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 "$(git ls-files -u)" ||
  14         die "You are in the middle of a conflicted merge."
  15
  16 LF='
  17 '
  18
  19 all_strategies='recur recursive octopus resolve stupid ours'
  20 default_twohead_strategies='recursive'
  21 default_octopus_strategies='octopus'
  22 no_trivial_merge_strategies='ours'
  23 use_strategies=
  24
  25 index_merge=t
  26
  27 dropsave() {
  28         rm -f -- "$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         else
 112                 echo "$rh               commit '$remote'"
 113         fi
 114 }
 115
 116 case "$#" in 0) usage ;; esac
 117
 118 have_message=
 119 while case "$#" in 0) break ;; esac
 120 do
 121         case "$1" in
 122         -n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
 123                 --no-summa|--no-summar|--no-summary)
 124                 no_summary=t ;;
 125         --sq|--squ|--squa|--squas|--squash)
 126                 squash=t no_commit=t ;;
 127         --no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
 128                 no_commit=t ;;
 129         -s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
 130                 --strateg=*|--strategy=*|\
 131         -s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
 132                 case "$#,$1" in
 133                 *,*=*)
 134                         strategy=`expr "z$1" : 'z-[^=]*=\(.*\)'` ;;
 135                 1,*)
 136                         usage ;;
 137                 *)
 138                         strategy="$2"
 139                         shift ;;
 140                 esac
 141                 case " $all_strategies " in
 142                 *" $strategy "*)
 143                         use_strategies="$use_strategies$strategy " ;;
 144                 *)
 145                         die "available strategies are: $all_strategies" ;;
 146                 esac
 147                 ;;
 148         -m=*|--m=*|--me=*|--mes=*|--mess=*|--messa=*|--messag=*|--message=*)
 149                 merge_msg=`expr "z$1" : 'z-[^=]*=\(.*\)'`
 150                 have_message=t
 151                 ;;
 152         -m|--m|--me|--mes|--mess|--messa|--messag|--message)
 153                 shift
 154                 case "$#" in
 155                 1)      usage ;;
 156                 esac
 157                 merge_msg="$1"
 158                 have_message=t
 159                 ;;
 160         -*)     usage ;;
 161         *)      break ;;
 162         esac
 163         shift
 164 done
 165
 166 # This could be traditional "merge <msg> HEAD <commit>..."  and the
 167 # way we can tell it is to see if the second token is HEAD, but some
 168 # people might have misused the interface and used a committish that
 169 # is the same as HEAD there instead.  Traditional format never would
 170 # have "-m" so it is an additional safety measure to check for it.
 171
 172 if test -z "$have_message" &&
 173         second_token=$(git-rev-parse --verify "$2^0" 2>/dev/null) &&
 174         head_commit=$(git-rev-parse --verify "HEAD" 2>/dev/null) &&
 175         test "$second_token" = "$head_commit"
 176 then
 177         merge_msg="$1"
 178         shift
 179         head_arg="$1"
 180         shift
 181 elif ! git-rev-parse --verify HEAD >/dev/null 2>&1
 182 then
 183         # If the merged head is a valid one there is no reason to
 184         # forbid "git merge" into a branch yet to be born.  We do
 185         # the same for "git pull".
 186         if test 1 -ne $#
 187         then
 188                 echo >&2 "Can merge only exactly one commit into empty head"
 189                 exit 1
 190         fi
 191
 192         rh=$(git rev-parse --verify "$1^0") ||
 193                 die "$1 - not something we can merge"
 194
 195         git-update-ref -m "initial pull" HEAD "$rh" "" &&
 196         git-read-tree --reset -u HEAD
 197         exit
 198
 199 else
 200         # We are invoked directly as the first-class UI.
 201         head_arg=HEAD
 202
 203         # All the rest are the commits being merged; prepare
 204         # the standard merge summary message to be appended to
 205         # the given message.  If remote is invalid we will die
 206         # later in the common codepath so we discard the error
 207         # in this loop.
 208         merge_name=$(for remote
 209                 do
 210                         merge_name "$remote"
 211                 done | git-fmt-merge-msg
 212         )
 213         merge_msg="${merge_msg:+$merge_msg$LF$LF}$merge_name"
 214 fi
 215 head=$(git-rev-parse --verify "$head_arg"^0) || usage
 216
 217 # All the rest are remote heads
 218 test "$#" = 0 && usage ;# we need at least one remote head.
