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                         # We want color (if set), but no pager
  94                         GIT_PAGER='' git-diff --stat --summary -M "$head" "$1"
  95                         ;;
  96                 esac
  97                 ;;
  98         esac
  99 }
 100
 101 merge_name () {
 102         remote="$1"
 103         rh=$(git-rev-parse --verify "$remote^0" 2>/dev/null) || return
 104         bh=$(git-show-ref -s --verify "refs/heads/$remote" 2>/dev/null)
 105         if test "$rh" = "$bh"
 106         then
 107                 echo "$rh               branch '$remote' of ."
 108         elif truname=$(expr "$remote" : '\(.*\)~[1-9][0-9]*$') &&
 109                 git-show-ref -q --verify "refs/heads/$truname" 2>/dev/null
 110         then
 111                 echo "$rh               branch '$truname' (early part) of ."
 112         elif test "$remote" = "FETCH_HEAD" -a -r "$GIT_DIR/FETCH_HEAD"
 113         then
 114                 sed -e 's/      not-for-merge   /               /' -e 1q \
 115                         "$GIT_DIR/FETCH_HEAD"
 116         else
 117                 echo "$rh               commit '$remote'"
 118         fi
 119 }
 120
 121 case "$#" in 0) usage ;; esac
 122
 123 have_message=
 124 while case "$#" in 0) break ;; esac
 125 do
 126         case "$1" in
 127         -n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
 128                 --no-summa|--no-summar|--no-summary)
 129                 no_summary=t ;;
 130         --sq|--squ|--squa|--squas|--squash)
 131                 squash=t no_commit=t ;;
 132         --no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
 133                 no_commit=t ;;
 134         -s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
 135                 --strateg=*|--strategy=*|\
 136         -s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
 137                 case "$#,$1" in
 138                 *,*=*)
 139                         strategy=`expr "z$1" : 'z-[^=]*=\(.*\)'` ;;
 140                 1,*)
 141                         usage ;;
 142                 *)
 143                         strategy="$2"
 144                         shift ;;
 145                 esac
 146                 case " $all_strategies " in
 147                 *" $strategy "*)
 148                         use_strategies="$use_strategies$strategy " ;;
 149                 *)
 150                         die "available strategies are: $all_strategies" ;;
 151                 esac
 152                 ;;
 153         -m=*|--m=*|--me=*|--mes=*|--mess=*|--messa=*|--messag=*|--message=*)
 154                 merge_msg=`expr "z$1" : 'z-[^=]*=\(.*\)'`
 155                 have_message=t
 156                 ;;
 157         -m|--m|--me|--mes|--mess|--messa|--messag|--message)
 158                 shift
 159                 case "$#" in
 160                 1)      usage ;;
 161                 esac
 162                 merge_msg="$1"
 163                 have_message=t
 164                 ;;
 165         -*)     usage ;;
 166         *)      break ;;
 167         esac
 168         shift
 169 done
 170
 171 # This could be traditional "merge <msg> HEAD <commit>..."  and the
 172 # way we can tell it is to see if the second token is HEAD, but some
 173 # people might have misused the interface and used a committish that
 174 # is the same as HEAD there instead.  Traditional format never would
 175 # have "-m" so it is an additional safety measure to check for it.
 176
 177 if test -z "$have_message" &&
 178         second_token=$(git-rev-parse --verify "$2^0" 2>/dev/null) &&
 179         head_commit=$(git-rev-parse --verify "HEAD" 2>/dev/null) &&
 180         test "$second_token" = "$head_commit"
 181 then
 182         merge_msg="$1"
 183         shift
 184         head_arg="$1"
 185         shift
 186 elif ! git-rev-parse --verify HEAD >/dev/null 2>&1
 187 then
 188         # If the merged head is a valid one there is no reason to
 189         # forbid "git merge" into a branch yet to be born.  We do
 190         # the same for "git pull".
 191         if test 1 -ne $#
 192         then
 193                 echo >&2 "Can merge only exactly one commit into empty head"
 194                 exit 1
 195         fi
 196
 197         rh=$(git rev-parse --verify "$1^0") ||
 198                 die "$1 - not something we can merge"
 199
 200         git-update-ref -m "initial pull" HEAD "$rh" "" &&
 201         git-read-tree --reset -u HEAD
 202         exit
 203
 204 else
 205         # We are invoked directly as the first-class UI.
 206         head_arg=HEAD
 207
 208         # All the rest are the commits being merged; prepare
 209         # the standard merge summary message to be appended to
 210         # the given message.  If remote is invalid we will die
 211         # later in the common codepath so we discard the error
 212         # in this loop.
