Merge fixes up to GIT 1.0.5
[git.git] / git-checkout.sh
1 #!/bin/sh
2
3 USAGE='[-f] [-b <new_branch>] [<branch>] [<paths>...]'
4 SUBDIRECTORY_OK=Sometimes
5 . git-sh-setup
6
7 old=$(git-rev-parse HEAD)
8 new=
9 force=
10 branch=
11 newbranch=
12 while [ "$#" != "0" ]; do
13     arg="$1"
14     shift
15     case "$arg" in
16         "-b")
17                 newbranch="$1"
18                 shift
19                 [ -z "$newbranch" ] &&
20                         die "git checkout: -b needs a branch name"
21                 [ -e "$GIT_DIR/refs/heads/$newbranch" ] &&
22                         die "git checkout: branch $newbranch already exists"
23                 git-check-ref-format "heads/$newbranch" ||
24                         die "we do not like '$newbranch' as a branch name."
25                 ;;
26         "-f")
27                 force=1
28                 ;;
29         --)
30                 break
31                 ;;
32         -*)
33                 usage
34                 ;;
35         *)
36                 if rev=$(git-rev-parse --verify "$arg^0" 2>/dev/null)
37                 then
38                         if [ -z "$rev" ]; then
39                                 echo "unknown flag $arg"
40                                 exit 1
41                         fi
42                         new="$rev"
43                         if [ -f "$GIT_DIR/refs/heads/$arg" ]; then
44                                 branch="$arg"
45                         fi
46                 elif rev=$(git-rev-parse --verify "$arg^{tree}" 2>/dev/null)
47                 then
48                         # checking out selected paths from a tree-ish.
49                         new="$rev"
50                         branch=
51                 else
52                         new=
53                         branch=
54                         set x "$arg" "$@"
55                         shift
56                 fi
57                 break
58                 ;;
59     esac
60 done
61
62 # The behaviour of the command with and without explicit path
63 # parameters is quite different.
64 #
65 # Without paths, we are checking out everything in the work tree,
66 # possibly switching branches.  This is the traditional behaviour.
67 #
68 # With paths, we are _never_ switching branch, but checking out
69 # the named paths from either index (when no rev is given),
70 # or the named tree-ish (when rev is given).
71
72 if test "$#" -ge 1
73 then
74         if test '' != "$newbranch$force"
75         then
76                 die "updating paths and switching branches or forcing are incompatible."
77         fi
78         if test '' != "$new"
79         then
80                 # from a specific tree-ish; note that this is for
81                 # rescuing paths and is never meant to remove what
82                 # is not in the named tree-ish.
83                 git-ls-tree --full-name -r "$new" "$@" |
84                 git-update-index --index-info || exit $?
85         fi
86         git-checkout-index -f -u -- "$@"
87         exit $?
88 else
89         # Make sure we did not fall back on $arg^{tree} codepath
90         # since we are not checking out from an arbitrary tree-ish,
91         # but switching branches.
92         if test '' != "$new"
93         then
94                 git-rev-parse --verify "$new^{commit}" >/dev/null 2>&1 ||
95                 die "Cannot switch branch to a non-commit."
96         fi
97 fi
98
99 # We are switching branches and checking out trees, so
100 # we *NEED* to be at the toplevel.
101 cdup=$(git-rev-parse --show-cdup)
102 if test ! -z "$cdup"
103 then
104         cd "$cdup"
105 fi
106
107 [ -z "$new" ] && new=$old
108
109 # If we don't have an old branch that we're switching to,
110 # and we don't have a new branch name for the target we
111 # are switching to, then we'd better just be checking out
112 # what we already had
113
114 [ -z "$branch$newbranch" ] &&
115         [ "$new" != "$old" ] &&
116         die "git checkout: you need to specify a new branch name"
117
118 if [ "$force" ]
119 then
120     git-read-tree --reset $new &&
121         git-checkout-index -q -f -u -a
122 else
123     git-update-index --refresh >/dev/null
124     git-read-tree -m -u $old $new
125 fi
126
127
128 # Switch the HEAD pointer to the new branch if we
129 # checked out a branch head, and remove any potential
130 # old MERGE_HEAD's (subsequent commits will clearly not
131 # be based on them, since we re-set the index)
132 #
133 if [ "$?" -eq 0 ]; then
134         if [ "$newbranch" ]; then
135                 leading=`expr "refs/heads/$newbranch" : '\(.*\)/'` &&
136                 mkdir -p "$GIT_DIR/$leading" &&
137                 echo $new >"$GIT_DIR/refs/heads/$newbranch" || exit
138                 branch="$newbranch"
139         fi
140         [ "$branch" ] &&
141         GIT_DIR="$GIT_DIR" git-symbolic-ref HEAD "refs/heads/$branch"
142         rm -f "$GIT_DIR/MERGE_HEAD"
143 else
144         exit 1
145 fi