On Tue, Dec 02, 2014 at 04:04:11PM +1100, Bryan Turner wrote: > > Can you say more about the context? For example, was this actually > > happening, or is this for the sake of understanding the protocol > > better? > > I ask because it's actually happening. Heavy CI load sometimes has > builds fail because git clone dies with "not our ref". That's the > specific context I'm working to try and address right now. Some teams > use rebase-heavy workflows, which also evades the check_non_tip easing > and fails with "not our ref", so I can't be 100% certain it's ref > deletion in specific causing it (but I guess which of those it is is > probably largely academic; as long as hosting spans multiple requests > it seems like this type of race condition is unavoidable). There is a practical reason to care. Ref deletion will also delete the reflog, leaving no trace of the reachability. Whereas a non-fast-forward push could be resolved by looking in the reflog. One problem with hunting for sha1s in the reflog is that upload-pack does not know which ref the client thinks they are requesting. So a search would involve looking in _every_ reflog, which could be expensive. It might not be too painful if you do the search only after hitting a "not our ref" condition, which should in theory be rare. A malicious client could convince you to grep your reflogs repeatedly, but that is hardly the only way to convince upload-pack to chew CPU. Asking it to make a pack comes to mind. :) > I'm trying to decide if there is something I can enable or tune to > prevent it, and the type of twilighting hinted at by the http-protocol > documentation seemed like it could be just the thing. For a public repository, it might make sense to provide a config option to loosen the is_our_ref check completely (i.e., to just has_sha1_file). But such an option does not yet exist. -Peff -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html