Andrew's git / gitweb.git / git-merge.sh
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git-merge.shon commit git-merge: add support for --commit and --no-squash (d08af0a)
   1#!/bin/sh
   2#
   3# Copyright (c) 2005 Junio C Hamano
   4#
   5
   6USAGE='[-n] [--summary] [--[no-]commit] [--[no-]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_SAVE" || exit 1
  32}
  33
  34savestate() {
  35        # Stash away any local modifications.
  36        git diff-index -z --name-only $head |
  37        cpio -0 -o >"$GIT_DIR/MERGE_SAVE"
  38}
  39
  40restorestate() {
  41        if test -f "$GIT_DIR/MERGE_SAVE"
  42        then
  43                git reset --hard $head >/dev/null
  44                cpio -iuv <"$GIT_DIR/MERGE_SAVE"
  45                git update-index --refresh >/dev/null
  46        fi
  47}
  48
  49finish_up_to_date () {
  50        case "$squash" in
  51        t)
  52                echo "$1 (nothing to squash)" ;;
  53        '')
  54                echo "$1" ;;
  55        esac
  56        dropsave
  57}
  58
  59squash_message () {
  60        echo Squashed commit of the following:
  61        echo
  62        git log --no-merges ^"$head" $remoteheads
  63}
  64
  65finish () {
  66        if test '' = "$2"
  67        then
  68                rlogm="$GIT_REFLOG_ACTION"
  69        else
  70                echo "$2"
  71                rlogm="$GIT_REFLOG_ACTION: $2"
  72        fi
  73        case "$squash" in
  74        t)
  75                echo "Squash commit -- not updating HEAD"
  76                squash_message >"$GIT_DIR/SQUASH_MSG"
  77                ;;
  78        '')
  79                case "$merge_msg" in
  80                '')
  81                        echo "No merge message -- not updating HEAD"
  82                        ;;
  83                *)
  84                        git update-ref -m "$rlogm" HEAD "$1" "$head" || exit 1
  85                        ;;
  86                esac
  87                ;;
  88        esac
  89        case "$1" in
  90        '')
  91                ;;
  92        ?*)
  93                if test "$show_diffstat" = t
  94                then
  95                        # We want color (if set), but no pager
  96                        GIT_PAGER='' git diff --stat --summary -M "$head" "$1"
  97                fi
  98                ;;
  99        esac
 100}
 101
 102merge_name () {
 103        remote="$1"
 104        rh=$(git rev-parse --verify "$remote^0" 2>/dev/null) || return
 105        bh=$(git show-ref -s --verify "refs/heads/$remote" 2>/dev/null)
 106        if test "$rh" = "$bh"
 107        then
 108                echo "$rh               branch '$remote' of ."
 109        elif truname=$(expr "$remote" : '\(.*\)~[1-9][0-9]*$') &&
 110                git show-ref -q --verify "refs/heads/$truname" 2>/dev/null
 111        then
 112                echo "$rh               branch '$truname' (early part) of ."