 219 set_reflog_action "merge $*"
 220
 221 remoteheads=
 222 for remote
 223 do
 224         remotehead=$(git-rev-parse --verify "$remote"^0 2>/dev/null) ||
 225             die "$remote - not something we can merge"
 226         remoteheads="${remoteheads}$remotehead "
 227         eval GITHEAD_$remotehead='"$remote"'
 228         export GITHEAD_$remotehead
 229 done
 230 set x $remoteheads ; shift
 231
 232 case "$use_strategies" in
 233 '')
 234         case "$#" in
 235         1)
 236                 var="`git-config --get pull.twohead`"
 237                 if test -n "$var"
 238                 then
 239                         use_strategies="$var"
 240                 else
 241                         use_strategies="$default_twohead_strategies"
 242                 fi ;;
 243         *)
 244                 var="`git-config --get pull.octopus`"
 245                 if test -n "$var"
 246                 then
 247                         use_strategies="$var"
 248                 else
 249                         use_strategies="$default_octopus_strategies"
 250                 fi ;;
 251         esac
 252         ;;
 253 esac
 254
 255 for s in $use_strategies
 256 do
 257         for nt in $no_trivial_merge_strategies
 258         do
 259                 case " $s " in
 260                 *" $nt "*)
 261                         index_merge=f
 262                         break
 263                         ;;
 264                 esac
 265         done
 266 done
 267
 268 case "$#" in
 269 1)
 270         common=$(git-merge-base --all $head "$@")
 271         ;;
 272 *)
 273         common=$(git-show-branch --merge-base $head "$@")
 274         ;;
 275 esac
 276 echo "$head" >"$GIT_DIR/ORIG_HEAD"
 277
 278 case "$index_merge,$#,$common,$no_commit" in
 279 f,*)
 280         # We've been told not to try anything clever.  Skip to real merge.
 281         ;;
 282 ?,*,'',*)
 283         # No common ancestors found. We need a real merge.
 284         ;;
 285 ?,1,"$1",*)
 286         # If head can reach all the merge then we are up to date.
 287         # but first the most common case of merging one remote.
 288         finish_up_to_date "Already up-to-date."
 289         exit 0
 290         ;;
 291 ?,1,"$head",*)
 292         # Again the most common case of merging one remote.
 293         echo "Updating $(git-rev-parse --short $head)..$(git-rev-parse --short $1)"
 294         git-update-index --refresh 2>/dev/null
 295         msg="Fast forward"
 296         if test -n "$have_message"
 297         then
 298                 msg="$msg (no commit created; -m option ignored)"
 299         fi
 300         new_head=$(git-rev-parse --verify "$1^0") &&
 301         git-read-tree -v -m -u --exclude-per-directory=.gitignore $head "$new_head" &&
 302         finish "$new_head" "$msg" || exit
 303         dropsave
 304         exit 0
 305         ;;
 306 ?,1,?*"$LF"?*,*)
 307         # We are not doing octopus and not fast forward.  Need a
 308         # real merge.
 309         ;;
 310 ?,1,*,)
 311         # We are not doing octopus, not fast forward, and have only
 312         # one common.
 313         git-update-index --refresh 2>/dev/null
 314         case " $use_strategies " in
 315         *' recursive '*|*' recur '*)
 316                 : run merge later
 317                 ;;
 318         *)
 319                 # See if it is really trivial.
 320                 git var GIT_COMMITTER_IDENT >/dev/null || exit
 321                 echo "Trying really trivial in-index merge..."
 322                 if git-read-tree --trivial -m -u -v $common $head "$1" &&
 323                    result_tree=$(git-write-tree)
 324                 then
 325                         echo "Wonderful."
 326                         result_commit=$(
 327                                 echo "$merge_msg" |
 328                                 git-commit-tree $result_tree -p HEAD -p "$1"
 329                         ) || exit
 330                         finish "$result_commit" "In-index merge"
 331                         dropsave
 332                         exit 0
 333                 fi
 334                 echo "Nope."
 335         esac
 336         ;;
 337 *)
 338         # An octopus.  If we can reach all the remote we are up to date.
 339         up_to_date=t
 340         for remote
 341         do
 342                 common_one=$(git-merge-base --all $head $remote)
 343                 if test "$common_one" != "$remote"
 344                 then
 345                         up_to_date=f
 346                         break
 347                 fi
 348         done
 349         if test "$up_to_date" = t
 350         then
 351                 finish_up_to_date "Already up-to-date. Yeeah!"
