contrib/examples/git-checkout.sh - git - Git at Google

 #!/bin/sh

 OPTIONS_KEEPDASHDASH=t
 OPTIONS_SPEC="\
 git-checkout [options] [<branch>] [<paths>...]
 --
 b=          create a new branch started at <branch>
 l           create the new branch's reflog
 track       arrange that the new branch tracks the remote branch
 f           proceed even if the index or working tree is not HEAD
 m           merge local modifications into the new branch
 q,quiet     be quiet
 "
 SUBDIRECTORY_OK=Sometimes
 . git-sh-setup
 require_work_tree

 old_name=HEAD
 old=$(git rev-parse --verify $old_name 2>/dev/null)
 oldbranch=$(git symbolic-ref $old_name 2>/dev/null)
 new=
 new_name=
 force=
 branch=
 track=
 newbranch=
 newbranch_log=
 merge=
 quiet=
 v=-v
 LF='
 '

 while test $# != 0; do
 	case "$1" in
 	-b)
 		shift
 		newbranch="$1"
 		[ -z "$newbranch" ] &&
 			die "git checkout: -b needs a branch name"
 		git show-ref --verify --quiet -- "refs/heads/$newbranch" &&
 			die "git checkout: branch $newbranch already exists"
 		git check-ref-format "heads/$newbranch" ||
 			die "git checkout: we do not like '$newbranch' as a branch name."
 		;;
 	-l)
 		newbranch_log=-l
 		;;
 	--track|--no-track)
 		track="$1"
 		;;
 	-f)
 		force=1
 		;;
 	-m)
 		merge=1
 		;;
 	-q|--quiet)
 		quiet=1
 		v=
 		;;
 	--)
 		shift
 		break
 		;;
 	*)
 		usage
 		;;
 	esac
 	shift
 done

 arg="$1"
 rev=$(git rev-parse --verify "$arg" 2>/dev/null)
 if rev=$(git rev-parse --verify "$rev^0" 2>/dev/null)
 then
 	[ -z "$rev" ] && die "unknown flag $arg"
 	new_name="$arg"
 	if git show-ref --verify --quiet -- "refs/heads/$arg"
 	then
 		rev=$(git rev-parse --verify "refs/heads/$arg^0")
 		branch="$arg"
 	fi
 	new="$rev"
 	shift
 elif rev=$(git rev-parse --verify "$rev^{tree}" 2>/dev/null)
 then
 	# checking out selected paths from a tree-ish.
 	new="$rev"
 	new_name="$rev^{tree}"
 	shift
 fi
 [ "$1" = "--" ] && shift

 case "$newbranch,$track" in
 ,--*)
 	die "git checkout: --track and --no-track require -b"
 esac

 case "$force$merge" in
 11)
 	die "git checkout: -f and -m are incompatible"
 esac

 # The behaviour of the command with and without explicit path
 # parameters is quite different.
 #
 # Without paths, we are checking out everything in the work tree,
 # possibly switching branches.  This is the traditional behaviour.
 #
 # With paths, we are _never_ switching branch, but checking out
 # the named paths from either index (when no rev is given),
 # or the named tree-ish (when rev is given).

 if test "$#" -ge 1
 then
 	hint=
 	if test "$#" -eq 1
 	then
 		hint="
 Did you intend to checkout '$@' which can not be resolved as commit?"
 	fi
 	if test '' != "$newbranch$force$merge"
 	then
 		die "git checkout: updating paths is incompatible with switching branches/forcing$hint"
 	fi
 	if test '' != "$new"
 	then
 		# from a specific tree-ish; note that this is for
 		# rescuing paths and is never meant to remove what
 		# is not in the named tree-ish.
 		git ls-tree --full-name -r "$new" "$@" |
 		git update-index --index-info || exit $?
 	fi

 	# Make sure the request is about existing paths.
 	git ls-files --full-name --error-unmatch -- "$@" >/dev/null || exit
 	git ls-files --full-name -- "$@" |
 		(cd_to_toplevel && git checkout-index -f -u --stdin)

 	# Run a post-checkout hook -- the HEAD does not change so the
 	# current HEAD is passed in for both args
 	if test -x "$GIT_DIR"/hooks/post-checkout; then
 	    "$GIT_DIR"/hooks/post-checkout $old $old 0
 	fi

 	exit $?
 else
 	# Make sure we did not fall back on $arg^{tree} codepath
 	# since we are not checking out from an arbitrary tree-ish,
 	# but switching branches.
 	if test '' != "$new"
 	then
 		git rev-parse --verify "$new^{commit}" >/dev/null 2>&1 ||
 		die "Cannot switch branch to a non-commit."
 	fi
 fi

 # We are switching branches and checking out trees, so
 # we *NEED* to be at the toplevel.
 cd_to_toplevel

 [ -z "$new" ] && new=$old && new_name="$old_name"