 113        elif test "$remote" = "FETCH_HEAD" -a -r "$GIT_DIR/FETCH_HEAD"
 114        then
 115                sed -e 's/      not-for-merge   /               /' -e 1q \
 116                        "$GIT_DIR/FETCH_HEAD"
 117        else
 118                echo "$rh               commit '$remote'"
 119        fi
 120}
 121
 122parse_option () {
 123        case "$1" in
 124        -n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
 125                --no-summa|--no-summar|--no-summary)
 126                show_diffstat=false ;;
 127        --summary)
 128                show_diffstat=t ;;
 129        --sq|--squ|--squa|--squas|--squash)
 130                squash=t no_commit=t ;;
 131        --no-sq|--no-squ|--no-squa|--no-squas|--no-squash)
 132                squash= no_commit= ;;
 133        --c|--co|--com|--comm|--commi|--commit)
 134                squash= no_commit= ;;
 135        --no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
 136                squash= no_commit=t ;;
 137        -s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
 138                --strateg=*|--strategy=*|\
 139        -s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
 140                case "$#,$1" in
 141                *,*=*)
 142                        strategy=`expr "z$1" : 'z-[^=]*=\(.*\)'` ;;
 143                1,*)
 144                        usage ;;
 145                *)
 146                        strategy="$2"
 147                        shift ;;
 148                esac
 149                case " $all_strategies " in
 150                *" $strategy "*)
 151                        use_strategies="$use_strategies$strategy " ;;
 152                *)
 153                        die "available strategies are: $all_strategies" ;;
 154                esac
 155                ;;
 156        -m=*|--m=*|--me=*|--mes=*|--mess=*|--messa=*|--messag=*|--message=*)
 157                merge_msg=`expr "z$1" : 'z-[^=]*=\(.*\)'`
 158                have_message=t
 159                ;;
 160        -m|--m|--me|--mes|--mess|--messa|--messag|--message)
 161                shift
 162                case "$#" in
 163                1)      usage ;;
 164                esac
 165                merge_msg="$1"
 166                have_message=t
 167                ;;
 168        -*)     usage ;;
 169        *)      return 1 ;;
 170        esac
 171        shift
 172        args_left=$#
 173}
 174
 175parse_config () {
 176        while test $# -gt 0
 177        do
 178                parse_option "$@" || usage
 179                while test $args_left -lt $#
 180                do
 181                        shift
 182                done
 183        done
 184}
 185
 186test $# != 0 || usage
 187
 188have_message=
 189
 190if branch=$(git-symbolic-ref -q HEAD)
 191then
 192        mergeopts=$(git config "branch.${branch#refs/heads/}.mergeoptions")
 193        if test -n "$mergeopts"
 194        then
 195                parse_config $mergeopts
 196        fi
 197fi
 198
 199while parse_option "$@"
 200do
 201        while test $args_left -lt $#
 202        do
 203                shift
 204        done
 205done
 206
 207if test -z "$show_diffstat"; then
 208    test "$(git config --bool merge.diffstat)" = false && show_diffstat=false
 209    test -z "$show_diffstat" && show_diffstat=t
 210fi
 211
 212# This could be traditional "merge <msg> HEAD <commit>..."  and the
 213# way we can tell it is to see if the second token is HEAD, but some
 214# people might have misused the interface and used a committish that
 215# is the same as HEAD there instead.  Traditional format never would
 216# have "-m" so it is an additional safety measure to check for it.
 217
 218if test -z "$have_message" &&
 219        second_token=$(git rev-parse --verify "$2^0" 2>/dev/null) &&
 220        head_commit=$(git rev-parse --verify "HEAD" 2>/dev/null) &&
 221        test "$second_token" = "$head_commit"
 222then
 223        merge_msg="$1"
 224        shift
 225        head_arg="$1"
 226        shift
 227elif ! git rev-parse --verify HEAD >/dev/null 2>&1
 228then
 229        # If the merged head is a valid one there is no reason to
 230        # forbid "git merge" into a branch yet to be born.  We do
 231        # the same for "git pull".
 232        if test 1 -ne $#
 233        then
 234                echo >&2 "Can merge only exactly one commit into empty head"
 235                exit 1
 236        fi
 237
 238        rh=$(git rev-parse --verify "$1^0") ||
 239                die "$1 - not something we can merge"
 240
 241        git update-ref -m "initial pull" HEAD "$rh" "" &&
 242        git read-tree --reset -u HEAD
 243        exit
 244
 245else
 246        # We are invoked directly as the first-class UI.
 247        head_arg=HEAD
 248
 249        # All the rest are the commits being merged; prepare
 250        # the standard merge summary message to be appended to
 251        # the given message.  If remote is invalid we will die
 252        # later in the common codepath so we discard the error
 253        # in this loop.
 254        merge_name=$(for remote
 255                do
 256                        merge_name "$remote"
 257                done | git fmt-merge-msg
 258        )
 259        merge_msg="${merge_msg:+$merge_msg$LF$LF}$merge_name"
 260fi
 261head=$(git rev-parse --verify "$head_arg"^0) || usage
 262
 263# All the rest are remote heads
 264test "$#" = 0 && usage ;# we need at least one remote head.
