Merge branch 'maint'
[git/git.git] / git-checkout.sh
1 #!/bin/sh
2
3 OPTIONS_KEEPDASHDASH=t
4 OPTIONS_SPEC="\
5 git-branch [options] [<branch>] [<paths>...]
6 --
7 b= create a new branch started at <branch>
8 l create the new branchs reflog
9 track tells if the new branch should track the remote branch
10 f proceed even if the index or working tree is not HEAD
11 m performa three-way merge on local modifications if needed
12 q,quiet be quiet
13 "
14 SUBDIRECTORY_OK=Sometimes
15 . git-sh-setup
16 require_work_tree
17
18 old_name=HEAD
19 old=$(git rev-parse --verify $old_name 2>/dev/null)
20 oldbranch=$(git symbolic-ref $old_name 2>/dev/null)
21 new=
22 new_name=
23 force=
24 branch=
25 track=
26 newbranch=
27 newbranch_log=
28 merge=
29 quiet=
30 v=-v
31 LF='
32 '
33
34 while test $# != 0; do
35 case "$1" in
36 -b)
37 shift
38 newbranch="$1"
39 [ -z "$newbranch" ] &&
40 die "git checkout: -b needs a branch name"
41 git show-ref --verify --quiet -- "refs/heads/$newbranch" &&
42 die "git checkout: branch $newbranch already exists"
43 git check-ref-format "heads/$newbranch" ||
44 die "git checkout: we do not like '$newbranch' as a branch name."
45 ;;
46 -l)
47 newbranch_log=-l
48 ;;
49 --track|--no-track)
50 track="$1"
51 ;;
52 -f)
53 force=1
54 ;;
55 -m)
56 merge=1
57 ;;
58 -q|--quiet)
59 quiet=1
60 v=
61 ;;
62 --)
63 shift
64 break
65 ;;
66 *)
67 usage
68 ;;
69 esac
70 shift
71 done
72
73 arg="$1"
74 if rev=$(git rev-parse --verify "$arg^0" 2>/dev/null)
75 then
76 [ -z "$rev" ] && die "unknown flag $arg"
77 new_name="$arg"
78 if git show-ref --verify --quiet -- "refs/heads/$arg"
79 then
80 rev=$(git rev-parse --verify "refs/heads/$arg^0")
81 branch="$arg"
82 fi
83 new="$rev"
84 shift
85 elif rev=$(git rev-parse --verify "$arg^{tree}" 2>/dev/null)
86 then
87 # checking out selected paths from a tree-ish.
88 new="$rev"
89 new_name="$arg^{tree}"
90 shift
91 fi
92 [ "$1" = "--" ] && shift
93
94 case "$newbranch,$track" in
95 ,--*)
96 die "git checkout: --track and --no-track require -b"
97 esac
98
99 case "$force$merge" in
100 11)
101 die "git checkout: -f and -m are incompatible"
102 esac
103
104 # The behaviour of the command with and without explicit path
105 # parameters is quite different.
106 #
107 # Without paths, we are checking out everything in the work tree,
108 # possibly switching branches. This is the traditional behaviour.
109 #
110 # With paths, we are _never_ switching branch, but checking out
111 # the named paths from either index (when no rev is given),
112 # or the named tree-ish (when rev is given).
113
114 if test "$#" -ge 1
115 then
116 hint=
117 if test "$#" -eq 1
118 then
119 hint="
120 Did you intend to checkout '$@' which can not be resolved as commit?"
121 fi
122 if test '' != "$newbranch$force$merge"
123 then
124 die "git checkout: updating paths is incompatible with switching branches/forcing$hint"
125 fi
126 if test '' != "$new"
127 then
128 # from a specific tree-ish; note that this is for
129 # rescuing paths and is never meant to remove what
130 # is not in the named tree-ish.
131 git ls-tree --full-name -r "$new" "$@" |
132 git update-index --index-info || exit $?
133 fi
134
135 # Make sure the request is about existing paths.
136 git ls-files --full-name --error-unmatch -- "$@" >/dev/null || exit
137 git ls-files --full-name -- "$@" |
138 (cd_to_toplevel && git checkout-index -f -u --stdin)
139
140 # Run a post-checkout hook -- the HEAD does not change so the
141 # current HEAD is passed in for both args
142 if test -x "$GIT_DIR"/hooks/post-checkout; then
143 "$GIT_DIR"/hooks/post-checkout $old $old 0
144 fi
145
146 exit $?
147 else
148 # Make sure we did not fall back on $arg^{tree} codepath
149 # since we are not checking out from an arbitrary tree-ish,
150 # but switching branches.
151 if test '' != "$new"
152 then
153 git rev-parse --verify "$new^{commit}" >/dev/null 2>&1 ||
154 die "Cannot switch branch to a non-commit."
155 fi
156 fi
157
158 # We are switching branches and checking out trees, so
159 # we *NEED* to be at the toplevel.
