gitweb: do not choke on recursive symlink
[git] / git-checkout.sh
1 #!/bin/sh
2
3 USAGE='[-q] [-f] [-b <new_branch>] [-m] [<branch>] [<paths>...]'
4 SUBDIRECTORY_OK=Sometimes
5 . git-sh-setup
6 require_work_tree
7
8 old_name=HEAD
9 old=$(git rev-parse --verify $old_name 2>/dev/null)
10 oldbranch=$(git symbolic-ref $old_name 2>/dev/null)
11 new=
12 new_name=
13 force=
14 branch=
15 track=
16 newbranch=
17 newbranch_log=
18 merge=
19 quiet=
20 v=-v
21 LF='
22 '
23 while [ "$#" != "0" ]; do
24     arg="$1"
25     shift
26     case "$arg" in
27         "-b")
28                 newbranch="$1"
29                 shift
30                 [ -z "$newbranch" ] &&
31                         die "git checkout: -b needs a branch name"
32                 git show-ref --verify --quiet -- "refs/heads/$newbranch" &&
33                         die "git checkout: branch $newbranch already exists"
34                 git check-ref-format "heads/$newbranch" ||
35                         die "git checkout: we do not like '$newbranch' as a branch name."
36                 ;;
37         "-l")
38                 newbranch_log=-l
39                 ;;
40         "--track"|"--no-track")
41                 track="$arg"
42                 ;;
43         "-f")
44                 force=1
45                 ;;
46         -m)
47                 merge=1
48                 ;;
49         "-q")
50                 quiet=1
51                 v=
52                 ;;
53         --)
54                 break
55                 ;;
56         -*)
57                 usage
58                 ;;
59         *)
60                 if rev=$(git rev-parse --verify "$arg^0" 2>/dev/null)
61                 then
62                         if [ -z "$rev" ]; then
63                                 echo "unknown flag $arg"
64                                 exit 1
65                         fi
66                         new_name="$arg"
67                         if git show-ref --verify --quiet -- "refs/heads/$arg"
68                         then
69                                 rev=$(git rev-parse --verify "refs/heads/$arg^0")
70                                 branch="$arg"
71                         fi
72                         new="$rev"
73                 elif rev=$(git rev-parse --verify "$arg^{tree}" 2>/dev/null)
74                 then
75                         # checking out selected paths from a tree-ish.
76                         new="$rev"
77                         new_name="$arg^{tree}"
78                         branch=
79                 else
80                         new=
81                         new_name=
82                         branch=
83                         set x "$arg" "$@"
84                         shift
85                 fi
86                 case "$1" in
87                 --)
88                         shift ;;
89                 esac
90                 break
91                 ;;
92     esac
93 done
94
95 case "$newbranch,$track" in
96 ,--*)
97         die "git checkout: --track and --no-track require -b"
98 esac
99
100 case "$force$merge" in
101 11)
102         die "git checkout: -f and -m are incompatible"
103 esac
104
105 # The behaviour of the command with and without explicit path
106 # parameters is quite different.
107 #
108 # Without paths, we are checking out everything in the work tree,
109 # possibly switching branches.  This is the traditional behaviour.
110 #
111 # With paths, we are _never_ switching branch, but checking out
112 # the named paths from either index (when no rev is given),
113 # or the named tree-ish (when rev is given).
114
115 if test "$#" -ge 1
116 then
117         hint=
118         if test "$#" -eq 1
119         then
120                 hint="
121 Did you intend to checkout '$@' which can not be resolved as commit?"
122         fi
123         if test '' != "$newbranch$force$merge"
124         then
125                 die "git checkout: updating paths is incompatible with switching branches/forcing$hint"
126         fi
127         if test '' != "$new"
128         then
129                 # from a specific tree-ish; note that this is for
130                 # rescuing paths and is never meant to remove what
131                 # is not in the named tree-ish.
132                 git ls-tree --full-name -r "$new" "$@" |
133                 git update-index --index-info || exit $?
134         fi
135
136         # Make sure the request is about existing paths.
137         git ls-files --error-unmatch -- "$@" >/dev/null || exit
138         git ls-files -- "$@" |
139         git checkout-index -f -u --stdin
140         exit $?
141 else
142         # Make sure we did not fall back on $arg^{tree} codepath
143         # since we are not checking out from an arbitrary tree-ish,
144         # but switching branches.
145         if test '' != "$new"
146         then
147                 git rev-parse --verify "$new^{commit}" >/dev/null 2>&1 ||
148                 die "Cannot switch branch to a non-commit."
149         fi
150 fi
151
152 # We are switching branches and checking out trees, so
153 # we *NEED* to be at the toplevel.
