Merge with gitk --parents change.
[git] / git-checkout-script
1 #!/bin/sh
2 . git-sh-setup-script || die "Not a git archive"
3
4 old=$(git-rev-parse HEAD)
5 new=
6 force=
7 branch=
8 newbranch=
9 while [ "$#" != "0" ]; do
10     arg="$1"
11     shift
12     case "$arg" in
13         "-b")
14                 newbranch="$1"
15                 shift
16                 [ -z "$newbranch" ] &&
17                         die "git checkout: -b needs a branch name"
18                 [ -e "$GIT_DIR/refs/heads/$newbranch" ] &&
19                         die "git checkout: branch $newbranch already exists"
20                 ;;
21         "-f")
22                 force=1
23                 ;;
24         *)
25                 rev=$(git-rev-parse --verify "$arg^0") || exit
26                 if [ -z "$rev" ]; then
27                         echo "unknown flag $arg"
28                         exit 1
29                 fi
30                 if [ "$new" ]; then
31                         echo "Multiple revisions?"
32                         exit 1
33                 fi
34                 new="$rev"
35                 if [ -f "$GIT_DIR/refs/heads/$arg" ]; then
36                         branch="$arg"
37                 fi
38                 ;;
39     esac
40     i=$(($i+1))
41 done
42 [ -z "$new" ] && new=$old
43
44 #
45 # If we don't have an old branch that we're switching to,
46 # and we don't have a new branch name for the target we
47 # are switching to, then we'd better just be checking out
48 # what we already had
49 #
50 [ -z "$branch$newbranch" ] &&
51         [ "$new" != "$old" ] &&
52         die "git checkout: you need to specify a new branch name"
53
54 if [ "$force" ]
55 then
56     git-read-tree --reset $new &&
57         git-checkout-cache -q -f -u -a
58 else
59     git-read-tree -m -u $old $new
60 fi
61
62
63 # Switch the HEAD pointer to the new branch if it we
64 # checked out a branch head, and remove any potential
65 # old MERGE_HEAD's (subsequent commits will clearly not
66 # be based on them, since we re-set the index)
67 #
68 if [ "$?" -eq 0 ]; then
69         if [ "$newbranch" ]; then
70                 echo $new > "$GIT_DIR/refs/heads/$newbranch"
71                 branch="$newbranch"
72         fi
73         [ "$branch" ] && ln -sf "refs/heads/$branch" "$GIT_DIR/HEAD"
74         rm -f "$GIT_DIR/MERGE_HEAD"
75 fi