Re: Creating remote branch called HEAD corrupts remote clones

From: Junio C Hamano <gitster@pobox.com>
Date: Jan 20, 2011, 21:43 UTC
Message-ID: <7vbp3bqmiy.fsf@alter.siamese.dyndns.org>
In-Reply-To: <20110120203840.GA11468@sigill.intra.peff.net>

Jeff King <peff@peff.net> writes:

Show 5 quoted lines

> Hmm. It seems like the symbolic ref is the culprit, not just HEAD. The
> HEAD thing is the most likely, of course, but I could do something like:
>
>   git symbolic-ref refs/remotes/origin/convenient-alias \
>                    refs/remotes/origin/some-name-you-dont-like

Isn't it already wrong to do the above locally, in the sense that it is equally wrong to do this?

    git update-ref refs/remotes/origin/no-such-thing-exists-over-there 
    	refs/heads/master

I agree that the symbolic ref is the real source of confusion in Stephen's case (I admit that I was scratching my head chasing a non-existent bug in transport_update_tracking_ref() before I realized what was happening), but the usual (and the only) way for refs/remotes hierarchy to get a symbolic ref is via a normal clone, and HEAD is the only name that can cause this conflict. Creating a branch called HEAD (or FETCH_HEAD for that matter) is infinitely more likely to be a mistake than being clever, I think.

Show 7 quoted lines

> ... Maybe we should not follow symbolic
> refs during fetch. So if we are fetching the refspec "foo:bar", and the
> RHS "bar" is a symref, we should _not_ follow it, but instead just
> overwrite the symref with a regular ref.
> 
> For pushing, one rule could be to allow pushing from a named symref, but
> not allow the matching rules to use a symref as a source....

I personally like this line of thought, especially as a thought experiment to see what corner cases we could find, but I doubt I will be able to say we covered all the corner cases with confidence without thinking long and very hard. For now, I do not find this issue worth spending that kind of deep thinking, especially when a lot simpler and easier to explain workaround is available, but others may disagree and perfect your idea.