Andrew's git / gitweb.git / git-merge.sh
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git-merge.shon commit Fix and improve t7004 (git-tag tests) (eb9d2b9)
   1#!/bin/sh
   2#
   3# Copyright (c) 2005 Junio C Hamano
   4#
   5
   6USAGE='[-n] [--summary] [--[no-]commit] [--[no-]squash] [--[no-]ff] [-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" $remoteheads
  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                        git gc --auto
  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" "$1"
  97                fi
  98                ;;
  99        esac
 100
 101        # Run a post-merge hook
 102        if test -x "$GIT_DIR"/hooks/post-merge
 103        then
 104            case "$squash" in
 105            t)
 106                "$GIT_DIR"/hooks/post-merge 1
 107                ;;
 108            '')
 109                "$GIT_DIR"/hooks/post-merge 0
 110                ;;
 111            esac
 112        fi
 113}
 114
 115merge_name () {
 116        remote="$1"
 117        rh=$(git rev-parse --verify "$remote^0" 2>/dev/null) || return
 118        bh=$(git show-ref -s --verify "refs/heads/$remote" 2>/dev/null)
 119        if test "$rh" = "$bh"
 120        then
 121                echo "$rh               branch '$remote' of ."
 122        elif truname=$(expr "$remote" : '\(.*\)~[1-9][0-9]*$') &&
 123                git show-ref -q --verify "refs/heads/$truname" 2>/dev/null
 124        then
 125                echo "$rh               branch '$truname' (early part) of ."
 126        elif test "$remote" = "FETCH_HEAD" -a -r "$GIT_DIR/FETCH_HEAD"
 127        then
 128                sed -e 's/      not-for-merge   /               /' -e 1q \
 129                        "$GIT_DIR/FETCH_HEAD"
 130        else
 131                echo "$rh               commit '$remote'"
 132        fi
 133}
 134
 135parse_option () {
 136        case "$1" in
 137        -n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
 138                --no-summa|--no-summar|--no-summary)
 139                show_diffstat=false ;;
 140        --summary)
 141                show_diffstat=t ;;
 142        --sq|--squ|--squa|--squas|--squash)
 143                allow_fast_forward=t squash=t no_commit=t ;;
 144        --no-sq|--no-squ|--no-squa|--no-squas|--no-squash)
 145                allow_fast_forward=t squash= no_commit= ;;
 146        --c|--co|--com|--comm|--commi|--commit)
 147                allow_fast_forward=t squash= no_commit= ;;
 148        --no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
 149                allow_fast_forward=t squash= no_commit=t ;;
 150        --ff)
 151                allow_fast_forward=t squash= no_commit= ;;
 152        --no-ff)
 153                allow_fast_forward=false squash= no_commit= ;;
 154        -s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
 155                --strateg=*|--strategy=*|\
 156        -s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
 157                case "$#,$1" in
 158                *,*=*)
 159                        strategy=`expr "z$1" : 'z-[^=]*=\(.*\)'` ;;
 160                1,*)
 161                        usage ;;
 162                *)
 163                        strategy="$2"
 164                        shift ;;
 165                esac
 166                case " $all_strategies " in
 167                *" $strategy "*)
 168                        use_strategies="$use_strategies$strategy " ;;
 169                *)
 170                        die "available strategies are: $all_strategies" ;;
 171                esac
 172                ;;
