Andrew's git / gitweb.git / git-merge.sh
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git-merge.shon commit git-merge: no reason to use cpio anymore (a64d778)
   1#!/bin/sh
   2#
   3# Copyright (c) 2005 Junio C Hamano
   4#
   5
   6USAGE='[-n] [--summary] [--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 "$(git ls-files -u)" ||
  14        die "You are in the middle of a conflicted merge."
  15
  16LF='
  17'
  18
  19all_strategies='recur recursive octopus resolve stupid ours subtree'
  20default_twohead_strategies='recursive'
  21default_octopus_strategies='octopus'
  22no_fast_forward_strategies='subtree ours'
  23no_trivial_strategies='recursive recur subtree ours'
  24use_strategies=
  25
  26allow_fast_forward=t
  27allow_trivial_merge=t
  28
  29dropsave() {
  30        rm -f -- "$GIT_DIR/MERGE_HEAD" "$GIT_DIR/MERGE_MSG" \
  31                 "$GIT_DIR/MERGE_STASH" || exit 1
  32}
  33
  34savestate() {
  35        # Stash away any local modifications.
  36        git stash create >"$GIT_DIR/MERGE_STASH"
  37}
  38
  39restorestate() {
  40        if test -f "$GIT_DIR/MERGE_STASH"
  41        then
  42                git reset --hard $head >/dev/null
  43                git stash apply $(cat "$GIT_DIR/MERGE_STASH")
  44                git update-index --refresh >/dev/null
  45        fi
  46}
  47
  48finish_up_to_date () {
  49        case "$squash" in
  50        t)
  51                echo "$1 (nothing to squash)" ;;
  52        '')
  53                echo "$1" ;;
  54        esac
  55        dropsave
  56}
  57
  58squash_message () {
  59        echo Squashed commit of the following:
  60        echo
  61        git log --no-merges ^"$head" $remote
  62}
  63
  64finish () {
  65        if test '' = "$2"
  66        then
  67                rlogm="$GIT_REFLOG_ACTION"
  68        else
  69                echo "$2"
  70                rlogm="$GIT_REFLOG_ACTION: $2"
  71        fi
  72        case "$squash" in
  73        t)
  74                echo "Squash commit -- not updating HEAD"
  75                squash_message >"$GIT_DIR/SQUASH_MSG"
  76                ;;
  77        '')
  78                case "$merge_msg" in
  79                '')
  80                        echo "No merge message -- not updating HEAD"
  81                        ;;
  82                *)
  83                        git update-ref -m "$rlogm" HEAD "$1" "$head" || exit 1
  84                        ;;
  85                esac
  86                ;;
  87        esac
  88        case "$1" in
  89        '')
  90                ;;
  91        ?*)
  92                if test "$show_diffstat" = t
  93                then
  94                        # We want color (if set), but no pager
  95                        GIT_PAGER='' git diff --stat --summary -M "$head" "$1"
  96                fi
  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 "$1" in
 127        -n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
 128                --no-summa|--no-summar|--no-summary)
 129                show_diffstat=false ;;
 130        --summary)
 131                show_diffstat=t ;;
 132        --sq|--squ|--squa|--squas|--squash)
 133                squash=t no_commit=t ;;
 134        --no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
 135                no_commit=t ;;
 136        -s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
 137                --strateg=*|--strategy=*|\
 138        -s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
 139                case "$#,$1" in
 140                *,*=*)
 141                        strategy=`expr "z$1" : 'z-[^=]*=\(.*\)'` ;;
 142                1,*)
 143                        usage ;;
 144                *)
 145                        strategy="$2"
 146                        shift ;;
 147                esac
 148                case " $all_strategies " in
 149                *" $strategy "*)
 150                        use_strategies="$use_strategies$strategy " ;;
 151                *)
 152                        die "available strategies are: $all_strategies" ;;
 153                esac
 154                ;;
 155        -m=*|--m=*|--me=*|--mes=*|--mess=*|--messa=*|--messag=*|--message=*)
 156                merge_msg=`expr "z$1" : 'z-[^=]*=\(.*\)'`
 157                have_message=t
 158                ;;
 159        -m|--m|--me|--mes|--mess|--messa|--messag|--message)
 160                shift
 161                case "$#" in
 162                1)      usage ;;
 163                esac
 164                merge_msg="$1"
 165                have_message=t
 166                ;;
 167        -*)     usage ;;
 168        *)      break ;;
 169        esac
 170        shift
 171done
 172
 173if test -z "$show_diffstat"; then
 174    test "$(git config --bool merge.diffstat)" = false && show_diffstat=false
 175    test -z "$show_diffstat" && show_diffstat=t
 176fi
 177
 178# This could be traditional "merge <msg> HEAD <commit>..."  and the
 179# way we can tell it is to see if the second token is HEAD, but some
 180# people might have misused the interface and used a committish that
 181# is the same as HEAD there instead.  Traditional format never would
 182# have "-m" so it is an additional safety measure to check for it.
