contrib/examples/git-merge.sh

   1 #!/bin/sh
   2 #
   3 # Copyright (c) 2005 Junio C Hamano
   4 #
   5
   6 OPTIONS_KEEPDASHDASH=
   7 OPTIONS_SPEC="\
   8 git merge [options] <remote>...
   9 git merge [options] <msg> HEAD <remote>
  10 --
  11 stat                 show a diffstat at the end of the merge
  12 n                    don't show a diffstat at the end of the merge
  13 summary              (synonym to --stat)
  14 log                  add list of one-line log to merge commit message
  15 squash               create a single commit instead of doing a merge
  16 commit               perform a commit if the merge succeeds (default)
  17 ff                   allow fast-forward (default)
  18 s,strategy=          merge strategy to use
  19 X=                   option for selected merge strategy
  20 m,message=           message to be used for the merge commit (if any)
  21 "
  22
  23 SUBDIRECTORY_OK=Yes
  24 . git-sh-setup
  25 require_work_tree
  26 cd_to_toplevel
  27
  28 test -z "$(git ls-files -u)" ||
  29         die "Merge is not possible because you have unmerged files."
  30
  31 ! test -e "$GIT_DIR/MERGE_HEAD" ||
  32         die 'You have not concluded your merge (MERGE_HEAD exists).'
  33
  34 LF='
  35 '
  36
  37 all_strategies='recur recursive octopus resolve stupid ours subtree'
  38 all_strategies="$all_strategies recursive-ours recursive-theirs"
  39 not_strategies='base file index tree'
  40 default_twohead_strategies='recursive'
  41 default_octopus_strategies='octopus'
  42 no_fast_forward_strategies='subtree ours'
  43 no_trivial_strategies='recursive recur subtree ours recursive-ours recursive-theirs'
  44 use_strategies=
  45 xopt=
  46
  47 allow_fast_forward=t
  48 allow_trivial_merge=t
  49 squash= no_commit= log_arg=
  50
  51 dropsave() {
  52         rm -f -- "$GIT_DIR/MERGE_HEAD" "$GIT_DIR/MERGE_MSG" \
  53                  "$GIT_DIR/MERGE_STASH" || exit 1
  54 }
  55
  56 savestate() {
  57         # Stash away any local modifications.
  58         git stash create >"$GIT_DIR/MERGE_STASH"
  59 }
  60
  61 restorestate() {
  62         if test -f "$GIT_DIR/MERGE_STASH"
  63         then
  64                 git reset --hard $head >/dev/null
  65                 git stash apply $(cat "$GIT_DIR/MERGE_STASH")
  66                 git update-index --refresh >/dev/null
  67         fi
  68 }
  69
  70 finish_up_to_date () {
  71         case "$squash" in
  72         t)
  73                 echo "$1 (nothing to squash)" ;;
  74         '')
  75                 echo "$1" ;;
  76         esac
  77         dropsave
  78 }
  79
  80 squash_message () {
  81         echo Squashed commit of the following:
  82         echo
  83         git log --no-merges --pretty=medium ^"$head" $remoteheads
  84 }
  85
  86 finish () {
  87         if test '' = "$2"
  88         then
  89                 rlogm="$GIT_REFLOG_ACTION"
  90         else
  91                 echo "$2"
  92                 rlogm="$GIT_REFLOG_ACTION: $2"
  93         fi
  94         case "$squash" in
  95         t)
  96                 echo "Squash commit -- not updating HEAD"
  97                 squash_message >"$GIT_DIR/SQUASH_MSG"
  98                 ;;
  99         '')
 100                 case "$merge_msg" in
 101                 '')
 102                         echo "No merge message -- not updating HEAD"
 103                         ;;
 104                 *)
 105                         git update-ref -m "$rlogm" HEAD "$1" "$head" || exit 1
 106                         git gc --auto
 107                         ;;
 108                 esac
 109                 ;;
 110         esac
 111         case "$1" in
 112         '')
 113                 ;;
 114         ?*)
 115                 if test "$show_diffstat" = t
 116                 then
 117                         # We want color (if set), but no pager
 118                         GIT_PAGER='' git diff --stat --summary -M "$head" "$1"
 119                 fi
 120                 ;;
 121         esac
 122
 123         # Run a post-merge hook
 124         if test -x "$GIT_DIR"/hooks/post-merge
 125         then
 126             case "$squash" in
 127             t)
 128                 "$GIT_DIR"/hooks/post-merge 1
 129                 ;;
 130             '')
 131                 "$GIT_DIR"/hooks/post-merge 0
 132                 ;;
 133             esac
 134         fi
 135 }
 136
 137 merge_name () {
 138         remote="$1"
 139         rh=$(git rev-parse --verify "$remote^0" 2>/dev/null) || return
 140         if truname=$(expr "$remote" : '\(.*\)~[0-9]*$') &&
 141                 git show-ref -q --verify "refs/heads/$truname" 2>/dev/null
 142         then
 143                 echo "$rh               branch '$truname' (early part) of ."
