Andrew's git - gitweb.git/blob

   1#!/bin/sh
   2#
   3# Copyright (c) 2005 Junio C Hamano
   4#
   5
   6
   7USAGE='[-n] [--no-commit] [-s <strategy>]... <merge-message> <head> <remote>+'
   8. git-sh-setup
   9
  10LF='
  11'
  12
  13all_strategies='recursive octopus resolve stupid ours'
  14default_strategies='recursive'
  15use_strategies=
  16
  17dropsave() {
  18        rm -f -- "$GIT_DIR/MERGE_HEAD" "$GIT_DIR/MERGE_MSG" \
  19                 "$GIT_DIR/MERGE_SAVE" || exit 1
  20}
  21
  22savestate() {
  23        # Stash away any local modifications.
  24        git-diff-index -z --name-only $head |
  25        cpio -0 -o >"$GIT_DIR/MERGE_SAVE"
  26}
  27
  28restorestate() {
  29        if test -f "$GIT_DIR/MERGE_SAVE"
  30        then
  31                git reset --hard $head
  32                cpio -iuv <"$GIT_DIR/MERGE_SAVE"
  33                git-update-index --refresh >/dev/null
  34        fi
  35}
  36
  37finish () {
  38        test '' = "$2" || echo "$2"
  39        case "$merge_msg" in
  40        '')
  41                echo "No merge message -- not updating HEAD"
  42                ;;
  43        *)
  44                git-update-ref HEAD "$1" "$head" || exit 1
  45                ;;
  46        esac
  47
  48        case "$no_summary" in
  49        '')
  50                git-diff-tree -p -M "$head" "$1" |
  51                git-apply --stat --summary
  52                ;;
  53        esac
  54}
  55
  56while case "$#" in 0) break ;; esac
  57do
  58        case "$1" in
  59        -n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
  60                --no-summa|--no-summar|--no-summary)
  61                no_summary=t ;;
  62        --no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
  63                no_commit=t ;;
  64        -s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
  65                --strateg=*|--strategy=*|\
  66        -s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
  67                case "$#,$1" in
  68                *,*=*)
  69                        strategy=`expr "$1" : '-[^=]*=\(.*\)'` ;;
  70                1,*)
  71                        usage ;;
  72                *)
  73                        strategy="$2"
  74                        shift ;;
  75                esac
  76                case " $all_strategies " in
  77                *" $strategy "*)
  78                        use_strategies="$use_strategies$strategy " ;;
  79                *)
  80                        die "available strategies are: $all_strategies" ;;
  81                esac
  82                ;;
  83        -*)     usage ;;
  84        *)      break ;;
  85        esac
  86        shift
  87done
  88
  89test "$#" -le 2 && usage ;# we need at least two heads.
  90
  91merge_msg="$1"
  92shift
  93head_arg="$1"
  94head=$(git-rev-parse --verify "$1"^0) || usage
  95shift
  96
  97# All the rest are remote heads
  98remoteheads=
  99for remote
 100do
 101        remotehead=$(git-rev-parse --verify "$remote"^0) ||
 102            die "$remote - not something we can merge"
 103        remoteheads="${remoteheads}$remotehead "
 104done
 105set x $remoteheads ; shift
 106
 107case "$#" in
 1081)
 109        common=$(git-merge-base --all $head "$@")
 110        ;;
 111*)
 112        common=$(git-show-branch --merge-base $head "$@")
 113        ;;
 114esac
 115echo "$head" >"$GIT_DIR/ORIG_HEAD"
 116
 117case "$#,$common,$no_commit" in
 118*,'',*)
 119        # No common ancestors found. We need a real merge.
 120        ;;
 1211,"$1",*)
 122        # If head can reach all the merge then we are up to date.
 123        # but first the most common case of merging one remote
 124        echo "Already up-to-date."
 125        dropsave
 126        exit 0
 127        ;;
 1281,"$head",*)
 129        # Again the most common case of merging one remote.
 130        echo "Updating from $head to $1."
 131        git-update-index --refresh 2>/dev/null
 132        new_head=$(git-rev-parse --verify "$1^0") &&
 133        git-read-tree -u -m $head "$new_head" &&
 134        finish "$new_head" "Fast forward"
 135        dropsave
 136        exit 0
 137        ;;
 1381,?*"$LF"?*,*)
 139        # We are not doing octopus and not fast forward.  Need a
 140        # real merge.
 141        ;;
 1421,*,)
 143        # We are not doing octopus, not fast forward, and have only
 144        # one common.  See if it is really trivial.
 145        echo "Trying really trivial in-index merge..."
