git-merge.sh - git - Git at Google

 #!/bin/sh
 #
 # Copyright (c) 2005 Junio C Hamano
 #

 USAGE='[-n] [--no-commit] [--squash] [-s <strategy>] [-m=<merge-message>] <commit>+'

 SUBDIRECTORY_OK=Yes
 . git-sh-setup
 require_work_tree
 cd_to_toplevel

 test -z "$(git ls-files -u)" ||
 	die "You are in the middle of a conflicted merge."

 LF='
 '

 all_strategies='recur recursive octopus resolve stupid ours'
 default_twohead_strategies='recursive'
 default_octopus_strategies='octopus'
 no_trivial_merge_strategies='ours'
 use_strategies=

 index_merge=t

 dropsave() {
 	rm -f -- "$GIT_DIR/MERGE_HEAD" "$GIT_DIR/MERGE_MSG" \
 		 "$GIT_DIR/MERGE_SAVE" || exit 1
 }

 savestate() {
 	# Stash away any local modifications.
 	git-diff-index -z --name-only $head |
 	cpio -0 -o >"$GIT_DIR/MERGE_SAVE"
 }

 restorestate() {
         if test -f "$GIT_DIR/MERGE_SAVE"
 	then
 		git reset --hard $head >/dev/null
 		cpio -iuv <"$GIT_DIR/MERGE_SAVE"
 		git-update-index --refresh >/dev/null
 	fi
 }

 finish_up_to_date () {
 	case "$squash" in
 	t)
 		echo "$1 (nothing to squash)" ;;
 	'')
 		echo "$1" ;;
 	esac
 	dropsave
 }

 squash_message () {
 	echo Squashed commit of the following:
 	echo
 	git-log --no-merges ^"$head" $remote
 }

 finish () {
 	if test '' = "$2"
 	then
 		rlogm="$GIT_REFLOG_ACTION"
 	else
 		echo "$2"
 		rlogm="$GIT_REFLOG_ACTION: $2"
 	fi
 	case "$squash" in
 	t)
 		echo "Squash commit -- not updating HEAD"
 		squash_message >"$GIT_DIR/SQUASH_MSG"
 		;;
 	'')
 		case "$merge_msg" in
 		'')
 			echo "No merge message -- not updating HEAD"
 			;;
 		*)
 			git-update-ref -m "$rlogm" HEAD "$1" "$head" || exit 1
 			;;
 		esac
 		;;
 	esac
 	case "$1" in
 	'')
 		;;
 	?*)
 		case "$no_summary" in
 		'')
 			git-diff-tree --stat --summary -M "$head" "$1"
 			;;
 		esac
 		;;
 	esac
 }

 merge_name () {
 	remote="$1"
 	rh=$(git-rev-parse --verify "$remote^0" 2>/dev/null) || return
 	bh=$(git-show-ref -s --verify "refs/heads/$remote" 2>/dev/null)
 	if test "$rh" = "$bh"
 	then
 		echo "$rh		branch '$remote' of ."
 	elif truname=$(expr "$remote" : '\(.*\)~[1-9][0-9]*$') &&
 		git-show-ref -q --verify "refs/heads/$truname" 2>/dev/null
 	then
 		echo "$rh		branch '$truname' (early part) of ."
 	elif test "$remote" = "FETCH_HEAD" -a -r "$GIT_DIR/FETCH_HEAD"
 	then
 		sed -e 's/	not-for-merge	/		/' -e 1q \
 			"$GIT_DIR/FETCH_HEAD"
 	else
 		echo "$rh		commit '$remote'"
 	fi
 }