 144                 return
 145         fi
 146         if found_ref=$(git rev-parse --symbolic-full-name --verify \
 147                                                         "$remote" 2>/dev/null)
 148         then
 149                 if test "${found_ref#refs/heads/}" != "$found_ref"
 150                 then
 151                         echo "$rh               branch '$remote' of ."
 152                         return
 153                 elif test "${found_ref#refs/remotes/}" != "$found_ref"
 154                 then
 155                         echo "$rh               remote branch '$remote' of ."
 156                         return
 157                 fi
 158         fi
 159         if test "$remote" = "FETCH_HEAD" -a -r "$GIT_DIR/FETCH_HEAD"
 160         then
 161                 sed -e 's/      not-for-merge   /               /' -e 1q \
 162                         "$GIT_DIR/FETCH_HEAD"
 163                 return
 164         fi
 165         echo "$rh               commit '$remote'"
 166 }
 167
 168 parse_config () {
 169         while test $# != 0; do
 170                 case "$1" in
 171                 -n|--no-stat|--no-summary)
 172                         show_diffstat=false ;;
 173                 --stat|--summary)
 174                         show_diffstat=t ;;
 175                 --log|--no-log)
 176                         log_arg=$1 ;;
 177                 --squash)
 178                         test "$allow_fast_forward" = t ||
 179                                 die "You cannot combine --squash with --no-ff."
 180                         squash=t no_commit=t ;;
 181                 --no-squash)
 182                         squash= no_commit= ;;
 183                 --commit)
 184                         no_commit= ;;
 185                 --no-commit)
 186                         no_commit=t ;;
 187                 --ff)
 188                         allow_fast_forward=t ;;
 189                 --no-ff)
 190                         test "$squash" != t ||
 191                                 die "You cannot combine --squash with --no-ff."
 192                         allow_fast_forward=f ;;
 193                 -s|--strategy)
 194                         shift
 195                         case " $all_strategies " in
 196                         *" $1 "*)
 197                                 use_strategies="$use_strategies$1 "
 198                                 ;;
 199                         *)
 200                                 case " $not_strategies " in
 201                                 *" $1 "*)
 202                                         false
 203                                 esac &&
 204                                 type "git-merge-$1" >/dev/null 2>&1 ||
 205                                         die "available strategies are: $all_strategies"
 206                                 use_strategies="$use_strategies$1 "
 207                                 ;;
 208                         esac
 209                         ;;
 210                 -X)
 211                         shift
 212                         xopt="${xopt:+$xopt }$(git rev-parse --sq-quote "--$1")"
 213                         ;;
 214                 -m|--message)
 215                         shift
 216                         merge_msg="$1"
 217                         have_message=t
 218                         ;;
 219                 --)
 220                         shift
 221                         break ;;
 222                 *)      usage ;;
 223                 esac
 224                 shift
 225         done
 226         args_left=$#
 227 }
 228
 229 test $# != 0 || usage
 230
 231 have_message=
 232
 233 if branch=$(git-symbolic-ref -q HEAD)
 234 then
 235         mergeopts=$(git config "branch.${branch#refs/heads/}.mergeoptions")
 236         if test -n "$mergeopts"
 237         then
 238                 parse_config $mergeopts --
 239         fi
 240 fi
 241
 242 parse_config "$@"
 243 while test $args_left -lt $#; do shift; done
 244
 245 if test -z "$show_diffstat"; then
 246     test "$(git config --bool merge.diffstat)" = false && show_diffstat=false
 247     test "$(git config --bool merge.stat)" = false && show_diffstat=false
 248     test -z "$show_diffstat" && show_diffstat=t
 249 fi
 250
 251 # This could be traditional "merge <msg> HEAD <commit>..."  and the
 252 # way we can tell it is to see if the second token is HEAD, but some
 253 # people might have misused the interface and used a committish that
 254 # is the same as HEAD there instead.  Traditional format never would
 255 # have "-m" so it is an additional safety measure to check for it.
