Andrew's git / gitweb.git / git-merge.sh
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git-merge.shon commit Teach mailsplit about Maildir's (d63bd9a)
   1#!/bin/sh
   2#
   3# Copyright (c) 2005 Junio C Hamano
   4#
   5
   6USAGE='[-n] [--no-commit] [--squash] [-s <strategy>] [-m=<merge-message>] <commit>+'
   7
   8SUBDIRECTORY_OK=Yes
   9. git-sh-setup
  10require_work_tree
  11cd_to_toplevel
  12
  13test -z "$(git ls-files -u)" ||
  14        die "You are in the middle of a conflicted merge."
  15
  16LF='
  17'
  18
  19all_strategies='recur recursive octopus resolve stupid ours subtree'
  20default_twohead_strategies='recursive'
  21default_octopus_strategies='octopus'
  22no_trivial_merge_strategies='ours subtree'
  23use_strategies=
  24
  25index_merge=t
  26
  27dropsave() {
  28        rm -f -- "$GIT_DIR/MERGE_HEAD" "$GIT_DIR/MERGE_MSG" \
  29                 "$GIT_DIR/MERGE_SAVE" || exit 1
  30}
  31
  32savestate() {
  33        # Stash away any local modifications.
  34        git-diff-index -z --name-only $head |
  35        cpio -0 -o >"$GIT_DIR/MERGE_SAVE"
  36}
  37
  38restorestate() {
  39        if test -f "$GIT_DIR/MERGE_SAVE"
  40        then
  41                git reset --hard $head >/dev/null
  42                cpio -iuv <"$GIT_DIR/MERGE_SAVE"
  43                git-update-index --refresh >/dev/null
  44        fi
  45}
  46
  47finish_up_to_date () {
  48        case "$squash" in
  49        t)
  50                echo "$1 (nothing to squash)" ;;
  51        '')
  52                echo "$1" ;;
  53        esac
  54        dropsave
  55}
  56
  57squash_message () {
  58        echo Squashed commit of the following:
  59        echo
  60        git-log --no-merges ^"$head" $remote
  61}
  62
  63finish () {
  64        if test '' = "$2"
  65        then
  66                rlogm="$GIT_REFLOG_ACTION"
  67        else
  68                echo "$2"
  69                rlogm="$GIT_REFLOG_ACTION: $2"
  70        fi
  71        case "$squash" in
  72        t)
  73                echo "Squash commit -- not updating HEAD"
  74                squash_message >"$GIT_DIR/SQUASH_MSG"
  75                ;;
  76        '')
  77                case "$merge_msg" in
  78                '')
  79                        echo "No merge message -- not updating HEAD"
  80                        ;;
  81                *)
  82                        git-update-ref -m "$rlogm" HEAD "$1" "$head" || exit 1
  83                        ;;
  84                esac
  85                ;;
  86        esac
  87        case "$1" in
  88        '')
  89                ;;
  90        ?*)
  91                case "$no_summary" in
  92                '')
  93                        # We want color (if set), but no pager
  94                        GIT_PAGER='' git-diff --stat --summary -M "$head" "$1"
  95                        ;;
  96                esac
  97                ;;
  98        esac
  99}
 100
 101merge_name () {
 102        remote="$1"
 103        rh=$(git-rev-parse --verify "$remote^0" 2>/dev/null) || return
 104        bh=$(git-show-ref -s --verify "refs/heads/$remote" 2>/dev/null)
 105        if test "$rh" = "$bh"
 106        then
 107                echo "$rh               branch '$remote' of ."
 108        elif truname=$(expr "$remote" : '\(.*\)~[1-9][0-9]*$') &&
 109                git-show-ref -q --verify "refs/heads/$truname" 2>/dev/null
 110        then
 111                echo "$rh               branch '$truname' (early part) of ."
