git-merge.sh

   1 #!/bin/sh
   2 #
   3 # Copyright (c) 2005 Junio C Hamano
   4 #
   5
   6 USAGE='[-n] [--summary] [--no-commit] [--squash] [-s <strategy>] [-m=<merge-message>] <commit>+'
   7
   8 SUBDIRECTORY_OK=Yes
   9 . git-sh-setup
  10 require_work_tree
  11 cd_to_toplevel
  12
  13 test -z "$(git ls-files -u)" ||
  14         die "You are in the middle of a conflicted merge."
  15
  16 LF='
  17 '
  18
  19 all_strategies='recur recursive octopus resolve stupid ours subtree'
  20 default_twohead_strategies='recursive'
  21 default_octopus_strategies='octopus'
  22 no_fast_forward_strategies='subtree ours'
  23 no_trivial_strategies='recursive recur subtree ours'
  24 use_strategies=
  25
  26 allow_fast_forward=t
  27 allow_trivial_merge=t
  28
  29 dropsave() {
  30         rm -f -- "$GIT_DIR/MERGE_HEAD" "$GIT_DIR/MERGE_MSG" \
  31                  "$GIT_DIR/MERGE_SAVE" || exit 1
  32 }
  33
  34 savestate() {
  35         # Stash away any local modifications.
  36         git diff-index -z --name-only $head |
  37         cpio -0 -o >"$GIT_DIR/MERGE_SAVE"
  38 }
  39
  40 restorestate() {
  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
  49 finish_up_to_date () {
  50         case "$squash" in
  51         t)
  52                 echo "$1 (nothing to squash)" ;;
  53         '')
  54                 echo "$1" ;;
  55         esac
  56         dropsave
  57 }
  58
  59 squash_message () {
  60         echo Squashed commit of the following:
  61         echo
  62         git log --no-merges ^"$head" $remoteheads
  63 }
  64
  65 finish () {
  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
 102 merge_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
 122 parse_option () {
 123         case "$1" in
 124         -n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
 125                 --no-summa|--no-summar|--no-summary)
 126                 show_diffstat=false ;;
 127         --summary)
 128                 show_diffstat=t ;;
 129         --sq|--squ|--squa|--squas|--squash)
 130                 squash=t no_commit=t ;;
 131         --no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
 132                 no_commit=t ;;
 133         -s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
 134                 --strateg=*|--strategy=*|\
 135         -s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
 136                 case "$#,$1" in
 137                 *,*=*)
 138                         strategy=`expr "z$1" : 'z-[^=]*=\(.*\)'` ;;
 139                 1,*)
 140                         usage ;;
 141                 *)
 142                         strategy="$2"
 143                         shift ;;
 144                 esac
 145                 case " $all_strategies " in
 146                 *" $strategy "*)
 147                         use_strategies="$use_strategies$strategy " ;;
 148                 *)
 149                         die "available strategies are: $all_strategies" ;;
 150                 esac
 151                 ;;
 152         -m=*|--m=*|--me=*|--mes=*|--mess=*|--messa=*|--messag=*|--message=*)
 153                 merge_msg=`expr "z$1" : 'z-[^=]*=\(.*\)'`
 154                 have_message=t
 155                 ;;
 156         -m|--m|--me|--mes|--mess|--messa|--messag|--message)
 157                 shift
 158                 case "$#" in
 159                 1)      usage ;;
 160                 esac
 161                 merge_msg="$1"
 162                 have_message=t
 163                 ;;
 164         -*)     usage ;;
 165         *)      return 1 ;;
 166         esac
 167         shift
 168         args_left=$#
 169 }
 170
 171 parse_config () {
 172         while test $# -gt 0
 173         do
 174                 parse_option "$@" || usage
 175                 while test $args_left -lt $#
 176                 do
 177                         shift
 178                 done
 179         done
 180 }
 181
 182 test $# != 0 || usage
 183
 184 have_message=
 185
 186 if branch=$(git-symbolic-ref -q HEAD)
 187 then
 188         mergeopts=$(git config "branch.${branch#refs/heads/}.mergeoptions")
 189         if test -n "$mergeopts"
 190         then
 191                 parse_config $mergeopts
 192         fi
 193 fi
 194
 195 while parse_option "$@"
 196 do
 197         while test $args_left -lt $#
 198         do
 199                 shift
 200         done
 201 done
 202
 203 if test -z "$show_diffstat"; then
 204     test "$(git config --bool merge.diffstat)" = false && show_diffstat=false
 205     test -z "$show_diffstat" && show_diffstat=t
 206 fi
 207
 208 # This could be traditional "merge <msg> HEAD <commit>..."  and the
 209 # way we can tell it is to see if the second token is HEAD, but some
 210 # people might have misused the interface and used a committish that
 211 # is the same as HEAD there instead.  Traditional format never would
 212 # have "-m" so it is an additional safety measure to check for it.
