git-merge.sh

   1 #!/bin/sh
   2 #
   3 # Copyright (c) 2005 Junio C Hamano
   4 #
   5
   6 USAGE='[-n] [--no-commit] [--squash] [-s <strategy>] [--reflog-action=<action>] [-m=<merge-message>] <commit>+'
   7
   8 . git-sh-setup
   9
  10 LF='
  11 '
  12
  13 all_strategies='recur recursive octopus resolve stupid ours'
  14 default_twohead_strategies='recursive'
  15 default_octopus_strategies='octopus'
  16 no_trivial_merge_strategies='ours'
  17 use_strategies=
  18
  19 index_merge=t
  20
  21 dropsave() {
  22         rm -f -- "$GIT_DIR/MERGE_HEAD" "$GIT_DIR/MERGE_MSG" \
  23                  "$GIT_DIR/MERGE_SAVE" || exit 1
  24 }
  25
  26 savestate() {
  27         # Stash away any local modifications.
  28         git-diff-index -z --name-only $head |
  29         cpio -0 -o >"$GIT_DIR/MERGE_SAVE"
  30 }
  31
  32 restorestate() {
  33         if test -f "$GIT_DIR/MERGE_SAVE"
  34         then
  35                 git reset --hard $head
  36                 cpio -iuv <"$GIT_DIR/MERGE_SAVE"
  37                 git-update-index --refresh >/dev/null
  38         fi
  39 }
  40
  41 finish_up_to_date () {
  42         case "$squash" in
  43         t)
  44                 echo "$1 (nothing to squash)" ;;
  45         '')
  46                 echo "$1" ;;
  47         esac
  48         dropsave
  49 }
  50
  51 squash_message () {
  52         echo Squashed commit of the following:
  53         echo
  54         git-log --no-merges ^"$head" $remote
  55 }
  56
  57 finish () {
  58         if test '' = "$2"
  59         then
  60                 rlogm="$rloga"
  61         else
  62                 echo "$2"
  63                 rlogm="$rloga: $2"
  64         fi
  65         case "$squash" in
  66         t)
  67                 echo "Squash commit -- not updating HEAD"
  68                 squash_message >"$GIT_DIR/SQUASH_MSG"
  69                 ;;
  70         '')
  71                 case "$merge_msg" in
  72                 '')
  73                         echo "No merge message -- not updating HEAD"
  74                         ;;
  75                 *)
  76                         git-update-ref -m "$rlogm" HEAD "$1" "$head" || exit 1
  77                         ;;
  78                 esac
  79                 ;;
  80         esac
  81         case "$1" in
  82         '')
  83                 ;;
  84         ?*)
  85                 case "$no_summary" in
  86                 '')
  87                         git-diff-tree --stat --summary -M "$head" "$1"
  88                         ;;
  89                 esac
  90                 ;;
  91         esac
  92 }
  93
  94 merge_name () {
  95         remote="$1"
  96         rh=$(git-rev-parse --verify "$remote^0" 2>/dev/null) || return
  97         bh=$(git-show-ref -s --verify "refs/heads/$remote" 2>/dev/null)
  98         if test "$rh" = "$bh"
  99         then
 100                 echo "$rh               branch '$remote' of ."
 101         elif truname=$(expr "$remote" : '\(.*\)~[1-9][0-9]*$') &&
 102                 git-show-ref -q --verify "refs/heads/$truname" 2>/dev/null
 103         then
 104                 echo "$rh               branch '$truname' (early part) of ."
