tag: clarify in the doc that a tag can refer to a non-commit object
[git/git.git] / Documentation / git-tag.txt
1 git-tag(1)
2 ==========
3
4 NAME
5 ----
6 git-tag - Create, list, delete or verify a tag object signed with GPG
7
8
9 SYNOPSIS
10 --------
11 [verse]
12 'git tag' [-a | -s | -u <keyid>] [-f] [-m <msg> | -F <file>] [-e]
13 <tagname> [<commit> | <object>]
14 'git tag' -d <tagname>...
15 'git tag' [-n[<num>]] -l [--contains <commit>] [--no-contains <commit>]
16 [--points-at <object>] [--column[=<options>] | --no-column]
17 [--create-reflog] [--sort=<key>] [--format=<format>]
18 [--[no-]merged [<commit>]] [<pattern>...]
19 'git tag' -v [--format=<format>] <tagname>...
20
21 DESCRIPTION
22 -----------
23
24 Add a tag reference in `refs/tags/`, unless `-d/-l/-v` is given
25 to delete, list or verify tags.
26
27 Unless `-f` is given, the named tag must not yet exist.
28
29 If one of `-a`, `-s`, or `-u <keyid>` is passed, the command
30 creates a 'tag' object, and requires a tag message. Unless
31 `-m <msg>` or `-F <file>` is given, an editor is started for the user to type
32 in the tag message.
33
34 If `-m <msg>` or `-F <file>` is given and `-a`, `-s`, and `-u <keyid>`
35 are absent, `-a` is implied.
36
37 Otherwise, a tag reference that points directly at the given object
38 (i.e., a lightweight tag) is created.
39
40 A GnuPG signed tag object will be created when `-s` or `-u
41 <keyid>` is used. When `-u <keyid>` is not used, the
42 committer identity for the current user is used to find the
43 GnuPG key for signing. The configuration variable `gpg.program`
44 is used to specify custom GnuPG binary.
45
46 Tag objects (created with `-a`, `-s`, or `-u`) are called "annotated"
47 tags; they contain a creation date, the tagger name and e-mail, a
48 tagging message, and an optional GnuPG signature. Whereas a
49 "lightweight" tag is simply a name for an object (usually a commit
50 object).
51
52 Annotated tags are meant for release while lightweight tags are meant
53 for private or temporary object labels. For this reason, some git
54 commands for naming objects (like `git describe`) will ignore
55 lightweight tags by default.
56
57
58 OPTIONS
59 -------
60 -a::
61 --annotate::
62 Make an unsigned, annotated tag object
63
64 -s::
65 --sign::
66 Make a GPG-signed tag, using the default e-mail address's key.
67
68 -u <keyid>::
69 --local-user=<keyid>::
70 Make a GPG-signed tag, using the given key.
71
72 -f::
73 --force::
74 Replace an existing tag with the given name (instead of failing)
75
76 -d::
77 --delete::
78 Delete existing tags with the given names.
79
80 -v::
81 --verify::
82 Verify the GPG signature of the given tag names.
83
84 -n<num>::
85 <num> specifies how many lines from the annotation, if any,
86 are printed when using -l. Implies `--list`.
87 +
88 The default is not to print any annotation lines.
89 If no number is given to `-n`, only the first line is printed.
90 If the tag is not annotated, the commit message is displayed instead.
91
92 -l::
93 --list::
94 List tags. With optional `<pattern>...`, e.g. `git tag --list
95 'v-*'`, list only the tags that match the pattern(s).
96 +
97 Running "git tag" without arguments also lists all tags. The pattern
98 is a shell wildcard (i.e., matched using fnmatch(3)). Multiple
99 patterns may be given; if any of them matches, the tag is shown.
100 +
101 This option is implicitly supplied if any other list-like option such
102 as `--contains` is provided. See the documentation for each of those
103 options for details.
104
105 --sort=<key>::
106 Sort based on the key given. Prefix `-` to sort in
107 descending order of the value. You may use the --sort=<key> option
108 multiple times, in which case the last key becomes the primary
109 key. Also supports "version:refname" or "v:refname" (tag
110 names are treated as versions). The "version:refname" sort
111 order can also be affected by the "versionsort.suffix"
112 configuration variable.
113 The keys supported are the same as those in `git for-each-ref`.
114 Sort order defaults to the value configured for the `tag.sort`
115 variable if it exists, or lexicographic order otherwise. See
116 linkgit:git-config[1].