 # If we don't have an existing branch that we're switching to,
 # and we don't have a new branch name for the target we
 # are switching to, then we are detaching our HEAD from any
 # branch.  However, if "git checkout HEAD" detaches the HEAD
 # from the current branch, even though that may be logically
 # correct, it feels somewhat funny.  More importantly, we do not
 # want "git checkout" nor "git checkout -f" to detach HEAD.

 detached=
 detach_warn=

 describe_detached_head () {
 	test -n "$quiet" || {
 		printf >&2 "$1 "
 		GIT_PAGER= git log >&2 -1 --pretty=oneline --abbrev-commit "$2" --
 	}
 }

 if test -z "$branch$newbranch" && test "$new_name" != "$old_name"
 then
 	detached="$new"
 	if test -n "$oldbranch" && test -z "$quiet"
 	then
 		detach_warn="Note: moving to \"$new_name\" which isn't a local branch
 If you want to create a new branch from this checkout, you may do so
 (now or later) by using -b with the checkout command again. Example:
   git checkout -b <new_branch_name>"
 	fi
 elif test -z "$oldbranch" && test "$new" != "$old"
 then
 	describe_detached_head 'Previous HEAD position was' "$old"
 fi

 if [ "X$old" = X ]
 then
 	if test -z "$quiet"
 	then
 		echo >&2 "warning: You appear to be on a branch yet to be born."
 		echo >&2 "warning: Forcing checkout of $new_name."
 	fi
 	force=1
 fi

 if [ "$force" ]
 then
     git read-tree $v --reset -u $new
 else
     git update-index --refresh >/dev/null
     git read-tree $v -m -u --exclude-per-directory=.gitignore $old $new || (
 	case "$merge,$v" in
 	,*)
 		exit 1 ;;
 	1,)
 		;; # quiet
 	*)
 		echo >&2 "Falling back to 3-way merge..." ;;
 	esac

 	# Match the index to the working tree, and do a three-way.
 	git diff-files --name-only | git update-index --remove --stdin &&
 	work=`git write-tree` &&
 	git read-tree $v --reset -u $new || exit

 	eval GITHEAD_$new='${new_name:-${branch:-$new}}' &&
 	eval GITHEAD_$work=local &&
 	export GITHEAD_$new GITHEAD_$work &&
 	git merge-recursive $old -- $new $work

 	# Do not register the cleanly merged paths in the index yet.
 	# this is not a real merge before committing, but just carrying
 	# the working tree changes along.
 	unmerged=`git ls-files -u`
 	git read-tree $v --reset $new
 	case "$unmerged" in
 	'')	;;
 	*)
 		(
 			z40=0000000000000000000000000000000000000000
 			echo "$unmerged" |
 			sed -e 's/^[0-7]* [0-9a-f]* /'"0 $z40 /"
 			echo "$unmerged"
 		) | git update-index --index-info
 		;;
 	esac
 	exit 0
     )
     saved_err=$?
     if test "$saved_err" = 0 && test -z "$quiet"
     then
 	git diff-index --name-status "$new"
     fi
     (exit $saved_err)
 fi

 #
 # Switch the HEAD pointer to the new branch if we
 # checked out a branch head, and remove any potential
 # old MERGE_HEAD's (subsequent commits will clearly not
 # be based on them, since we re-set the index)
 #
 if [ "$?" -eq 0 ]; then
 	if [ "$newbranch" ]; then
 		git branch $track $newbranch_log "$newbranch" "$new_name" || exit
 		branch="$newbranch"
 	fi
 	if test -n "$branch"
 	then
 		old_branch_name=`expr "z$oldbranch" : 'zrefs/heads/\(.*\)'`
 		GIT_DIR="$GIT_DIR" git symbolic-ref -m "checkout: moving from ${old_branch_name:-$old} to $branch" HEAD "refs/heads/$branch"
 		if test -n "$quiet"
 		then
 			true	# nothing
 		elif test "refs/heads/$branch" = "$oldbranch"
 		then
 			echo >&2 "Already on branch \"$branch\""
 		else
 			echo >&2 "Switched to${newbranch:+ a new} branch \"$branch\""
 		fi
 	elif test -n "$detached"
 	then
 		old_branch_name=`expr "z$oldbranch" : 'zrefs/heads/\(.*\)'`
 		git update-ref --no-deref -m "checkout: moving from ${old_branch_name:-$old} to $arg" HEAD "$detached" ||
 			die "Cannot detach HEAD"
 		if test -n "$detach_warn"
 		then
 			echo >&2 "$detach_warn"
 		fi
 		describe_detached_head 'HEAD is now at' HEAD
 	fi
 	rm -f "$GIT_DIR/MERGE_HEAD"
 else
 	exit 1
 fi