 105         else
 106                 echo "$rh               commit '$remote'"
 107         fi
 108 }
 109
 110 case "$#" in 0) usage ;; esac
 111
 112 rloga= have_message=
 113 while case "$#" in 0) break ;; esac
 114 do
 115         case "$1" in
 116         -n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
 117                 --no-summa|--no-summar|--no-summary)
 118                 no_summary=t ;;
 119         --sq|--squ|--squa|--squas|--squash)
 120                 squash=t no_commit=t ;;
 121         --no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
 122                 no_commit=t ;;
 123         -s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
 124                 --strateg=*|--strategy=*|\
 125         -s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
 126                 case "$#,$1" in
 127                 *,*=*)
 128                         strategy=`expr "z$1" : 'z-[^=]*=\(.*\)'` ;;
 129                 1,*)
 130                         usage ;;
 131                 *)
 132                         strategy="$2"
 133                         shift ;;
 134                 esac
 135                 case " $all_strategies " in
 136                 *" $strategy "*)
 137                         use_strategies="$use_strategies$strategy " ;;
 138                 *)
 139                         die "available strategies are: $all_strategies" ;;
 140                 esac
 141                 ;;
 142         --reflog-action=*)
 143                 rloga=`expr "z$1" : 'z-[^=]*=\(.*\)'`
 144                 ;;
 145         -m=*|--m=*|--me=*|--mes=*|--mess=*|--messa=*|--messag=*|--message=*)
 146                 merge_msg=`expr "z$1" : 'z-[^=]*=\(.*\)'`
 147                 have_message=t
 148                 ;;
 149         -m|--m|--me|--mes|--mess|--messa|--messag|--message)
 150                 shift
 151                 case "$#" in
 152                 1)      usage ;;
 153                 esac
 154                 merge_msg="$1"
 155                 have_message=t
 156                 ;;
 157         -*)     usage ;;
 158         *)      break ;;
 159         esac
 160         shift
 161 done
 162
 163 # This could be traditional "merge <msg> HEAD <commit>..."  and the
 164 # way we can tell it is to see if the second token is HEAD, but some
 165 # people might have misused the interface and used a committish that
 166 # is the same as HEAD there instead.  Traditional format never would
 167 # have "-m" so it is an additional safety measure to check for it.
 168
 169 if test -z "$have_message" &&
 170         second_token=$(git-rev-parse --verify "$2^0" 2>/dev/null) &&
 171         head_commit=$(git-rev-parse --verify "HEAD" 2>/dev/null) &&
 172         test "$second_token" = "$head_commit"
 173 then
 174         merge_msg="$1"
 175         shift
 176         head_arg="$1"
 177         shift
 178 elif ! git-rev-parse --verify HEAD >/dev/null 2>&1
 179 then
 180         # If the merged head is a valid one there is no reason to
 181         # forbid "git merge" into a branch yet to be born.  We do
 182         # the same for "git pull".
 183         if test 1 -ne $#
 184         then
 185                 echo >&2 "Can merge only exactly one commit into empty head"
 186                 exit 1
 187         fi
 188
 189         rh=$(git rev-parse --verify "$1^0") ||
 190                 die "$1 - not something we can merge"
 191
 192         git-update-ref -m "initial pull" HEAD "$rh" "" &&
 193         git-read-tree --reset -u HEAD
 194         exit
 195
 196 else
 197         # We are invoked directly as the first-class UI.
 198         head_arg=HEAD
 199
 200         # All the rest are the commits being merged; prepare
 201         # the standard merge summary message to be appended to
 202         # the given message.  If remote is invalid we will die
 203         # later in the common codepath so we discard the error
 204         # in this loop.
 205         merge_name=$(for remote
 206                 do
 207                         merge_name "$remote"
 208                 done | git-fmt-merge-msg
 209         )
 210         merge_msg="${merge_msg:+$merge_msg$LF$LF}$merge_name"
 211 fi
 212 head=$(git-rev-parse --verify "$head_arg"^0) || usage
 213
 214 # All the rest are remote heads
 215 test "$#" = 0 && usage ;# we need at least one remote head.