 case "$#" in 0) usage ;; esac

 have_message=
 while case "$#" in 0) break ;; esac
 do
 	case "$1" in
 	-n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
 		--no-summa|--no-summar|--no-summary)
 		no_summary=t ;;
 	--sq|--squ|--squa|--squas|--squash)
 		squash=t no_commit=t ;;
 	--no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
 		no_commit=t ;;
 	-s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
 		--strateg=*|--strategy=*|\
 	-s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
 		case "$#,$1" in
 		*,*=*)
 			strategy=`expr "z$1" : 'z-[^=]*=\(.*\)'` ;;
 		1,*)
 			usage ;;
 		*)
 			strategy="$2"
 			shift ;;
 		esac
 		case " $all_strategies " in
 		*" $strategy "*)
 			use_strategies="$use_strategies$strategy " ;;
 		*)
 			die "available strategies are: $all_strategies" ;;
 		esac
 		;;
 	-m=*|--m=*|--me=*|--mes=*|--mess=*|--messa=*|--messag=*|--message=*)
 		merge_msg=`expr "z$1" : 'z-[^=]*=\(.*\)'`
 		have_message=t
 		;;
 	-m|--m|--me|--mes|--mess|--messa|--messag|--message)
 		shift
 		case "$#" in
 		1)	usage ;;
 		esac
 		merge_msg="$1"
 		have_message=t
 		;;
 	-*)	usage ;;
 	*)	break ;;
 	esac
 	shift
 done

 # This could be traditional "merge <msg> HEAD <commit>..."  and the
 # way we can tell it is to see if the second token is HEAD, but some
 # people might have misused the interface and used a committish that
 # is the same as HEAD there instead.  Traditional format never would
 # have "-m" so it is an additional safety measure to check for it.

 if test -z "$have_message" &&
 	second_token=$(git-rev-parse --verify "$2^0" 2>/dev/null) &&
 	head_commit=$(git-rev-parse --verify "HEAD" 2>/dev/null) &&
 	test "$second_token" = "$head_commit"
 then
 	merge_msg="$1"
 	shift
 	head_arg="$1"
 	shift
 elif ! git-rev-parse --verify HEAD >/dev/null 2>&1
 then
 	# If the merged head is a valid one there is no reason to
 	# forbid "git merge" into a branch yet to be born.  We do
 	# the same for "git pull".
 	if test 1 -ne $#
 	then
 		echo >&2 "Can merge only exactly one commit into empty head"
 		exit 1
 	fi

 	rh=$(git rev-parse --verify "$1^0") ||
 		die "$1 - not something we can merge"

 	git-update-ref -m "initial pull" HEAD "$rh" "" &&
 	git-read-tree --reset -u HEAD
 	exit

 else
 	# We are invoked directly as the first-class UI.
 	head_arg=HEAD

 	# All the rest are the commits being merged; prepare
 	# the standard merge summary message to be appended to
 	# the given message.  If remote is invalid we will die
 	# later in the common codepath so we discard the error
 	# in this loop.
 	merge_name=$(for remote
 		do
 			merge_name "$remote"
 		done | git-fmt-merge-msg
 	)
 	merge_msg="${merge_msg:+$merge_msg$LF$LF}$merge_name"
 fi
 head=$(git-rev-parse --verify "$head_arg"^0) || usage

 # All the rest are remote heads
 test "$#" = 0 && usage ;# we need at least one remote head.
 set_reflog_action "merge $*"

 remoteheads=
 for remote
 do
 	remotehead=$(git-rev-parse --verify "$remote"^0 2>/dev/null) ||
 	    die "$remote - not something we can merge"
 	remoteheads="${remoteheads}$remotehead "
 	eval GITHEAD_$remotehead='"$remote"'
 	export GITHEAD_$remotehead
 done
 set x $remoteheads ; shift

 case "$use_strategies" in
 '')
 	case "$#" in
 	1)
 		var="`git-config --get pull.twohead`"
 		if test -n "$var"
 		then
 			use_strategies="$var"
 		else
 			use_strategies="$default_twohead_strategies"
 		fi ;;
 	*)
 		var="`git-config --get pull.octopus`"
 		if test -n "$var"
 		then
 			use_strategies="$var"
 		else
 			use_strategies="$default_octopus_strategies"
 		fi ;;
 	esac
 	;;
 esac

 for s in $use_strategies
 do
 	for nt in $no_trivial_merge_strategies
 	do
 		case " $s " in
 		*" $nt "*)
 			index_merge=f
 			break
 			;;
 		esac
 	done
 done

 case "$#" in
 1)
 	common=$(git-merge-base --all $head "$@")
 	;;
 *)
 	common=$(git-show-branch --merge-base $head "$@")
 	;;
 esac
 echo "$head" >"$GIT_DIR/ORIG_HEAD"