160 cd_to_toplevel
161
162 [ -z "$new" ] && new=$old && new_name="$old_name"
163
164 # If we don't have an existing branch that we're switching to,
165 # and we don't have a new branch name for the target we
166 # are switching to, then we are detaching our HEAD from any
167 # branch. However, if "git checkout HEAD" detaches the HEAD
168 # from the current branch, even though that may be logically
169 # correct, it feels somewhat funny. More importantly, we do not
170 # want "git checkout" nor "git checkout -f" to detach HEAD.
171
172 detached=
173 detach_warn=
174
175 describe_detached_head () {
176 test -n "$quiet" || {
177 printf >&2 "$1 "
178 GIT_PAGER= git log >&2 -1 --pretty=oneline --abbrev-commit "$2" --
179 }
180 }
181
182 if test -z "$branch$newbranch" && test "$new_name" != "$old_name"
183 then
184 detached="$new"
185 if test -n "$oldbranch" && test -z "$quiet"
186 then
187 detach_warn="Note: moving to \"$new_name\" which isn't a local branch
188 If you want to create a new branch from this checkout, you may do so
189 (now or later) by using -b with the checkout command again. Example:
190 git checkout -b <new_branch_name>"
191 fi
192 elif test -z "$oldbranch" && test "$new" != "$old"
193 then
194 describe_detached_head 'Previous HEAD position was' "$old"
195 fi
196
197 if [ "X$old" = X ]
198 then
199 if test -z "$quiet"
200 then
201 echo >&2 "warning: You appear to be on a branch yet to be born."
202 echo >&2 "warning: Forcing checkout of $new_name."
203 fi
204 force=1
205 fi
206
207 if [ "$force" ]
208 then
209 git read-tree $v --reset -u $new
210 else
211 git update-index --refresh >/dev/null
212 merge_error=$(git read-tree -m -u --exclude-per-directory=.gitignore $old $new 2>&1) || (
213 case "$merge" in
214 '')
215 echo >&2 "$merge_error"
216 exit 1 ;;
217 esac
218
219 # Match the index to the working tree, and do a three-way.
220 git diff-files --name-only | git update-index --remove --stdin &&
221 work=`git write-tree` &&
222 git read-tree $v --reset -u $new || exit
223
224 eval GITHEAD_$new='${new_name:-${branch:-$new}}' &&
225 eval GITHEAD_$work=local &&
226 export GITHEAD_$new GITHEAD_$work &&
227 git merge-recursive $old -- $new $work
228
229 # Do not register the cleanly merged paths in the index yet.
230 # this is not a real merge before committing, but just carrying
231 # the working tree changes along.
232 unmerged=`git ls-files -u`
233 git read-tree $v --reset $new
234 case "$unmerged" in
235 '') ;;
236 *)
237 (
238 z40=0000000000000000000000000000000000000000
239 echo "$unmerged" |
240 sed -e 's/^[0-7]* [0-9a-f]* /'"0 $z40 /"
241 echo "$unmerged"
242 ) | git update-index --index-info
243 ;;
244 esac
245 exit 0
246 )
247 saved_err=$?
248 if test "$saved_err" = 0 && test -z "$quiet"
249 then
250 git diff-index --name-status "$new"
251 fi
252 (exit $saved_err)
253 fi
254
255 #
256 # Switch the HEAD pointer to the new branch if we
257 # checked out a branch head, and remove any potential
258 # old MERGE_HEAD's (subsequent commits will clearly not
259 # be based on them, since we re-set the index)
260 #
261 if [ "$?" -eq 0 ]; then
262 if [ "$newbranch" ]; then
263 git branch $track $newbranch_log "$newbranch" "$new_name" || exit
264 branch="$newbranch"
265 fi
266 if test -n "$branch"
267 then
268 old_branch_name=`expr "z$oldbranch" : 'zrefs/heads/\(.*\)'`
269 GIT_DIR="$GIT_DIR" git symbolic-ref -m "checkout: moving from $old_branch_name to $branch" HEAD "refs/heads/$branch"
270 if test -n "$quiet"
271 then
272 true # nothing
273 elif test "refs/heads/$branch" = "$oldbranch"
274 then
275 echo >&2 "Already on branch \"$branch\""
276 else
277 echo >&2 "Switched to${newbranch:+ a new} branch \"$branch\""
278 fi
279 elif test -n "$detached"
280 then
281 git update-ref --no-deref -m "checkout: moving to $arg" HEAD "$detached" ||
282 die "Cannot detach HEAD"
283 if test -n "$detach_warn"
284 then
285 echo >&2 "$detach_warn"
286 fi
287 describe_detached_head 'HEAD is now at' HEAD
288 fi
289 rm -f "$GIT_DIR/MERGE_HEAD"
290 else
291 exit 1
292 fi
293
294 # Run a post-checkout hook
295 if test -x "$GIT_DIR"/hooks/post-checkout; then
296 "$GIT_DIR"/hooks/post-checkout $old $new 1
297 fi