 183
 184if test -z "$have_message" &&
 185        second_token=$(git rev-parse --verify "$2^0" 2>/dev/null) &&
 186        head_commit=$(git rev-parse --verify "HEAD" 2>/dev/null) &&
 187        test "$second_token" = "$head_commit"
 188then
 189        merge_msg="$1"
 190        shift
 191        head_arg="$1"
 192        shift
 193elif ! git rev-parse --verify HEAD >/dev/null 2>&1
 194then
 195        # If the merged head is a valid one there is no reason to
 196        # forbid "git merge" into a branch yet to be born.  We do
 197        # the same for "git pull".
 198        if test 1 -ne $#
 199        then
 200                echo >&2 "Can merge only exactly one commit into empty head"
 201                exit 1
 202        fi
 203
 204        rh=$(git rev-parse --verify "$1^0") ||
 205                die "$1 - not something we can merge"
 206
 207        git update-ref -m "initial pull" HEAD "$rh" "" &&
 208        git read-tree --reset -u HEAD
 209        exit
 210
 211else
 212        # We are invoked directly as the first-class UI.
 213        head_arg=HEAD
 214
 215        # All the rest are the commits being merged; prepare
 216        # the standard merge summary message to be appended to
 217        # the given message.  If remote is invalid we will die
 218        # later in the common codepath so we discard the error
 219        # in this loop.
 220        merge_name=$(for remote
 221                do
 222                        merge_name "$remote"
 223                done | git fmt-merge-msg
 224        )
 225        merge_msg="${merge_msg:+$merge_msg$LF$LF}$merge_name"
 226fi
 227head=$(git rev-parse --verify "$head_arg"^0) || usage
 228
 229# All the rest are remote heads
 230test "$#" = 0 && usage ;# we need at least one remote head.
 231set_reflog_action "merge $*"
 232
 233remoteheads=
 234for remote
 235do
 236        remotehead=$(git rev-parse --verify "$remote"^0 2>/dev/null) ||
 237            die "$remote - not something we can merge"
 238        remoteheads="${remoteheads}$remotehead "
 239        eval GITHEAD_$remotehead='"$remote"'
 240        export GITHEAD_$remotehead
 241done
 242set x $remoteheads ; shift
 243
 244case "$use_strategies" in
 245'')
 246        case "$#" in
 247        1)
 248                var="`git config --get pull.twohead`"
 249                if test -n "$var"
 250                then
 251                        use_strategies="$var"
 252                else
 253                        use_strategies="$default_twohead_strategies"
 254                fi ;;
 255        *)
 256                var="`git config --get pull.octopus`"
 257                if test -n "$var"
 258                then
 259                        use_strategies="$var"
 260                else
 261                        use_strategies="$default_octopus_strategies"
 262                fi ;;
 263        esac
 264        ;;
 265esac
 266
 267for s in $use_strategies
 268do
 269        for ss in $no_fast_forward_strategies
 270        do
 271                case " $s " in
 272                *" $ss "*)
 273                        allow_fast_forward=f
 274                        break
 275                        ;;
 276                esac
 277        done
 278        for ss in $no_trivial_strategies
 279        do
 280                case " $s " in
 281                *" $ss "*)
 282                        allow_trivial_merge=f
 283                        break
 284                        ;;
 285                esac
 286        done
 287done
 288
 289case "$#" in
 2901)
 291        common=$(git merge-base --all $head "$@")
 292        ;;
 293*)
 294        common=$(git show-branch --merge-base $head "$@")
 295        ;;
 296esac
 297echo "$head" >"$GIT_DIR/ORIG_HEAD"
 298
 299case "$allow_fast_forward,$#,$common,$no_commit" in
 300?,*,'',*)
 301        # No common ancestors found. We need a real merge.