 265set_reflog_action "merge $*"
 266
 267remoteheads=
 268for remote
 269do
 270        remotehead=$(git rev-parse --verify "$remote"^0 2>/dev/null) ||
 271            die "$remote - not something we can merge"
 272        remoteheads="${remoteheads}$remotehead "
 273        eval GITHEAD_$remotehead='"$remote"'
 274        export GITHEAD_$remotehead
 275done
 276set x $remoteheads ; shift
 277
 278case "$use_strategies" in
 279'')
 280        case "$#" in
 281        1)
 282                var="`git config --get pull.twohead`"
 283                if test -n "$var"
 284                then
 285                        use_strategies="$var"
 286                else
 287                        use_strategies="$default_twohead_strategies"
 288                fi ;;
 289        *)
 290                var="`git config --get pull.octopus`"
 291                if test -n "$var"
 292                then
 293                        use_strategies="$var"
 294                else
 295                        use_strategies="$default_octopus_strategies"
 296                fi ;;
 297        esac
 298        ;;
 299esac
 300
 301for s in $use_strategies
 302do
 303        for ss in $no_fast_forward_strategies
 304        do
 305                case " $s " in
 306                *" $ss "*)
 307                        allow_fast_forward=f
 308                        break
 309                        ;;
 310                esac
 311        done
 312        for ss in $no_trivial_strategies
 313        do
 314                case " $s " in
 315                *" $ss "*)
 316                        allow_trivial_merge=f
 317                        break
 318                        ;;
 319                esac
 320        done
 321done
 322
 323case "$#" in
 3241)
 325        common=$(git merge-base --all $head "$@")
 326        ;;
 327*)
 328        common=$(git show-branch --merge-base $head "$@")
 329        ;;
 330esac
 331echo "$head" >"$GIT_DIR/ORIG_HEAD"
 332
 333case "$allow_fast_forward,$#,$common,$no_commit" in
 334?,*,'',*)
 335        # No common ancestors found. We need a real merge.
 336        ;;
 337?,1,"$1",*)
 338        # If head can reach all the merge then we are up to date.
 339        # but first the most common case of merging one remote.
 340        finish_up_to_date "Already up-to-date."
 341        exit 0
 342        ;;
 343t,1,"$head",*)
 344        # Again the most common case of merging one remote.
 345        echo "Updating $(git rev-parse --short $head)..$(git rev-parse --short $1)"
 346        git update-index --refresh 2>/dev/null
 347        msg="Fast forward"
 348        if test -n "$have_message"
 349        then
 350                msg="$msg (no commit created; -m option ignored)"
 351        fi
 352        new_head=$(git rev-parse --verify "$1^0") &&
 353        git read-tree -v -m -u --exclude-per-directory=.gitignore $head "$new_head" &&
 354        finish "$new_head" "$msg" || exit
 355        dropsave
 356        exit 0
 357        ;;
 358?,1,?*"$LF"?*,*)
 359        # We are not doing octopus and not fast forward.  Need a
 360        # real merge.
 361        ;;
 362?,1,*,)
 363        # We are not doing octopus, not fast forward, and have only
 364        # one common.
 365        git update-index --refresh 2>/dev/null
 366        case "$allow_trivial_merge" in
 367        t)
 368                # See if it is really trivial.
 369                git var GIT_COMMITTER_IDENT >/dev/null || exit
 370                echo "Trying really trivial in-index merge..."
 371                if git read-tree --trivial -m -u -v $common $head "$1" &&
 372                   result_tree=$(git write-tree)
 373                then
 374                        echo "Wonderful."
 375                        result_commit=$(
 376                                printf '%s\n' "$merge_msg" |
 377                                git commit-tree $result_tree -p HEAD -p "$1"
 378                        ) || exit
 379                        finish "$result_commit" "In-index merge"
 380                        dropsave
 381                        exit 0
 382                fi
 383                echo "Nope."
 384        esac
 385        ;;
 386*)
 387        # An octopus.  If we can reach all the remote we are up to date.
 388        up_to_date=t
 389        for remote
 390        do
 391                common_one=$(git merge-base --all $head $remote)
 392                if test "$common_one" != "$remote"
 393                then
 394                        up_to_date=f
 395                        break
 396                fi
 397        done
 398        if test "$up_to_date" = t
 399        then
 400                finish_up_to_date "Already up-to-date. Yeeah!"
 401                exit 0
 402        fi
 403        ;;
 404esac
 405
 406# We are going to make a new commit.