 213         merge_name=$(for remote
 214                 do
 215                         merge_name "$remote"
 216                 done | git-fmt-merge-msg
 217         )
 218         merge_msg="${merge_msg:+$merge_msg$LF$LF}$merge_name"
 219 fi
 220 head=$(git-rev-parse --verify "$head_arg"^0) || usage
 221
 222 # All the rest are remote heads
 223 test "$#" = 0 && usage ;# we need at least one remote head.
 224 set_reflog_action "merge $*"
 225
 226 remoteheads=
 227 for remote
 228 do
 229         remotehead=$(git-rev-parse --verify "$remote"^0 2>/dev/null) ||
 230             die "$remote - not something we can merge"
 231         remoteheads="${remoteheads}$remotehead "
 232         eval GITHEAD_$remotehead='"$remote"'
 233         export GITHEAD_$remotehead
 234 done
 235 set x $remoteheads ; shift
 236
 237 case "$use_strategies" in
 238 '')
 239         case "$#" in
 240         1)
 241                 var="`git-config --get pull.twohead`"
 242                 if test -n "$var"
 243                 then
 244                         use_strategies="$var"
 245                 else
 246                         use_strategies="$default_twohead_strategies"
 247                 fi ;;
 248         *)
 249                 var="`git-config --get pull.octopus`"
 250                 if test -n "$var"
 251                 then
 252                         use_strategies="$var"
 253                 else
 254                         use_strategies="$default_octopus_strategies"
 255                 fi ;;
 256         esac
 257         ;;
 258 esac
 259
 260 for s in $use_strategies
 261 do
 262         for nt in $no_trivial_merge_strategies
 263         do
 264                 case " $s " in
 265                 *" $nt "*)
 266                         index_merge=f
 267                         break
 268                         ;;
 269                 esac
 270         done
 271 done
 272
 273 case "$#" in
 274 1)
 275         common=$(git-merge-base --all $head "$@")
 276         ;;
 277 *)
 278         common=$(git-show-branch --merge-base $head "$@")
 279         ;;
 280 esac
 281 echo "$head" >"$GIT_DIR/ORIG_HEAD"
 282
 283 case "$index_merge,$#,$common,$no_commit" in
 284 f,*)
 285         # We've been told not to try anything clever.  Skip to real merge.
 286         ;;
 287 ?,*,'',*)
 288         # No common ancestors found. We need a real merge.
 289         ;;
 290 ?,1,"$1",*)
 291         # If head can reach all the merge then we are up to date.
 292         # but first the most common case of merging one remote.
 293         finish_up_to_date "Already up-to-date."
 294         exit 0
 295         ;;
 296 ?,1,"$head",*)
 297         # Again the most common case of merging one remote.
 298         echo "Updating $(git-rev-parse --short $head)..$(git-rev-parse --short $1)"
 299         git-update-index --refresh 2>/dev/null
 300         msg="Fast forward"
 301         if test -n "$have_message"
 302         then
 303                 msg="$msg (no commit created; -m option ignored)"
 304         fi
 305         new_head=$(git-rev-parse --verify "$1^0") &&
 306         git-read-tree -v -m -u --exclude-per-directory=.gitignore $head "$new_head" &&
 307         finish "$new_head" "$msg" || exit
 308         dropsave
 309         exit 0
 310         ;;
 311 ?,1,?*"$LF"?*,*)
 312         # We are not doing octopus and not fast forward.  Need a
 313         # real merge.
 314         ;;
 315 ?,1,*,)
 316         # We are not doing octopus, not fast forward, and have only
 317         # one common.
 318         git-update-index --refresh 2>/dev/null
 319         case " $use_strategies " in
 320         *' recursive '*|*' recur '*)
 321                 : run merge later
 322                 ;;
 323         *)
 324                 # See if it is really trivial.
 325                 git var GIT_COMMITTER_IDENT >/dev/null || exit
 326                 echo "Trying really trivial in-index merge..."
 327                 if git-read-tree --trivial -m -u -v $common $head "$1" &&
 328                    result_tree=$(git-write-tree)
 329                 then
 330                         echo "Wonderful."
 331                         result_commit=$(
 332                                 printf '%s\n' "$merge_msg" |
 333                                 git-commit-tree $result_tree -p HEAD -p "$1"
 334                         ) || exit
 335                         finish "$result_commit" "In-index merge"
 336                         dropsave
 337                         exit 0
 338                 fi
 339                 echo "Nope."
 340         esac
 341         ;;
 342 *)
 343         # An octopus.  If we can reach all the remote we are up to date.
 344         up_to_date=t
 345         for remote
 346         do
 347                 common_one=$(git-merge-base --all $head $remote)
 348                 if test "$common_one" != "$remote"
 349                 then
 350                         up_to_date=f
 351                         break
 352                 fi
 353         done
 354         if test "$up_to_date" = t
 355         then
 356                 finish_up_to_date "Already up-to-date. Yeeah!"
