From: Petr Baudis <pasky@suse.cz>
Date: Sat, 07 Oct 2006 12:58:02 GMT
Subject: Re: [PATCH] gitweb: prepare for repositories with packed refs.
Message-ID: <20061007125802.GA20017@pasky.or.cz>
In-Reply-To: <7vzmc8tqqe.fsf@assigned-by-dhcp.cox.net>

Dear diary, on Sat, Oct 07, 2006 at 11:33:29AM CEST, I got a letter
where Junio C Hamano <junkio@cox.net> said that...
> When we introduced symref, "cat .git/HEAD" stopped being the way
> to read the value of the tip of the current branch, "echo
> $commit >.git/HEAD" stopped being the way to update it, and
> "rev-parse --verify HEAD" and "update-ref HEAD $commit" were
> introduced at the same time as the official alternatives to
> support both old and new implementations of .git/HEAD.
> 
> The way to find out which branch we are currently on used to be
> "readlink .git/HEAD"; that stopped to be true, and we introduced
> "symbolic-ref HEAD" as the official alternative to support both
> old and new implementation.
> 
> The way to see if a random symbolic link whose name happens to
> be HEAD is a symref has been to see if it points at a path that
> begins with "refs/".

Cogito does

	[ ! -s "$_git/HEAD" ] || { _git_head="$(git-symbolic-ref HEAD)"; _git_head="${_git_head#refs/heads/}"; }

in the common initialization code, so that cg-reset works even on
repositories with broken HEAD. It hasn't been an issue in the past since
HEAD as a dangling symlink indeed _has_ been broken HEAD in the past.

That said, at least cg-reset will indeed repair it:

	if ! [ -s "$_git/HEAD" ]; then
		rm -f "$_git/HEAD"
		# XXX: git-symbolic-ref is a weenie and won't do the job at this point.
		echo "ref: refs/heads/$_git_head" >"$_git/HEAD"
	fi

But it's still not nice.

-- 
				Petr "Pasky" Baudis
Stuff: http://pasky.or.cz/
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lK[d2%Sa2/d0$^Ixp"|dc`;s/\W//g;$_=pack('H*',/((..)*)$/)