Andrew's git / gitweb.git / git-merge.sh
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git-merge.shon commit Merge http://www.kernel.org/pub/scm/gitk/gitk (302ebfe)
   1#!/bin/sh
   2#
   3# Copyright (c) 2005 Junio C Hamano
   4#
   5
   6. git-sh-setup || die "Not a git archive"
   7
   8LF='
   9'
  10
  11usage () {
  12    die "git-merge [-n] [--no-commit] [-s <strategy>]... <merge-message> <head> <remote>+"
  13}
  14
  15# all_strategies='resolve recursive stupid octopus'
  16
  17all_strategies='recursive octopus resolve stupid ours'
  18default_strategies='resolve octopus'
  19use_strategies=
  20
  21dropsave() {
  22        rm -f -- "$GIT_DIR/MERGE_HEAD" "$GIT_DIR/MERGE_MSG" \
  23                 "$GIT_DIR/MERGE_SAVE" || exit 1
  24}
  25
  26savestate() {
  27        # Stash away any local modifications.
  28        git-diff-index -z --name-only $head |
  29        cpio -0 -o >"$GIT_DIR/MERGE_SAVE"
  30}
  31
  32restorestate() {
  33        if test -f "$GIT_DIR/MERGE_SAVE"
  34        then
  35                git reset --hard $head
  36                cpio -iuv <"$GIT_DIR/MERGE_SAVE"
  37                git-update-index --refresh >/dev/null
  38        fi
  39}
  40
  41finish () {
  42        test '' = "$2" || echo "$2"
  43        case "$merge_msg" in
  44        '')
  45                echo "No merge message -- not updating HEAD"
  46                ;;
  47        *)
  48                git-update-ref HEAD "$1" "$head" || exit 1
  49                ;;
  50        esac
  51
  52        case "$no_summary" in
  53        '')
  54                git-diff-tree -p -M "$head" "$1" |
  55                git-apply --stat --summary
  56                ;;
  57        esac
  58}
  59
  60while case "$#" in 0) break ;; esac
  61do
  62        case "$1" in
  63        -n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
  64                --no-summa|--no-summar|--no-summary)
  65                no_summary=t ;;
  66        --no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
  67                no_commit=t ;;
  68        -s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
  69                --strateg=*|--strategy=*|\
  70        -s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
  71                case "$#,$1" in
  72                *,*=*)
  73                        strategy=`expr "$1" : '-[^=]*=\(.*\)'` ;;
  74                1,*)
  75                        usage ;;
  76                *)
  77                        strategy="$2"
  78                        shift ;;
  79                esac
  80                case " $all_strategies " in
  81                *" $strategy "*)
  82                        use_strategies="$use_strategies$strategy " ;;
  83                *)
  84                        die "available strategies are: $all_strategies" ;;
  85                esac
  86                ;;
  87        -*)     usage ;;
  88        *)      break ;;
  89        esac
  90        shift
  91done
  92
  93case "$use_strategies" in
  94'')
  95        use_strategies=$default_strategies
  96        ;;
  97esac
  98test "$#" -le 2 && usage ;# we need at least two heads.
  99
 100merge_msg="$1"
 101shift
 102head_arg="$1"
 103head=$(git-rev-parse --verify "$1"^0) || usage
 104shift
 105
 106# All the rest are remote heads
 107for remote
 108do
 109        git-rev-parse --verify "$remote"^0 >/dev/null ||
 110            die "$remote - not something we can merge"
 111done
 112
 113case "$#" in
 1141)
 115        common=$(git-merge-base --all $head "$@")
 116        ;;
 117*)
 118        common=$(git-show-branch --merge-base $head "$@")
 119        ;;
 120esac
 121echo "$head" >"$GIT_DIR/ORIG_HEAD"
 122
 123case "$#,$common,$no_commit" in
 124*,'',*)
 125        # No common ancestors found. We need a real merge.
 126        ;;
 1271,"$1",*)
 128        # If head can reach all the merge then we are up to date.
 129        # but first the most common case of merging one remote
 130        echo "Already up-to-date."
 131        dropsave
 132        exit 0
 133        ;;
 1341,"$head",*)
 135        # Again the most common case of merging one remote.
 136        echo "Updating from $head to $1."
 137        git-update-index --refresh 2>/dev/null
 138        new_head=$(git-rev-parse --verify "$1^0") &&
 139        git-read-tree -u -m $head "$new_head" &&
 140        finish "$new_head" "Fast forward"
 141        dropsave
 142        exit 0
 143        ;;
 1441,?*"$LF"?*,*)
 145        # We are not doing octopus and not fast forward.  Need a
 146        # real merge.