 302        ;;
 303?,1,"$1",*)
 304        # If head can reach all the merge then we are up to date.
 305        # but first the most common case of merging one remote.
 306        finish_up_to_date "Already up-to-date."
 307        exit 0
 308        ;;
 309t,1,"$head",*)
 310        # Again the most common case of merging one remote.
 311        echo "Updating $(git rev-parse --short $head)..$(git rev-parse --short $1)"
 312        git update-index --refresh 2>/dev/null
 313        msg="Fast forward"
 314        if test -n "$have_message"
 315        then
 316                msg="$msg (no commit created; -m option ignored)"
 317        fi
 318        new_head=$(git rev-parse --verify "$1^0") &&
 319        git read-tree -v -m -u --exclude-per-directory=.gitignore $head "$new_head" &&
 320        finish "$new_head" "$msg" || exit
 321        dropsave
 322        exit 0
 323        ;;
 324?,1,?*"$LF"?*,*)
 325        # We are not doing octopus and not fast forward.  Need a
 326        # real merge.
 327        ;;
 328?,1,*,)
 329        # We are not doing octopus, not fast forward, and have only
 330        # one common.
 331        git update-index --refresh 2>/dev/null
 332        case "$allow_trivial_merge" in
 333        t)
 334                # See if it is really trivial.
 335                git var GIT_COMMITTER_IDENT >/dev/null || exit
 336                echo "Trying really trivial in-index merge..."
 337                if git read-tree --trivial -m -u -v $common $head "$1" &&
 338                   result_tree=$(git write-tree)
 339                then
 340                        echo "Wonderful."
 341                        result_commit=$(
 342                                printf '%s\n' "$merge_msg" |
 343                                git commit-tree $result_tree -p HEAD -p "$1"
 344                        ) || exit
 345                        finish "$result_commit" "In-index merge"
 346                        dropsave
 347                        exit 0
 348                fi
 349                echo "Nope."
 350        esac
 351        ;;
 352*)
 353        # An octopus.  If we can reach all the remote we are up to date.
 354        up_to_date=t
 355        for remote
 356        do
 357                common_one=$(git merge-base --all $head $remote)
 358                if test "$common_one" != "$remote"
 359                then
 360                        up_to_date=f
 361                        break
 362                fi
 363        done
 364        if test "$up_to_date" = t
 365        then
 366                finish_up_to_date "Already up-to-date. Yeeah!"
 367                exit 0
 368        fi
 369        ;;
 370esac
 371
 372# We are going to make a new commit.
 373git var GIT_COMMITTER_IDENT >/dev/null || exit
 374
 375# At this point, we need a real merge.  No matter what strategy
 376# we use, it would operate on the index, possibly affecting the
 377# working tree, and when resolved cleanly, have the desired tree
 378# in the index -- this means that the index must be in sync with
 379# the $head commit.  The strategies are responsible to ensure this.
