git-merge.sh

   1 #!/bin/sh
   2 #
   3 # Copyright (c) 2005 Junio C Hamano
   4 #
   5
   6 USAGE='[-n] [--summary] [--[no-]commit] [--[no-]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 "$1" in
 124         -n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
 125                 --no-summa|--no-summar|--no-summary)
 126                 show_diffstat=false ;;
 127         --summary)
 128                 show_diffstat=t ;;
 129         --sq|--squ|--squa|--squas|--squash)
 130                 squash=t no_commit=t ;;
 131         --no-sq|--no-squ|--no-squa|--no-squas|--no-squash)
 132                 squash= no_commit= ;;
 133         --c|--co|--com|--comm|--commi|--commit)
 134                 squash= no_commit= ;;
 135         --no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
 136                 squash= no_commit=t ;;
 137         -s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
 138                 --strateg=*|--strategy=*|\
 139         -s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
 140                 case "$#,$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
 175 parse_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
 186 test $# != 0 || usage
 187
 188 have_message=
 189
 190 if branch=$(git-symbolic-ref -q HEAD)
 191 then
 192         mergeopts=$(git config "branch.${branch#refs/heads/}.mergeoptions")
 193         if test -n "$mergeopts"
 194         then
 195                 parse_config $mergeopts
 196         fi
 197 fi
 198
 199 while parse_option "$@"
 200 do
 201         while test $args_left -lt $#
 202         do
 203                 shift
 204         done
 205 done
 206
 207 if test -z "$show_diffstat"; then
 208     test "$(git config --bool merge.diffstat)" = false && show_diffstat=false
 209     test -z "$show_diffstat" && show_diffstat=t
 210 fi
 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
 218 if 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"
 222 then
 223         merge_msg="$1"
 224         shift
 225         head_arg="$1"
 226         shift
 227 elif ! git rev-parse --verify HEAD >/dev/null 2>&1
 228 then
 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
 245 else
 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}$merge_name"
 260 fi
 261 head=$(git rev-parse --verify "$head_arg"^0) || usage
 262
 263 # All the rest are remote heads
 264 test "$#" = 0 && usage ;# we need at least one remote head.
 265 set_reflog_action "merge $*"
 266
 267 remoteheads=
 268 for remote
 269 do
 270         remotehead=$(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
 275 done
 276 set x $remoteheads ; shift
 277
 278 case "$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         ;;
 299 esac
 300
 301 for s in $use_strategies
 302 do
 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                 *" $ss "*)
 316                         allow_trivial_merge=f
 317                         break
 318                         ;;
 319                 esac
 320         done
 321 done
 322
 323 case "$#" in
 324 1)
 325         common=$(git merge-base --all $head "$@")
 326         ;;
 327 *)
 328         common=$(git show-branch --merge-base $head "$@")
 329         ;;
 330 esac
 331 echo "$head" >"$GIT_DIR/ORIG_HEAD"
 332
 333 case "$allow_fast_forward,$#,$common,$no_commit" in
 334 ?,*,'',*)
 335         # No common ancestors found. We need a real merge.
 336         ;;
 337 ?,1,"$1",*)
 338         # If head can reach all the merge then we are up to date.
 339         # but first the most common case of merging one remote.
 340         finish_up_to_date "Already up-to-date."
 341         exit 0
 342         ;;
 343 t,1,"$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         ;;
 404 esac
 405
 406 # We are going to make a new commit.
 407 git 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 $head commit.  The strategies are responsible to ensure this.
 414
 415 case "$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     ;;
 425 esac
 426
 427 result_tree= best_cnt=-1 best_strategy= wt_strategy=
 428 merge_was_ok=
 429 for strategy in $use_strategies
 430 do
 431     test "$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
 474 done
 475
 476 # If we have a resulting tree, that means the strategy module
 477 # auto resolved the merge cleanly.
 478 if test '' != "$result_tree"
 479 then
 480     parents=$(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 $wt_strategy."
 483     dropsave
 484     exit 0
 485 fi
 486
 487 # Pick the result from the best strategy and have the user fix it up.
 488 case "$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" "$@"
 509         ;;
 510 esac
 511
 512 if test "$squash" = t
 513 then
 514         finish
 515 else
 516         for remote
 517         do
 518                 echo $remote
 519         done >"$GIT_DIR/MERGE_HEAD"
 520         printf '%s\n' "$merge_msg" >"$GIT_DIR/MERGE_MSG"
 521 fi
 522
 523 if test "$merge_was_ok" = t
 524 then
 525         echo >&2 \
 526         "Automatic merge went well; stopped before committing as requested"
 527         exit 0
 528 else
 529         {
 530             echo '
 531 Conflicts:
 532 '
 533                 git ls-files --unmerged |
 534                 sed -e 's/^[^   ]*      /       /' |
 535                 uniq
 536         } >>"$GIT_DIR/MERGE_MSG"
 537         git rerere
 538         die "Automatic merge failed; fix conflicts and then commit the result."
 539 fi