 173        -m=*|--m=*|--me=*|--mes=*|--mess=*|--messa=*|--messag=*|--message=*)
 174                merge_msg=`expr "z$1" : 'z-[^=]*=\(.*\)'`
 175                have_message=t
 176                ;;
 177        -m|--m|--me|--mes|--mess|--messa|--messag|--message)
 178                shift
 179                case "$#" in
 180                1)      usage ;;
 181                esac
 182                merge_msg="$1"
 183                have_message=t
 184                ;;
 185        -*)     usage ;;
 186        *)      return 1 ;;
 187        esac
 188        shift
 189        args_left=$#
 190}
 191
 192parse_config () {
 193        while test $# -gt 0
 194        do
 195                parse_option "$@" || usage
 196                while test $args_left -lt $#
 197                do
 198                        shift
 199                done
 200        done
 201}
 202
 203test $# != 0 || usage
 204
 205have_message=
 206
 207if branch=$(git-symbolic-ref -q HEAD)
 208then
 209        mergeopts=$(git config "branch.${branch#refs/heads/}.mergeoptions")
 210        if test -n "$mergeopts"
 211        then
 212                parse_config $mergeopts
 213        fi
 214fi
 215
 216while parse_option "$@"
 217do
 218        while test $args_left -lt $#
 219        do
 220                shift
 221        done
 222done
 223
 224if test -z "$show_diffstat"; then
 225    test "$(git config --bool merge.diffstat)" = false && show_diffstat=false
 226    test -z "$show_diffstat" && show_diffstat=t
 227fi
 228
 229# This could be traditional "merge <msg> HEAD <commit>..."  and the
 230# way we can tell it is to see if the second token is HEAD, but some
 231# people might have misused the interface and used a committish that
 232# is the same as HEAD there instead.  Traditional format never would
 233# have "-m" so it is an additional safety measure to check for it.
 234
 235if test -z "$have_message" &&
 236        second_token=$(git rev-parse --verify "$2^0" 2>/dev/null) &&
 237        head_commit=$(git rev-parse --verify "HEAD" 2>/dev/null) &&
 238        test "$second_token" = "$head_commit"
 239then
 240        merge_msg="$1"
 241        shift
 242        head_arg="$1"
 243        shift
 244elif ! git rev-parse --verify HEAD >/dev/null 2>&1
 245then
 246        # If the merged head is a valid one there is no reason to
 247        # forbid "git merge" into a branch yet to be born.  We do
 248        # the same for "git pull".
 249        if test 1 -ne $#
 250        then
 251                echo >&2 "Can merge only exactly one commit into empty head"
 252                exit 1
 253        fi
 254
 255        rh=$(git rev-parse --verify "$1^0") ||
 256                die "$1 - not something we can merge"
 257
 258        git update-ref -m "initial pull" HEAD "$rh" "" &&
 259        git read-tree --reset -u HEAD
 260        exit
 261
 262else
 263        # We are invoked directly as the first-class UI.
 264        head_arg=HEAD
 265
 266        # All the rest are the commits being merged; prepare
 267        # the standard merge summary message to be appended to
 268        # the given message.  If remote is invalid we will die
 269        # later in the common codepath so we discard the error
 270        # in this loop.
 271        merge_name=$(for remote
 272                do
 273                        merge_name "$remote"
 274                done | git fmt-merge-msg
 275        )
 276        merge_msg="${merge_msg:+$merge_msg$LF$LF}$merge_name"
 277fi
 278head=$(git rev-parse --verify "$head_arg"^0) || usage
 279
 280# All the rest are remote heads
 281test "$#" = 0 && usage ;# we need at least one remote head.