 # Run a post-checkout hook
 if test -x "$GIT_DIR"/hooks/post-checkout; then
 	"$GIT_DIR"/hooks/post-checkout $old $new 1
 fi
	#!/bin/sh

	OPTIONS_KEEPDASHDASH=t
	OPTIONS_SPEC="\
	git-checkout [options] [<branch>] [<paths>...]
	--
	b= create a new branch started at <branch>
	l create the new branch's reflog
	track arrange that the new branch tracks the remote branch
	f proceed even if the index or working tree is not HEAD
	m merge local modifications into the new branch
	q,quiet be quiet
	"
	SUBDIRECTORY_OK=Sometimes
	. git-sh-setup
	require_work_tree

	old_name=HEAD
	old=$(git rev-parse --verify $old_name 2>/dev/null)
	oldbranch=$(git symbolic-ref $old_name 2>/dev/null)
	new=
	new_name=
	force=
	branch=
	track=
	newbranch=
	newbranch_log=
	merge=
	quiet=
	v=-v
	LF='
	'

	while test $# != 0; do
	case "$1" in
	-b)
	shift
	newbranch="$1"
	[ -z "$newbranch" ] &&
	die "git checkout: -b needs a branch name"
	git show-ref --verify --quiet -- "refs/heads/$newbranch" &&
	die "git checkout: branch $newbranch already exists"
	git check-ref-format "heads/$newbranch" \|\|
	die "git checkout: we do not like '$newbranch' as a branch name."
	;;
	-l)
	newbranch_log=-l
	;;
	--track\|--no-track)
	track="$1"
	;;
	-f)
	force=1
	;;
	-m)
	merge=1
	;;
	-q\|--quiet)
	quiet=1
	v=
	;;
	--)
	shift
	break
	;;
	*)
	usage
	;;
	esac
	shift
	done

	arg="$1"
	rev=$(git rev-parse --verify "$arg" 2>/dev/null)
	if rev=$(git rev-parse --verify "$rev^0" 2>/dev/null)
	then
	[ -z "$rev" ] && die "unknown flag $arg"
	new_name="$arg"
	if git show-ref --verify --quiet -- "refs/heads/$arg"
	then
	rev=$(git rev-parse --verify "refs/heads/$arg^0")
	branch="$arg"
	fi
	new="$rev"
	shift
	elif rev=$(git rev-parse --verify "$rev^{tree}" 2>/dev/null)
	then
	# checking out selected paths from a tree-ish.
	new="$rev"
	new_name="$rev^{tree}"
	shift
	fi
	[ "$1" = "--" ] && shift

	case "$newbranch,$track" in
	,--*)
	die "git checkout: --track and --no-track require -b"
	esac

	case "$force$merge" in
	11)
	die "git checkout: -f and -m are incompatible"
	esac

	# The behaviour of the command with and without explicit path
	# parameters is quite different.
	#
	# Without paths, we are checking out everything in the work tree,
	# possibly switching branches. This is the traditional behaviour.
	#
	# With paths, we are _never_ switching branch, but checking out
	# the named paths from either index (when no rev is given),
	# or the named tree-ish (when rev is given).

	if test "$#" -ge 1
	then
	hint=
	if test "$#" -eq 1
	then
	hint="
	Did you intend to checkout '$@' which can not be resolved as commit?"
	fi
	if test '' != "$newbranch$force$merge"
	then
	die "git checkout: updating paths is incompatible with switching branches/forcing$hint"
	fi
	if test '' != "$new"
	then
	# from a specific tree-ish; note that this is for
	# rescuing paths and is never meant to remove what
	# is not in the named tree-ish.
	git ls-tree --full-name -r "$new" "$@" \|
	git update-index --index-info \|\| exit $?
	fi

	# Make sure the request is about existing paths.
	git ls-files --full-name --error-unmatch -- "$@" >/dev/null \|\| exit
	git ls-files --full-name -- "$@" \|
	(cd_to_toplevel && git checkout-index -f -u --stdin)

	# Run a post-checkout hook -- the HEAD does not change so the
	# current HEAD is passed in for both args
	if test -x "$GIT_DIR"/hooks/post-checkout; then
	"$GIT_DIR"/hooks/post-checkout $old $old 0
	fi

	exit $?
	else
	# Make sure we did not fall back on $arg^{tree} codepath
	# since we are not checking out from an arbitrary tree-ish,
	# but switching branches.
	if test '' != "$new"
	then
	git rev-parse --verify "$new^{commit}" >/dev/null 2>&1 \|\|
	die "Cannot switch branch to a non-commit."
	fi
	fi

	# We are switching branches and checking out trees, so
	# we NEED to be at the toplevel.
	cd_to_toplevel

	[ -z "$new" ] && new=$old && new_name="$old_name"

