Andrew's git / gitweb.git / git-merge.sh
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git-merge.shon commit Add revspec documentation for ':path', ':[0-3]:path' and git-describe (6b09c78)
   1#!/bin/sh
   2#
   3# Copyright (c) 2005 Junio C Hamano
   4#
   5
   6USAGE='[-n] [--no-commit] [--squash] [-s <strategy>]... <merge-message> <head> <remote>+'
   7. git-sh-setup
   8
   9LF='
  10'
  11
  12all_strategies='recur recursive recursive-old octopus resolve stupid ours'
  13default_twohead_strategies='recursive'
  14default_octopus_strategies='octopus'
  15no_trivial_merge_strategies='ours'
  16use_strategies=
  17
  18index_merge=t
  19if test "@@NO_PYTHON@@"; then
  20        all_strategies='recur recursive resolve octopus stupid ours'
  21fi
  22
  23dropsave() {
  24        rm -f -- "$GIT_DIR/MERGE_HEAD" "$GIT_DIR/MERGE_MSG" \
  25                 "$GIT_DIR/MERGE_SAVE" || exit 1
  26}
  27
  28savestate() {
  29        # Stash away any local modifications.
  30        git-diff-index -z --name-only $head |
  31        cpio -0 -o >"$GIT_DIR/MERGE_SAVE"
  32}
  33
  34restorestate() {
  35        if test -f "$GIT_DIR/MERGE_SAVE"
  36        then
  37                git reset --hard $head
  38                cpio -iuv <"$GIT_DIR/MERGE_SAVE"
  39                git-update-index --refresh >/dev/null
  40        fi
  41}
  42
  43finish_up_to_date () {
  44        case "$squash" in
  45        t)
  46                echo "$1 (nothing to squash)" ;;
  47        '')
  48                echo "$1" ;;
  49        esac
  50        dropsave
  51}
  52
  53squash_message () {
  54        echo Squashed commit of the following:
  55        echo
  56        git-log --no-merges ^"$head" $remote
  57}
  58
  59finish () {
  60        if test '' = "$2"
  61        then
  62                rlogm="$rloga"
  63        else
  64                echo "$2"
  65                rlogm="$rloga: $2"
  66        fi
  67        case "$squash" in
  68        t)
  69                echo "Squash commit -- not updating HEAD"
  70                squash_message >"$GIT_DIR/SQUASH_MSG"
  71                ;;
  72        '')
  73                case "$merge_msg" in
  74                '')
  75                        echo "No merge message -- not updating HEAD"
  76                        ;;
  77                *)
  78                        git-update-ref -m "$rlogm" HEAD "$1" "$head" || exit 1
  79                        ;;
  80                esac
  81                ;;
  82        esac
  83        case "$1" in
  84        '')
  85                ;;
  86        ?*)
  87                case "$no_summary" in
  88                '')
  89                        git-diff-tree --stat --summary -M "$head" "$1"
  90                        ;;
  91                esac
  92                ;;
  93        esac
  94}
  95
  96rloga=
  97while case "$#" in 0) break ;; esac
  98do
  99        case "$1" in
 100        -n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
 101                --no-summa|--no-summar|--no-summary)
 102                no_summary=t ;;
 103        --sq|--squ|--squa|--squas|--squash)
 104                squash=t no_commit=t ;;
 105        --no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
 106                no_commit=t ;;
 107        -s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
 108                --strateg=*|--strategy=*|\
 109        -s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
 110                case "$#,$1" in
 111                *,*=*)
 112                        strategy=`expr "z$1" : 'z-[^=]*=\(.*\)'` ;;
 113                1,*)
 114                        usage ;;
 115                *)
 116                        strategy="$2"
 117                        shift ;;
 118                esac
 119                case " $all_strategies " in
 120                *" $strategy "*)
 121                        use_strategies="$use_strategies$strategy " ;;
 122                *)
 123                        die "available strategies are: $all_strategies" ;;
 124                esac
 125                ;;
 126        --reflog-action=*)
 127                rloga=`expr "z$1" : 'z-[^=]*=\(.*\)'`
 128                ;;
 129        -*)     usage ;;
 130        *)      break ;;
 131        esac
 132        shift
 133done
 134
 135merge_msg="$1"
 136shift
 137head_arg="$1"
 138head=$(git-rev-parse --verify "$1"^0) || usage
 139shift
 140
 141# All the rest are remote heads
 142test "$#" = 0 && usage ;# we need at least one remote head.