 282set_reflog_action "merge $*"
 283
 284remoteheads=
 285for remote
 286do
 287        remotehead=$(git rev-parse --verify "$remote"^0 2>/dev/null) ||
 288            die "$remote - not something we can merge"
 289        remoteheads="${remoteheads}$remotehead "
 290        eval GITHEAD_$remotehead='"$remote"'
 291        export GITHEAD_$remotehead
 292done
 293set x $remoteheads ; shift
 294
 295case "$use_strategies" in
 296'')
 297        case "$#" in
 298        1)
 299                var="`git config --get pull.twohead`"
 300                if test -n "$var"
 301                then
 302                        use_strategies="$var"
 303                else
 304                        use_strategies="$default_twohead_strategies"
 305                fi ;;
 306        *)
 307                var="`git config --get pull.octopus`"
 308                if test -n "$var"
 309                then
 310                        use_strategies="$var"
 311                else
 312                        use_strategies="$default_octopus_strategies"
 313                fi ;;
 314        esac
 315        ;;
 316esac
 317
 318for s in $use_strategies
 319do
 320        for ss in $no_fast_forward_strategies
 321        do
 322                case " $s " in
 323                *" $ss "*)
 324                        allow_fast_forward=f
 325                        break
 326                        ;;
 327                esac
 328        done
 329        for ss in $no_trivial_strategies
 330        do
 331                case " $s " in
 332                *" $ss "*)
 333                        allow_trivial_merge=f
 334                        break
 335                        ;;
 336                esac
 337        done
 338done
 339
 340case "$#" in
 3411)
 342        common=$(git merge-base --all $head "$@")
 343        ;;
 344*)
 345        common=$(git show-branch --merge-base $head "$@")
 346        ;;
 347esac
 348echo "$head" >"$GIT_DIR/ORIG_HEAD"
 349
 350case "$allow_fast_forward,$#,$common,$no_commit" in
 351?,*,'',*)
 352        # No common ancestors found. We need a real merge.
 353        ;;
 354?,1,"$1",*)
 355        # If head can reach all the merge then we are up to date.
 356        # but first the most common case of merging one remote.
 357        finish_up_to_date "Already up-to-date."
 358        exit 0
 359        ;;
 360t,1,"$head",*)
 361        # Again the most common case of merging one remote.
 362        echo "Updating $(git rev-parse --short $head)..$(git rev-parse --short $1)"
 363        git update-index --refresh 2>/dev/null
 364        msg="Fast forward"
 365        if test -n "$have_message"
 366        then
 367                msg="$msg (no commit created; -m option ignored)"
 368        fi
 369        new_head=$(git rev-parse --verify "$1^0") &&
 370        git read-tree -v -m -u --exclude-per-directory=.gitignore $head "$new_head" &&
 371        finish "$new_head" "$msg" || exit
 372        dropsave
 373        exit 0
 374        ;;
 375?,1,?*"$LF"?*,*)
 376        # We are not doing octopus and not fast forward.  Need a
 377        # real merge.
 378        ;;
 379?,1,*,)
 380        # We are not doing octopus, not fast forward, and have only
 381        # one common.
 382        git update-index --refresh 2>/dev/null
 383        case "$allow_trivial_merge" in
 384        t)
 385                # See if it is really trivial.
 386                git var GIT_COMMITTER_IDENT >/dev/null || exit
 387                echo "Trying really trivial in-index merge..."
 388                if git read-tree --trivial -m -u -v $common $head "$1" &&
 389                   result_tree=$(git write-tree)
 390                then
 391                        echo "Wonderful."
 392                        result_commit=$(
 393                                printf '%s\n' "$merge_msg" |
 394                                git commit-tree $result_tree -p HEAD -p "$1"
 395                        ) || exit
 396                        finish "$result_commit" "In-index merge"
 397                        dropsave
 398                        exit 0
 399                fi
 400                echo "Nope."
 401        esac
 402        ;;
 403*)
 404        # An octopus.  If we can reach all the remote we are up to date.
 405        up_to_date=t
 406        for remote
 407        do
 408                common_one=$(git merge-base --all $head $remote)
 409                if test "$common_one" != "$remote"
 410                then
 411                        up_to_date=f
 412                        break
 413                fi
 414        done
 415        if test "$up_to_date" = t
 416        then
 417                finish_up_to_date "Already up-to-date. Yeeah!"
 418                exit 0
 419        fi
 420        ;;
 421esac
 422
 423# We are going to make a new commit.
 424git var GIT_COMMITTER_IDENT >/dev/null || exit
 425
 426# At this point, we need a real merge.  No matter what strategy
 427# we use, it would operate on the index, possibly affecting the
 428# working tree, and when resolved cleanly, have the desired tree
 429# in the index -- this means that the index must be in sync with
 430# the $head commit.  The strategies are responsible to ensure this.
 431
 432case "$use_strategies" in
 433?*' '?*)
 434    # Stash away the local changes so that we can try more than one.