 352                 exit 0
 353         fi
 354         ;;
 355 esac
 356
 357 # We are going to make a new commit.
 358 git var GIT_COMMITTER_IDENT >/dev/null || exit
 359
 360 # At this point, we need a real merge.  No matter what strategy
 361 # we use, it would operate on the index, possibly affecting the
 362 # working tree, and when resolved cleanly, have the desired tree
 363 # in the index -- this means that the index must be in sync with
 364 # the $head commit.  The strategies are responsible to ensure this.
 365
 366 case "$use_strategies" in
 367 ?*' '?*)
 368     # Stash away the local changes so that we can try more than one.
 369     savestate
 370     single_strategy=no
 371     ;;
 372 *)
 373     rm -f "$GIT_DIR/MERGE_SAVE"
 374     single_strategy=yes
 375     ;;
 376 esac
 377
 378 result_tree= best_cnt=-1 best_strategy= wt_strategy=
 379 merge_was_ok=
 380 for strategy in $use_strategies
 381 do
 382     test "$wt_strategy" = '' || {
 383         echo "Rewinding the tree to pristine..."
 384         restorestate
 385     }
 386     case "$single_strategy" in
 387     no)
 388         echo "Trying merge strategy $strategy..."
 389         ;;
 390     esac
 391
 392     # Remember which strategy left the state in the working tree
 393     wt_strategy=$strategy
 394
 395     git-merge-$strategy $common -- "$head_arg" "$@"
 396     exit=$?
 397     if test "$no_commit" = t && test "$exit" = 0
 398     then
 399         merge_was_ok=t
 400         exit=1 ;# pretend it left conflicts.
 401     fi
 402
 403     test "$exit" = 0 || {
 404
 405         # The backend exits with 1 when conflicts are left to be resolved,
 406         # with 2 when it does not handle the given merge at all.
 407
 408         if test "$exit" -eq 1
 409         then
 410             cnt=`{
 411                 git-diff-files --name-only
 412                 git-ls-files --unmerged
 413             } | wc -l`
 414             if test $best_cnt -le 0 -o $cnt -le $best_cnt
 415             then
 416                 best_strategy=$strategy
 417                 best_cnt=$cnt
 418             fi
 419         fi
 420         continue
 421     }
 422
 423     # Automerge succeeded.
 424     result_tree=$(git-write-tree) && break
 425 done
 426
 427 # If we have a resulting tree, that means the strategy module
 428 # auto resolved the merge cleanly.
 429 if test '' != "$result_tree"
 430 then
 431     parents=$(git-show-branch --independent "$head" "$@" | sed -e 's/^/-p /')
 432     result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents) || exit
 433     finish "$result_commit" "Merge made by $wt_strategy."
 434     dropsave
 435     exit 0
 436 fi
 437
 438 # Pick the result from the best strategy and have the user fix it up.
 439 case "$best_strategy" in
 440 '')
 441         restorestate
 442         case "$use_strategies" in
 443         ?*' '?*)
 444                 echo >&2 "No merge strategy handled the merge."
 445                 ;;
 446         *)
 447                 echo >&2 "Merge with strategy $use_strategies failed."
 448                 ;;
 449         esac
 450         exit 2
 451         ;;
 452 "$wt_strategy")
 453         # We already have its result in the working tree.
 454         ;;
 455 *)
 456         echo "Rewinding the tree to pristine..."
 457         restorestate
 458         echo "Using the $best_strategy to prepare resolving by hand."
 459         git-merge-$best_strategy $common -- "$head_arg" "$@"
 460         ;;
 461 esac
 462
 463 if test "$squash" = t
 464 then
 465         finish
 466 else
 467         for remote
 468         do
 469                 echo $remote
 470         done >"$GIT_DIR/MERGE_HEAD"
 471         echo "$merge_msg" >"$GIT_DIR/MERGE_MSG"
 472 fi
 473
 474 if test "$merge_was_ok" = t
 475 then
 476         echo >&2 \
 477         "Automatic merge went well; stopped before committing as requested"
 478         exit 0
 479 else
 480         {
 481             echo '
 482 Conflicts:
 483 '
 484                 git ls-files --unmerged |
 485                 sed -e 's/^[^   ]*      /       /' |
 486                 uniq
 487         } >>"$GIT_DIR/MERGE_MSG"
 488         if test -d "$GIT_DIR/rr-cache"
 489         then
 490                 git-rerere
 491         fi
 492         die "Automatic merge failed; fix conflicts and then commit the result."
 493 fi