git-merge.sh

   1 #!/bin/sh
   2 #
   3 # Copyright (c) 2005 Junio C Hamano
   4 #
   5
   6 USAGE='[-n] [--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 "$(git ls-files -u)" ||
  14         die "You are in the middle of a conflicted merge."
  15
  16 LF='
  17 '
  18
  19 all_strategies='recur recursive octopus resolve stupid ours subtree'
  20 default_twohead_strategies='recursive'
  21 default_octopus_strategies='octopus'
  22 no_trivial_merge_strategies='ours subtree'
  23 use_strategies=
  24
  25 index_merge=t
  26
  27 dropsave() {
  28         rm -f -- "$GIT_DIR/MERGE_HEAD" "$GIT_DIR/MERGE_MSG" \
  29                  "$GIT_DIR/MERGE_SAVE" || exit 1
  30 }
  31
  32 savestate() {
  33         # Stash away any local modifications.
  34         git-diff-index -z --name-only $head |
  35         cpio -0 -o >"$GIT_DIR/MERGE_SAVE"
  36 }
  37
  38 restorestate() {
  39         if test -f "$GIT_DIR/MERGE_SAVE"
  40         then
  41                 git reset --hard $head >/dev/null
  42                 cpio -iuv <"$GIT_DIR/MERGE_SAVE"
  43                 git-update-index --refresh >/dev/null
  44         fi
  45 }
  46
  47 finish_up_to_date () {
  48         case "$squash" in
  49         t)
  50                 echo "$1 (nothing to squash)" ;;
  51         '')
  52                 echo "$1" ;;
  53         esac
  54         dropsave
  55 }
  56
  57 squash_message () {
  58         echo Squashed commit of the following:
  59         echo
  60         git-log --no-merges ^"$head" $remote
  61 }
  62
  63 finish () {
  64         if test '' = "$2"
  65         then
  66                 rlogm="$GIT_REFLOG_ACTION"
  67         else
  68                 echo "$2"
  69                 rlogm="$GIT_REFLOG_ACTION: $2"
  70         fi
  71         case "$squash" in
  72         t)
  73                 echo "Squash commit -- not updating HEAD"
  74                 squash_message >"$GIT_DIR/SQUASH_MSG"
  75                 ;;
  76         '')
  77                 case "$merge_msg" in
  78                 '')
  79                         echo "No merge message -- not updating HEAD"
  80                         ;;
  81                 *)
  82                         git-update-ref -m "$rlogm" HEAD "$1" "$head" || exit 1
  83                         ;;
  84                 esac
  85                 ;;
  86         esac
  87         case "$1" in
  88         '')
  89                 ;;
  90         ?*)
  91                 case "$no_summary" in
  92                 '')
  93                         git-diff-tree --stat --summary -M "$head" "$1"
  94                         ;;
  95                 esac
  96                 ;;
  97         esac
  98 }
  99
 100 merge_name () {
 101         remote="$1"
 102         rh=$(git-rev-parse --verify "$remote^0" 2>/dev/null) || return
 103         bh=$(git-show-ref -s --verify "refs/heads/$remote" 2>/dev/null)
 104         if test "$rh" = "$bh"
 105         then
 106                 echo "$rh               branch '$remote' of ."
 107         elif truname=$(expr "$remote" : '\(.*\)~[1-9][0-9]*$') &&
 108                 git-show-ref -q --verify "refs/heads/$truname" 2>/dev/null
 109         then
 110                 echo "$rh               branch '$truname' (early part) of ."
