git/git-checkout.sh
Junio C Hamano 13d1cc3604 Do not fail on hierarchical branch names.
"git-checkout -b frotz/nitfol master" failed to create
$GIT_DIR/refs/heads/frotz/nitfol but went ahead and updated
$GIT_DIR/HEAD to point at it, resulting in a corrupt repository.
Exit when we cannot create the new branch with an error status.

While we are at it, there is no reason to forbid subdirectories
in refs/heads, so make sure we handle that correctly.

Signed-off-by: Junio C Hamano <junkio@cox.net>
2005-11-02 16:50:58 -08:00

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#!/bin/sh
. git-sh-setup || die "Not a git archive"
usage () {
die "usage: git checkout [-f] [-b <new_branch>] [<branch>] [<paths>...]"
}
old=$(git-rev-parse HEAD)
new=
force=
branch=
newbranch=
while [ "$#" != "0" ]; do
arg="$1"
shift
case "$arg" in
"-b")
newbranch="$1"
shift
[ -z "$newbranch" ] &&
die "git checkout: -b needs a branch name"
[ -e "$GIT_DIR/refs/heads/$newbranch" ] &&
die "git checkout: branch $newbranch already exists"
git-check-ref-format "heads/$newbranch" ||
die "we do not like '$newbranch' as a branch name."
;;
"-f")
force=1
;;
--)
break
;;
-*)
usage
;;
*)
if rev=$(git-rev-parse --verify "$arg^0" 2>/dev/null)
then
if [ -z "$rev" ]; then
echo "unknown flag $arg"
exit 1
fi
new="$rev"
if [ -f "$GIT_DIR/refs/heads/$arg" ]; then
branch="$arg"
fi
elif rev=$(git-rev-parse --verify "$arg^{tree}" 2>/dev/null)
then
# checking out selected paths from a tree-ish.
new="$rev"
branch=
else
new=
branch=
set x "$arg" "$@"
shift
fi
break
;;
esac
done
# 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 "$#" -ge 1
then
if test '' != "$newbranch$force"
then
die "updating paths and switching branches or forcing are incompatible."
fi
if test '' != "$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 -r "$new" "$@" |
sed -ne 's/^\([0-7]*\) blob \(.*\)$/\1 \2/p' |
git-update-index --index-info || exit $?
fi
git-checkout-index -f -u -- "$@"
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 "$new^{commit}" >/dev/null 2>&1 ||
die "Cannot switch branch to a non-commit."
fi
fi
[ -z "$new" ] && new=$old
# If we don't have an old branch that we're switching to,
# and we don't have a new branch name for the target we
# are switching to, then we'd better just be checking out
# what we already had
[ -z "$branch$newbranch" ] &&
[ "$new" != "$old" ] &&
die "git checkout: you need to specify a new branch name"
if [ "$force" ]
then
git-read-tree --reset $new &&
git-checkout-index -q -f -u -a
else
git-update-index --refresh >/dev/null
git-read-tree -m -u $old $new
fi
#
# Switch the HEAD pointer to the new branch if it we
# checked out a branch head, and remove any potential
# old MERGE_HEAD's (subsequent commits will clearly not
# be based on them, since we re-set the index)
#
if [ "$?" -eq 0 ]; then
if [ "$newbranch" ]; then
leading=`expr "refs/heads/$newbranch" : '\(.*\)/'` &&
mkdir -p "$GIT_DIR/$leading" &&
echo $new >"$GIT_DIR/refs/heads/$newbranch" || exit
branch="$newbranch"
fi
[ "$branch" ] &&
GIT_DIR="$GIT_DIR" git-symbolic-ref HEAD "refs/heads/$branch"
rm -f "$GIT_DIR/MERGE_HEAD"
else
exit 1
fi