117
118 --color[=<when>]:
119 Respect any colors specified in the `--format` option. The
120 `<when>` field must be one of `always`, `never`, or `auto` (if
121 `<when>` is absent, behave as if `always` was given).
122
123 -i::
124 --ignore-case::
125 Sorting and filtering tags are case insensitive.
126
127 --column[=<options>]::
128 --no-column::
129 Display tag listing in columns. See configuration variable
130 column.tag for option syntax.`--column` and `--no-column`
131 without options are equivalent to 'always' and 'never' respectively.
132 +
133 This option is only applicable when listing tags without annotation lines.
134
135 --contains [<commit>]::
136 Only list tags which contain the specified commit (HEAD if not
137 specified). Implies `--list`.
138
139 --no-contains [<commit>]::
140 Only list tags which don't contain the specified commit (HEAD if
141 not specified). Implies `--list`.
142
143 --merged [<commit>]::
144 Only list tags whose commits are reachable from the specified
145 commit (`HEAD` if not specified), incompatible with `--no-merged`.
146
147 --no-merged [<commit>]::
148 Only list tags whose commits are not reachable from the specified
149 commit (`HEAD` if not specified), incompatible with `--merged`.
150
151 --points-at <object>::
152 Only list tags of the given object (HEAD if not
153 specified). Implies `--list`.
154
155 -m <msg>::
156 --message=<msg>::
157 Use the given tag message (instead of prompting).
158 If multiple `-m` options are given, their values are
159 concatenated as separate paragraphs.
160 Implies `-a` if none of `-a`, `-s`, or `-u <keyid>`
161 is given.
162
163 -F <file>::
164 --file=<file>::
165 Take the tag message from the given file. Use '-' to
166 read the message from the standard input.
167 Implies `-a` if none of `-a`, `-s`, or `-u <keyid>`
168 is given.
169
170 -e::
171 --edit::
172 The message taken from file with `-F` and command line with
173 `-m` are usually used as the tag message unmodified.
174 This option lets you further edit the message taken from these sources.
175
176 --cleanup=<mode>::
177 This option sets how the tag message is cleaned up.
178 The '<mode>' can be one of 'verbatim', 'whitespace' and 'strip'. The
179 'strip' mode is default. The 'verbatim' mode does not change message at
180 all, 'whitespace' removes just leading/trailing whitespace lines and
181 'strip' removes both whitespace and commentary.
182
183 --create-reflog::
184 Create a reflog for the tag. To globally enable reflogs for tags, see
185 `core.logAllRefUpdates` in linkgit:git-config[1].
186 The negated form `--no-create-reflog` only overrides an earlier
187 `--create-reflog`, but currently does not negate the setting of
188 `core.logAllRefUpdates`.
189
190 <tagname>::
191 The name of the tag to create, delete, or describe.
192 The new tag name must pass all checks defined by
193 linkgit:git-check-ref-format[1]. Some of these checks
194 may restrict the characters allowed in a tag name.
195
196 <commit>::
197 <object>::
198 The object that the new tag will refer to, usually a commit.
199 Defaults to HEAD.
200
201 <format>::
202 A string that interpolates `%(fieldname)` from a tag ref being shown
203 and the object it points at. The format is the same as
204 that of linkgit:git-for-each-ref[1]. When unspecified,
205 defaults to `%(refname:strip=2)`.
206
207 CONFIGURATION
208 -------------
209 By default, 'git tag' in sign-with-default mode (-s) will use your
210 committer identity (of the form `Your Name <your@email.address>`) to
211 find a key. If you want to use a different default key, you can specify
212 it in the repository configuration as follows:
213
214 -------------------------------------
215 [user]
216 signingKey = <gpg-keyid>
217 -------------------------------------
218
219 `pager.tag` is only respected when listing tags, i.e., when `-l` is
220 used or implied. The default is to use a pager.
221 See linkgit:git-config[1].
222
223 DISCUSSION
224 ----------
225
226 On Re-tagging
227 ~~~~~~~~~~~~~
228
229 What should you do when you tag a wrong commit and you would
230 want to re-tag?
231
232 If you never pushed anything out, just re-tag it. Use "-f" to
233 replace the old one. And you're done.
234
235 But if you have pushed things out (or others could just read
236 your repository directly), then others will have already seen
237 the old tag. In that case you can do one of two things:
238
239 . The sane thing.
240 Just admit you screwed up, and use a different name. Others have
241 already seen one tag-name, and if you keep the same name, you
242 may be in the situation that two people both have "version X",
243 but they actually have 'different' "X"'s. So just call it "X.1"
244 and be done with it.
245
246 . The insane thing.