 147        ;;
 1481,*,)
 149        # We are not doing octopus, not fast forward, and have only
 150        # one common.  See if it is really trivial.
 151        echo "Trying really trivial in-index merge..."
 152        git-update-index --refresh 2>/dev/null
 153        if git-read-tree --trivial -m -u $common $head "$1" &&
 154           result_tree=$(git-write-tree)
 155        then
 156            echo "Wonderful."
 157            result_commit=$(
 158                echo "$merge_msg" |
 159                git-commit-tree $result_tree -p HEAD -p "$1"
 160            ) || exit
 161            finish "$result_commit" "In-index merge"
 162            dropsave
 163            exit 0
 164        fi
 165        echo "Nope."
 166        ;;
 167*)
 168        # An octopus.  If we can reach all the remote we are up to date.
 169        up_to_date=t
 170        for remote
 171        do
 172                common_one=$(git-merge-base --all $head $remote)
 173                if test "$common_one" != "$remote"
 174                then
 175                        up_to_date=f
 176                        break
 177                fi
 178        done
 179        if test "$up_to_date" = t
 180        then
 181                echo "Already up-to-date. Yeeah!"
 182                dropsave
 183                exit 0
 184        fi
 185        ;;
 186esac
 187
 188# At this point, we need a real merge.  No matter what strategy
 189# we use, it would operate on the index, possibly affecting the
 190# working tree, and when resolved cleanly, have the desired tree
 191# in the index -- this means that the index must be in sync with
 192# the $head commit.  The strategies are responsible to ensure this.
 193
 194case "$use_strategies" in
 195?*' '?*)
 196    # Stash away the local changes so that we can try more than one.
 197    savestate
 198    single_strategy=no
 199    ;;
 200*)
 201    rm -f "$GIT_DIR/MERGE_SAVE"
 202    single_strategy=yes
 203    ;;
 204esac
 205
 206result_tree= best_cnt=-1 best_strategy= wt_strategy=
 207for strategy in $use_strategies
 208do
 209    test "$wt_strategy" = '' || {
 210        echo "Rewinding the tree to pristine..."
 211        restorestate
 212    }
 213    case "$single_strategy" in
 214    no)
 215        echo "Trying merge strategy $strategy..."
 216        ;;
 217    esac
 218
 219    # Remember which strategy left the state in the working tree
 220    wt_strategy=$strategy
 221
 222    git-merge-$strategy $common -- "$head_arg" "$@"
 223    exit=$?
 224    if test "$no_commit" = t && test "$exit" = 0
 225    then
 226        exit=1 ;# pretend it left conflicts.
 227    fi
 228
 229    test "$exit" = 0 || {
 230
 231        # The backend exits with 1 when conflicts are left to be resolved,
 232        # with 2 when it does not handle the given merge at all.
 233
 234        if test "$exit" -eq 1
 235        then
 236            cnt=`{
 237                git-diff-files --name-only
 238                git-ls-files --unmerged
 239            } | wc -l`
 240            if test $best_cnt -le 0 -o $cnt -le $best_cnt
 241            then
 242                best_strategy=$strategy
 243                best_cnt=$cnt
 244            fi
 245        fi
 246        continue
 247    }
 248
 249    # Automerge succeeded.
 250    result_tree=$(git-write-tree) && break
 251done
 252
 253# If we have a resulting tree, that means the strategy module
 254# auto resolved the merge cleanly.
 255if test '' != "$result_tree"
 256then
 257    parents="-p $head"
 258    for remote
 259    do
 260        parents="$parents -p $remote"
 261    done
 262    result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents) || exit
 263    finish "$result_commit" "Merge $result_commit, made by $wt_strategy."
 264    dropsave
 265    exit 0
 266fi
 267
 268# Pick the result from the best strategy and have the user fix it up.
 269case "$best_strategy" in
 270'')
 271        restorestate
 272        die "No merge strategy handled the merge."
 273        ;;
 274"$wt_strategy")
 275        # We already have its result in the working tree.
 276        ;;
 277*)
 278        echo "Rewinding the tree to pristine..."
 279        restorestate
 280        echo "Using the $best_strategy to prepare resolving by hand."
 281        git-merge-$best_strategy $common -- "$head_arg" "$@"
 282        ;;
 283esac
 284for remote
 285do
 286        echo $remote
 287done >"$GIT_DIR/MERGE_HEAD"
 288echo $merge_msg >"$GIT_DIR/MERGE_MSG"
 289
 290die "Automatic merge failed/prevented; fix up by hand"