Merge branch 'maint'
[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 -- "$@" |
139         git checkout-index -f -u --stdin
140
141         # Run a post-checkout hook -- the HEAD does not change so the
142         # current HEAD is passed in for both args
143         if test -x "$GIT_DIR"/hooks/post-checkout; then
144             "$GIT_DIR"/hooks/post-checkout $old $old 0
145         fi
146
147         exit $?
148 else
149         # Make sure we did not fall back on $arg^{tree} codepath
150         # since we are not checking out from an arbitrary tree-ish,
151         # but switching branches.
152         if test '' != "$new"
153         then
154                 git rev-parse --verify "$new^{commit}" >/dev/null 2>&1 ||
155                 die "Cannot switch branch to a non-commit."
156         fi
157 fi
158
159 # We are switching branches and checking out trees, so
160 # we *NEED* to be at the toplevel.
161 cd_to_toplevel
162
163 [ -z "$new" ] && new=$old && new_name="$old_name"
164
165 # If we don't have an existing branch that we're switching to,
166 # and we don't have a new branch name for the target we
167 # are switching to, then we are detaching our HEAD from any
168 # branch.  However, if "git checkout HEAD" detaches the HEAD
169 # from the current branch, even though that may be logically
170 # correct, it feels somewhat funny.  More importantly, we do not
171 # want "git checkout" nor "git checkout -f" to detach HEAD.
172
173 detached=
174 detach_warn=
175
176 describe_detached_head () {
177         test -n "$quiet" || {
178                 printf >&2 "$1 "
179                 GIT_PAGER= git log >&2 -1 --pretty=oneline --abbrev-commit "$2"
180         }
181 }
182
183 if test -z "$branch$newbranch" && test "$new_name" != "$old_name"
184 then
185         detached="$new"
186         if test -n "$oldbranch" && test -z "$quiet"
187         then
188                 detach_warn="Note: moving to \"$new_name\" which isn't a local branch
189 If you want to create a new branch from this checkout, you may do so
190 (now or later) by using -b with the checkout command again. Example:
191   git checkout -b <new_branch_name>"
192         fi
193 elif test -z "$oldbranch" && test "$new" != "$old"
194 then
195         describe_detached_head 'Previous HEAD position was' "$old"
196 fi
197
198 if [ "X$old" = X ]
199 then
200         if test -z "$quiet"
201         then
202                 echo >&2 "warning: You appear to be on a branch yet to be born."
203                 echo >&2 "warning: Forcing checkout of $new_name."
204         fi
205         force=1
206 fi
207
208 if [ "$force" ]
209 then
210     git read-tree $v --reset -u $new
211 else
212     git update-index --refresh >/dev/null
213     merge_error=$(git read-tree -m -u --exclude-per-directory=.gitignore $old $new 2>&1) || (
214         case "$merge" in
215         '')
216                 echo >&2 "$merge_error"
217                 exit 1 ;;
218         esac
219
220         # Match the index to the working tree, and do a three-way.
221         git diff-files --name-only | git update-index --remove --stdin &&
222         work=`git write-tree` &&
223         git read-tree $v --reset -u $new || exit
224
225         eval GITHEAD_$new='${new_name:-${branch:-$new}}' &&
226         eval GITHEAD_$work=local &&
227         export GITHEAD_$new GITHEAD_$work &&
228         git merge-recursive $old -- $new $work
229
230         # Do not register the cleanly merged paths in the index yet.
231         # this is not a real merge before committing, but just carrying
232         # the working tree changes along.
233         unmerged=`git ls-files -u`
234         git read-tree $v --reset $new
235         case "$unmerged" in
236         '')     ;;
237         *)
238                 (
239                         z40=0000000000000000000000000000000000000000
240                         echo "$unmerged" |
241                         sed -e 's/^[0-7]* [0-9a-f]* /'"0 $z40 /"
242                         echo "$unmerged"
243                 ) | git update-index --index-info
244                 ;;
245         esac
246         exit 0
247     )
248     saved_err=$?
249     if test "$saved_err" = 0 && test -z "$quiet"
250     then
251         git diff-index --name-status "$new"
252     fi
253     (exit $saved_err)
254 fi
255
256 #
257 # Switch the HEAD pointer to the new branch if we
258 # checked out a branch head, and remove any potential
259 # old MERGE_HEAD's (subsequent commits will clearly not
260 # be based on them, since we re-set the index)
261 #
262 if [ "$?" -eq 0 ]; then
263         if [ "$newbranch" ]; then
264                 git branch $track $newbranch_log "$newbranch" "$new_name" || exit
265                 branch="$newbranch"
266         fi
267         if test -n "$branch"
268         then
269                 old_branch_name=`expr "z$oldbranch" : 'zrefs/heads/\(.*\)'`
270                 GIT_DIR="$GIT_DIR" git symbolic-ref -m "checkout: moving from $old_branch_name to $branch" HEAD "refs/heads/$branch"
271                 if test -n "$quiet"
272                 then
273                         true    # nothing
274                 elif test "refs/heads/$branch" = "$oldbranch"
275                 then
276                         echo >&2 "Already on branch \"$branch\""
277                 else
278                         echo >&2 "Switched to${newbranch:+ a new} branch \"$branch\""
279                 fi
280         elif test -n "$detached"
281         then
282                 git update-ref --no-deref -m "checkout: moving to $arg" HEAD "$detached" ||
283                         die "Cannot detach HEAD"
284                 if test -n "$detach_warn"
285                 then
286                         echo >&2 "$detach_warn"
287                 fi
288                 describe_detached_head 'HEAD is now at' HEAD
289         fi
290         rm -f "$GIT_DIR/MERGE_HEAD"
291 else
292         exit 1
293 fi
294
295 # Run a post-checkout hook
296 if test -x "$GIT_DIR"/hooks/post-checkout; then
297         "$GIT_DIR"/hooks/post-checkout $old $new 1
298 fi