Re: Gitk feature - show nearby tags

["Marco Costalba" <mcostalba@gmail.com>]

On 6/3/06, Junio C Hamano <junkio@cox.net> wrote:
> Paul Mackerras <paulus@samba.org> writes:
>
> > I just pushed out an update to the "new" branch of the gitk.git
> > repository, which adds a feature that I have often wished for: it will
> > now show the nearest preceding and following tags when you select a
> > commit.  This is very useful if you need to identify which release was
> > the first to incorporate a particular patch, or if you need to know
> > which release a patch might have been based on.
>
> Another thing that would equally be useful is to show which
> branch a particular commit is on, so for example I can pick one
> commit while doing "gitk next" to view the next branch and see
> which topic it belongs to, and "gitk this-topic" to see which
> commits on that topic, if any, are not yet in the "next" branch.
>

If I have understood correctly the patch runs a 'git rev-list --all
--topo-order --parents'
and then does a tree walking.

I am wandering if there exist any native git way to found the previous tag.

As example given a selected revision with id <sha> is it possible to
do something like this to fond the ancestor?

1) get the tag list with git-peek-remote or something similar if tags
are not already loaded

2) given the tagList vector with n elements run

    git-rev-list  --topo-order <sha> ^tagList[0]  ^tagList[1]   ....
  ^tagList[n-1]

3) take the last sha spit out by git-rev-list, be it <lastSha>.

4) Previous nearest tag is the parent of lastSha

I've missed something?

      Marco