 111         elif test "$remote" = "FETCH_HEAD" -a -r "$GIT_DIR/FETCH_HEAD"
 112         then
 113                 sed -e 's/      not-for-merge   /               /' -e 1q \
 114                         "$GIT_DIR/FETCH_HEAD"
 115         else
 116                 echo "$rh               commit '$remote'"
 117         fi
 118 }
 119
 120 case "$#" in 0) usage ;; esac
 121
 122 have_message=
 123 while case "$#" in 0) break ;; esac
 124 do
 125         case "$1" in
 126         -n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
 127                 --no-summa|--no-summar|--no-summary)
 128                 no_summary=t ;;
 129         --sq|--squ|--squa|--squas|--squash)
 130                 squash=t no_commit=t ;;
 131         --no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
 132                 no_commit=t ;;
 133         -s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
 134                 --strateg=*|--strategy=*|\
 135         -s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
 136                 case "$#,$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="$1"
 162                 have_message=t
 163                 ;;
 164         -*)     usage ;;
 165         *)      break ;;
 166         esac
 167         shift
 168 done
 169
 170 # This could be traditional "merge <msg> HEAD <commit>..."  and the
 171 # way we can tell it is to see if the second token is HEAD, but some
 172 # people might have misused the interface and used a committish that
 173 # is the same as HEAD there instead.  Traditional format never would
 174 # have "-m" so it is an additional safety measure to check for it.
 175
 176 if test -z "$have_message" &&
 177         second_token=$(git-rev-parse --verify "$2^0" 2>/dev/null) &&
 178         head_commit=$(git-rev-parse --verify "HEAD" 2>/dev/null) &&
 179         test "$second_token" = "$head_commit"
 180 then
 181         merge_msg="$1"
 182         shift
 183         head_arg="$1"
 184         shift
 185 elif ! git-rev-parse --verify HEAD >/dev/null 2>&1
 186 then
 187         # If the merged head is a valid one there is no reason to
 188         # forbid "git merge" into a branch yet to be born.  We do
 189         # the same for "git pull".
 190         if test 1 -ne $#
 191         then
 192                 echo >&2 "Can merge only exactly one commit into empty head"
 193                 exit 1
 194         fi
 195
 196         rh=$(git rev-parse --verify "$1^0") ||
 197                 die "$1 - not something we can merge"
 198
 199         git-update-ref -m "initial pull" HEAD "$rh" "" &&
 200         git-read-tree --reset -u HEAD
 201         exit
 202
 203 else
 204         # We are invoked directly as the first-class UI.
 205         head_arg=HEAD
 206
 207         # All the rest are the commits being merged; prepare
 208         # the standard merge summary message to be appended to
 209         # the given message.  If remote is invalid we will die
 210         # later in the common codepath so we discard the error
 211         # in this loop.
 212         merge_name=$(for remote
 213                 do
 214                         merge_name "$remote"
 215                 done | git-fmt-merge-msg
 216         )
 217         merge_msg="${merge_msg:+$merge_msg$LF$LF}$merge_name"
 218 fi
 219 head=$(git-rev-parse --verify "$head_arg"^0) || usage
 220
 221 # All the rest are remote heads
 222 test "$#" = 0 && usage ;# we need at least one remote head.
 223 set_reflog_action "merge $*"
 224
 225 remoteheads=
 226 for remote
 227 do
 228         remotehead=$(git-rev-parse --verify "$remote"^0 2>/dev/null) ||
 229             die "$remote - not something we can merge"
 230         remoteheads="${remoteheads}$remotehead "
 231         eval GITHEAD_$remotehead='"$remote"'
 232         export GITHEAD_$remotehead
 233 done
 234 set x $remoteheads ; shift
 235
 236 case "$use_strategies" in
 237 '')
 238         case "$#" in
 239         1)
 240                 var="`git-config --get pull.twohead`"
 241                 if test -n "$var"
 242                 then
 243                         use_strategies="$var"
 244                 else
 245                         use_strategies="$default_twohead_strategies"
 246                 fi ;;
 247         *)
 248                 var="`git-config --get pull.octopus`"
 249                 if test -n "$var"
 250                 then
 251                         use_strategies="$var"
 252                 else
 253                         use_strategies="$default_octopus_strategies"
 254                 fi ;;
 255         esac
 256         ;;
 257 esac
 258
 259 for s in $use_strategies
 260 do
 261         for nt in $no_trivial_merge_strategies
 262         do
 263                 case " $s " in
 264                 *" $nt "*)
 265                         index_merge=f
 266                         break
 267                         ;;
 268                 esac
 269         done
 270 done
 271
 272 case "$#" in
 273 1)
 274         common=$(git-merge-base --all $head "$@")
 275         ;;
 276 *)
 277         common=$(git-show-branch --merge-base $head "$@")
 278         ;;
 279 esac
 280 echo "$head" >"$GIT_DIR/ORIG_HEAD"
 281
 282 case "$index_merge,$#,$common,$no_commit" in
 283 f,*)
 284         # We've been told not to try anything clever.  Skip to real merge.