 380
 381case "$use_strategies" in
 382?*' '?*)
 383    # Stash away the local changes so that we can try more than one.
 384    savestate
 385    single_strategy=no
 386    ;;
 387*)
 388    rm -f "$GIT_DIR/MERGE_STASH"
 389    single_strategy=yes
 390    ;;
 391esac
 392
 393result_tree= best_cnt=-1 best_strategy= wt_strategy=
 394merge_was_ok=
 395for strategy in $use_strategies
 396do
 397    test "$wt_strategy" = '' || {
 398        echo "Rewinding the tree to pristine..."
 399        restorestate
 400    }
 401    case "$single_strategy" in
 402    no)
 403        echo "Trying merge strategy $strategy..."
 404        ;;
 405    esac
 406
 407    # Remember which strategy left the state in the working tree
 408    wt_strategy=$strategy
 409
 410    git-merge-$strategy $common -- "$head_arg" "$@"
 411    exit=$?
 412    if test "$no_commit" = t && test "$exit" = 0
 413    then
 414        merge_was_ok=t
 415        exit=1 ;# pretend it left conflicts.
 416    fi
 417
 418    test "$exit" = 0 || {
 419
 420        # The backend exits with 1 when conflicts are left to be resolved,
 421        # with 2 when it does not handle the given merge at all.
 422
 423        if test "$exit" -eq 1
 424        then
 425            cnt=`{
 426                git diff-files --name-only
 427                git ls-files --unmerged
 428            } | wc -l`
 429            if test $best_cnt -le 0 -o $cnt -le $best_cnt
 430            then
 431                best_strategy=$strategy
 432                best_cnt=$cnt
 433            fi
 434        fi
 435        continue
 436    }
 437
 438    # Automerge succeeded.
 439    result_tree=$(git write-tree) && break
 440done
 441
 442# If we have a resulting tree, that means the strategy module
 443# auto resolved the merge cleanly.
 444if test '' != "$result_tree"
 445then
 446    parents=$(git show-branch --independent "$head" "$@" | sed -e 's/^/-p /')
 447    result_commit=$(printf '%s\n' "$merge_msg" | git commit-tree $result_tree $parents) || exit
 448    finish "$result_commit" "Merge made by $wt_strategy."
 449    dropsave
 450    exit 0
 451fi
 452
 453# Pick the result from the best strategy and have the user fix it up.
 454case "$best_strategy" in
 455'')
 456        restorestate
 457        case "$use_strategies" in
 458        ?*' '?*)
 459                echo >&2 "No merge strategy handled the merge."
 460                ;;
 461        *)
 462                echo >&2 "Merge with strategy $use_strategies failed."
 463                ;;
 464        esac
 465        exit 2
 466        ;;
 467"$wt_strategy")
 468        # We already have its result in the working tree.
 469        ;;
 470*)
 471        echo "Rewinding the tree to pristine..."
 472        restorestate
 473        echo "Using the $best_strategy to prepare resolving by hand."
 474        git-merge-$best_strategy $common -- "$head_arg" "$@"
 475        ;;
 476esac
 477
 478if test "$squash" = t
 479then
 480        finish
 481else
 482        for remote
 483        do
 484                echo $remote
 485        done >"$GIT_DIR/MERGE_HEAD"
 486        printf '%s\n' "$merge_msg" >"$GIT_DIR/MERGE_MSG"
 487fi
 488
 489if test "$merge_was_ok" = t
 490then
 491        echo >&2 \
 492        "Automatic merge went well; stopped before committing as requested"
 493        exit 0
 494else
 495        {
 496            echo '
 497Conflicts:
 498'
 499                git ls-files --unmerged |
 500                sed -e 's/^[^   ]*      /       /' |
 501                uniq
 502        } >>"$GIT_DIR/MERGE_MSG"
 503        git rerere
 504        die "Automatic merge failed; fix conflicts and then commit the result."
 505fi