Andrew's git - gitweb.git/blob

   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 "$remote - not something we can merge"
 111done
 112
 113common=$(git-show-branch --merge-base $head "$@")
 114echo "$head" >"$GIT_DIR/ORIG_HEAD"
 115
 116case "$#,$common,$no_commit" in
 117*,'',*)
 118        # No common ancestors found. We need a real merge.
 119        ;;
 1201,"$1",*)
 121        # If head can reach all the merge then we are up to date.
 122        # but first the most common case of merging one remote
 123        echo "Already up-to-date."
 124        dropsave
 125        exit 0
 126        ;;
 1271,"$head",*)
 128        # Again the most common case of merging one remote.
 129        echo "Updating from $head to $1."
 130        git-update-index --refresh 2>/dev/null
 131        new_head=$(git-rev-parse --verify "$1^0") &&
 132        git-read-tree -u -m $head "$new_head" &&
 133        finish "$new_head" "Fast forward"
 134        dropsave
 135        exit 0
 136        ;;
 1371,?*"$LF"?*,*)
 138        # We are not doing octopus and not fast forward.  Need a
 139        # real merge.
 140        ;;
 1411,*,)
 142        # We are not doing octopus, not fast forward, and have only
 143        # one common.  See if it is really trivial.
 144        echo "Trying really trivial in-index merge..."
 145        git-update-index --refresh 2>/dev/null
 146        if git-read-tree --trivial -m -u $common $head "$1" &&
 147           result_tree=$(git-write-tree)
 148        then
 149            echo "Wonderful."
 150            result_commit=$(
 151                echo "$merge_msg" |
 152                git-commit-tree $result_tree -p HEAD -p "$1"
 153            ) || exit
 154            finish "$result_commit" "In-index merge"
 155            dropsave
 156            exit 0
 157        fi
 158        echo "Nope."
 159        ;;
 160*)
 161        # An octopus.  If we can reach all the remote we are up to date.
 162        up_to_date=t
 163        for remote
 164        do
 165                common_one=$(git-merge-base $head $remote)
 166                if test "$common_one" != "$remote"
 167                then
 168                        up_to_date=f
 169                        break
 170                fi
 171        done
 172        if test "$up_to_date" = t
 173        then
 174                echo "Already up-to-date. Yeeah!"
 175                dropsave
 176                exit 0
 177        fi
 178        ;;
 179esac
 180
 181# At this point, we need a real merge.  No matter what strategy
 182# we use, it would operate on the index, possibly affecting the
 183# working tree, and when resolved cleanly, have the desired tree
 184# in the index -- this means that the index must be in sync with
 185# the $head commit.  The strategies are responsible to ensure this.
 186
 187case "$use_strategies" in
 188?*' '?*)
 189    # Stash away the local changes so that we can try more than one.
 190    savestate
 191    single_strategy=no
 192    ;;
 193*)
 194    rm -f "$GIT_DIR/MERGE_SAVE"
 195    single_strategy=yes
 196    ;;
 197esac
 198
 199result_tree= best_cnt=-1 best_strategy= wt_strategy=
 200for strategy in $use_strategies
 201do
 202    test "$wt_strategy" = '' || {
 203        echo "Rewinding the tree to pristine..."
 204        restorestate
 205    }
 206    case "$single_strategy" in
 207    no)
 208        echo "Trying merge strategy $strategy..."
 209        ;;
 210    esac
 211
 212    # Remember which strategy left the state in the working tree
 213    wt_strategy=$strategy
 214
 215    git-merge-$strategy $common -- "$head_arg" "$@"
 216    exit=$?
 217    if test "$no_commit" = t && test "$exit" = 0
 218    then
 219        exit=1 ;# pretend it left conflicts.
 220    fi
 221
 222    test "$exit" = 0 || {
 223
 224        # The backend exits with 1 when conflicts are left to be resolved,
 225        # with 2 when it does not handle the given merge at all.
 226
 227        if test "$exit" -eq 1
 228        then
 229            cnt=`{
 230                git-diff-files --name-only
 231                git-ls-files --unmerged
 232            } | wc -l`
 233            if test $best_cnt -le 0 -o $cnt -le $best_cnt
 234            then
 235                best_strategy=$strategy
 236                best_cnt=$cnt
 237            fi
 238        fi
 239        continue
 240    }
 241
 242    # Automerge succeeded.
 243    result_tree=$(git-write-tree) && break
 244done
 245
 246# If we have a resulting tree, that means the strategy module
 247# auto resolved the merge cleanly.
 248if test '' != "$result_tree"
 249then
 250    parents="-p $head"
 251    for remote
 252    do
 253        parents="$parents -p $remote"
 254    done
 255    result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents) || exit
 256    finish "$result_commit" "Merge $result_commit, made by $wt_strategy."
 257    dropsave
 258    exit 0
 259fi
 260
 261# Pick the result from the best strategy and have the user fix it up.
 262case "$best_strategy" in
 263'')
 264        restorestate
 265        die "No merge strategy handled the merge."
 266        ;;
 267"$wt_strategy")
 268        # We already have its result in the working tree.
 269        ;;
 270*)
 271        echo "Rewinding the tree to pristine..."
 272        restorestate
 273        echo "Using the $best_strategy to prepare resolving by hand."
 274        git-merge-$best_strategy $common -- "$head_arg" "$@"
 275        ;;
 276esac
 277for remote
 278do
 279        echo $remote
 280done >"$GIT_DIR/MERGE_HEAD"
 281echo $merge_msg >"$GIT_DIR/MERGE_MSG"
 282
 283die "Automatic merge failed/prevented; fix up by hand"