247 You really want to call the new version "X" too, 'even though'
248 others have already seen the old one. So just use 'git tag -f'
249 again, as if you hadn't already published the old one.
250
251 However, Git does *not* (and it should not) change tags behind
252 users back. So if somebody already got the old tag, doing a
253 'git pull' on your tree shouldn't just make them overwrite the old
254 one.
255
256 If somebody got a release tag from you, you cannot just change
257 the tag for them by updating your own one. This is a big
258 security issue, in that people MUST be able to trust their
259 tag-names. If you really want to do the insane thing, you need
260 to just fess up to it, and tell people that you messed up. You
261 can do that by making a very public announcement saying:
262
263 ------------
264 Ok, I messed up, and I pushed out an earlier version tagged as X. I
265 then fixed something, and retagged the *fixed* tree as X again.
266
267 If you got the wrong tag, and want the new one, please delete
268 the old one and fetch the new one by doing:
269
270 git tag -d X
271 git fetch origin tag X
272
273 to get my updated tag.
274
275 You can test which tag you have by doing
276
277 git rev-parse X
278
279 which should return 0123456789abcdef.. if you have the new version.
280
281 Sorry for the inconvenience.
282 ------------
283
284 Does this seem a bit complicated? It *should* be. There is no
285 way that it would be correct to just "fix" it automatically.
286 People need to know that their tags might have been changed.
287
288
289 On Automatic following
290 ~~~~~~~~~~~~~~~~~~~~~~
291
292 If you are following somebody else's tree, you are most likely
293 using remote-tracking branches (eg. `refs/remotes/origin/master`).
294 You usually want the tags from the other end.
295
296 On the other hand, if you are fetching because you would want a
297 one-shot merge from somebody else, you typically do not want to
298 get tags from there. This happens more often for people near
299 the toplevel but not limited to them. Mere mortals when pulling
300 from each other do not necessarily want to automatically get
301 private anchor point tags from the other person.
302
303 Often, "please pull" messages on the mailing list just provide
304 two pieces of information: a repo URL and a branch name; this
305 is designed to be easily cut&pasted at the end of a 'git fetch'
306 command line:
307
308 ------------
309 Linus, please pull from
310
311 git://git..../proj.git master
312
313 to get the following updates...
314 ------------
315
316 becomes:
317
318 ------------
319 $ git pull git://git..../proj.git master
320 ------------
321
322 In such a case, you do not want to automatically follow the other
323 person's tags.
324
325 One important aspect of Git is its distributed nature, which
326 largely means there is no inherent "upstream" or
327 "downstream" in the system. On the face of it, the above
328 example might seem to indicate that the tag namespace is owned
329 by the upper echelon of people and that tags only flow downwards, but
330 that is not the case. It only shows that the usage pattern
331 determines who are interested in whose tags.
332
333 A one-shot pull is a sign that a commit history is now crossing
334 the boundary between one circle of people (e.g. "people who are
335 primarily interested in the networking part of the kernel") who may
336 have their own set of tags (e.g. "this is the third release
337 candidate from the networking group to be proposed for general
338 consumption with 2.6.21 release") to another circle of people
339 (e.g. "people who integrate various subsystem improvements").
340 The latter are usually not interested in the detailed tags used
341 internally in the former group (that is what "internal" means).
342 That is why it is desirable not to follow tags automatically in
343 this case.
344
345 It may well be that among networking people, they may want to
346 exchange the tags internal to their group, but in that workflow
347 they are most likely tracking each other's progress by
348 having remote-tracking branches. Again, the heuristic to automatically
349 follow such tags is a good thing.
350
351
352 On Backdating Tags
353 ~~~~~~~~~~~~~~~~~~
354
355 If you have imported some changes from another VCS and would like
356 to add tags for major releases of your work, it is useful to be able
357 to specify the date to embed inside of the tag object; such data in
358 the tag object affects, for example, the ordering of tags in the
359 gitweb interface.
360
361 To set the date used in future tag objects, set the environment
362 variable GIT_COMMITTER_DATE (see the later discussion of possible
363 values; the most common form is "YYYY-MM-DD HH:MM").
364
365 For example:
366
367 ------------
368 $ GIT_COMMITTER_DATE="2006-10-02 10:31" git tag -s v1.0.1
369 ------------
370
371 include::date-formats.txt[]
372
373 SEE ALSO
374 --------
375 linkgit:git-check-ref-format[1].
376 linkgit:git-config[1].
377
378 GIT
379 ---
380 Part of the linkgit:git[1] suite