 112        elif test "$remote" = "FETCH_HEAD" -a -r "$GIT_DIR/FETCH_HEAD"
 113        then
 114                sed -e 's/      not-for-merge   /               /' -e 1q \
 115                        "$GIT_DIR/FETCH_HEAD"
 116        else
 117                echo "$rh               commit '$remote'"
 118        fi
 119}
 120
 121case "$#" in 0) usage ;; esac
 122
 123have_message=
 124while case "$#" in 0) break ;; esac
 125do
 126        case "$1" in
 127        -n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
 128                --no-summa|--no-summar|--no-summary)
 129                no_summary=t ;;
 130        --sq|--squ|--squa|--squas|--squash)
 131                squash=t no_commit=t ;;
 132        --no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
 133                no_commit=t ;;
 134        -s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
 135                --strateg=*|--strategy=*|\
 136        -s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
 137                case "$#,$1" in
 138                *,*=*)
 139                        strategy=`expr "z$1" : 'z-[^=]*=\(.*\)'` ;;
 140                1,*)
 141                        usage ;;
 142                *)
 143                        strategy="$2"
 144                        shift ;;
 145                esac
 146                case " $all_strategies " in
 147                *" $strategy "*)
 148                        use_strategies="$use_strategies$strategy " ;;
 149                *)
 150                        die "available strategies are: $all_strategies" ;;
 151                esac
 152                ;;
 153        -m=*|--m=*|--me=*|--mes=*|--mess=*|--messa=*|--messag=*|--message=*)
 154                merge_msg=`expr "z$1" : 'z-[^=]*=\(.*\)'`
 155                have_message=t
 156                ;;
 157        -m|--m|--me|--mes|--mess|--messa|--messag|--message)
 158                shift
 159                case "$#" in
 160                1)      usage ;;
 161                esac
 162                merge_msg="$1"
 163                have_message=t
 164                ;;
 165        -*)     usage ;;
 166        *)      break ;;
 167        esac
 168        shift
 169done
 170
 171# This could be traditional "merge <msg> HEAD <commit>..."  and the
 172# way we can tell it is to see if the second token is HEAD, but some
 173# people might have misused the interface and used a committish that
 174# is the same as HEAD there instead.  Traditional format never would
 175# have "-m" so it is an additional safety measure to check for it.
 176
 177if test -z "$have_message" &&
 178        second_token=$(git-rev-parse --verify "$2^0" 2>/dev/null) &&
 179        head_commit=$(git-rev-parse --verify "HEAD" 2>/dev/null) &&
 180        test "$second_token" = "$head_commit"
 181then
 182        merge_msg="$1"
 183        shift
 184        head_arg="$1"
 185        shift
 186elif ! git-rev-parse --verify HEAD >/dev/null 2>&1
 187then
 188        # If the merged head is a valid one there is no reason to
 189        # forbid "git merge" into a branch yet to be born.  We do
 190        # the same for "git pull".
 191        if test 1 -ne $#
 192        then
 193                echo >&2 "Can merge only exactly one commit into empty head"
 194                exit 1
 195        fi
 196
 197        rh=$(git rev-parse --verify "$1^0") ||
 198                die "$1 - not something we can merge"
 199
 200        git-update-ref -m "initial pull" HEAD "$rh" "" &&
 201        git-read-tree --reset -u HEAD
 202        exit
 203
 204else
 205        # We are invoked directly as the first-class UI.
 206        head_arg=HEAD
 207
 208        # All the rest are the commits being merged; prepare
 209        # the standard merge summary message to be appended to
 210        # the given message.  If remote is invalid we will die
 211        # later in the common codepath so we discard the error
 212        # in this loop.
 213        merge_name=$(for remote
 214                do
 215                        merge_name "$remote"
 216                done | git-fmt-merge-msg
 217        )
 218        merge_msg="${merge_msg:+$merge_msg$LF$LF}$merge_name"
 219fi
 220head=$(git-rev-parse --verify "$head_arg"^0) || usage
 221
 222# All the rest are remote heads
 223test "$#" = 0 && usage ;# we need at least one remote head.