 285         ;;
 286 ?,*,'',*)
 287         # No common ancestors found. We need a real merge.
 288         ;;
 289 ?,1,"$1",*)
 290         # If head can reach all the merge then we are up to date.
 291         # but first the most common case of merging one remote.
 292         finish_up_to_date "Already up-to-date."
 293         exit 0
 294         ;;
 295 ?,1,"$head",*)
 296         # Again the most common case of merging one remote.
 297         echo "Updating $(git-rev-parse --short $head)..$(git-rev-parse --short $1)"
 298         git-update-index --refresh 2>/dev/null
 299         msg="Fast forward"
 300         if test -n "$have_message"
 301         then
 302                 msg="$msg (no commit created; -m option ignored)"
 303         fi
 304         new_head=$(git-rev-parse --verify "$1^0") &&
 305         git-read-tree -v -m -u --exclude-per-directory=.gitignore $head "$new_head" &&
 306         finish "$new_head" "$msg" || exit
 307         dropsave
 308         exit 0
 309         ;;
 310 ?,1,?*"$LF"?*,*)
 311         # We are not doing octopus and not fast forward.  Need a
 312         # real merge.
 313         ;;
 314 ?,1,*,)
 315         # We are not doing octopus, not fast forward, and have only
 316         # one common.
 317         git-update-index --refresh 2>/dev/null
 318         case " $use_strategies " in
 319         *' recursive '*|*' recur '*)
 320                 : run merge later
 321                 ;;
 322         *)
 323                 # See if it is really trivial.
 324                 git var GIT_COMMITTER_IDENT >/dev/null || exit
 325                 echo "Trying really trivial in-index merge..."
 326                 if git-read-tree --trivial -m -u -v $common $head "$1" &&
 327                    result_tree=$(git-write-tree)
 328                 then
 329                         echo "Wonderful."
 330                         result_commit=$(
 331                                 printf '%s\n' "$merge_msg" |
 332                                 git-commit-tree $result_tree -p HEAD -p "$1"
 333                         ) || exit
 334                         finish "$result_commit" "In-index merge"
 335                         dropsave
 336                         exit 0
 337                 fi
 338                 echo "Nope."
 339         esac
 340         ;;
 341 *)
 342         # An octopus.  If we can reach all the remote we are up to date.
 343         up_to_date=t
 344         for remote
 345         do
 346                 common_one=$(git-merge-base --all $head $remote)
 347                 if test "$common_one" != "$remote"
 348                 then
 349                         up_to_date=f
 350                         break
 351                 fi
 352         done
 353         if test "$up_to_date" = t
 354         then
 355                 finish_up_to_date "Already up-to-date. Yeeah!"
 356                 exit 0
 357         fi
 358         ;;
 359 esac
 360
 361 # We are going to make a new commit.
 362 git var GIT_COMMITTER_IDENT >/dev/null || exit
 363
 364 # At this point, we need a real merge.  No matter what strategy
 365 # we use, it would operate on the index, possibly affecting the
 366 # working tree, and when resolved cleanly, have the desired tree
 367 # in the index -- this means that the index must be in sync with
 368 # the $head commit.  The strategies are responsible to ensure this.
 369
 370 case "$use_strategies" in
 371 ?*' '?*)
 372     # Stash away the local changes so that we can try more than one.