 case "$index_merge,$#,$common,$no_commit" in
 f,*)
 	# We've been told not to try anything clever.  Skip to real merge.
 	;;
 ?,*,'',*)
 	# No common ancestors found. We need a real merge.
 	;;
 ?,1,"$1",*)
 	# If head can reach all the merge then we are up to date.
 	# but first the most common case of merging one remote.
 	finish_up_to_date "Already up-to-date."
 	exit 0
 	;;
 ?,1,"$head",*)
 	# Again the most common case of merging one remote.
 	echo "Updating $(git-rev-parse --short $head)..$(git-rev-parse --short $1)"
 	git-update-index --refresh 2>/dev/null
 	msg="Fast forward"
 	if test -n "$have_message"
 	then
 		msg="$msg (no commit created; -m option ignored)"
 	fi
 	new_head=$(git-rev-parse --verify "$1^0") &&
 	git-read-tree -v -m -u --exclude-per-directory=.gitignore $head "$new_head" &&
 	finish "$new_head" "$msg" || exit
 	dropsave
 	exit 0
 	;;
 ?,1,?*"$LF"?*,*)
 	# We are not doing octopus and not fast forward.  Need a
 	# real merge.
 	;;
 ?,1,*,)
 	# We are not doing octopus, not fast forward, and have only
 	# one common.
 	git-update-index --refresh 2>/dev/null
 	case " $use_strategies " in
 	*' recursive '*|*' recur '*)
 		: run merge later
 		;;
 	*)
 		# See if it is really trivial.
 		git var GIT_COMMITTER_IDENT >/dev/null || exit
 		echo "Trying really trivial in-index merge..."
 		if git-read-tree --trivial -m -u -v $common $head "$1" &&
 		   result_tree=$(git-write-tree)
 		then
 			echo "Wonderful."
 			result_commit=$(
 				echo "$merge_msg" |
 				git-commit-tree $result_tree -p HEAD -p "$1"
 			) || exit
 			finish "$result_commit" "In-index merge"
 			dropsave
 			exit 0
 		fi
 		echo "Nope."
 	esac
 	;;
 *)
 	# An octopus.  If we can reach all the remote we are up to date.
 	up_to_date=t
 	for remote
 	do
 		common_one=$(git-merge-base --all $head $remote)
 		if test "$common_one" != "$remote"
 		then
 			up_to_date=f
 			break
 		fi
 	done
 	if test "$up_to_date" = t
 	then
 		finish_up_to_date "Already up-to-date. Yeeah!"
 		exit 0
 	fi
 	;;
 esac

 # We are going to make a new commit.
 git var GIT_COMMITTER_IDENT >/dev/null || exit

 # At this point, we need a real merge.  No matter what strategy
 # we use, it would operate on the index, possibly affecting the
 # working tree, and when resolved cleanly, have the desired tree
 # in the index -- this means that the index must be in sync with
 # the $head commit.  The strategies are responsible to ensure this.

 case "$use_strategies" in
 ?*' '?*)
     # Stash away the local changes so that we can try more than one.
     savestate
     single_strategy=no
     ;;
 *)
     rm -f "$GIT_DIR/MERGE_SAVE"
     single_strategy=yes
     ;;
 esac

 result_tree= best_cnt=-1 best_strategy= wt_strategy=
 merge_was_ok=
 for strategy in $use_strategies
 do
     test "$wt_strategy" = '' || {
 	echo "Rewinding the tree to pristine..."
 	restorestate
     }
     case "$single_strategy" in
     no)
 	echo "Trying merge strategy $strategy..."
 	;;
     esac

     # Remember which strategy left the state in the working tree
     wt_strategy=$strategy

     git-merge-$strategy $common -- "$head_arg" "$@"
     exit=$?
     if test "$no_commit" = t && test "$exit" = 0
     then
         merge_was_ok=t
 	exit=1 ;# pretend it left conflicts.
     fi

     test "$exit" = 0 || {

 	# The backend exits with 1 when conflicts are left to be resolved,
 	# with 2 when it does not handle the given merge at all.