 143test "$rloga" = '' && rloga="merge: $@"
 144
 145remoteheads=
 146for remote
 147do
 148        remotehead=$(git-rev-parse --verify "$remote"^0) ||
 149            die "$remote - not something we can merge"
 150        remoteheads="${remoteheads}$remotehead "
 151done
 152set x $remoteheads ; shift
 153
 154case "$use_strategies" in
 155'')
 156        case "$#" in
 157        1)
 158                use_strategies="$default_twohead_strategies" ;;
 159        *)
 160                use_strategies="$default_octopus_strategies" ;;
 161        esac
 162        ;;
 163esac
 164
 165for s in $use_strategies
 166do
 167        case " $s " in
 168        *" $no_trivial_merge_strategies "*)
 169                index_merge=f
 170                break
 171                ;;
 172        esac
 173done
 174
 175case "$#" in
 1761)
 177        common=$(git-merge-base --all $head "$@")
 178        ;;
 179*)
 180        common=$(git-show-branch --merge-base $head "$@")
 181        ;;
 182esac
 183echo "$head" >"$GIT_DIR/ORIG_HEAD"
 184
 185case "$index_merge,$#,$common,$no_commit" in
 186f,*)
 187        # We've been told not to try anything clever.  Skip to real merge.
 188        ;;
 189?,*,'',*)
 190        # No common ancestors found. We need a real merge.
 191        ;;
 192?,1,"$1",*)
 193        # If head can reach all the merge then we are up to date.
 194        # but first the most common case of merging one remote.
 195        finish_up_to_date "Already up-to-date."
 196        exit 0
 197        ;;
 198?,1,"$head",*)
 199        # Again the most common case of merging one remote.
 200        echo "Updating from $head to $1"
 201        git-update-index --refresh 2>/dev/null
 202        new_head=$(git-rev-parse --verify "$1^0") &&
 203        git-read-tree -u -v -m $head "$new_head" &&
 204        finish "$new_head" "Fast forward"
 205        dropsave
 206        exit 0
 207        ;;
 208?,1,?*"$LF"?*,*)
 209        # We are not doing octopus and not fast forward.  Need a
 210        # real merge.
 211        ;;
 212?,1,*,)
 213        # We are not doing octopus, not fast forward, and have only
 214        # one common.  See if it is really trivial.
 215        git var GIT_COMMITTER_IDENT >/dev/null || exit
 216
 217        echo "Trying really trivial in-index merge..."
 218        git-update-index --refresh 2>/dev/null
 219        if git-read-tree --trivial -m -u -v $common $head "$1" &&
 220           result_tree=$(git-write-tree)
 221        then
 222            echo "Wonderful."
 223            result_commit=$(
 224                echo "$merge_msg" |
 225                git-commit-tree $result_tree -p HEAD -p "$1"
 226            ) || exit
 227            finish "$result_commit" "In-index merge"
 228            dropsave
 229            exit 0
 230        fi
 231        echo "Nope."
 232        ;;
 233*)
 234        # An octopus.  If we can reach all the remote we are up to date.
 235        up_to_date=t
 236        for remote
 237        do
 238                common_one=$(git-merge-base --all $head $remote)
 239                if test "$common_one" != "$remote"
 240                then
 241                        up_to_date=f
 242                        break
 243                fi
 244        done
 245        if test "$up_to_date" = t
 246        then
 247                finish_up_to_date "Already up-to-date. Yeeah!"
 248                exit 0
 249        fi
 250        ;;
 251esac
 252
 253# We are going to make a new commit.