 216 test "$rloga" = '' && rloga="merge: $@"
 217
 218 remoteheads=
 219 for remote
 220 do
 221         remotehead=$(git-rev-parse --verify "$remote"^0 2>/dev/null) ||
 222             die "$remote - not something we can merge"
 223         remoteheads="${remoteheads}$remotehead "
 224 done
 225 set x $remoteheads ; shift
 226
 227 case "$use_strategies" in
 228 '')
 229         case "$#" in
 230         1)
 231                 use_strategies="$default_twohead_strategies" ;;
 232         *)
 233                 use_strategies="$default_octopus_strategies" ;;
 234         esac
 235         ;;
 236 esac
 237
 238 for s in $use_strategies
 239 do
 240         case " $s " in
 241         *" $no_trivial_merge_strategies "*)
 242                 index_merge=f
 243                 break
 244                 ;;
 245         esac
 246 done
 247
 248 case "$#" in
 249 1)
 250         common=$(git-merge-base --all $head "$@")
 251         ;;
 252 *)
 253         common=$(git-show-branch --merge-base $head "$@")
 254         ;;
 255 esac
 256 echo "$head" >"$GIT_DIR/ORIG_HEAD"
 257
 258 case "$index_merge,$#,$common,$no_commit" in
 259 f,*)
 260         # We've been told not to try anything clever.  Skip to real merge.
 261         ;;
 262 ?,*,'',*)
 263         # No common ancestors found. We need a real merge.
 264         ;;
 265 ?,1,"$1",*)
 266         # If head can reach all the merge then we are up to date.
 267         # but first the most common case of merging one remote.
 268         finish_up_to_date "Already up-to-date."
 269         exit 0
 270         ;;
 271 ?,1,"$head",*)
 272         # Again the most common case of merging one remote.
 273         echo "Updating $(git-rev-parse --short $head)..$(git-rev-parse --short $1)"
 274         git-update-index --refresh 2>/dev/null
 275         new_head=$(git-rev-parse --verify "$1^0") &&
 276         git-read-tree -v -m -u --exclude-per-directory=.gitignore $head "$new_head" &&
 277         finish "$new_head" "Fast forward"
 278         dropsave
 279         exit 0
 280         ;;
 281 ?,1,?*"$LF"?*,*)
 282         # We are not doing octopus and not fast forward.  Need a
 283         # real merge.
 284         ;;
 285 ?,1,*,)
 286         # We are not doing octopus, not fast forward, and have only
 287         # one common.  See if it is really trivial.
 288         git var GIT_COMMITTER_IDENT >/dev/null || exit
 289
 290         echo "Trying really trivial in-index merge..."
 291         git-update-index --refresh 2>/dev/null
 292         if git-read-tree --trivial -m -u -v $common $head "$1" &&
 293            result_tree=$(git-write-tree)
 294         then
 295             echo "Wonderful."
 296             result_commit=$(
 297                 echo "$merge_msg" |
 298                 git-commit-tree $result_tree -p HEAD -p "$1"
 299             ) || exit
 300             finish "$result_commit" "In-index merge"
 301             dropsave
 302             exit 0
 303         fi
 304         echo "Nope."
 305         ;;
 306 *)
 307         # An octopus.  If we can reach all the remote we are up to date.
 308         up_to_date=t
 309         for remote
 310         do
 311                 common_one=$(git-merge-base --all $head $remote)
 312                 if test "$common_one" != "$remote"
 313                 then
 314                         up_to_date=f
 315                         break
 316                 fi
 317         done
 318         if test "$up_to_date" = t
 319         then
 320                 finish_up_to_date "Already up-to-date. Yeeah!"
 321                 exit 0
 322         fi
 323         ;;
 324 esac
 325
 326 # We are going to make a new commit.
 327 git var GIT_COMMITTER_IDENT >/dev/null || exit
 328
 329 # At this point, we need a real merge.  No matter what strategy
 330 # we use, it would operate on the index, possibly affecting the
 331 # working tree, and when resolved cleanly, have the desired tree
 332 # in the index -- this means that the index must be in sync with
 333 # the $head commit.  The strategies are responsible to ensure this.
 334
 335 case "$use_strategies" in
 336 ?*' '?*)
 337     # Stash away the local changes so that we can try more than one.