 	if test "$exit" -eq 1
 	then
 	    cnt=`{
 		git-diff-files --name-only
 		git-ls-files --unmerged
 	    } | wc -l`
 	    if test $best_cnt -le 0 -o $cnt -le $best_cnt
 	    then
 		best_strategy=$strategy
 		best_cnt=$cnt
 	    fi
 	fi
 	continue
     }

     # Automerge succeeded.
     result_tree=$(git-write-tree) && break
 done

 # If we have a resulting tree, that means the strategy module
 # auto resolved the merge cleanly.
 if test '' != "$result_tree"
 then
     parents=$(git-show-branch --independent "$head" "$@" | sed -e 's/^/-p /')
     result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents) || exit
     finish "$result_commit" "Merge made by $wt_strategy."
     dropsave
     exit 0
 fi

 # Pick the result from the best strategy and have the user fix it up.
 case "$best_strategy" in
 '')
 	restorestate
 	case "$use_strategies" in
 	?*' '?*)
 		echo >&2 "No merge strategy handled the merge."
 		;;
 	*)
 		echo >&2 "Merge with strategy $use_strategies failed."
 		;;
 	esac
 	exit 2
 	;;
 "$wt_strategy")
 	# We already have its result in the working tree.
 	;;
 *)
 	echo "Rewinding the tree to pristine..."
 	restorestate
 	echo "Using the $best_strategy to prepare resolving by hand."
 	git-merge-$best_strategy $common -- "$head_arg" "$@"
 	;;
 esac

 if test "$squash" = t
 then
 	finish
 else
 	for remote
 	do
 		echo $remote
 	done >"$GIT_DIR/MERGE_HEAD"
 	echo "$merge_msg" >"$GIT_DIR/MERGE_MSG"
 fi

 if test "$merge_was_ok" = t
 then
 	echo >&2 \
 	"Automatic merge went well; stopped before committing as requested"
 	exit 0
 else
 	{
 	    echo '
 Conflicts:
 '
 		git ls-files --unmerged |
 		sed -e 's/^[^	]*	/	/' |
 		uniq
 	} >>"$GIT_DIR/MERGE_MSG"
 	if test -d "$GIT_DIR/rr-cache"
 	then
 		git-rerere
 	fi
 	die "Automatic merge failed; fix conflicts and then commit the result."
 fi
	#!/bin/sh
	#
	# Copyright (c) 2005 Junio C Hamano
	#

	USAGE='[-n] [--no-commit] [--squash] [-s <strategy>] [-m=<merge-message>] <commit>+'

	SUBDIRECTORY_OK=Yes
	. git-sh-setup
	require_work_tree
	cd_to_toplevel

	test -z "$(git ls-files -u)" \|\|
	die "You are in the middle of a conflicted merge."

	LF='
	'

	all_strategies='recur recursive octopus resolve stupid ours'
	default_twohead_strategies='recursive'
	default_octopus_strategies='octopus'
	no_trivial_merge_strategies='ours'
	use_strategies=

	index_merge=t

	dropsave() {
	rm -f -- "$GIT_DIR/MERGE_HEAD" "$GIT_DIR/MERGE_MSG" \
	"$GIT_DIR/MERGE_SAVE" \|\| exit 1
	}

	savestate() {
	# Stash away any local modifications.
	git-diff-index -z --name-only $head \|
	cpio -0 -o >"$GIT_DIR/MERGE_SAVE"
	}

	restorestate() {
	if test -f "$GIT_DIR/MERGE_SAVE"
	then
	git reset --hard $head >/dev/null
	cpio -iuv <"$GIT_DIR/MERGE_SAVE"
	git-update-index --refresh >/dev/null
	fi
	}

	finish_up_to_date () {
	case "$squash" in
	t)
	echo "$1 (nothing to squash)" ;;
	'')
	echo "$1" ;;
	esac
	dropsave
	}

	squash_message () {
	echo Squashed commit of the following:
	echo
	git-log --no-merges ^"$head" $remote
	}