 224set_reflog_action "merge $*"
 225
 226remoteheads=
 227for remote
 228do
 229        remotehead=$(git-rev-parse --verify "$remote"^0 2>/dev/null) ||
 230            die "$remote - not something we can merge"
 231        remoteheads="${remoteheads}$remotehead "
 232        eval GITHEAD_$remotehead='"$remote"'
 233        export GITHEAD_$remotehead
 234done
 235set x $remoteheads ; shift
 236
 237case "$use_strategies" in
 238'')
 239        case "$#" in
 240        1)
 241                var="`git-config --get pull.twohead`"
 242                if test -n "$var"
 243                then
 244                        use_strategies="$var"
 245                else
 246                        use_strategies="$default_twohead_strategies"
 247                fi ;;
 248        *)
 249                var="`git-config --get pull.octopus`"
 250                if test -n "$var"
 251                then
 252                        use_strategies="$var"
 253                else
 254                        use_strategies="$default_octopus_strategies"
 255                fi ;;
 256        esac
 257        ;;
 258esac
 259
 260for s in $use_strategies
 261do
 262        for nt in $no_trivial_merge_strategies
 263        do
 264                case " $s " in
 265                *" $nt "*)
 266                        index_merge=f
 267                        break
 268                        ;;
 269                esac
 270        done
 271done
 272
 273case "$#" in
 2741)
 275        common=$(git-merge-base --all $head "$@")
 276        ;;
 277*)
 278        common=$(git-show-branch --merge-base $head "$@")
 279        ;;
 280esac
 281echo "$head" >"$GIT_DIR/ORIG_HEAD"
 282
 283case "$index_merge,$#,$common,$no_commit" in
 284f,*)
 285        # We've been told not to try anything clever.  Skip to real merge.
 286        ;;
 287?,*,'',*)
 288        # No common ancestors found. We need a real merge.
 289        ;;
 290?,1,"$1",*)
 291        # If head can reach all the merge then we are up to date.
 292        # but first the most common case of merging one remote.
 293        finish_up_to_date "Already up-to-date."
 294        exit 0
 295        ;;
 296?,1,"$head",*)
 297        # Again the most common case of merging one remote.
 298        echo "Updating $(git-rev-parse --short $head)..$(git-rev-parse --short $1)"
 299        git-update-index --refresh 2>/dev/null
 300        msg="Fast forward"
 301        if test -n "$have_message"
 302        then
 303                msg="$msg (no commit created; -m option ignored)"
 304        fi
 305        new_head=$(git-rev-parse --verify "$1^0") &&
 306        git-read-tree -v -m -u --exclude-per-directory=.gitignore $head "$new_head" &&
 307        finish "$new_head" "$msg" || exit
 308        dropsave
 309        exit 0
 310        ;;
 311?,1,?*"$LF"?*,*)
 312        # We are not doing octopus and not fast forward.  Need a
 313        # real merge.
 314        ;;
 315?,1,*,)
 316        # We are not doing octopus, not fast forward, and have only
 317        # one common.
 318        git-update-index --refresh 2>/dev/null
 319        case " $use_strategies " in
 320        *' recursive '*|*' recur '*)
 321                : run merge later
 322                ;;
 323        *)
 324                # See if it is really trivial.
 325                git var GIT_COMMITTER_IDENT >/dev/null || exit
 326                echo "Trying really trivial in-index merge..."
 327                if git-read-tree --trivial -m -u -v $common $head "$1" &&
 328                   result_tree=$(git-write-tree)
 329                then
 330                        echo "Wonderful."
 331                        result_commit=$(
 332                                echo "$merge_msg" |
 333                                git-commit-tree $result_tree -p HEAD -p "$1"
 334                        ) || exit
 335                        finish "$result_commit" "In-index merge"
 336                        dropsave
 337                        exit 0
 338                fi
 339                echo "Nope."
 340        esac
 341        ;;
 342*)
 343        # An octopus.  If we can reach all the remote we are up to date.
 344        up_to_date=t
 345        for remote
 346        do
 347                common_one=$(git-merge-base --all $head $remote)
 348                if test "$common_one" != "$remote"
 349                then
 350                        up_to_date=f
 351                        break
 352                fi
 353        done
 354        if test "$up_to_date" = t
 355        then
 356                finish_up_to_date "Already up-to-date. Yeeah!"
 357                exit 0
 358        fi
 359        ;;
 360esac
 361
 362# We are going to make a new commit.