 213
 214 if test -z "$have_message" &&
 215         second_token=$(git rev-parse --verify "$2^0" 2>/dev/null) &&
 216         head_commit=$(git rev-parse --verify "HEAD" 2>/dev/null) &&
 217         test "$second_token" = "$head_commit"
 218 then
 219         merge_msg="$1"
 220         shift
 221         head_arg="$1"
 222         shift
 223 elif ! git rev-parse --verify HEAD >/dev/null 2>&1
 224 then
 225         # If the merged head is a valid one there is no reason to
 226         # forbid "git merge" into a branch yet to be born.  We do
 227         # the same for "git pull".
 228         if test 1 -ne $#
 229         then
 230                 echo >&2 "Can merge only exactly one commit into empty head"
 231                 exit 1
 232         fi
 233
 234         rh=$(git rev-parse --verify "$1^0") ||
 235                 die "$1 - not something we can merge"
 236
 237         git update-ref -m "initial pull" HEAD "$rh" "" &&
 238         git read-tree --reset -u HEAD
 239         exit
 240
 241 else
 242         # We are invoked directly as the first-class UI.
 243         head_arg=HEAD
 244
 245         # All the rest are the commits being merged; prepare
 246         # the standard merge summary message to be appended to
 247         # the given message.  If remote is invalid we will die
 248         # later in the common codepath so we discard the error
 249         # in this loop.
 250         merge_name=$(for remote
 251                 do
 252                         merge_name "$remote"
 253                 done | git fmt-merge-msg
 254         )
 255         merge_msg="${merge_msg:+$merge_msg$LF$LF}$merge_name"
 256 fi
 257 head=$(git rev-parse --verify "$head_arg"^0) || usage
 258
 259 # All the rest are remote heads
 260 test "$#" = 0 && usage ;# we need at least one remote head.
 261 set_reflog_action "merge $*"
 262
 263 remoteheads=
 264 for remote
 265 do
 266         remotehead=$(git rev-parse --verify "$remote"^0 2>/dev/null) ||
 267             die "$remote - not something we can merge"
 268         remoteheads="${remoteheads}$remotehead "
 269         eval GITHEAD_$remotehead='"$remote"'
 270         export GITHEAD_$remotehead
 271 done
 272 set x $remoteheads ; shift
 273
 274 case "$use_strategies" in
 275 '')
 276         case "$#" in
 277         1)
 278                 var="`git config --get pull.twohead`"
 279                 if test -n "$var"
 280                 then
 281                         use_strategies="$var"
 282                 else
 283                         use_strategies="$default_twohead_strategies"
 284                 fi ;;
 285         *)
 286                 var="`git config --get pull.octopus`"
 287                 if test -n "$var"
 288                 then
 289                         use_strategies="$var"
 290                 else
 291                         use_strategies="$default_octopus_strategies"
 292                 fi ;;
 293         esac
 294         ;;
 295 esac
 296
 297 for s in $use_strategies
 298 do
 299         for ss in $no_fast_forward_strategies
 300         do
 301                 case " $s " in
 302                 *" $ss "*)
 303                         allow_fast_forward=f
 304                         break
 305                         ;;
 306                 esac
 307         done
 308         for ss in $no_trivial_strategies
 309         do
 310                 case " $s " in
 311                 *" $ss "*)
 312                         allow_trivial_merge=f
 313                         break
 314                         ;;
 315                 esac
 316         done
 317 done
 318
 319 case "$#" in
 320 1)
 321         common=$(git merge-base --all $head "$@")
 322         ;;
 323 *)
 324         common=$(git show-branch --merge-base $head "$@")
 325         ;;
 326 esac
 327 echo "$head" >"$GIT_DIR/ORIG_HEAD"
 328
 329 case "$allow_fast_forward,$#,$common,$no_commit" in
 330 ?,*,'',*)
 331         # No common ancestors found. We need a real merge.