	finish () {
	if test '' = "$2"
	then
	rlogm="$GIT_REFLOG_ACTION"
	else
	echo "$2"
	rlogm="$GIT_REFLOG_ACTION: $2"
	fi
	case "$squash" in
	t)
	echo "Squash commit -- not updating HEAD"
	squash_message >"$GIT_DIR/SQUASH_MSG"
	;;
	'')
	case "$merge_msg" in
	'')
	echo "No merge message -- not updating HEAD"
	;;
	*)
	git-update-ref -m "$rlogm" HEAD "$1" "$head" \|\| exit 1
	;;
	esac
	;;
	esac
	case "$1" in
	'')
	;;
	?*)
	case "$no_summary" in
	'')
	git-diff-tree --stat --summary -M "$head" "$1"
	;;
	esac
	;;
	esac
	}

	merge_name () {
	remote="$1"
	rh=$(git-rev-parse --verify "$remote^0" 2>/dev/null) \|\| return
	bh=$(git-show-ref -s --verify "refs/heads/$remote" 2>/dev/null)
	if test "$rh" = "$bh"
	then
	echo "$rh branch '$remote' of ."
	elif truname=$(expr "$remote" : '\(.\)~[1-9][0-9]$') &&
	git-show-ref -q --verify "refs/heads/$truname" 2>/dev/null
	then
	echo "$rh branch '$truname' (early part) of ."
	elif test "$remote" = "FETCH_HEAD" -a -r "$GIT_DIR/FETCH_HEAD"
	then
	sed -e 's/ not-for-merge / /' -e 1q \
	"$GIT_DIR/FETCH_HEAD"
	else
	echo "$rh commit '$remote'"
	fi
	}

	case "$#" in 0) usage ;; esac

	have_message=
	while case "$#" in 0) break ;; esac
	do
	case "$1" in
	-n\|--n\|--no\|--no-\|--no-s\|--no-su\|--no-sum\|--no-summ\|\
	--no-summa\|--no-summar\|--no-summary)
	no_summary=t ;;
	--sq\|--squ\|--squa\|--squas\|--squash)
	squash=t no_commit=t ;;
	--no-c\|--no-co\|--no-com\|--no-comm\|--no-commi\|--no-commit)
	no_commit=t ;;
	-s=\|--s=\|--st=\|--str=\|--stra=\|--strat=\|--strate=*\|\
	--strateg=\|--strategy=\|\
	-s\|--s\|--st\|--str\|--stra\|--strat\|--strate\|--strateg\|--strategy)
	case "$#,$1" in
	,=*)
	strategy=`expr "z$1" : 'z-[^=]=\(.\)'` ;;
	1,*)
	usage ;;
	*)
	strategy="$2"
	shift ;;
	esac
	case " $all_strategies " in
	" $strategy ")
	use_strategies="$use_strategies$strategy " ;;
	*)
	die "available strategies are: $all_strategies" ;;
	esac
	;;
	-m=\|--m=\|--me=\|--mes=\|--mess=\|--messa=\|--messag=\|--message=)
	merge_msg=`expr "z$1" : 'z-[^=]=\(.\)'`
	have_message=t
	;;
	-m\|--m\|--me\|--mes\|--mess\|--messa\|--messag\|--message)
	shift
	case "$#" in
	1) usage ;;
	esac
	merge_msg="$1"
	have_message=t
	;;
	-*) usage ;;
	*) break ;;
	esac
	shift
	done

	# This could be traditional "merge <msg> HEAD <commit>..." and the
	# way we can tell it is to see if the second token is HEAD, but some
	# people might have misused the interface and used a committish that
	# is the same as HEAD there instead. Traditional format never would
	# have "-m" so it is an additional safety measure to check for it.

	if test -z "$have_message" &&
	second_token=$(git-rev-parse --verify "$2^0" 2>/dev/null) &&
	head_commit=$(git-rev-parse --verify "HEAD" 2>/dev/null) &&
	test "$second_token" = "$head_commit"
	then
	merge_msg="$1"
	shift
	head_arg="$1"
	shift
	elif ! git-rev-parse --verify HEAD >/dev/null 2>&1
	then
	# If the merged head is a valid one there is no reason to
	# forbid "git merge" into a branch yet to be born. We do
	# the same for "git pull".
	if test 1 -ne $#
	then
	echo >&2 "Can merge only exactly one commit into empty head"
	exit 1
	fi

