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

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

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