Documentation / git-tag.txton commit Documentation: Add definition of "evil merge" to GIT Glossary (c1bab28)
   1git-tag(1)
   2==========
   3
   4NAME
   5----
   6git-tag - Create, list, delete or verify a tag object signed with GPG
   7
   8
   9SYNOPSIS
  10--------
  11[verse]
  12'git-tag' [-a | -s | -u <key-id>] [-f | -v] [-m <msg> | -F <file>]  <name> [<head>]
  13'git-tag' -d <name>...
  14'git-tag' -l [<pattern>]
  15
  16DESCRIPTION
  17-----------
  18Adds a 'tag' reference in `.git/refs/tags/`
  19
  20Unless `-f` is given, the tag must not yet exist in
  21`.git/refs/tags/` directory.
  22
  23If one of `-a`, `-s`, or `-u <key-id>` is passed, the command
  24creates a 'tag' object, and requires the tag message.  Unless
  25`-m <msg>` is given, an editor is started for the user to type
  26in the tag message.
  27
  28Otherwise just the SHA1 object name of the commit object is
  29written (i.e. a lightweight tag).
  30
  31A GnuPG signed tag object will be created when `-s` or `-u
  32<key-id>` is used.  When `-u <key-id>` is not used, the
  33committer identity for the current user is used to find the
  34GnuPG key for signing.
  35
  36`-d <tag>` deletes the tag.
  37
  38`-v <tag>` verifies the gpg signature of the tag.
  39
  40`-l <pattern>` lists tags that match the given pattern (or all
  41if no pattern is given).
  42
  43OPTIONS
  44-------
  45-a::
  46        Make an unsigned, annotated tag object
  47
  48-s::
  49        Make a GPG-signed tag, using the default e-mail address's key
  50
  51-u <key-id>::
  52        Make a GPG-signed tag, using the given key
  53
  54-f::
  55        Replace an existing tag with the given name (instead of failing)
  56
  57-d::
  58        Delete existing tags with the given names.
  59
  60-v::
  61        Verify the gpg signature of given the tag
  62
  63-l <pattern>::
  64        List tags that match the given pattern (or all if no pattern is given).
  65
  66-m <msg>::
  67        Use the given tag message (instead of prompting)
  68
  69-F <file>::
  70        Take the tag message from the given file.  Use '-' to
  71        read the message from the standard input.
  72
  73CONFIGURATION
  74-------------
  75By default, git-tag in sign-with-default mode (-s) will use your
  76committer identity (of the form "Your Name <your@email.address>") to
  77find a key.  If you want to use a different default key, you can specify
  78it in the repository configuration as follows:
  79
  80[user]
  81    signingkey = <gpg-key-id>
  82
  83
  84DISCUSSION
  85----------
  86
  87On Re-tagging
  88~~~~~~~~~~~~~
  89
  90What should you do when you tag a wrong commit and you would
  91want to re-tag?
  92
  93If you never pushed anything out, just re-tag it. Use "-f" to
  94replace the old one. And you're done.
  95
  96But if you have pushed things out (or others could just read
  97your repository directly), then others will have already seen
  98the old tag. In that case you can do one of two things:
  99
 100. The sane thing.
 101Just admit you screwed up, and use a different name. Others have
 102already seen one tag-name, and if you keep the same name, you
 103may be in the situation that two people both have "version X",
 104but they actually have 'different' "X"'s.  So just call it "X.1"
 105and be done with it.
 106
 107. The insane thing.
 108You really want to call the new version "X" too, 'even though'
 109others have already seen the old one. So just use "git tag -f"
 110again, as if you hadn't already published the old one.
 111
 112However, Git does *not* (and it should not)change tags behind
 113users back. So if somebody already got the old tag, doing a "git
 114pull" on your tree shouldn't just make them overwrite the old
 115one.
 116
 117If somebody got a release tag from you, you cannot just change
 118the tag for them by updating your own one. This is a big
 119security issue, in that people MUST be able to trust their
 120tag-names.  If you really want to do the insane thing, you need
 121to just fess up to it, and tell people that you messed up. You
 122can do that by making a very public announcement saying:
 123
 124------------
 125Ok, I messed up, and I pushed out an earlier version tagged as X. I
 126then fixed something, and retagged the *fixed* tree as X again.
 127
 128If you got the wrong tag, and want the new one, please delete
 129the old one and fetch the new one by doing:
 130
 131        git tag -d X
 132        git fetch origin tag X
 133
 134to get my updated tag.
 135
 136You can test which tag you have by doing
 137
 138        git rev-parse X
 139
 140which should return 0123456789abcdef.. if you have the new version.
 141
 142Sorry for inconvenience.
 143------------
 144
 145Does this seem a bit complicated?  It *should* be. There is no
 146way that it would be correct to just "fix" it behind peoples
 147backs. People need to know that their tags might have been
 148changed.
 149
 150
 151On Automatic following
 152~~~~~~~~~~~~~~~~~~~~~~
 153
 154If you are following somebody else's tree, you are most likely
 155using tracking branches (`refs/heads/origin` in traditional
 156layout, or `refs/remotes/origin/master` in the separate-remote
 157layout).  You usually want the tags from the other end.
 158
 159On the other hand, if you are fetching because you would want a
 160one-shot merge from somebody else, you typically do not want to
 161get tags from there.  This happens more often for people near
 162the toplevel but not limited to them.  Mere mortals when pulling
 163from each other do not necessarily want to automatically get
 164private anchor point tags from the other person.
 165
 166You would notice "please pull" messages on the mailing list says
 167repo URL and branch name alone.  This is designed to be easily
 168cut&pasted to "git fetch" command line:
 169
 170------------
 171Linus, please pull from
 172
 173        git://git..../proj.git master
 174
 175to get the following updates...
 176------------
 177
 178becomes:
 179
 180------------
 181$ git pull git://git..../proj.git master
 182------------
 183
 184In such a case, you do not want to automatically follow other's
 185tags.
 186
 187One important aspect of git is it is distributed, and being
 188distributed largely means there is no inherent "upstream" or
 189"downstream" in the system.  On the face of it, the above
 190example might seem to indicate that the tag namespace is owned
 191by upper echelon of people and tags only flow downwards, but
 192that is not the case.  It only shows that the usage pattern
 193determines who are interested in whose tags.
 194
 195A one-shot pull is a sign that a commit history is now crossing
 196the boundary between one circle of people (e.g. "people who are
 197primarily interested in networking part of the kernel") who may
 198have their own set of tags (e.g. "this is the third release
 199candidate from the networking group to be proposed for general
 200consumption with 2.6.21 release") to another circle of people
 201(e.g. "people who integrate various subsystem improvements").
 202The latter are usually not interested in the detailed tags used
 203internally in the former group (that is what "internal" means).
 204That is why it is desirable not to follow tags automatically in
 205this case.
 206
 207It may well be that among networking people, they may want to
 208exchange the tags internal to their group, but in that workflow
 209they are most likely tracking with each other's progress by
 210having tracking branches.  Again, the heuristic to automatically
 211follow such tags is a good thing.
 212
 213
 214Author
 215------
 216Written by Linus Torvalds <torvalds@osdl.org>,
 217Junio C Hamano <junkio@cox.net> and Chris Wright <chrisw@osdl.org>.
 218
 219Documentation
 220--------------
 221Documentation by David Greaves, Junio C Hamano and the git-list <git@vger.kernel.org>.
 222
 223GIT
 224---
 225Part of the gitlink:git[7] suite