git-merge.sh - jrn/git - Git at Google

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

 . git-sh-setup

 LF='
 '

 usage () {
     die "git-merge [-n] [--no-commit] [-s <strategy>]... <merge-message> <head> <remote>+"
 }

 all_strategies='recursive octopus resolve stupid ours'
 default_strategies='recursive'
 use_strategies=

 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 $head
 		cpio -iuv <"$GIT_DIR/MERGE_SAVE"
 		git-update-index --refresh >/dev/null
 	fi
 }

 finish () {
 	test '' = "$2" || echo "$2"
 	case "$merge_msg" in
 	'')
 		echo "No merge message -- not updating HEAD"
 		;;
 	*)
 		git-update-ref HEAD "$1" "$head" || exit 1
 		;;
 	esac

 	case "$no_summary" in
 	'')
 		git-diff-tree -p -M "$head" "$1" |
 		git-apply --stat --summary
 		;;
 	esac
 }

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

 test "$#" -le 2 && usage ;# we need at least two heads.

 merge_msg="$1"
 shift
 head_arg="$1"
 head=$(git-rev-parse --verify "$1"^0) || usage
 shift

 # All the rest are remote heads
 for remote
 do
 	git-rev-parse --verify "$remote"^0 >/dev/null ||
 	    die "$remote - not something we can merge"
 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 "$#,$common,$no_commit" in
 *,'',*)
 	# No common ancestors found. We need a real merge.
 	;;
 1,"$1",*)
 	# If head can reach all the merge then we are up to date.
 	# but first the most common case of merging one remote
 	echo "Already up-to-date."
 	dropsave
 	exit 0
 	;;
 1,"$head",*)
 	# Again the most common case of merging one remote.
 	echo "Updating from $head to $1."
 	git-update-index --refresh 2>/dev/null
 	new_head=$(git-rev-parse --verify "$1^0") &&
 	git-read-tree -u -m $head "$new_head" &&
 	finish "$new_head" "Fast forward"
 	dropsave
 	exit 0
 	;;
 1,?*"$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.  See if it is really trivial.
 	echo "Trying really trivial in-index merge..."
 	git-update-index --refresh 2>/dev/null
 	if git-read-tree --trivial -m -u $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."
 	;;
 *)
 	# 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
 		echo "Already up-to-date. Yeeah!"
 		dropsave
 		exit 0
 	fi
 	;;
 esac

 case "$use_strategies" in
 '')
 	case "$#" in
 	1)
 		use_strategies="$default_strategies" ;;
 	*)
 		use_strategies=octopus ;;
 	esac
 	;;
 esac

 # 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=
 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
 	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="-p $head"
     for remote
     do
         parents="$parents -p $remote"
     done
     result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents) || exit
     finish "$result_commit" "Merge $result_commit, made by $wt_strategy."
     dropsave
     exit 0
 fi

 # Pick the result from the best strategy and have the user fix it up.
 case "$best_strategy" in
 '')
 	restorestate
 	echo >&2 "No merge strategy handled the merge."
 	exit 2
 	;;
 "$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
 for remote
 do
 	echo $remote
 done >"$GIT_DIR/MERGE_HEAD"
 echo $merge_msg >"$GIT_DIR/MERGE_MSG"

 die "Automatic merge failed/prevented; fix up by hand"
	#!/bin/sh
	#
	# Copyright (c) 2005 Junio C Hamano
	#

	. git-sh-setup

	LF='
	'

	usage () {
	die "git-merge [-n] [--no-commit] [-s <strategy>]... <merge-message> <head> <remote>+"
	}

	all_strategies='recursive octopus resolve stupid ours'
	default_strategies='recursive'
	use_strategies=

	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 $head
	cpio -iuv <"$GIT_DIR/MERGE_SAVE"
	git-update-index --refresh >/dev/null
	fi
	}

	finish () {
	test '' = "$2" \|\| echo "$2"
	case "$merge_msg" in
	'')
	echo "No merge message -- not updating HEAD"
	;;
	*)
	git-update-ref HEAD "$1" "$head" \|\| exit 1
	;;
	esac

	case "$no_summary" in
	'')
	git-diff-tree -p -M "$head" "$1" \|
	git-apply --stat --summary
	;;
	esac
	}

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

	test "$#" -le 2 && usage ;# we need at least two heads.

	merge_msg="$1"
	shift
	head_arg="$1"
	head=$(git-rev-parse --verify "$1"^0) \|\| usage
	shift

	# All the rest are remote heads
	for remote
	do
	git-rev-parse --verify "$remote"^0 >/dev/null \|\|
	die "$remote - not something we can merge"
	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 "$#,$common,$no_commit" in
	,'',)
	# No common ancestors found. We need a real merge.
	;;
	1,"$1",*)
	# If head can reach all the merge then we are up to date.
	# but first the most common case of merging one remote
	echo "Already up-to-date."
	dropsave
	exit 0
	;;
	1,"$head",*)
	# Again the most common case of merging one remote.
	echo "Updating from $head to $1."
	git-update-index --refresh 2>/dev/null
	new_head=$(git-rev-parse --verify "$1^0") &&
	git-read-tree -u -m $head "$new_head" &&
	finish "$new_head" "Fast forward"
	dropsave
	exit 0
	;;
	1,?"$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. See if it is really trivial.
	echo "Trying really trivial in-index merge..."
	git-update-index --refresh 2>/dev/null
	if git-read-tree --trivial -m -u $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."
	;;
	*)
	# 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
	echo "Already up-to-date. Yeeah!"
	dropsave
	exit 0
	fi
	;;
	esac

	case "$use_strategies" in
	'')
	case "$#" in
	1)
	use_strategies="$default_strategies" ;;
	*)
	use_strategies=octopus ;;
	esac
	;;
	esac

	# 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=
	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
	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="-p $head"
	for remote
	do
	parents="$parents -p $remote"
	done
	result_commit=$(echo "$merge_msg" \| git-commit-tree $result_tree $parents) \|\| exit
	finish "$result_commit" "Merge $result_commit, made by $wt_strategy."
	dropsave
	exit 0
	fi

	# Pick the result from the best strategy and have the user fix it up.
	case "$best_strategy" in
	'')
	restorestate
	echo >&2 "No merge strategy handled the merge."
	exit 2
	;;
	"$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
	for remote
	do
	echo $remote
	done >"$GIT_DIR/MERGE_HEAD"
	echo $merge_msg >"$GIT_DIR/MERGE_MSG"

	die "Automatic merge failed/prevented; fix up by hand"