summaryrefslogtreecommitdiff
path: root/git-checkout.sh
blob: f241d4ba6ba5a988f801e3307022d188204ff572 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
#!/bin/sh
 
USAGE='[-f] [-b <new_branch>] [<branch>] [<paths>...]'
. git-sh-setup
 
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 "$new" "$@" |
		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