 407git var GIT_COMMITTER_IDENT >/dev/null || exit
 408
 409# At this point, we need a real merge.  No matter what strategy
 410# we use, it would operate on the index, possibly affecting the
 411# working tree, and when resolved cleanly, have the desired tree
 412# in the index -- this means that the index must be in sync with
 413# the $head commit.  The strategies are responsible to ensure this.
 414
 415case "$use_strategies" in
 416?*' '?*)
 417    # Stash away the local changes so that we can try more than one.
 418    savestate
 419    single_strategy=no
 420    ;;
 421*)
 422    rm -f "$GIT_DIR/MERGE_SAVE"
 423    single_strategy=yes
 424    ;;
 425esac
 426
 427result_tree= best_cnt=-1 best_strategy= wt_strategy=
 428merge_was_ok=
 429for strategy in $use_strategies
 430do
 431    test "$wt_strategy" = '' || {
 432        echo "Rewinding the tree to pristine..."
 433        restorestate
 434    }
 435    case "$single_strategy" in
 436    no)
 437        echo "Trying merge strategy $strategy..."
 438        ;;
 439    esac
 440
 441    # Remember which strategy left the state in the working tree
 442    wt_strategy=$strategy
 443
 444    git-merge-$strategy $common -- "$head_arg" "$@"
 445    exit=$?
 446    if test "$no_commit" = t && test "$exit" = 0
 447    then
 448        merge_was_ok=t
 449        exit=1 ;# pretend it left conflicts.
 450    fi
 451
 452    test "$exit" = 0 || {
 453
 454        # The backend exits with 1 when conflicts are left to be resolved,
 455        # with 2 when it does not handle the given merge at all.
 456
 457        if test "$exit" -eq 1
 458        then
 459            cnt=`{
 460                git diff-files --name-only
 461                git ls-files --unmerged
 462            } | wc -l`
 463            if test $best_cnt -le 0 -o $cnt -le $best_cnt
 464            then
 465                best_strategy=$strategy
 466                best_cnt=$cnt
 467            fi
 468        fi
 469        continue
 470    }
 471
 472    # Automerge succeeded.
 473    result_tree=$(git write-tree) && break
 474done
 475
 476# If we have a resulting tree, that means the strategy module
 477# auto resolved the merge cleanly.
 478if test '' != "$result_tree"
 479then
 480    parents=$(git show-branch --independent "$head" "$@" | sed -e 's/^/-p /')
 481    result_commit=$(printf '%s\n' "$merge_msg" | git commit-tree $result_tree $parents) || exit
 482    finish "$result_commit" "Merge made by $wt_strategy."
 483    dropsave
 484    exit 0
 485fi
 486
 487# Pick the result from the best strategy and have the user fix it up.
 488case "$best_strategy" in
 489'')
 490        restorestate
 491        case "$use_strategies" in
 492        ?*' '?*)
 493                echo >&2 "No merge strategy handled the merge."
 494                ;;
 495        *)
 496                echo >&2 "Merge with strategy $use_strategies failed."
 497                ;;
 498        esac
 499        exit 2
 500        ;;
 501"$wt_strategy")
 502        # We already have its result in the working tree.
 503        ;;
 504*)
 505        echo "Rewinding the tree to pristine..."
 506        restorestate
 507        echo "Using the $best_strategy to prepare resolving by hand."
 508        git-merge-$best_strategy $common -- "$head_arg" "$@"
 509        ;;
 510esac
 511
 512if test "$squash" = t
 513then
 514        finish
 515else
 516        for remote
 517        do
 518                echo $remote
 519        done >"$GIT_DIR/MERGE_HEAD"
 520        printf '%s\n' "$merge_msg" >"$GIT_DIR/MERGE_MSG"
 521fi
 522
 523if test "$merge_was_ok" = t
 524then
 525        echo >&2 \
 526        "Automatic merge went well; stopped before committing as requested"
 527        exit 0
 528else
 529        {
 530            echo '
 531Conflicts:
 532'
 533                git ls-files --unmerged |
 534                sed -e 's/^[^   ]*      /       /' |
 535                uniq
 536        } >>"$GIT_DIR/MERGE_MSG"
 537        git rerere
 538        die "Automatic merge failed; fix conflicts and then commit the result."
 539fi