Git terminology

Hi all,

In the process of learning git, and browsing the docs, I realized that many particular terms are used, but I had difficulties finding their definitions. 

Among those I found a bit arcane, there are (in no particular order) "refspec", "rebase", "rewound", "pickaxe", "refnames", "objectnames" ,"refnames", "fast-forward update".

Also, doing a "grep -rohE '<[a-z\-]+>' * | sort | uniq" in git source tree gave me the list of "parameter types" for git commands, where some would benefit from a formal definition : <base>, <blob>, <branch>, <branchname>, <comitish>, <tree>, <tree-ish>, <head>, <headsha>, <refspec>, and so on. Of course, some of these terms are already explained in the man pages, but it would be nice to have a "git terminlogy reference".

If some of you are willing to detail/explain/define those terms (and some others not mentioned here), I would be glad to collect the definitions and make a "git terminology" document.

 -- Sébastien

On Wed, Mar 29, 2006 at 05:21:13AM -0500, Sébastien Pierre wrote:

See Documentation/glossary.txt. It's missing some of the terms your looking for, but I'm sure patches would be accepted.

--b.

Sébastien Pierre <sebastien@xprima.com> writes:

I had difficulties reading your message.  Please fold your lines.

I see some are missing from our glossary but some others are found there.

refspec is used by fetch and push to describe the mapping between remote ref and local ref. E.g. "git fetch $URL refs/heads/master:refs/heads/origin" means "grab the master branch head from there and store it as my origin branch head". "git push $URL refs/heads/master:refs/heads/to-upstream" for "publish my master branch head as to-upstream master head at $URL".

Probably we can just say "ref" where we say "refname".

Probably we can just say "ref" where we say "refname".

A fast-forward is where you have a revision and you are "merging" other's change that happen to be a descendant what you have. In such a case, you do not make a new merge commit but just update to his revision. That is:

          o---o---o---o his               o---o---o---o his
         /                      ->       /             \
    o---o---o---o yours             o---o---o---o-------* yours

updating to his needs a merge like above, but in this case:

          o---o---o---o his               o---o---o---o his = yours
         /                      ->       /
    o---o yours                     o---o

you just update to his.

A related concept is "being already up-to-date". In the latter picture, if he attempts to "merge" your changes and notices he is simply ahead of you (i.e. his revision is a descendant of yours), nothing happens.

Thanks, and what J Bruce Fields already said.

On Wed, 29 Mar 2006 07:59:16 -0800
Junio C Hamano <junkio@cox.net> wrote:
 

Ah, ok. The diagrams are really helpful to get what "fast forward" is.

Thanks !

 -- Sébastien