 256
 257 if test -z "$have_message" &&
 258         second_token=$(git rev-parse --verify "$2^0" 2>/dev/null) &&
 259         head_commit=$(git rev-parse --verify "HEAD" 2>/dev/null) &&
 260         test "$second_token" = "$head_commit"
 261 then
 262         merge_msg="$1"
 263         shift
 264         head_arg="$1"
 265         shift
 266 elif ! git rev-parse --verify HEAD >/dev/null 2>&1
 267 then
 268         # If the merged head is a valid one there is no reason to
 269         # forbid "git merge" into a branch yet to be born.  We do
 270         # the same for "git pull".
 271         if test 1 -ne $#
 272         then
 273                 echo >&2 "Can merge only exactly one commit into empty head"
 274                 exit 1
 275         fi
 276
 277         test "$squash" != t ||
 278                 die "Squash commit into empty head not supported yet"
 279         test "$allow_fast_forward" = t ||
 280                 die "Non-fast-forward into an empty head does not make sense"
 281         rh=$(git rev-parse --verify "$1^0") ||
 282                 die "$1 - not something we can merge"
 283
 284         git update-ref -m "initial pull" HEAD "$rh" "" &&
 285         git read-tree --reset -u HEAD
 286         exit
 287
 288 else
 289         # We are invoked directly as the first-class UI.
 290         head_arg=HEAD
 291
 292         # All the rest are the commits being merged; prepare
 293         # the standard merge summary message to be appended to
 294         # the given message.  If remote is invalid we will die
 295         # later in the common codepath so we discard the error
 296         # in this loop.
 297         merge_msg="$(
 298                 for remote
 299                 do
 300                         merge_name "$remote"
 301                 done |
 302                 if test "$have_message" = t
 303                 then
 304                         git fmt-merge-msg -m "$merge_msg" $log_arg
 305                 else
 306                         git fmt-merge-msg $log_arg
 307                 fi
 308         )"
 309 fi
 310 head=$(git rev-parse --verify "$head_arg"^0) || usage
 311
 312 # All the rest are remote heads
 313 test "$#" = 0 && usage ;# we need at least one remote head.
 314 set_reflog_action "merge $*"
 315
 316 remoteheads=
 317 for remote
 318 do
 319         remotehead=$(git rev-parse --verify "$remote"^0 2>/dev/null) ||
 320             die "$remote - not something we can merge"
 321         remoteheads="${remoteheads}$remotehead "
 322         eval GITHEAD_$remotehead='"$remote"'
 323         export GITHEAD_$remotehead
 324 done
 325 set x $remoteheads ; shift
 326
 327 case "$use_strategies" in
 328 '')
 329         case "$#" in
 330         1)
 331                 var="`git config --get pull.twohead`"
 332                 if test -n "$var"
 333                 then
 334                         use_strategies="$var"
 335                 else
 336                         use_strategies="$default_twohead_strategies"
 337                 fi ;;
 338         *)
 339                 var="`git config --get pull.octopus`"
 340                 if test -n "$var"
 341                 then
 342                         use_strategies="$var"
 343                 else
 344                         use_strategies="$default_octopus_strategies"
 345                 fi ;;
 346         esac
 347         ;;
 348 esac
 349
 350 for s in $use_strategies
 351 do
 352         for ss in $no_fast_forward_strategies
 353         do
 354                 case " $s " in
 355                 *" $ss "*)
 356                         allow_fast_forward=f
 357                         break
 358                         ;;
 359                 esac
 360         done
 361         for ss in $no_trivial_strategies
 362         do
 363                 case " $s " in
 364                 *" $ss "*)
 365                         allow_trivial_merge=f
 366                         break
 367                         ;;
 368                 esac
 369         done
 370 done
 371
 372 case "$#" in
 373 1)
 374         common=$(git merge-base --all $head "$@")
 375         ;;
 376 *)
 377         common=$(git merge-base --all --octopus $head "$@")
 378         ;;
 379 esac
 380 echo "$head" >"$GIT_DIR/ORIG_HEAD"
 381
 382 case "$allow_fast_forward,$#,$common,$no_commit" in
 383 ?,*,'',*)
 384         # No common ancestors found. We need a real merge.