 146        git-update-index --refresh 2>/dev/null
 147        if git-read-tree --trivial -m -u $common $head "$1" &&
 148           result_tree=$(git-write-tree)
 149        then
 150            echo "Wonderful."
 151            result_commit=$(
 152                echo "$merge_msg" |
 153                git-commit-tree $result_tree -p HEAD -p "$1"
 154            ) || exit
 155            finish "$result_commit" "In-index merge"
 156            dropsave
 157            exit 0
 158        fi
 159        echo "Nope."
 160        ;;
 161*)
 162        # An octopus.  If we can reach all the remote we are up to date.
 163        up_to_date=t
 164        for remote
 165        do
 166                common_one=$(git-merge-base --all $head $remote)
 167                if test "$common_one" != "$remote"
 168                then
 169                        up_to_date=f
 170                        break
 171                fi
 172        done
 173        if test "$up_to_date" = t
 174        then
 175                echo "Already up-to-date. Yeeah!"
 176                dropsave
 177                exit 0
 178        fi
 179        ;;
 180esac
 181
 182case "$use_strategies" in
 183'')
 184        case "$#" in
 185        1)
 186                use_strategies="$default_strategies" ;;
 187        *)
 188                use_strategies=octopus ;;
 189        esac            
 190        ;;
 191esac
 192
 193# At this point, we need a real merge.  No matter what strategy
 194# we use, it would operate on the index, possibly affecting the
 195# working tree, and when resolved cleanly, have the desired tree
 196# in the index -- this means that the index must be in sync with
 197# the $head commit.  The strategies are responsible to ensure this.
 198
 199case "$use_strategies" in
 200?*' '?*)
 201    # Stash away the local changes so that we can try more than one.
 202    savestate
 203    single_strategy=no
 204    ;;
 205*)
 206    rm -f "$GIT_DIR/MERGE_SAVE"
 207    single_strategy=yes
 208    ;;
 209esac
 210
 211result_tree= best_cnt=-1 best_strategy= wt_strategy=
 212for strategy in $use_strategies
 213do
 214    test "$wt_strategy" = '' || {
 215        echo "Rewinding the tree to pristine..."
 216        restorestate
 217    }
 218    case "$single_strategy" in
 219    no)
 220        echo "Trying merge strategy $strategy..."
 221        ;;
 222    esac
 223
 224    # Remember which strategy left the state in the working tree
 225    wt_strategy=$strategy
 226
 227    git-merge-$strategy $common -- "$head_arg" "$@"
 228    exit=$?
 229    if test "$no_commit" = t && test "$exit" = 0
 230    then
 231        exit=1 ;# pretend it left conflicts.
 232    fi
 233
 234    test "$exit" = 0 || {
 235
 236        # The backend exits with 1 when conflicts are left to be resolved,
 237        # with 2 when it does not handle the given merge at all.
 238
 239        if test "$exit" -eq 1
 240        then
 241            cnt=`{
 242                git-diff-files --name-only
 243                git-ls-files --unmerged
 244            } | wc -l`
 245            if test $best_cnt -le 0 -o $cnt -le $best_cnt
 246            then
 247                best_strategy=$strategy
 248                best_cnt=$cnt
 249            fi
 250        fi
 251        continue
 252    }
 253
 254    # Automerge succeeded.
 255    result_tree=$(git-write-tree) && break
 256done
 257
 258# If we have a resulting tree, that means the strategy module
 259# auto resolved the merge cleanly.
 260if test '' != "$result_tree"
 261then
 262    parents="-p $head"
 263    for remote
 264    do
 265        parents="$parents -p $remote"
 266    done
 267    result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents) || exit
 268    finish "$result_commit" "Merge $result_commit, made by $wt_strategy."
 269    dropsave
 270    exit 0
 271fi
 272
 273# Pick the result from the best strategy and have the user fix it up.
 274case "$best_strategy" in
 275'')
 276        restorestate
 277        echo >&2 "No merge strategy handled the merge."
 278        exit 2
 279        ;;
 280"$wt_strategy")
 281        # We already have its result in the working tree.
 282        ;;
 283*)
 284        echo "Rewinding the tree to pristine..."
 285        restorestate
 286        echo "Using the $best_strategy to prepare resolving by hand."
 287        git-merge-$best_strategy $common -- "$head_arg" "$@"
 288        ;;
 289esac
 290for remote
 291do
 292        echo $remote
 293done >"$GIT_DIR/MERGE_HEAD"
 294echo $merge_msg >"$GIT_DIR/MERGE_MSG"
 295
 296die "Automatic merge failed/prevented; fix up by hand"