Merge branch 'master' into next
[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=$(git-rev-parse HEAD)
8 old_name=HEAD
9 new=
10 new_name=
11 force=
12 branch=
13 newbranch=
14 newbranch_log=
15 merge=
16 while [ "$#" != "0" ]; do
17     arg="$1"
18     shift
19     case "$arg" in
20         "-b")
21                 newbranch="$1"
22                 shift
23                 [ -z "$newbranch" ] &&
24                         die "git checkout: -b needs a branch name"
25                 [ -e "$GIT_DIR/refs/heads/$newbranch" ] &&
26                         die "git checkout: branch $newbranch already exists"
27                 git-check-ref-format "heads/$newbranch" ||
28                         die "git checkout: we do not like '$newbranch' as a branch name."
29                 ;;
30         "-l")
31                 newbranch_log=1
32                 ;;
33         "-f")
34                 force=1
35                 ;;
36         -m)
37                 merge=1
38                 ;;
39         --)
40                 break
41                 ;;
42         -*)
43                 usage
44                 ;;
45         *)
46                 if rev=$(git-rev-parse --verify "$arg^0" 2>/dev/null)
47                 then
48                         if [ -z "$rev" ]; then
49                                 echo "unknown flag $arg"
50                                 exit 1
51                         fi
52                         new="$rev"
53                         new_name="$arg^0"
54                         if [ -f "$GIT_DIR/refs/heads/$arg" ]; then
55                                 branch="$arg"
56                         fi
57                 elif rev=$(git-rev-parse --verify "$arg^{tree}" 2>/dev/null)
58                 then
59                         # checking out selected paths from a tree-ish.
60                         new="$rev"
61                         new_name="$arg^{tree}"
62                         branch=
63                 else
64                         new=
65                         new_name=
66                         branch=
67                         set x "$arg" "$@"
68                         shift
69                 fi
70                 break
71                 ;;
72     esac
73 done
74
75 # The behaviour of the command with and without explicit path
76 # parameters is quite different.
77 #
78 # Without paths, we are checking out everything in the work tree,
79 # possibly switching branches.  This is the traditional behaviour.
80 #
81 # With paths, we are _never_ switching branch, but checking out
82 # the named paths from either index (when no rev is given),
83 # or the named tree-ish (when rev is given).
84
85 if test "$#" -ge 1
86 then
87         hint=
88         if test "$#" -eq 1
89         then
90                 hint="
91 Did you intend to checkout '$@' which can not be resolved as commit?"
92         fi
93         if test '' != "$newbranch$force$merge"
94         then
95                 die "git checkout: updating paths is incompatible with switching branches/forcing$hint"
96         fi
97         if test '' != "$new"
98         then
99                 # from a specific tree-ish; note that this is for
100                 # rescuing paths and is never meant to remove what
101                 # is not in the named tree-ish.
102                 git-ls-tree --full-name -r "$new" "$@" |
103                 git-update-index --index-info || exit $?
104         fi
105         git-checkout-index -f -u -- "$@"
106         exit $?
107 else
108         # Make sure we did not fall back on $arg^{tree} codepath
109         # since we are not checking out from an arbitrary tree-ish,
110         # but switching branches.
111         if test '' != "$new"
112         then
113                 git-rev-parse --verify "$new^{commit}" >/dev/null 2>&1 ||
114                 die "Cannot switch branch to a non-commit."
115         fi
116 fi
117
118 # We are switching branches and checking out trees, so
119 # we *NEED* to be at the toplevel.
120 cdup=$(git-rev-parse --show-cdup)
121 if test ! -z "$cdup"
122 then
123         cd "$cdup"
124 fi
125
126 [ -z "$new" ] && new=$old && new_name="$old_name"
127
128 # If we don't have an old branch that we're switching to,
129 # and we don't have a new branch name for the target we
130 # are switching to, then we'd better just be checking out
131 # what we already had
132
133 [ -z "$branch$newbranch" ] &&
134         [ "$new" != "$old" ] &&
135         die "git checkout: to checkout the requested commit you need to specify 
136               a name for a new branch which is created and switched to"
137
138 if [ "$force" ]
139 then
140     git-read-tree --reset $new &&
141         git-checkout-index -q -f -u -a
142 else
143     git-update-index --refresh >/dev/null
144     merge_error=$(git-read-tree -m -u $old $new 2>&1) || (
145         case "$merge" in
146         '')
147                 echo >&2 "$merge_error"
148                 exit 1 ;;
149         esac
150
151         # Match the index to the working tree, and do a three-way.
152         git diff-files --name-only | git update-index --remove --stdin &&
153         work=`git write-tree` &&
154         git read-tree --reset $new &&
155         git checkout-index -f -u -q -a &&
156         git read-tree -m -u --aggressive $old $new $work || exit
157
158         if result=`git write-tree 2>/dev/null`
159         then
160             echo >&2 "Trivially automerged."
161         else
162             git merge-index -o git-merge-one-file -a
163         fi
164
165         # Do not register the cleanly merged paths in the index yet.
166         # this is not a real merge before committing, but just carrying
167         # the working tree changes along.
168         unmerged=`git ls-files -u`
169         git read-tree --reset $new
170         case "$unmerged" in
171         '')     ;;
172         *)
173                 (
174                         z40=0000000000000000000000000000000000000000
175                         echo "$unmerged" |
176                         sed -e 's/^[0-7]* [0-9a-f]* /'"0 $z40 /"
177                         echo "$unmerged"
178                 ) | git update-index --index-info
179                 ;;
180         esac
181         exit 0
182     )
183     saved_err=$?
184     if test "$saved_err" = 0
185     then
186         test "$new" = "$old" || git diff-index --name-status "$new"
187     fi
188     (exit $saved_err)
189 fi
190
191
192 # Switch the HEAD pointer to the new branch if we
193 # checked out a branch head, and remove any potential
194 # old MERGE_HEAD's (subsequent commits will clearly not
195 # be based on them, since we re-set the index)
196 #
197 if [ "$?" -eq 0 ]; then
198         if [ "$newbranch" ]; then
199                 if [ "$newbranch_log" ]; then
200                         mkdir -p $(dirname "$GIT_DIR/logs/refs/heads/$branchname")
201                         touch "$GIT_DIR/logs/refs/heads/$branchname"
202                 fi
203                 git-update-ref -m "checkout: Created from $new_name" "refs/heads/$newbranch" $new || exit
204                 branch="$newbranch"
205         fi
206         [ "$branch" ] &&
207         GIT_DIR="$GIT_DIR" git-symbolic-ref HEAD "refs/heads/$branch"
208         rm -f "$GIT_DIR/MERGE_HEAD"
209 else
210         exit 1
211 fi