Re: [PATCH] git-revover-tags-script

[Junio C Hamano <junkio@cox.net>]

ebiederm@xmission.com (Eric W. Biederman) writes:

> What we care about are the tag objects, those are the only kind
> that are verifiable and usable remotely.  
>
> Now that I know we do not pull tags currently with any of the
> optimized transports, I would suggest taking the list of commit
> objects we are transporting and for each commit look in the
> remote repo/refs/tags and transferring every tag object we can find
> that refers to that commit.

I do not think it is particularly a good idea to fetch a tag
that refers to a commit when the user asks only for that commit
(e.g. the user said "the head of this remote branch I am
tracking", and the head happened to have been tagged).  Yes, it
may be convenient, but retrieving the commit chain and
retrieving tags are conceptually separate issues.  A tag does
not necessarily refer to a commit, so your reverse index does
not make sense for a tag pointing at a blob, for example.

I think if we have discovery mechanism of remote tags/heads, we
do not need anything else.  You _could_ say something like:

    $ git-list-remote --tags linux-2.6
    9e734775f7c22d2f89943ad6c745571f1930105f	v2.6.12-rc2
    26791a8bcf0e6d33f43aef7682bdb555236d56de	v2.6.12
    ...
    a339981ec18d304f9efeb9ccf01b1f04302edf32	v2.6.13-rc3
    $ git-list-remote --tags linux-2.6 |
      while read sha1 tag;
      do
          git fetch linux-2.6 tag $tag
      done

and you are done.  We did not use the reverse index, nor we used
the --all-tags flag to git-fetch-script.  You do not even need
git-list-remote if you are willing to wget a=summary output from
gitweb and parse the bottom of the page ;-).

The above may not exactly work for linux-2.6 repository because
I think the "tag" form of git-fetch-script may expect to find a
tag that resolves to a commit object and there is the oddball
v2.6.11-tree tag, but you got the general idea.