	# If we don't have an existing branch that we're switching to,
	# and we don't have a new branch name for the target we
	# are switching to, then we are detaching our HEAD from any
	# branch. However, if "git checkout HEAD" detaches the HEAD
	# from the current branch, even though that may be logically
	# correct, it feels somewhat funny. More importantly, we do not
	# want "git checkout" nor "git checkout -f" to detach HEAD.

	detached=
	detach_warn=

	describe_detached_head () {
	test -n "$quiet" \|\| {
	printf >&2 "$1 "
	GIT_PAGER= git log >&2 -1 --pretty=oneline --abbrev-commit "$2" --
	}
	}

	if test -z "$branch$newbranch" && test "$new_name" != "$old_name"
	then
	detached="$new"
	if test -n "$oldbranch" && test -z "$quiet"
	then
	detach_warn="Note: moving to \"$new_name\" which isn't a local branch
	If you want to create a new branch from this checkout, you may do so
	(now or later) by using -b with the checkout command again. Example:
	git checkout -b <new_branch_name>"
	fi
	elif test -z "$oldbranch" && test "$new" != "$old"
	then
	describe_detached_head 'Previous HEAD position was' "$old"
	fi

	if [ "X$old" = X ]
	then
	if test -z "$quiet"
	then
	echo >&2 "warning: You appear to be on a branch yet to be born."
	echo >&2 "warning: Forcing checkout of $new_name."
	fi
	force=1
	fi

	if [ "$force" ]
	then
	git read-tree $v --reset -u $new
	else
	git update-index --refresh >/dev/null
	git read-tree $v -m -u --exclude-per-directory=.gitignore $old $new \|\| (
	case "$merge,$v" in
	,*)
	exit 1 ;;
	1,)
	;; # quiet
	*)
	echo >&2 "Falling back to 3-way merge..." ;;
	esac

	# Match the index to the working tree, and do a three-way.
	git diff-files --name-only \| git update-index --remove --stdin &&
	work=`git write-tree` &&
	git read-tree $v --reset -u $new \|\| exit

	eval GITHEAD_$new='${new_name:-${branch:-$new}}' &&
	eval GITHEAD_$work=local &&
	export GITHEAD_$new GITHEAD_$work &&
	git merge-recursive $old -- $new $work

	# Do not register the cleanly merged paths in the index yet.
	# this is not a real merge before committing, but just carrying
	# the working tree changes along.
	unmerged=`git ls-files -u`
	git read-tree $v --reset $new
	case "$unmerged" in
	'') ;;
	*)
	(
	z40=0000000000000000000000000000000000000000
	echo "$unmerged" \|
	sed -e 's/^[0-7]* [0-9a-f]* /'"0 $z40 /"
	echo "$unmerged"
	) \| git update-index --index-info
	;;
	esac
	exit 0
	)
	saved_err=$?
	if test "$saved_err" = 0 && test -z "$quiet"
	then
	git diff-index --name-status "$new"
	fi
	(exit $saved_err)
	fi

	#
	# Switch the HEAD pointer to the new branch if we
	# checked out a branch head, and remove any potential
	# old MERGE_HEAD's (subsequent commits will clearly not
	# be based on them, since we re-set the index)
	#
	if [ "$?" -eq 0 ]; then
	if [ "$newbranch" ]; then
	git branch $track $newbranch_log "$newbranch" "$new_name" \|\| exit
	branch="$newbranch"
	fi
	if test -n "$branch"
	then
	old_branch_name=`expr "z$oldbranch" : 'zrefs/heads/\(.*\)'`
	GIT_DIR="$GIT_DIR" git symbolic-ref -m "checkout: moving from ${old_branch_name:-$old} to $branch" HEAD "refs/heads/$branch"
	if test -n "$quiet"
	then
	true # nothing
	elif test "refs/heads/$branch" = "$oldbranch"
	then
	echo >&2 "Already on branch \"$branch\""
	else
	echo >&2 "Switched to${newbranch:+ a new} branch \"$branch\""
	fi
	elif test -n "$detached"
	then
	old_branch_name=`expr "z$oldbranch" : 'zrefs/heads/\(.*\)'`
	git update-ref --no-deref -m "checkout: moving from ${old_branch_name:-$old} to $arg" HEAD "$detached" \|\|
	die "Cannot detach HEAD"
	if test -n "$detach_warn"
	then
	echo >&2 "$detach_warn"
	fi
	describe_detached_head 'HEAD is now at' HEAD
	fi
	rm -f "$GIT_DIR/MERGE_HEAD"
	else
	exit 1
	fi

	# Run a post-checkout hook
	if test -x "$GIT_DIR"/hooks/post-checkout; then
	"$GIT_DIR"/hooks/post-checkout $old $new 1
	fi