 357                 exit 0
 358         fi
 359         ;;
 360 esac
 361
 362 # We are going to make a new commit.
 363 git var GIT_COMMITTER_IDENT >/dev/null || exit
 364
 365 # At this point, we need a real merge.  No matter what strategy
 366 # we use, it would operate on the index, possibly affecting the
 367 # working tree, and when resolved cleanly, have the desired tree
 368 # in the index -- this means that the index must be in sync with
 369 # the $head commit.  The strategies are responsible to ensure this.
 370
 371 case "$use_strategies" in
 372 ?*' '?*)
 373     # Stash away the local changes so that we can try more than one.
 374     savestate
 375     single_strategy=no
 376     ;;
 377 *)
 378     rm -f "$GIT_DIR/MERGE_SAVE"
 379     single_strategy=yes
 380     ;;
 381 esac
 382
 383 result_tree= best_cnt=-1 best_strategy= wt_strategy=
 384 merge_was_ok=
 385 for strategy in $use_strategies
 386 do
 387     test "$wt_strategy" = '' || {
 388         echo "Rewinding the tree to pristine..."
 389         restorestate
 390     }
 391     case "$single_strategy" in
 392     no)
 393         echo "Trying merge strategy $strategy..."
 394         ;;
 395     esac
 396
 397     # Remember which strategy left the state in the working tree
 398     wt_strategy=$strategy
 399
 400     git-merge-$strategy $common -- "$head_arg" "$@"
 401     exit=$?
 402     if test "$no_commit" = t && test "$exit" = 0
 403     then
 404         merge_was_ok=t
 405         exit=1 ;# pretend it left conflicts.
 406     fi
 407
 408     test "$exit" = 0 || {
 409
 410         # The backend exits with 1 when conflicts are left to be resolved,
 411         # with 2 when it does not handle the given merge at all.
 412
 413         if test "$exit" -eq 1
 414         then
 415             cnt=`{
 416                 git-diff-files --name-only
 417                 git-ls-files --unmerged
 418             } | wc -l`
 419             if test $best_cnt -le 0 -o $cnt -le $best_cnt
 420             then
 421                 best_strategy=$strategy
 422                 best_cnt=$cnt
 423             fi
 424         fi
 425         continue
 426     }
 427
 428     # Automerge succeeded.
 429     result_tree=$(git-write-tree) && break
 430 done
 431
 432 # If we have a resulting tree, that means the strategy module
 433 # auto resolved the merge cleanly.
 434 if test '' != "$result_tree"
 435 then
 436     parents=$(git-show-branch --independent "$head" "$@" | sed -e 's/^/-p /')
 437     result_commit=$(printf '%s\n' "$merge_msg" | git-commit-tree $result_tree $parents) || exit
 438     finish "$result_commit" "Merge made by $wt_strategy."
 439     dropsave
 440     exit 0
 441 fi
 442
 443 # Pick the result from the best strategy and have the user fix it up.
 444 case "$best_strategy" in
 445 '')
 446         restorestate
 447         case "$use_strategies" in
 448         ?*' '?*)
 449                 echo >&2 "No merge strategy handled the merge."
 450                 ;;
 451         *)
 452                 echo >&2 "Merge with strategy $use_strategies failed."
 453                 ;;
 454         esac
 455         exit 2
 456         ;;
 457 "$wt_strategy")
 458         # We already have its result in the working tree.
 459         ;;
 460 *)
 461         echo "Rewinding the tree to pristine..."
 462         restorestate
 463         echo "Using the $best_strategy to prepare resolving by hand."
 464         git-merge-$best_strategy $common -- "$head_arg" "$@"
 465         ;;
 466 esac
 467
 468 if test "$squash" = t
 469 then
 470         finish
 471 else
 472         for remote
 473         do
 474                 echo $remote
 475         done >"$GIT_DIR/MERGE_HEAD"
 476         printf '%s\n' "$merge_msg" >"$GIT_DIR/MERGE_MSG"
 477 fi
 478
 479 if test "$merge_was_ok" = t
 480 then
 481         echo >&2 \
 482         "Automatic merge went well; stopped before committing as requested"
 483         exit 0
 484 else
 485         {
 486             echo '
 487 Conflicts:
 488 '
 489                 git ls-files --unmerged |
 490                 sed -e 's/^[^   ]*      /       /' |
 491                 uniq
 492         } >>"$GIT_DIR/MERGE_MSG"
 493         if test -d "$GIT_DIR/rr-cache"
 494         then
 495                 git-rerere
 496         fi
 497         die "Automatic merge failed; fix conflicts and then commit the result."
 498 fi