 373     savestate
 374     single_strategy=no
 375     ;;
 376 *)
 377     rm -f "$GIT_DIR/MERGE_SAVE"
 378     single_strategy=yes
 379     ;;
 380 esac
 381
 382 result_tree= best_cnt=-1 best_strategy= wt_strategy=
 383 merge_was_ok=
 384 for strategy in $use_strategies
 385 do
 386     test "$wt_strategy" = '' || {
 387         echo "Rewinding the tree to pristine..."
 388         restorestate
 389     }
 390     case "$single_strategy" in
 391     no)
 392         echo "Trying merge strategy $strategy..."
 393         ;;
 394     esac
 395
 396     # Remember which strategy left the state in the working tree
 397     wt_strategy=$strategy
 398
 399     git-merge-$strategy $common -- "$head_arg" "$@"
 400     exit=$?
 401     if test "$no_commit" = t && test "$exit" = 0
 402     then
 403         merge_was_ok=t
 404         exit=1 ;# pretend it left conflicts.
 405     fi
 406
 407     test "$exit" = 0 || {
 408
 409         # The backend exits with 1 when conflicts are left to be resolved,
 410         # with 2 when it does not handle the given merge at all.
 411
 412         if test "$exit" -eq 1
 413         then
 414             cnt=`{
 415                 git-diff-files --name-only
 416                 git-ls-files --unmerged
 417             } | wc -l`
 418             if test $best_cnt -le 0 -o $cnt -le $best_cnt
 419             then
 420                 best_strategy=$strategy
 421                 best_cnt=$cnt
 422             fi
 423         fi
 424         continue
 425     }
 426
 427     # Automerge succeeded.
 428     result_tree=$(git-write-tree) && break
 429 done
 430
 431 # If we have a resulting tree, that means the strategy module
 432 # auto resolved the merge cleanly.
 433 if test '' != "$result_tree"
 434 then
 435     parents=$(git-show-branch --independent "$head" "$@" | sed -e 's/^/-p /')
 436     result_commit=$(printf '%s\n' "$merge_msg" | git-commit-tree $result_tree $parents) || exit
 437     finish "$result_commit" "Merge made by $wt_strategy."
 438     dropsave
 439     exit 0
 440 fi
 441
 442 # Pick the result from the best strategy and have the user fix it up.
 443 case "$best_strategy" in
 444 '')
 445         restorestate
 446         case "$use_strategies" in
 447         ?*' '?*)
 448                 echo >&2 "No merge strategy handled the merge."
 449                 ;;
 450         *)
 451                 echo >&2 "Merge with strategy $use_strategies failed."
 452                 ;;
 453         esac
 454         exit 2
 455         ;;
 456 "$wt_strategy")
 457         # We already have its result in the working tree.
 458         ;;
 459 *)
 460         echo "Rewinding the tree to pristine..."
 461         restorestate
 462         echo "Using the $best_strategy to prepare resolving by hand."
 463         git-merge-$best_strategy $common -- "$head_arg" "$@"
 464         ;;
 465 esac
 466
 467 if test "$squash" = t
 468 then
 469         finish
 470 else
 471         for remote
 472         do
 473                 echo $remote
 474         done >"$GIT_DIR/MERGE_HEAD"
 475         printf '%s\n' "$merge_msg" >"$GIT_DIR/MERGE_MSG"
 476 fi
 477
 478 if test "$merge_was_ok" = t
 479 then
 480         echo >&2 \
 481         "Automatic merge went well; stopped before committing as requested"
 482         exit 0
 483 else
 484         {
 485             echo '
 486 Conflicts:
 487 '
 488                 git ls-files --unmerged |
 489                 sed -e 's/^[^   ]*      /       /' |
 490                 uniq
 491         } >>"$GIT_DIR/MERGE_MSG"
 492         if test -d "$GIT_DIR/rr-cache"
 493         then
 494                 git-rerere
 495         fi
 496         die "Automatic merge failed; fix conflicts and then commit the result."
 497 fi