 332         ;;
 333 ?,1,"$1",*)
 334         # If head can reach all the merge then we are up to date.
 335         # but first the most common case of merging one remote.
 336         finish_up_to_date "Already up-to-date."
 337         exit 0
 338         ;;
 339 t,1,"$head",*)
 340         # Again the most common case of merging one remote.
 341         echo "Updating $(git rev-parse --short $head)..$(git rev-parse --short $1)"
 342         git update-index --refresh 2>/dev/null
 343         msg="Fast forward"
 344         if test -n "$have_message"
 345         then
 346                 msg="$msg (no commit created; -m option ignored)"
 347         fi
 348         new_head=$(git rev-parse --verify "$1^0") &&
 349         git read-tree -v -m -u --exclude-per-directory=.gitignore $head "$new_head" &&
 350         finish "$new_head" "$msg" || exit
 351         dropsave
 352         exit 0
 353         ;;
 354 ?,1,?*"$LF"?*,*)
 355         # We are not doing octopus and not fast forward.  Need a
 356         # real merge.
 357         ;;
 358 ?,1,*,)
 359         # We are not doing octopus, not fast forward, and have only
 360         # one common.
 361         git update-index --refresh 2>/dev/null
 362         case "$allow_trivial_merge" in
 363         t)
 364                 # See if it is really trivial.
 365                 git var GIT_COMMITTER_IDENT >/dev/null || exit
 366                 echo "Trying really trivial in-index merge..."
 367                 if git read-tree --trivial -m -u -v $common $head "$1" &&
 368                    result_tree=$(git write-tree)
 369                 then
 370                         echo "Wonderful."
 371                         result_commit=$(
 372                                 printf '%s\n' "$merge_msg" |
 373                                 git commit-tree $result_tree -p HEAD -p "$1"
 374                         ) || exit
 375                         finish "$result_commit" "In-index merge"
 376                         dropsave
 377                         exit 0
 378                 fi
 379                 echo "Nope."
 380         esac
 381         ;;
 382 *)
 383         # An octopus.  If we can reach all the remote we are up to date.
 384         up_to_date=t
 385         for remote
 386         do
 387                 common_one=$(git merge-base --all $head $remote)
 388                 if test "$common_one" != "$remote"
 389                 then
 390                         up_to_date=f
 391                         break
 392                 fi
 393         done
 394         if test "$up_to_date" = t
 395         then
 396                 finish_up_to_date "Already up-to-date. Yeeah!"
 397                 exit 0
 398         fi
 399         ;;
 400 esac
 401
 402 # We are going to make a new commit.
 403 git var GIT_COMMITTER_IDENT >/dev/null || exit
 404
 405 # At this point, we need a real merge.  No matter what strategy
 406 # we use, it would operate on the index, possibly affecting the
 407 # working tree, and when resolved cleanly, have the desired tree
 408 # in the index -- this means that the index must be in sync with
 409 # the $head commit.  The strategies are responsible to ensure this.
 410
 411 case "$use_strategies" in
 412 ?*' '?*)
 413     # Stash away the local changes so that we can try more than one.