 385         ;;
 386 ?,1,"$1",*)
 387         # If head can reach all the merge then we are up to date.
 388         # but first the most common case of merging one remote.
 389         finish_up_to_date "Already up-to-date."
 390         exit 0
 391         ;;
 392 t,1,"$head",*)
 393         # Again the most common case of merging one remote.
 394         echo "Updating $(git rev-parse --short $head)..$(git rev-parse --short $1)"
 395         git update-index --refresh 2>/dev/null
 396         msg="Fast-forward"
 397         if test -n "$have_message"
 398         then
 399                 msg="$msg (no commit created; -m option ignored)"
 400         fi
 401         new_head=$(git rev-parse --verify "$1^0") &&
 402         git read-tree -v -m -u --exclude-per-directory=.gitignore $head "$new_head" &&
 403         finish "$new_head" "$msg" || exit
 404         dropsave
 405         exit 0
 406         ;;
 407 ?,1,?*"$LF"?*,*)
 408         # We are not doing octopus and not fast-forward.  Need a
 409         # real merge.
 410         ;;
 411 ?,1,*,)
 412         # We are not doing octopus, not fast-forward, and have only
 413         # one common.
 414         git update-index --refresh 2>/dev/null
 415         case "$allow_trivial_merge" in
 416         t)
 417                 # See if it is really trivial.
 418                 git var GIT_COMMITTER_IDENT >/dev/null || exit
 419                 echo "Trying really trivial in-index merge..."
 420                 if git read-tree --trivial -m -u -v $common $head "$1" &&
 421                    result_tree=$(git write-tree)
 422                 then
 423                         echo "Wonderful."
 424                         result_commit=$(
 425                                 printf '%s\n' "$merge_msg" |
 426                                 git commit-tree $result_tree -p HEAD -p "$1"
 427                         ) || exit
 428                         finish "$result_commit" "In-index merge"
 429                         dropsave
 430                         exit 0
 431                 fi
 432                 echo "Nope."
 433         esac
 434         ;;
 435 *)
 436         # An octopus.  If we can reach all the remote we are up to date.
 437         up_to_date=t
 438         for remote
 439         do
 440                 common_one=$(git merge-base --all $head $remote)
 441                 if test "$common_one" != "$remote"
 442                 then
 443                         up_to_date=f
 444                         break
 445                 fi
 446         done
 447         if test "$up_to_date" = t
 448         then
 449                 finish_up_to_date "Already up-to-date. Yeeah!"
 450                 exit 0
 451         fi
 452         ;;
 453 esac
 454
 455 # We are going to make a new commit.
 456 git var GIT_COMMITTER_IDENT >/dev/null || exit
 457
 458 # At this point, we need a real merge.  No matter what strategy
 459 # we use, it would operate on the index, possibly affecting the
 460 # working tree, and when resolved cleanly, have the desired tree
 461 # in the index -- this means that the index must be in sync with
 462 # the $head commit.  The strategies are responsible to ensure this.
 463
 464 case "$use_strategies" in
 465 ?*' '?*)
 466     # Stash away the local changes so that we can try more than one.