154 cd_to_toplevel
155
156 [ -z "$new" ] && new=$old && new_name="$old_name"
157
158 # If we don't have an existing branch that we're switching to,
159 # and we don't have a new branch name for the target we
160 # are switching to, then we are detaching our HEAD from any
161 # branch.  However, if "git checkout HEAD" detaches the HEAD
162 # from the current branch, even though that may be logically
163 # correct, it feels somewhat funny.  More importantly, we do not
164 # want "git checkout" nor "git checkout -f" to detach HEAD.
165
166 detached=
167 detach_warn=
168
169 describe_detached_head () {
170         test -n "$quiet" || {
171                 printf >&2 "$1 "
172                 GIT_PAGER= git log >&2 -1 --pretty=oneline --abbrev-commit "$2"
173         }
174 }
175
176 if test -z "$branch$newbranch" && test "$new_name" != "$old_name"
177 then
178         detached="$new"
179         if test -n "$oldbranch" && test -z "$quiet"
180         then
181                 detach_warn="Note: moving to \"$new_name\" which isn't a local branch
182 If you want to create a new branch from this checkout, you may do so
183 (now or later) by using -b with the checkout command again. Example:
184   git checkout -b <new_branch_name>"
185         fi
186 elif test -z "$oldbranch" && test "$new" != "$old"
187 then
188         describe_detached_head 'Previous HEAD position was' "$old"
189 fi
190
191 if [ "X$old" = X ]
192 then
193         if test -z "$quiet"
194         then
195                 echo >&2 "warning: You appear to be on a branch yet to be born."
196                 echo >&2 "warning: Forcing checkout of $new_name."
197         fi
198         force=1
199 fi
200
201 if [ "$force" ]
202 then
203     git read-tree $v --reset -u $new
204 else
205     git update-index --refresh >/dev/null
206     merge_error=$(git read-tree -m -u --exclude-per-directory=.gitignore $old $new 2>&1) || (
207         case "$merge" in
208         '')
209                 echo >&2 "$merge_error"
210                 exit 1 ;;
211         esac
212
213         # Match the index to the working tree, and do a three-way.
214         git diff-files --name-only | git update-index --remove --stdin &&
215         work=`git write-tree` &&
216         git read-tree $v --reset -u $new || exit
217
218         eval GITHEAD_$new='${new_name:-${branch:-$new}}' &&
219         eval GITHEAD_$work=local &&
220         export GITHEAD_$new GITHEAD_$work &&
221         git merge-recursive $old -- $new $work
222
223         # Do not register the cleanly merged paths in the index yet.
224         # this is not a real merge before committing, but just carrying
225         # the working tree changes along.
226         unmerged=`git ls-files -u`
227         git read-tree $v --reset $new
228         case "$unmerged" in
229         '')     ;;
230         *)
231                 (
232                         z40=0000000000000000000000000000000000000000
233                         echo "$unmerged" |
234                         sed -e 's/^[0-7]* [0-9a-f]* /'"0 $z40 /"
235                         echo "$unmerged"
236                 ) | git update-index --index-info
237                 ;;
238         esac
239         exit 0
240     )
241     saved_err=$?
242     if test "$saved_err" = 0 && test -z "$quiet"
243     then
244         git diff-index --name-status "$new"
245     fi
246     (exit $saved_err)
247 fi
248
249 #
250 # Switch the HEAD pointer to the new branch if we
251 # checked out a branch head, and remove any potential
252 # old MERGE_HEAD's (subsequent commits will clearly not
253 # be based on them, since we re-set the index)
254 #
255 if [ "$?" -eq 0 ]; then
256         if [ "$newbranch" ]; then
257                 git branch $track $newbranch_log "$newbranch" "$new_name" || exit
258                 branch="$newbranch"
259         fi
260         if test -n "$branch"
261         then
262                 old_branch_name=`expr "z$oldbranch" : 'zrefs/heads/\(.*\)'`
263                 GIT_DIR="$GIT_DIR" git symbolic-ref -m "checkout: moving from $old_branch_name to $branch" HEAD "refs/heads/$branch"
264                 if test -n "$quiet"
265                 then
266                         true    # nothing
267                 elif test "refs/heads/$branch" = "$oldbranch"
268                 then
269                         echo >&2 "Already on branch \"$branch\""
270                 else
271                         echo >&2 "Switched to${newbranch:+ a new} branch \"$branch\""
272                 fi
273         elif test -n "$detached"
274         then
275                 git update-ref --no-deref -m "checkout: moving to $arg" HEAD "$detached" ||
276                         die "Cannot detach HEAD"
277                 if test -n "$detach_warn"
278                 then
279                         echo >&2 "$detach_warn"
280                 fi
281                 describe_detached_head 'HEAD is now at' HEAD
282         fi
283         rm -f "$GIT_DIR/MERGE_HEAD"
284 else
285         exit 1
286 fi