Andrew's git / gitweb.git / git-merge.sh
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git-merge.shon commit ls-tree: major rewrite to do pathspec (3c5e846)
   1#!/bin/sh
   2#
   3# Copyright (c) 2005 Junio C Hamano
   4#
   5
   6. git-sh-setup
   7
   8LF='
   9'
  10
  11usage () {
  12    die "git-merge [-n] [--no-commit] [-s <strategy>]... <merge-message> <head> <remote>+"
  13}
  14
  15all_strategies='recursive octopus resolve stupid ours'
  16default_strategies='recursive'
  17use_strategies=
  18
  19dropsave() {
  20        rm -f -- "$GIT_DIR/MERGE_HEAD" "$GIT_DIR/MERGE_MSG" \
  21                 "$GIT_DIR/MERGE_SAVE" || exit 1
  22}
  23
  24savestate() {
  25        # Stash away any local modifications.
  26        git-diff-index -z --name-only $head |
  27        cpio -0 -o >"$GIT_DIR/MERGE_SAVE"
  28}
  29
  30restorestate() {
  31        if test -f "$GIT_DIR/MERGE_SAVE"
  32        then
  33                git reset --hard $head
  34                cpio -iuv <"$GIT_DIR/MERGE_SAVE"
  35                git-update-index --refresh >/dev/null
  36        fi
  37}
  38
  39finish () {
  40        test '' = "$2" || echo "$2"
  41        case "$merge_msg" in
  42        '')
  43                echo "No merge message -- not updating HEAD"
  44                ;;
  45        *)
  46                git-update-ref HEAD "$1" "$head" || exit 1
  47                ;;
  48        esac
  49
  50        case "$no_summary" in
  51        '')
  52                git-diff-tree -p -M "$head" "$1" |
  53                git-apply --stat --summary
  54                ;;
  55        esac
  56}
  57
  58while case "$#" in 0) break ;; esac
  59do
  60        case "$1" in
  61        -n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
  62                --no-summa|--no-summar|--no-summary)
  63                no_summary=t ;;
  64        --no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
  65                no_commit=t ;;
  66        -s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
  67                --strateg=*|--strategy=*|\
  68        -s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
  69                case "$#,$1" in
  70                *,*=*)
  71                        strategy=`expr "$1" : '-[^=]*=\(.*\)'` ;;
  72                1,*)
  73                        usage ;;
  74                *)
  75                        strategy="$2"
  76                        shift ;;
  77                esac
  78                case " $all_strategies " in
  79                *" $strategy "*)
  80                        use_strategies="$use_strategies$strategy " ;;
  81                *)
  82                        die "available strategies are: $all_strategies" ;;
  83                esac
  84                ;;
  85        -*)     usage ;;
  86        *)      break ;;
  87        esac
  88        shift
  89done
  90
  91test "$#" -le 2 && usage ;# we need at least two heads.
  92
  93merge_msg="$1"
  94shift
  95head_arg="$1"
  96head=$(git-rev-parse --verify "$1"^0) || usage
  97shift
  98
  99# All the rest are remote heads
 100for remote
 101do
 102        git-rev-parse --verify "$remote"^0 >/dev/null ||
 103            die "$remote - not something we can merge"
 104done
 105
 106case "$#" in
 1071)
 108        common=$(git-merge-base --all $head "$@")
 109        ;;
 110*)
 111        common=$(git-show-branch --merge-base $head "$@")
 112        ;;
 113esac
 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 --all $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
 181case "$use_strategies" in
 182'')
 183        case "$#" in
 184        1)
 185                use_strategies="$default_strategies" ;;
 186        *)
 187                use_strategies=octopus ;;
 188        esac            
 189        ;;
 190esac
 191
 192# At this point, we need a real merge.  No matter what strategy
 193# we use, it would operate on the index, possibly affecting the
 194# working tree, and when resolved cleanly, have the desired tree
 195# in the index -- this means that the index must be in sync with
 196# the $head commit.  The strategies are responsible to ensure this.
 197
 198case "$use_strategies" in
 199?*' '?*)
 200    # Stash away the local changes so that we can try more than one.
 201    savestate
 202    single_strategy=no
 203    ;;
 204*)
 205    rm -f "$GIT_DIR/MERGE_SAVE"
 206    single_strategy=yes
 207    ;;
 208esac
 209
 210result_tree= best_cnt=-1 best_strategy= wt_strategy=
 211for strategy in $use_strategies
 212do
 213    test "$wt_strategy" = '' || {
 214        echo "Rewinding the tree to pristine..."
 215        restorestate
 216    }
 217    case "$single_strategy" in
 218    no)
 219        echo "Trying merge strategy $strategy..."
 220        ;;
 221    esac
 222
 223    # Remember which strategy left the state in the working tree
 224    wt_strategy=$strategy
 225
 226    git-merge-$strategy $common -- "$head_arg" "$@"
 227    exit=$?
 228    if test "$no_commit" = t && test "$exit" = 0
 229    then
 230        exit=1 ;# pretend it left conflicts.
 231    fi
 232
 233    test "$exit" = 0 || {
 234
 235        # The backend exits with 1 when conflicts are left to be resolved,
 236        # with 2 when it does not handle the given merge at all.
 237
 238        if test "$exit" -eq 1
 239        then
 240            cnt=`{
 241                git-diff-files --name-only
 242                git-ls-files --unmerged
 243            } | wc -l`
 244            if test $best_cnt -le 0 -o $cnt -le $best_cnt
 245            then
 246                best_strategy=$strategy
 247                best_cnt=$cnt
 248            fi
 249        fi
 250        continue
 251    }
 252
 253    # Automerge succeeded.
 254    result_tree=$(git-write-tree) && break
 255done
 256
 257# If we have a resulting tree, that means the strategy module
 258# auto resolved the merge cleanly.
 259if test '' != "$result_tree"
 260then
 261    parents="-p $head"
 262    for remote
 263    do
 264        parents="$parents -p $remote"
 265    done
 266    result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents) || exit
 267    finish "$result_commit" "Merge $result_commit, made by $wt_strategy."
 268    dropsave
 269    exit 0
 270fi
 271
 272# Pick the result from the best strategy and have the user fix it up.
 273case "$best_strategy" in
 274'')
 275        restorestate
 276        die "No merge strategy handled the merge."
 277        ;;
 278"$wt_strategy")
 279        # We already have its result in the working tree.
 280        ;;
 281*)
 282        echo "Rewinding the tree to pristine..."
 283        restorestate
 284        echo "Using the $best_strategy to prepare resolving by hand."
 285        git-merge-$best_strategy $common -- "$head_arg" "$@"
 286        ;;
 287esac
 288for remote
 289do
 290        echo $remote
 291done >"$GIT_DIR/MERGE_HEAD"
 292echo $merge_msg >"$GIT_DIR/MERGE_MSG"
 293
 294die "Automatic merge failed/prevented; fix up by hand"