 363git var GIT_COMMITTER_IDENT >/dev/null || exit
 364
 365# At this point, we need a real merge.  No matter what strategy
 366# we use, it would operate on the index, possibly affecting the
 367# working tree, and when resolved cleanly, have the desired tree
 368# in the index -- this means that the index must be in sync with
 369# the $head commit.  The strategies are responsible to ensure this.
 370
 371case "$use_strategies" in
 372?*' '?*)
 373    # Stash away the local changes so that we can try more than one.
 374    savestate
 375    single_strategy=no
 376    ;;
 377*)
 378    rm -f "$GIT_DIR/MERGE_SAVE"
 379    single_strategy=yes
 380    ;;
 381esac
 382
 383result_tree= best_cnt=-1 best_strategy= wt_strategy=
 384merge_was_ok=
 385for strategy in $use_strategies
 386do
 387    test "$wt_strategy" = '' || {
 388        echo "Rewinding the tree to pristine..."
 389        restorestate
 390    }
 391    case "$single_strategy" in
 392    no)
 393        echo "Trying merge strategy $strategy..."
 394        ;;
 395    esac
 396
 397    # Remember which strategy left the state in the working tree
 398    wt_strategy=$strategy
 399
 400    git-merge-$strategy $common -- "$head_arg" "$@"
 401    exit=$?
 402    if test "$no_commit" = t && test "$exit" = 0
 403    then
 404        merge_was_ok=t
 405        exit=1 ;# pretend it left conflicts.
 406    fi
 407
 408    test "$exit" = 0 || {
 409
 410        # The backend exits with 1 when conflicts are left to be resolved,
 411        # with 2 when it does not handle the given merge at all.
 412
 413        if test "$exit" -eq 1
 414        then
 415            cnt=`{
 416                git-diff-files --name-only
 417                git-ls-files --unmerged
 418            } | wc -l`
 419            if test $best_cnt -le 0 -o $cnt -le $best_cnt
 420            then
 421                best_strategy=$strategy
 422                best_cnt=$cnt
 423            fi
 424        fi
 425        continue
 426    }
 427
 428    # Automerge succeeded.
 429    result_tree=$(git-write-tree) && break
 430done
 431
 432# If we have a resulting tree, that means the strategy module
 433# auto resolved the merge cleanly.
 434if test '' != "$result_tree"
 435then
 436    parents=$(git-show-branch --independent "$head" "$@" | sed -e 's/^/-p /')
 437    result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents) || exit
 438    finish "$result_commit" "Merge made by $wt_strategy."
 439    dropsave
 440    exit 0
 441fi
 442
 443# Pick the result from the best strategy and have the user fix it up.
 444case "$best_strategy" in
 445'')
 446        restorestate
 447        case "$use_strategies" in
 448        ?*' '?*)
 449                echo >&2 "No merge strategy handled the merge."
 450                ;;
 451        *)
 452                echo >&2 "Merge with strategy $use_strategies failed."
 453                ;;
 454        esac
 455        exit 2
 456        ;;
 457"$wt_strategy")
 458        # We already have its result in the working tree.
 459        ;;
 460*)
 461        echo "Rewinding the tree to pristine..."
 462        restorestate
 463        echo "Using the $best_strategy to prepare resolving by hand."
 464        git-merge-$best_strategy $common -- "$head_arg" "$@"
 465        ;;
 466esac
 467
 468if test "$squash" = t
 469then
 470        finish
 471else
 472        for remote
 473        do
 474                echo $remote
 475        done >"$GIT_DIR/MERGE_HEAD"
 476        echo "$merge_msg" >"$GIT_DIR/MERGE_MSG"
 477fi
 478
 479if test "$merge_was_ok" = t
 480then
 481        echo >&2 \
 482        "Automatic merge went well; stopped before committing as requested"
 483        exit 0
 484else
 485        {
 486            echo '
 487Conflicts:
 488'
 489                git ls-files --unmerged |
 490                sed -e 's/^[^   ]*      /       /' |
 491                uniq
 492        } >>"$GIT_DIR/MERGE_MSG"
 493        if test -d "$GIT_DIR/rr-cache"
 494        then
 495                git-rerere
 496        fi
 497        die "Automatic merge failed; fix conflicts and then commit the result."
 498fi