Re: git-pull from git.git - no remote ref for pu or next?

On Tue, 12 Dec 2006, Randal L. Schwartz wrote:

It's mirroring.

The way that kernel.org works is that there is one master site, which is not actually running any public services at all. That's the one that people who have write access can ssh into, and rather than run any public services, it runs the security-conscious things, like the secure logins and the automated signing scripts.

The actual _public_ sites are just mirrors, with just rsync between the things. All to keep the services on the master site minimal.

But because the public sites just mirror using rsync, and aren't really aware of git repositories etc at that stage, what can happen is that a mirroring is on-going when Junio does a push, and then the changes to the "refs/" directory might get rsync'ed before the "object/" directory does, and you end up with the public sites having references to objects that don't even _exist_ on those public sites any more.

When they then run git-daemon, git-deamon will basically see a corrupt git archive, and not expose those "broken" refs at all. Which explains what you see.

And once the mirroring completes, the issue just goes away, which explains why it just magically works five minutes later.

If the public sites used git itself to synchronize git repositories, they'd never see anything like this (because git itself will only write the new refs after it has actually updated the data). But since the thing needs mirroring for non-git uses too, and since rsync generally _works_ apart from the slight race-condition issue, that's what it just uses.