 435    savestate
 436    single_strategy=no
 437    ;;
 438*)
 439    rm -f "$GIT_DIR/MERGE_STASH"
 440    single_strategy=yes
 441    ;;
 442esac
 443
 444result_tree= best_cnt=-1 best_strategy= wt_strategy=
 445merge_was_ok=
 446for strategy in $use_strategies
 447do
 448    test "$wt_strategy" = '' || {
 449        echo "Rewinding the tree to pristine..."
 450        restorestate
 451    }
 452    case "$single_strategy" in
 453    no)
 454        echo "Trying merge strategy $strategy..."
 455        ;;
 456    esac
 457
 458    # Remember which strategy left the state in the working tree
 459    wt_strategy=$strategy
 460
 461    git-merge-$strategy $common -- "$head_arg" "$@"
 462    exit=$?
 463    if test "$no_commit" = t && test "$exit" = 0
 464    then
 465        merge_was_ok=t
 466        exit=1 ;# pretend it left conflicts.
 467    fi
 468
 469    test "$exit" = 0 || {
 470
 471        # The backend exits with 1 when conflicts are left to be resolved,
 472        # with 2 when it does not handle the given merge at all.
 473
 474        if test "$exit" -eq 1
 475        then
 476            cnt=`{
 477                git diff-files --name-only
 478                git ls-files --unmerged
 479            } | wc -l`
 480            if test $best_cnt -le 0 -o $cnt -le $best_cnt
 481            then
 482                best_strategy=$strategy
 483                best_cnt=$cnt
 484            fi
 485        fi
 486        continue
 487    }
 488
 489    # Automerge succeeded.
 490    result_tree=$(git write-tree) && break
 491done
 492
 493# If we have a resulting tree, that means the strategy module
 494# auto resolved the merge cleanly.
 495if test '' != "$result_tree"
 496then
 497    if test "$allow_fast_forward" = "t"
 498    then
 499        parents=$(git show-branch --independent "$head" "$@")
 500    else
 501        parents=$(git rev-parse "$head" "$@")
 502    fi
 503    parents=$(echo "$parents" | sed -e 's/^/-p /')
 504    result_commit=$(printf '%s\n' "$merge_msg" | git commit-tree $result_tree $parents) || exit
 505    finish "$result_commit" "Merge made by $wt_strategy."
 506    dropsave
 507    exit 0
 508fi
 509
 510# Pick the result from the best strategy and have the user fix it up.
 511case "$best_strategy" in
 512'')
 513        restorestate
 514        case "$use_strategies" in
 515        ?*' '?*)
 516                echo >&2 "No merge strategy handled the merge."
 517                ;;
 518        *)
 519                echo >&2 "Merge with strategy $use_strategies failed."
 520                ;;
 521        esac
 522        exit 2
 523        ;;
 524"$wt_strategy")
 525        # We already have its result in the working tree.
 526        ;;
 527*)
 528        echo "Rewinding the tree to pristine..."
 529        restorestate
 530        echo "Using the $best_strategy to prepare resolving by hand."
 531        git-merge-$best_strategy $common -- "$head_arg" "$@"
 532        ;;
 533esac
 534
 535if test "$squash" = t
 536then
 537        finish
 538else
 539        for remote
 540        do
 541                echo $remote
 542        done >"$GIT_DIR/MERGE_HEAD"
 543        printf '%s\n' "$merge_msg" >"$GIT_DIR/MERGE_MSG"
 544fi
 545
 546if test "$merge_was_ok" = t
 547then
 548        echo >&2 \
 549        "Automatic merge went well; stopped before committing as requested"
 550        exit 0
 551else
 552        {
 553            echo '
 554Conflicts:
 555'
 556                git ls-files --unmerged |
 557                sed -e 's/^[^   ]*      /       /' |
 558                uniq
 559        } >>"$GIT_DIR/MERGE_MSG"
 560        git rerere
 561        die "Automatic merge failed; fix conflicts and then commit the result."
 562fi