Fix extended short SHA1 name completion
[git.git] / git-checkout.sh
1 #!/bin/sh
2 . git-sh-setup || 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 "$arg^0" 2>/dev/null) ||
26                         die "I don't know any '$arg'."
27                 if [ -z "$rev" ]; then
28                         echo "unknown flag $arg"
29                         exit 1
30                 fi
31                 if [ "$new" ]; then
32                         echo "Multiple revisions?"
33                         exit 1
34                 fi
35                 new="$rev"
36                 if [ -f "$GIT_DIR/refs/heads/$arg" ]; then
37                         branch="$arg"
38                 fi
39                 ;;
40     esac
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-index -q -f -u -a
58 else
59     git-update-index --refresh >/dev/null
60     git-read-tree -m -u $old $new
61 fi
62
63
64 # Switch the HEAD pointer to the new branch if it we
65 # checked out a branch head, and remove any potential
66 # old MERGE_HEAD's (subsequent commits will clearly not
67 # be based on them, since we re-set the index)
68 #
69 if [ "$?" -eq 0 ]; then
70         if [ "$newbranch" ]; then
71                 echo $new > "$GIT_DIR/refs/heads/$newbranch"
72                 branch="$newbranch"
73         fi
74         [ "$branch" ] && ln -sf "refs/heads/$branch" "$GIT_DIR/HEAD"
75         rm -f "$GIT_DIR/MERGE_HEAD"
76 else
77         exit 1
78 fi