	rh=$(git rev-parse --verify "$1^0") \|\|
	die "$1 - not something we can merge"

	git-update-ref -m "initial pull" HEAD "$rh" "" &&
	git-read-tree --reset -u HEAD
	exit

	else
	# We are invoked directly as the first-class UI.
	head_arg=HEAD

	# All the rest are the commits being merged; prepare
	# the standard merge summary message to be appended to
	# the given message. If remote is invalid we will die
	# later in the common codepath so we discard the error
	# in this loop.
	merge_name=$(for remote
	do
	merge_name "$remote"
	done \| git-fmt-merge-msg
	)
	merge_msg="${merge_msg:+$merge_msg$LF$LF}$merge_name"
	fi
	head=$(git-rev-parse --verify "$head_arg"^0) \|\| usage

	# All the rest are remote heads
	test "$#" = 0 && usage ;# we need at least one remote head.
	set_reflog_action "merge $*"

	remoteheads=
	for remote
	do
	remotehead=$(git-rev-parse --verify "$remote"^0 2>/dev/null) \|\|
	die "$remote - not something we can merge"
	remoteheads="${remoteheads}$remotehead "
	eval GITHEAD_$remotehead='"$remote"'
	export GITHEAD_$remotehead
	done
	set x $remoteheads ; shift

	case "$use_strategies" in
	'')
	case "$#" in
	1)
	var="`git-config --get pull.twohead`"
	if test -n "$var"
	then
	use_strategies="$var"
	else
	use_strategies="$default_twohead_strategies"
	fi ;;
	*)
	var="`git-config --get pull.octopus`"
	if test -n "$var"
	then
	use_strategies="$var"
	else
	use_strategies="$default_octopus_strategies"
	fi ;;
	esac
	;;
	esac

	for s in $use_strategies
	do
	for nt in $no_trivial_merge_strategies
	do
	case " $s " in
	" $nt ")
	index_merge=f
	break
	;;
	esac
	done
	done

	case "$#" in
	1)
	common=$(git-merge-base --all $head "$@")
	;;
	*)
	common=$(git-show-branch --merge-base $head "$@")
	;;
	esac
	echo "$head" >"$GIT_DIR/ORIG_HEAD"

	case "$index_merge,$#,$common,$no_commit" in
	f,*)
	# We've been told not to try anything clever. Skip to real merge.
	;;
	?,,'',)
	# No common ancestors found. We need a real merge.
	;;
	?,1,"$1",*)
	# If head can reach all the merge then we are up to date.
	# but first the most common case of merging one remote.
	finish_up_to_date "Already up-to-date."
	exit 0
	;;
	?,1,"$head",*)
	# Again the most common case of merging one remote.
	echo "Updating $(git-rev-parse --short $head)..$(git-rev-parse --short $1)"
	git-update-index --refresh 2>/dev/null
	msg="Fast forward"
	if test -n "$have_message"
	then
	msg="$msg (no commit created; -m option ignored)"
	fi
	new_head=$(git-rev-parse --verify "$1^0") &&
	git-read-tree -v -m -u --exclude-per-directory=.gitignore $head "$new_head" &&
	finish "$new_head" "$msg" \|\| exit
	dropsave
	exit 0
	;;
	?,1,?"$LF"?,*)
	# We are not doing octopus and not fast forward. Need a
	# real merge.
	;;
	?,1,*,)
	# We are not doing octopus, not fast forward, and have only
	# one common.
	git-update-index --refresh 2>/dev/null
	case " $use_strategies " in
	' recursive '\|' recur ')
	: run merge later
	;;
	*)
	# See if it is really trivial.
	git var GIT_COMMITTER_IDENT >/dev/null \|\| exit
	echo "Trying really trivial in-index merge..."
	if git-read-tree --trivial -m -u -v $common $head "$1" &&
	result_tree=$(git-write-tree)
	then
	echo "Wonderful."
	result_commit=$(
	echo "$merge_msg" \|
	git-commit-tree $result_tree -p HEAD -p "$1"
	) \|\| exit
	finish "$result_commit" "In-index merge"
	dropsave
	exit 0
	fi
	echo "Nope."
	esac
	;;
	*)
	# An octopus. If we can reach all the remote we are up to date.
	up_to_date=t
	for remote
	do
	common_one=$(git-merge-base --all $head $remote)
	if test "$common_one" != "$remote"
	then
	up_to_date=f
	break
	fi
	done
	if test "$up_to_date" = t
	then
	finish_up_to_date "Already up-to-date. Yeeah!"
	exit 0
	fi
	;;
	esac

