Re: [PATCH v2 2/3] send-pack: fix push nego. when remote has refs

From: Jeff King <peff@peff.net>
Date: Jul 27, 2021, 16:46 UTC
Message-ID: <YQA4bzFxdOHSQva7@coredump.intra.peff.net>
In-Reply-To: <87v94wqi6k.fsf@evledraar.gmail.com>

On Tue, Jul 27, 2021 at 10:09:35AM +0200, Ævar Arnfjörð Bjarmason wrote:

Show 8 quoted lines

> I.e. now we make the implicit assumption that an OID we see in the
> advertisement is one the server isn't going to aggressively prune while
> our push is underday (Jeff King has a good E-Mail summarizing that
> somewhere, not digging it up now, but I could...).
> 
> So such a remote will negotiate with us using that OID, but unlike with
> advertised OIDs we can't safely assume that the OID won't be racily
> deleted during our negotiation.

I haven't been following the push-negotiation stuff closely, nor do I have a specific email in mind that summarizes this. So take my input with a grain of salt. But...

Wouldn't this also be a problem for multi-round fetch negotiation? An object may become unreachable or even go away entirely during the course of a fetch. I'd expect that to be rare, but when it does happen, for the fetch to end up barfing (the server says "hey, I don't know about that object").

-Peff