 414     savestate
 415     single_strategy=no
 416     ;;
 417 *)
 418     rm -f "$GIT_DIR/MERGE_SAVE"
 419     single_strategy=yes
 420     ;;
 421 esac
 422
 423 result_tree= best_cnt=-1 best_strategy= wt_strategy=
 424 merge_was_ok=
 425 for strategy in $use_strategies
 426 do
 427     test "$wt_strategy" = '' || {
 428         echo "Rewinding the tree to pristine..."
 429         restorestate
 430     }
 431     case "$single_strategy" in
 432     no)
 433         echo "Trying merge strategy $strategy..."
 434         ;;
 435     esac
 436
 437     # Remember which strategy left the state in the working tree
 438     wt_strategy=$strategy
 439
 440     git-merge-$strategy $common -- "$head_arg" "$@"
 441     exit=$?
 442     if test "$no_commit" = t && test "$exit" = 0
 443     then
 444         merge_was_ok=t
 445         exit=1 ;# pretend it left conflicts.
 446     fi
 447
 448     test "$exit" = 0 || {
 449
 450         # The backend exits with 1 when conflicts are left to be resolved,
 451         # with 2 when it does not handle the given merge at all.
 452
 453         if test "$exit" -eq 1
 454         then
 455             cnt=`{
 456                 git diff-files --name-only
 457                 git ls-files --unmerged
 458             } | wc -l`
 459             if test $best_cnt -le 0 -o $cnt -le $best_cnt
 460             then
 461                 best_strategy=$strategy
 462                 best_cnt=$cnt
 463             fi
 464         fi
 465         continue
 466     }
 467
 468     # Automerge succeeded.
 469     result_tree=$(git write-tree) && break
 470 done
 471
 472 # If we have a resulting tree, that means the strategy module
 473 # auto resolved the merge cleanly.
 474 if test '' != "$result_tree"
 475 then
 476     parents=$(git show-branch --independent "$head" "$@" | sed -e 's/^/-p /')
 477     result_commit=$(printf '%s\n' "$merge_msg" | git commit-tree $result_tree $parents) || exit
 478     finish "$result_commit" "Merge made by $wt_strategy."
 479     dropsave
 480     exit 0
 481 fi
 482
 483 # Pick the result from the best strategy and have the user fix it up.
 484 case "$best_strategy" in
 485 '')
 486         restorestate
 487         case "$use_strategies" in
 488         ?*' '?*)
 489                 echo >&2 "No merge strategy handled the merge."
 490                 ;;
 491         *)
 492                 echo >&2 "Merge with strategy $use_strategies failed."
 493                 ;;
 494         esac
 495         exit 2
 496         ;;
 497 "$wt_strategy")
 498         # We already have its result in the working tree.
 499         ;;
 500 *)
 501         echo "Rewinding the tree to pristine..."
 502         restorestate
 503         echo "Using the $best_strategy to prepare resolving by hand."
 504         git-merge-$best_strategy $common -- "$head_arg" "$@"
 505         ;;
 506 esac
 507
 508 if test "$squash" = t
 509 then
 510         finish
 511 else
 512         for remote
 513         do
 514                 echo $remote
 515         done >"$GIT_DIR/MERGE_HEAD"
 516         printf '%s\n' "$merge_msg" >"$GIT_DIR/MERGE_MSG"
 517 fi
 518
 519 if test "$merge_was_ok" = t
 520 then
 521         echo >&2 \
 522         "Automatic merge went well; stopped before committing as requested"
 523         exit 0
 524 else
 525         {
 526             echo '
 527 Conflicts:
 528 '
 529                 git ls-files --unmerged |
 530                 sed -e 's/^[^   ]*      /       /' |
 531                 uniq
 532         } >>"$GIT_DIR/MERGE_MSG"
 533         git rerere
 534         die "Automatic merge failed; fix conflicts and then commit the result."
 535 fi