From: Jeff King <peff@peff.net>
To: Junio C Hamano <gitster@pobox.com>
Cc: Jonathan Nieder <jrnieder@gmail.com>,
git@vger.kernel.org,
Konstantin Ryabitsev <konstantin@linuxfoundation.org>,
Taylor Blau <me@ttaylorr.com>
Subject: Re: [PATCH/RFC] config: default to protocol v2
Date: Thu, 9 Jul 2020 19:00:38 -0400 [thread overview]
Message-ID: <20200709230038.GB664420@coredump.intra.peff.net> (raw)
In-Reply-To: <xmqq7dve2etl.fsf@gitster.c.googlers.com>
On Wed, Jul 08, 2020 at 08:42:46AM -0700, Junio C Hamano wrote:
> I am afraid that "there probably aren't other" may be overly
> optimistic, as the bug in 2.26 crippled the negotiation logic and
> forced it to punt, which was so severe that it would have hidden any
> other bugs in the negotiation logic. If there is another bug in v2
> negotiation logic that makes the sender to omit objects that should
> be sent, it would not have been observed in 2.26 because the effect
> of the more severe bug was to cripple the negotiation logic itself
> and to make it punt, sending more objects all the way down the
> history. Now, with that larger bug fixed post 2.26, we can start to
> see if there are other bugs hidden by it.
I half-agree with this. The negotiation logic wasn't completely broken,
and usually did the right thing. It was only the max_in_vain counting
that was wrong. So definitely there could be another bug lurking that
was hidden by that failure, and/or our fix could be incomplete. But I
think we can have some confidence that there aren't other show-stopping
bugs (in the negotiation code or elsewhere in v2) that showed up in
other situations (and the real-world success reports we already got for
that particular bug are also encouraging).
So I'm not especially worried about having a repeat of the v2.26
situation (but I agree it's not impossible).
> In any case, we've learned in 2.26 that it is unlikely that such
> bugs would be uncovered until v2 is made the default again in a
> released version to be used by more users.
>
> So, let's flip the default in -rc0; we can revert if we see
> something funny in 2.28.1 in the worst case.
And obviously I'm fine with this, given that my assessment of the risk
is even less than yours. :)
-Peff
prev parent reply other threads:[~2020-07-09 23:00 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-07 5:38 [PATCH/RFC] config: default to protocol v2 Jonathan Nieder
2020-07-08 4:50 ` Jeff King
2020-07-08 15:42 ` Junio C Hamano
2020-07-09 23:00 ` Jeff King [this message]
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