	# We are going to make a new commit.
	git var GIT_COMMITTER_IDENT >/dev/null \|\| exit

	# At this point, we need a real merge. No matter what strategy
	# we use, it would operate on the index, possibly affecting the
	# working tree, and when resolved cleanly, have the desired tree
	# in the index -- this means that the index must be in sync with
	# the $head commit. The strategies are responsible to ensure this.

	case "$use_strategies" in
	?' '?)
	# Stash away the local changes so that we can try more than one.
	savestate
	single_strategy=no
	;;
	*)
	rm -f "$GIT_DIR/MERGE_SAVE"
	single_strategy=yes
	;;
	esac

	result_tree= best_cnt=-1 best_strategy= wt_strategy=
	merge_was_ok=
	for strategy in $use_strategies
	do
	test "$wt_strategy" = '' \|\| {
	echo "Rewinding the tree to pristine..."
	restorestate
	}
	case "$single_strategy" in
	no)
	echo "Trying merge strategy $strategy..."
	;;
	esac

	# Remember which strategy left the state in the working tree
	wt_strategy=$strategy

	git-merge-$strategy $common -- "$head_arg" "$@"
	exit=$?
	if test "$no_commit" = t && test "$exit" = 0
	then
	merge_was_ok=t
	exit=1 ;# pretend it left conflicts.
	fi

	test "$exit" = 0 \|\| {

	# The backend exits with 1 when conflicts are left to be resolved,
	# with 2 when it does not handle the given merge at all.

	if test "$exit" -eq 1
	then
	cnt=`{
	git-diff-files --name-only
	git-ls-files --unmerged
	} \| wc -l`
	if test $best_cnt -le 0 -o $cnt -le $best_cnt
	then
	best_strategy=$strategy
	best_cnt=$cnt
	fi
	fi
	continue
	}

	# Automerge succeeded.
	result_tree=$(git-write-tree) && break
	done

	# If we have a resulting tree, that means the strategy module
	# auto resolved the merge cleanly.
	if test '' != "$result_tree"
	then
	parents=$(git-show-branch --independent "$head" "$@" \| sed -e 's/^/-p /')
	result_commit=$(echo "$merge_msg" \| git-commit-tree $result_tree $parents) \|\| exit
	finish "$result_commit" "Merge made by $wt_strategy."
	dropsave
	exit 0
	fi

	# Pick the result from the best strategy and have the user fix it up.
	case "$best_strategy" in
	'')
	restorestate
	case "$use_strategies" in
	?' '?)
	echo >&2 "No merge strategy handled the merge."
	;;
	*)
	echo >&2 "Merge with strategy $use_strategies failed."
	;;
	esac
	exit 2
	;;
	"$wt_strategy")
	# We already have its result in the working tree.
	;;
	*)
	echo "Rewinding the tree to pristine..."
	restorestate
	echo "Using the $best_strategy to prepare resolving by hand."
	git-merge-$best_strategy $common -- "$head_arg" "$@"
	;;
	esac

	if test "$squash" = t
	then
	finish
	else
	for remote
	do
	echo $remote
	done >"$GIT_DIR/MERGE_HEAD"
	echo "$merge_msg" >"$GIT_DIR/MERGE_MSG"
	fi

	if test "$merge_was_ok" = t
	then
	echo >&2 \
	"Automatic merge went well; stopped before committing as requested"
	exit 0
	else
	{
	echo '
	Conflicts:
	'
	git ls-files --unmerged \|
	sed -e 's/^[^ ]* / /' \|
	uniq
	} >>"$GIT_DIR/MERGE_MSG"
	if test -d "$GIT_DIR/rr-cache"
	then
	git-rerere
	fi
	die "Automatic merge failed; fix conflicts and then commit the result."
	fi