Merge fixes up to GIT 1.1.6
[git.git] / git-checkout.sh
1 #!/bin/sh
2
3 USAGE='[-f] [-b <new_branch>] [-m] [<branch>] [<paths>...]'
4 SUBDIRECTORY_OK=Sometimes
5 . git-sh-setup
6
7 old=$(git-rev-parse HEAD)
8 new=
9 force=
10 branch=
11 newbranch=
12 merge=
13 while [ "$#" != "0" ]; do
14     arg="$1"
15     shift
16     case "$arg" in
17         "-b")
18                 newbranch="$1"
19                 shift
20                 [ -z "$newbranch" ] &&
21                         die "git checkout: -b needs a branch name"
22                 [ -e "$GIT_DIR/refs/heads/$newbranch" ] &&
23                         die "git checkout: branch $newbranch already exists"
24                 git-check-ref-format "heads/$newbranch" ||
25                         die "we do not like '$newbranch' as a branch name."
26                 ;;
27         "-f")
28                 force=1
29                 ;;
30         -m)
31                 merge=1
32                 ;;
33         --)
34                 break
35                 ;;
36         -*)
37                 usage
38                 ;;
39         *)
40                 if rev=$(git-rev-parse --verify "$arg^0" 2>/dev/null)
41                 then
42                         if [ -z "$rev" ]; then
43                                 echo "unknown flag $arg"
44                                 exit 1
45                         fi
46                         new="$rev"
47                         if [ -f "$GIT_DIR/refs/heads/$arg" ]; then
48                                 branch="$arg"
49                         fi
50                 elif rev=$(git-rev-parse --verify "$arg^{tree}" 2>/dev/null)
51                 then
52                         # checking out selected paths from a tree-ish.
53                         new="$rev"
54                         branch=
55                 else
56                         new=
57                         branch=
58                         set x "$arg" "$@"
59                         shift
60                 fi
61                 break
62                 ;;
63     esac
64 done
65
66 # The behaviour of the command with and without explicit path
67 # parameters is quite different.
68 #
69 # Without paths, we are checking out everything in the work tree,
70 # possibly switching branches.  This is the traditional behaviour.
71 #
72 # With paths, we are _never_ switching branch, but checking out
73 # the named paths from either index (when no rev is given),
74 # or the named tree-ish (when rev is given).
75
76 if test "$#" -ge 1
77 then
78         if test '' != "$newbranch$force$merge"
79         then
80                 die "updating paths and switching branches or forcing are incompatible."
81         fi
82         if test '' != "$new"
83         then
84                 # from a specific tree-ish; note that this is for
85                 # rescuing paths and is never meant to remove what
86                 # is not in the named tree-ish.
87                 git-ls-tree --full-name -r "$new" "$@" |
88                 git-update-index --index-info || exit $?
89         fi
90         git-checkout-index -f -u -- "$@"
91         exit $?
92 else
93         # Make sure we did not fall back on $arg^{tree} codepath
94         # since we are not checking out from an arbitrary tree-ish,
95         # but switching branches.
96         if test '' != "$new"
97         then
98                 git-rev-parse --verify "$new^{commit}" >/dev/null 2>&1 ||
99                 die "Cannot switch branch to a non-commit."
100         fi
101 fi
102
103 # We are switching branches and checking out trees, so
104 # we *NEED* to be at the toplevel.
105 cdup=$(git-rev-parse --show-cdup)
106 if test ! -z "$cdup"
107 then
108         cd "$cdup"
109 fi
110
111 [ -z "$new" ] && new=$old
112
113 # If we don't have an old branch that we're switching to,
114 # and we don't have a new branch name for the target we
115 # are switching to, then we'd better just be checking out
116 # what we already had
117
118 [ -z "$branch$newbranch" ] &&
119         [ "$new" != "$old" ] &&
120         die "git checkout: you need to specify a new branch name"
121
122 if [ "$force" ]
123 then
124     git-read-tree --reset $new &&
125         git-checkout-index -q -f -u -a
126 else
127     git-update-index --refresh >/dev/null
128     merge_error=$(git-read-tree -m -u $old $new 2>&1) || (
129         case "$merge" in
130         '')
131                 echo >&2 "$merge_error"
132                 exit 1 ;;
133         esac
134
135         # Match the index to the working tree, and do a three-way.
136         git diff-files --name-only | git update-index --remove --stdin &&
137         work=`git write-tree` &&
138         git read-tree --reset $new &&
139         git checkout-index -f -u -q -a &&
140         git read-tree -m -u $old $new $work || exit
141
142         if result=`git write-tree 2>/dev/null`
143         then
144             echo >&2 "Trivially automerged."
145         else
146             git merge-index -o git-merge-one-file -a
147         fi
148
149         # Do not register the cleanly merged paths in the index yet.
150         # this is not a real merge before committing, but just carrying
151         # the working tree changes along.
152         unmerged=`git ls-files -u`
153         git read-tree --reset $new
154         case "$unmerged" in
155         '')     ;;
156         *)
157                 (
158                         z40=0000000000000000000000000000000000000000
159                         echo "$unmerged" |
160                         sed -e 's/^[0-7]* [0-9a-f]* /'"0 $z40 /"
161                         echo "$unmerged"
162                 ) | git update-index --index-info
163                 ;;
164         esac
165         exit 0
166     )
167     saved_err=$?
168     git diff-files --name-status
169     (exit $saved_err)
170 fi
171
172
173 # Switch the HEAD pointer to the new branch if we
174 # checked out a branch head, and remove any potential
175 # old MERGE_HEAD's (subsequent commits will clearly not
176 # be based on them, since we re-set the index)
177 #
178 if [ "$?" -eq 0 ]; then
179         if [ "$newbranch" ]; then
180                 leading=`expr "refs/heads/$newbranch" : '\(.*\)/'` &&
181                 mkdir -p "$GIT_DIR/$leading" &&
182                 echo $new >"$GIT_DIR/refs/heads/$newbranch" || exit
183                 branch="$newbranch"
184         fi
185         [ "$branch" ] &&
186         GIT_DIR="$GIT_DIR" git-symbolic-ref HEAD "refs/heads/$branch"
187         rm -f "$GIT_DIR/MERGE_HEAD"
188 else
189         exit 1
190 fi