Andrew's git / gitweb.git / git-merge.sh
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git-merge.shon commit http-push: support for updating remote info/refs (197e895)
   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=
  16if test "@@NO_PYTHON@@"; then
  17        all_strategies='resolve octopus stupid ours'
  18        default_strategies='resolve'
  19fi
  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: $all_strategies" ;;
  85                esac
  86                ;;
  87        -*)     usage ;;
  88        *)      break ;;
  89        esac
  90        shift
  91done
  92
  93test "$#" -le 2 && usage ;# we need at least two heads.
  94
  95merge_msg="$1"
  96shift
  97head_arg="$1"
  98head=$(git-rev-parse --verify "$1"^0) || usage
  99shift
 100
 101# All the rest are remote heads
 102remoteheads=
 103for remote
 104do
 105        remotehead=$(git-rev-parse --verify "$remote"^0) ||
 106            die "$remote - not something we can merge"
 107        remoteheads="${remoteheads}$remotehead "
 108done
 109set x $remoteheads ; shift
 110
 111case "$#" in
 1121)
 113        common=$(git-merge-base --all $head "$@")
 114        ;;
 115*)
 116        common=$(git-show-branch --merge-base $head "$@")
 117        ;;
 118esac
 119echo "$head" >"$GIT_DIR/ORIG_HEAD"
 120
 121case "$#,$common,$no_commit" in
 122*,'',*)
 123        # No common ancestors found. We need a real merge.
 124        ;;
 1251,"$1",*)
 126        # If head can reach all the merge then we are up to date.
 127        # but first the most common case of merging one remote
 128        echo "Already up-to-date."
 129        dropsave
 130        exit 0
 131        ;;
 1321,"$head",*)
 133        # Again the most common case of merging one remote.
 134        echo "Updating from $head to $1"
 135        git-update-index --refresh 2>/dev/null
 136        new_head=$(git-rev-parse --verify "$1^0") &&
 137        git-read-tree -u -v -m $head "$new_head" &&
 138        finish "$new_head" "Fast forward"
 139        dropsave
 140        exit 0
 141        ;;
 1421,?*"$LF"?*,*)
 143        # We are not doing octopus and not fast forward.  Need a
 144        # real merge.
 145        ;;
 1461,*,)
 147        # We are not doing octopus, not fast forward, and have only
 148        # one common.  See if it is really trivial.
 149        git var GIT_COMMITTER_IDENT >/dev/null || exit
 150
 151        echo "Trying really trivial in-index merge..."
 152        git-update-index --refresh 2>/dev/null
 153        if git-read-tree --trivial -m -u -v $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# We are going to make a new commit.
 189git var GIT_COMMITTER_IDENT >/dev/null || exit
 190
 191case "$use_strategies" in
 192'')
 193        case "$#" in
 194        1)
 195                use_strategies="$default_strategies" ;;
 196        *)
 197                use_strategies=octopus ;;
 198        esac            
 199        ;;
 200esac
 201
 202# At this point, we need a real merge.  No matter what strategy
 203# we use, it would operate on the index, possibly affecting the
 204# working tree, and when resolved cleanly, have the desired tree
 205# in the index -- this means that the index must be in sync with
 206# the $head commit.  The strategies are responsible to ensure this.
 207
 208case "$use_strategies" in
 209?*' '?*)
 210    # Stash away the local changes so that we can try more than one.
 211    savestate
 212    single_strategy=no
 213    ;;
 214*)
 215    rm -f "$GIT_DIR/MERGE_SAVE"
 216    single_strategy=yes
 217    ;;
 218esac
 219
 220result_tree= best_cnt=-1 best_strategy= wt_strategy=
 221merge_was_ok=
 222for strategy in $use_strategies
 223do
 224    test "$wt_strategy" = '' || {
 225        echo "Rewinding the tree to pristine..."
 226        restorestate
 227    }
 228    case "$single_strategy" in
 229    no)
 230        echo "Trying merge strategy $strategy..."
 231        ;;
 232    esac
 233
 234    # Remember which strategy left the state in the working tree
 235    wt_strategy=$strategy
 236
 237    git-merge-$strategy $common -- "$head_arg" "$@"
 238    exit=$?
 239    if test "$no_commit" = t && test "$exit" = 0
 240    then
 241        merge_was_ok=t
 242        exit=1 ;# pretend it left conflicts.
 243    fi
 244
 245    test "$exit" = 0 || {
 246
 247        # The backend exits with 1 when conflicts are left to be resolved,
 248        # with 2 when it does not handle the given merge at all.
 249
 250        if test "$exit" -eq 1
 251        then
 252            cnt=`{
 253                git-diff-files --name-only
 254                git-ls-files --unmerged
 255            } | wc -l`
 256            if test $best_cnt -le 0 -o $cnt -le $best_cnt
 257            then
 258                best_strategy=$strategy
 259                best_cnt=$cnt
 260            fi
 261        fi
 262        continue
 263    }
 264
 265    # Automerge succeeded.
 266    result_tree=$(git-write-tree) && break
 267done
 268
 269# If we have a resulting tree, that means the strategy module
 270# auto resolved the merge cleanly.
 271if test '' != "$result_tree"
 272then
 273    parents="-p $head"
 274    for remote
 275    do
 276        parents="$parents -p $remote"
 277    done
 278    result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents) || exit
 279    finish "$result_commit" "Merge $result_commit, made by $wt_strategy."
 280    dropsave
 281    exit 0
 282fi
 283
 284# Pick the result from the best strategy and have the user fix it up.
 285case "$best_strategy" in
 286'')
 287        restorestate
 288        echo >&2 "No merge strategy handled the merge."
 289        exit 2
 290        ;;
 291"$wt_strategy")
 292        # We already have its result in the working tree.
 293        ;;
 294*)
 295        echo "Rewinding the tree to pristine..."
 296        restorestate
 297        echo "Using the $best_strategy to prepare resolving by hand."
 298        git-merge-$best_strategy $common -- "$head_arg" "$@"
 299        ;;
 300esac
 301for remote
 302do
 303        echo $remote
 304done >"$GIT_DIR/MERGE_HEAD"
 305echo "$merge_msg" >"$GIT_DIR/MERGE_MSG"
 306
 307if test "$merge_was_ok" = t
 308then
 309        echo >&2 \
 310        "Automatic merge went well; stopped before committing as requested"
 311        exit 0
 312else
 313        {
 314            echo '
 315Conflicts:
 316'
 317                git ls-files --unmerged |
 318                sed -e 's/^[^   ]*      /       /' |
 319                uniq
 320        } >>"$GIT_DIR/MERGE_MSG"
 321        if test -d "$GIT_DIR/rr-cache"
 322        then
 323                git-rerere
 324        fi
 325        die "Automatic merge failed; fix up by hand"
 326fi