 254git var GIT_COMMITTER_IDENT >/dev/null || exit
 255
 256# At this point, we need a real merge.  No matter what strategy
 257# we use, it would operate on the index, possibly affecting the
 258# working tree, and when resolved cleanly, have the desired tree
 259# in the index -- this means that the index must be in sync with
 260# the $head commit.  The strategies are responsible to ensure this.
 261
 262case "$use_strategies" in
 263?*' '?*)
 264    # Stash away the local changes so that we can try more than one.
 265    savestate
 266    single_strategy=no
 267    ;;
 268*)
 269    rm -f "$GIT_DIR/MERGE_SAVE"
 270    single_strategy=yes
 271    ;;
 272esac
 273
 274result_tree= best_cnt=-1 best_strategy= wt_strategy=
 275merge_was_ok=
 276for strategy in $use_strategies
 277do
 278    test "$wt_strategy" = '' || {
 279        echo "Rewinding the tree to pristine..."
 280        restorestate
 281    }
 282    case "$single_strategy" in
 283    no)
 284        echo "Trying merge strategy $strategy..."
 285        ;;
 286    esac
 287
 288    # Remember which strategy left the state in the working tree
 289    wt_strategy=$strategy
 290
 291    git-merge-$strategy $common -- "$head_arg" "$@"
 292    exit=$?
 293    if test "$no_commit" = t && test "$exit" = 0
 294    then
 295        merge_was_ok=t
 296        exit=1 ;# pretend it left conflicts.
 297    fi
 298
 299    test "$exit" = 0 || {
 300
 301        # The backend exits with 1 when conflicts are left to be resolved,
 302        # with 2 when it does not handle the given merge at all.
 303
 304        if test "$exit" -eq 1
 305        then
 306            cnt=`{
 307                git-diff-files --name-only
 308                git-ls-files --unmerged
 309            } | wc -l`
 310            if test $best_cnt -le 0 -o $cnt -le $best_cnt
 311            then
 312                best_strategy=$strategy
 313                best_cnt=$cnt
 314            fi
 315        fi
 316        continue
 317    }
 318
 319    # Automerge succeeded.
 320    result_tree=$(git-write-tree) && break
 321done
 322
 323# If we have a resulting tree, that means the strategy module
 324# auto resolved the merge cleanly.
 325if test '' != "$result_tree"
 326then
 327    parents=$(git-show-branch --independent "$head" "$@" | sed -e 's/^/-p /')
 328    result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents) || exit
 329    finish "$result_commit" "Merge made by $wt_strategy."
 330    dropsave
 331    exit 0
 332fi
 333
 334# Pick the result from the best strategy and have the user fix it up.
 335case "$best_strategy" in
 336'')
 337        restorestate
 338        echo >&2 "No merge strategy handled the merge."
 339        exit 2
 340        ;;
 341"$wt_strategy")
 342        # We already have its result in the working tree.
 343        ;;
 344*)
 345        echo "Rewinding the tree to pristine..."
 346        restorestate
 347        echo "Using the $best_strategy to prepare resolving by hand."
 348        git-merge-$best_strategy $common -- "$head_arg" "$@"
 349        ;;
 350esac
 351
 352if test "$squash" = t
 353then
 354        finish
 355else
 356        for remote
 357        do
 358                echo $remote
 359        done >"$GIT_DIR/MERGE_HEAD"
 360        echo "$merge_msg" >"$GIT_DIR/MERGE_MSG"
 361fi
 362
 363if test "$merge_was_ok" = t
 364then
 365        echo >&2 \
 366        "Automatic merge went well; stopped before committing as requested"
 367        exit 0
 368else
 369        {
 370            echo '
 371Conflicts:
 372'
 373                git ls-files --unmerged |
 374                sed -e 's/^[^   ]*      /       /' |
 375                uniq
 376        } >>"$GIT_DIR/MERGE_MSG"
 377        if test -d "$GIT_DIR/rr-cache"
 378        then
 379                git-rerere
 380        fi
 381        die "Automatic merge failed; fix conflicts and then commit the result."
 382fi