case "$#" in
 2641)
 265        common=$(git-merge-base --all $head "$@")
 266        ;;
 267*)
 268        common=$(git-show-branch --merge-base $head "$@")
 269        ;;
 270esac
 271echo "$head" >"$GIT_DIR/ORIG_HEAD"
 272
 273case "$index_merge,$#,$common,$no_commit" in
 274f,*)
 275        # We've been told not to try anything clever.  Skip to real merge.
 276        ;;
 277?,*,'',*)
 278        # No common ancestors found. We need a real merge.
 279        ;;
 280?,1,"$1",*)
 281        # If head can reach all the merge then we are up to date.
 282        # but first the most common case of merging one remote.
 283        finish_up_to_date "Already up-to-date."
 284        exit 0
 285        ;;
 286?,1,"$head",*)
 287        # Again the most common case of merging one remote.
 288        echo "Updating $(git-rev-parse --short $head)..$(git-rev-parse --short $1)"
 289        git-update-index --refresh 2>/dev/null
 290        new_head=$(git-rev-parse --verify "$1^0") &&
 291        git-read-tree -v -m -u --exclude-per-directory=.gitignore $head "$new_head" &&
 292        finish "$new_head" "Fast forward"
 293        dropsave
 294        exit 0
 295        ;;
 296?,1,?*"$LF"?*,*)
 297        # We are not doing octopus and not fast forward.  Need a
 298        # real merge.
 299        ;;
 300?,1,*,)
 301        # We are not doing octopus, not fast forward, and have only
 302        # one common.  See if it is really trivial.
 303        git var GIT_COMMITTER_IDENT >/dev/null || exit
 304
 305        echo "Trying really trivial in-index merge..."
 306        git-update-index --refresh 2>/dev/null
 307        if git-read-tree --trivial -m -u -v $common $head "$1" &&
 308           result_tree=$(git-write-tree)
 309        then
 310            echo "Wonderful."
 311            result_commit=$(
 312                echo "$merge_msg" |
 313                git-commit-tree $result_tree -p HEAD -p "$1"
 314            ) || exit
 315            finish "$result_commit" "In-index merge"
 316            dropsave
 317            exit 0
 318        fi
 319        echo "Nope."
 320        ;;
 321*)
 322        # An octopus.  If we can reach all the remote we are up to date.
 323        up_to_date=t
 324        for remote
 325        do
 326                common_one=$(git-merge-base --all $head $remote)
 327                if test "$common_one" != "$remote"
 328                then
 329                        up_to_date=f
 330                        break
 331                fi
 332        done
 333        if test "$up_to_date" = t
 334        then
 335                finish_up_to_date "Already up-to-date. Yeeah!"
 336                exit 0
 337        fi
 338        ;;
 339esac
 340
 341# We are going to make a new commit.
 342git var GIT_COMMITTER_IDENT >/dev/null || exit
 343
 344# At this point, we need a real merge.  No matter what strategy
 345# we use, it would operate on the index, possibly affecting the
 346# working tree, and when resolved cleanly, have the desired tree
 347# in the index -- this means that the index must be in sync with
 348# the $head commit.  The strategies are responsible to ensure this.
 349
 350case "$use_strategies" in
 351?*' '?*)
 352    # Stash away the local changes so that we can try more than one.
 353    savestate
 354    single_strategy=no
 355    ;;
 356*)
 357    rm -f "$GIT_DIR/MERGE_SAVE"
 358    single_strategy=yes
 359    ;;
 360esac
 361
 362result_tree= best_cnt=-1 best_strategy= wt_strategy=
 363merge_was_ok=
 364for strategy in $use_strategies
 365do
 366    test "$wt_strategy" = '' || {
 367        echo "Rewinding the tree to pristine..."
 368        restorestate
 369    }
 370    case "$single_strategy" in
 371    no)
 372        echo "Trying merge strategy $strategy..."
 373        ;;
 374    esac
 375
 376    # Remember which strategy left the state in the working tree
 377    wt_strategy=$strategy
 378
 379    git-merge-$strategy $common -- "$head_arg" "$@"
 380    exit=$?
 381    if test "$no_commit" = t && test "$exit" = 0
 382    then
 383        merge_was_ok=t
 384        exit=1 ;# pretend it left conflicts.
 385    fi
 386
 387    test "$exit" = 0 || {
 388
 389        # The backend exits with 1 when conflicts are left to be resolved,
 390        # with 2 when it does not handle the given merge at all.
 391
 392        if test "$exit" -eq 1
 393        then
 394            cnt=`{
 395                git-diff-files --name-only
 396                git-ls-files --unmerged
 397            } | wc -l`
 398            if test $best_cnt -le 0 -o $cnt -le $best_cnt
 399            then
 400                best_strategy=$strategy
 401                best_cnt=$cnt
 402            fi
 403        fi
 404        continue
 405    }
 406
 407    # Automerge succeeded.
 408    result_tree=$(git-write-tree) && break
 409done
 410
 411# If we have a resulting tree, that means the strategy module
 412# auto resolved the merge cleanly.
 413if test '' != "$result_tree"
 414then
 415    parents=$(git-show-branch --independent "$head" "$@" | sed -e 's/^/-p /')
 416    result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents) || exit
 417    finish "$result_commit" "Merge made by $wt_strategy."
 418    dropsave
 419    exit 0
 420fi
 421
 422# Pick the result from the best strategy and have the user fix it up.
 423case "$best_strategy" in
 424'')
 425        restorestate
 426        case "$use_strategies" in
 427        ?*' '?*)
 428                echo >&2 "No merge strategy handled the merge."
 429                ;;
 430        *)
 431                echo >&2 "Merge with strategy $use_strategies failed."
 432                ;;
 433        esac
 434        exit 2
 435        ;;
 436"$wt_strategy")
 437        # We already have its result in the working tree.
 438        ;;
 439*)
 440        echo "Rewinding the tree to pristine..."
 441        restorestate
 442        echo "Using the $best_strategy to prepare resolving by hand."
 443        git-merge-$best_strategy $common -- "$head_arg" "$@"
 444        ;;
 445esac
 446
 447if test "$squash" = t
 448then
 449        finish
 450else
 451        for remote
 452        do
 453                echo $remote
 454        done >"$GIT_DIR/MERGE_HEAD"
 455        echo "$merge_msg" >"$GIT_DIR/MERGE_MSG"
 456fi
 457
 458if test "$merge_was_ok" = t
 459then
 460        echo >&2 \
 461        "Automatic merge went well; stopped before committing as requested"
 462        exit 0
 463else
 464        {
 465            echo '
 466Conflicts:
 467'
 468                git ls-files --unmerged |
 469                sed -e 's/^[^   ]*      /       /' |
 470                uniq
 471        } >>"$GIT_DIR/MERGE_MSG"
 472        if test -d "$GIT_DIR/rr-cache"
 473        then
 474                git-rerere
 475        fi
 476        die "Automatic merge failed; fix conflicts and then commit the result."
 477fi