 338     savestate
 339     single_strategy=no
 340     ;;
 341 *)
 342     rm -f "$GIT_DIR/MERGE_SAVE"
 343     single_strategy=yes
 344     ;;
 345 esac
 346
 347 result_tree= best_cnt=-1 best_strategy= wt_strategy=
 348 merge_was_ok=
 349 for strategy in $use_strategies
 350 do
 351     test "$wt_strategy" = '' || {
 352         echo "Rewinding the tree to pristine..."
 353         restorestate
 354     }
 355     case "$single_strategy" in
 356     no)
 357         echo "Trying merge strategy $strategy..."
 358         ;;
 359     esac
 360
 361     # Remember which strategy left the state in the working tree
 362     wt_strategy=$strategy
 363
 364     git-merge-$strategy $common -- "$head_arg" "$@"
 365     exit=$?
 366     if test "$no_commit" = t && test "$exit" = 0
 367     then
 368         merge_was_ok=t
 369         exit=1 ;# pretend it left conflicts.
 370     fi
 371
 372     test "$exit" = 0 || {
 373
 374         # The backend exits with 1 when conflicts are left to be resolved,
 375         # with 2 when it does not handle the given merge at all.
 376
 377         if test "$exit" -eq 1
 378         then
 379             cnt=`{
 380                 git-diff-files --name-only
 381                 git-ls-files --unmerged
 382             } | wc -l`
 383             if test $best_cnt -le 0 -o $cnt -le $best_cnt
 384             then
 385                 best_strategy=$strategy
 386                 best_cnt=$cnt
 387             fi
 388         fi
 389         continue
 390     }
 391
 392     # Automerge succeeded.
 393     result_tree=$(git-write-tree) && break
 394 done
 395
 396 # If we have a resulting tree, that means the strategy module
 397 # auto resolved the merge cleanly.
 398 if test '' != "$result_tree"
 399 then
 400     parents=$(git-show-branch --independent "$head" "$@" | sed -e 's/^/-p /')
 401     result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents) || exit
 402     finish "$result_commit" "Merge made by $wt_strategy."
 403     dropsave
 404     exit 0
 405 fi
 406
 407 # Pick the result from the best strategy and have the user fix it up.
 408 case "$best_strategy" in
 409 '')
 410         restorestate
 411         case "$use_strategies" in
 412         ?*' '?*)
 413                 echo >&2 "No merge strategy handled the merge."
 414                 ;;
 415         *)
 416                 echo >&2 "Merge with strategy $use_strategies failed."
 417                 ;;
 418         esac
 419         exit 2
 420         ;;
 421 "$wt_strategy")
 422         # We already have its result in the working tree.
 423         ;;
 424 *)
 425         echo "Rewinding the tree to pristine..."
 426         restorestate
 427         echo "Using the $best_strategy to prepare resolving by hand."
 428         git-merge-$best_strategy $common -- "$head_arg" "$@"
 429         ;;
 430 esac
 431
 432 if test "$squash" = t
 433 then
 434         finish
 435 else
 436         for remote
 437         do
 438                 echo $remote
 439         done >"$GIT_DIR/MERGE_HEAD"
 440         echo "$merge_msg" >"$GIT_DIR/MERGE_MSG"
 441 fi
 442
 443 if test "$merge_was_ok" = t
 444 then
 445         echo >&2 \
 446         "Automatic merge went well; stopped before committing as requested"
 447         exit 0
 448 else
 449         {
 450             echo '
 451 Conflicts:
 452 '
 453                 git ls-files --unmerged |
 454                 sed -e 's/^[^   ]*      /       /' |
 455                 uniq
 456         } >>"$GIT_DIR/MERGE_MSG"
 457         if test -d "$GIT_DIR/rr-cache"
 458         then
 459                 git-rerere
 460         fi
 461         die "Automatic merge failed; fix conflicts and then commit the result."
 462 fi