Re: git fetch refs and tags

From: Johan Herland <johan@herland.net>
Date: Apr 23, 2013, 11:25 UTC
Message-ID: <CALKQrge2vHqA1HitpdJKYQu0KY5+XkFdrN_Gg254gW_ih57o=Q@mail.gmail.com>
In-Reply-To: <1366714421.2899.10.camel@lws-weitzel>

On Tue, Apr 23, 2013 at 12:53 PM, Jan Weitzel <J.Weitzel@phytec.de> wrote:

Show 12 quoted lines

> Hello,
> I have the following problem: I have 2 bare git repositories one has
> several branches and tags.
> If I try this in the second repository:
> git fetch -f ../main.git refs/heads/master:refs/heads/master
> I'm getting also tags from other branches, if I have an old object from
> one of the other branches.
> I would expect to have only tags pointing to master ref. (Although the
> man pages points to the behaviour regarding dangling objects). Is there
> a way to avoid this? I only find --no-tags which results in having no
> tags at all. Or need I git purge to remove the old objects first?
> My goal is to fetch only specific branches and the related tags.

AFAIK, Git should only auto-follow tags that are reachable from the branches you fetch (in this case master). Are you saying that you get tags pointing to other history that is NOT reachable from the master branch? (i.e. are you getting tags for which "git merge-base $tag master" is not equal to "git rev-parse $tag")?

Re-reading the man page, I do see the following:

"if the repository has objects that are pointed by remote tags that it does not yet have, then fetch those missing tags. If the other end has tags that point at branches you are not interested in, you will not get them."

This can be interpreted as saying that even unreachable objects in your local repo that are pointed to by some remote tag will cause that tag to be fetched, and in effect resuscitate the previously-unreachable object. If this is indeed how it works, I would be tempted to label this a bug in the auto-following behavior, as it's probably not what most people would expect. In that case, yes, you should be able to get your desired behavior by first purging all unreachable objects. Something like "git gc --prune=now" should do the job.

Hope this helps,

...Johan

-- 
Johan Herland, <johan@herland.net>
www.herland.net