From 4853534e180c237331cb8395fe87ff6e09bbcf21 Mon Sep 17 00:00:00 2001 From: Junio C Hamano Date: Sun, 11 Feb 2007 22:29:12 -0800 Subject: Add discussion section to git-tag documentation. Signed-off-by: Junio C Hamano diff --git a/Documentation/git-tag.txt b/Documentation/git-tag.txt index 3f01e0b..70235e8 100644 --- a/Documentation/git-tag.txt +++ b/Documentation/git-tag.txt @@ -80,6 +80,137 @@ it in the repository configuration as follows: [user] signingkey = + +DISCUSSION +---------- + +On Re-tagging +~~~~~~~~~~~~~ + +What should you do when you tag a wrong commit and you would +want to re-tag? + +If you never pushed anything out, just re-tag it. Use "-f" to +replace the old one. And you're done. + +But if you have pushed things out (or others could just read +your repository directly), then others will have already seen +the old tag. In that case you can do one of two things: + +. The sane thing. +Just admit you screwed up, and use a different name. Others have +already seen one tag-name, and if you keep the same name, you +may be in the situation that two people both have "version X", +but they actually have 'different' "X"'s. So just call it "X.1" +and be done with it. + +. The insane thing. +You really want to call the new version "X" too, 'even though' +others have already seen the old one. So just use "git tag -f" +again, as if you hadn't already published the old one. + +However, Git does *not* (and it should not)change tags behind +users back. So if somebody already got the old tag, doing a "git +pull" on your tree shouldn't just make them overwrite the old +one. + +If somebody got a release tag from you, you cannot just change +the tag for them by updating your own one. This is a big +security issue, in that people MUST be able to trust their +tag-names. If you really want to do the insane thing, you need +to just fess up to it, and tell people that you messed up. You +can do that by making a very public announcement saying: + +------------ +Ok, I messed up, and I pushed out an earlier version tagged as X. I +then fixed something, and retagged the *fixed* tree as X again. + +If you got the wrong tag, and want the new one, please delete +the old one and fetch the new one by doing: + + git tag -d X + git fetch origin tag X + +to get my updated tag. + +You can test which tag you have by doing + + git rev-parse X + +which should return 0123456789abcdef.. if you have the new version. + +Sorry for inconvenience. +------------ + +Does this seem a bit complicated? It *should* be. There is no +way that it would be correct to just "fix" it behind peoples +backs. People need to know that their tags might have been +changed. + + +On Automatic following +~~~~~~~~~~~~~~~~~~~~~~ + +If you are following somebody else's tree, you are most likely +using tracking branches (`refs/heads/origin` in traditional +layout, or `refs/remotes/origin/master` in the separate-remote +layout). You usually want the tags from the other end. + +On the other hand, if you are fetching because you would want a +one-shot merge from somebody else, you typically do not want to +get tags from there. This happens more often for people near +the toplevel but not limited to them. Mere mortals when pulling +from each other do not necessarily want to automatically get +private anchor point tags from the other person. + +You would notice "please pull" messages on the mailing list says +repo URL and branch name alone. This is designed to be easily +cut&pasted to "git fetch" command line: + +------------ +Linus, please pull from + + git://git..../proj.git master + +to get the following updates... +------------ + +becomes: + +------------ +$ git pull git://git..../proj.git master +------------ + +In such a case, you do not want to automatically follow other's +tags. + +One important aspect of git is it is distributed, and being +distributed largely means there is no inherent "upstream" or +"downstream" in the system. On the face of it, the above +example might seem to indicate that the tag namespace is owned +by upper echelon of people and tags only flow downwards, but +that is not the case. It only shows that the usage pattern +determines who are interested in whose tags. + +A one-shot pull is a sign that a commit history is now crossing +the boundary between one circle of people (e.g. "people who are +primarily interested in networking part of the kernel") who may +have their own set of tags (e.g. "this is the third release +candidate from the networking group to be proposed for general +consumption with 2.6.21 release") to another circle of people +(e.g. "people who integrate various subsystem improvements"). +The latter are usually not interested in the detailed tags used +internally in the former group (that is what "internal" means). +That is why it is desirable not to follow tags automatically in +this case. + +It may well be that among networking people, they may want to +exchange the tags internal to their group, but in that workflow +they are most likely tracking with each other's progress by +having tracking branches. Again, the heuristic to automatically +follow such tags is a good thing. + + Author ------ Written by Linus Torvalds , -- cgit v0.10.2-6-g49f6