 467     savestate
 468     single_strategy=no
 469     ;;
 470 *)
 471     rm -f "$GIT_DIR/MERGE_STASH"
 472     single_strategy=yes
 473     ;;
 474 esac
 475
 476 result_tree= best_cnt=-1 best_strategy= wt_strategy=
 477 merge_was_ok=
 478 for strategy in $use_strategies
 479 do
 480     test "$wt_strategy" = '' || {
 481         echo "Rewinding the tree to pristine..."
 482         restorestate
 483     }
 484     case "$single_strategy" in
 485     no)
 486         echo "Trying merge strategy $strategy..."
 487         ;;
 488     esac
 489
 490     # Remember which strategy left the state in the working tree
 491     wt_strategy=$strategy
 492
 493     eval 'git-merge-$strategy '"$xopt"' $common -- "$head_arg" "$@"'
 494     exit=$?
 495     if test "$no_commit" = t && test "$exit" = 0
 496     then
 497         merge_was_ok=t
 498         exit=1 ;# pretend it left conflicts.
 499     fi
 500
 501     test "$exit" = 0 || {
 502
 503         # The backend exits with 1 when conflicts are left to be resolved,
 504         # with 2 when it does not handle the given merge at all.
 505
 506         if test "$exit" -eq 1
 507         then
 508             cnt=`{
 509                 git diff-files --name-only
 510                 git ls-files --unmerged
 511             } | wc -l`
 512             if test $best_cnt -le 0 -o $cnt -le $best_cnt
 513             then
 514                 best_strategy=$strategy
 515                 best_cnt=$cnt
 516             fi
 517         fi
 518         continue
 519     }
 520
 521     # Automerge succeeded.
 522     result_tree=$(git write-tree) && break
 523 done
 524
 525 # If we have a resulting tree, that means the strategy module
 526 # auto resolved the merge cleanly.
 527 if test '' != "$result_tree"
 528 then
 529     if test "$allow_fast_forward" = "t"
 530     then
 531         parents=$(git merge-base --independent "$head" "$@")
 532     else
 533         parents=$(git rev-parse "$head" "$@")
 534     fi
 535     parents=$(echo "$parents" | sed -e 's/^/-p /')
 536     result_commit=$(printf '%s\n' "$merge_msg" | git commit-tree $result_tree $parents) || exit
 537     finish "$result_commit" "Merge made by $wt_strategy."
 538     dropsave
 539     exit 0
 540 fi
 541
 542 # Pick the result from the best strategy and have the user fix it up.
 543 case "$best_strategy" in
 544 '')
 545         restorestate
 546         case "$use_strategies" in
 547         ?*' '?*)
 548                 echo >&2 "No merge strategy handled the merge."
 549                 ;;
 550         *)
 551                 echo >&2 "Merge with strategy $use_strategies failed."
 552                 ;;
 553         esac
 554         exit 2
 555         ;;
 556 "$wt_strategy")
 557         # We already have its result in the working tree.
 558         ;;
 559 *)
 560         echo "Rewinding the tree to pristine..."
 561         restorestate
 562         echo "Using the $best_strategy to prepare resolving by hand."
 563         git-merge-$best_strategy $common -- "$head_arg" "$@"
 564         ;;
 565 esac
 566
 567 if test "$squash" = t
 568 then
 569         finish
 570 else
 571         for remote
 572         do
 573                 echo $remote
 574         done >"$GIT_DIR/MERGE_HEAD"
 575         printf '%s\n' "$merge_msg" >"$GIT_DIR/MERGE_MSG"
 576 fi
 577
 578 if test "$merge_was_ok" = t
 579 then
 580         echo >&2 \
 581         "Automatic merge went well; stopped before committing as requested"
 582         exit 0
 583 else
 584         {
 585             echo '
 586 Conflicts:
 587 '
 588                 git ls-files --unmerged |
 589                 sed -e 's/^[^   ]*      /       /' |
 590                 uniq
 591         } >>"$GIT_DIR/MERGE_MSG"
 592         git rerere
 593         die "Automatic merge failed; fix conflicts and then commit the result."
 594 fi