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From: Jeff King <peff@peff.net>
To: Junio C Hamano <gitster@pobox.com>
Cc: Denton Liu <liu.denton@gmail.com>,
	Git Mailing List <git@vger.kernel.org>,
	Eric Sunshine <sunshine@sunshineco.com>
Subject: Re: [PATCH v2 0/7] remote-curl: fix deadlocks when remote server disconnects
Date: Mon, 18 May 2020 22:38:19 -0400	[thread overview]
Message-ID: <20200519023819.GA70483@coredump.intra.peff.net> (raw)
In-Reply-To: <xmqqh7wc26v9.fsf@gitster.c.googlers.com>

On Mon, May 18, 2020 at 03:52:42PM -0700, Junio C Hamano wrote:

> Jeff King <peff@peff.net> writes:
> 
> > So I think our options are probably:
> >
> >   1. detect flush packets in remote-curl, and either:
> >
> >      a. don't print an error, just hang up. That prevents a hang in the
> > 	caller and produces no extra message on a real error. It may be
> > 	less informative than it could be if the connection hangs up
> > 	(though we may print a curl error message, and the caller will
> > 	at least say "the helper hung up")
> >
> >      b. like (a), but always print an error; this is your original
> > 	patch, but I _suspect_ (but didn't test) that it would produce
> > 	extra useless messages for errors the server reports
> >
> >      c. between the two: inspect the final packet data for evidence of
> >         ERR/sideband 3 and suppress any message if found
> >
> >   2. helper signals end-of-response to caller (then it never produces a
> >      message itself; only the caller does, and it would abort on an ERR
> >      packet before then)
> >
> >      a. using a special pktline (your "0002" patch)
> >
> >      b. some other out-of-band mechanism (e.g., could be another fd)
> >
> > I think this is pushing me towards 2a, your "0002" patch. It sidesteps
> > the error-message questions entirely (and I think 2b is too convoluted
> > to be worth pursuing, especially on Windows where setting up extra pipes
> > is tricky). But I'd also be OK with 1a or 1c.
> 
> Thanks for a detailed analysis.  I guess we'd take 0002, then?

Yeah, that's how I lean. I think I did have a few comments on the patch
that I'd like Denton to consider, so hopefully we'll see a re-roll.

-Peff

  reply	other threads:[~2020-05-19  2:38 UTC|newest]

Thread overview: 62+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-13 18:04 [PATCH 0/6] remote-curl: partial fix for a deadlock with stateless rpc Denton Liu
2020-05-13 18:04 ` [PATCH 1/6] remote-curl: fix typo Denton Liu
2020-05-13 18:04 ` [PATCH 2/6] remote-curl: remove label indentation Denton Liu
2020-05-13 18:04 ` [PATCH 3/6] transport: combine common cases with a fallthrough Denton Liu
2020-05-13 23:14   ` Eric Sunshine
2020-05-18  9:18     ` Denton Liu
2020-05-18 17:43       ` Eric Sunshine
2020-05-13 18:04 ` [PATCH 4/6] pkt-line: extern packet_length() Denton Liu
2020-05-13 23:23   ` Eric Sunshine
2020-05-15 20:56   ` Jeff King
2020-05-15 20:57     ` Jeff King
2020-05-13 18:04 ` [PATCH 5/6] remote-curl: error on incomplete packet Denton Liu
2020-05-15 21:38   ` Jeff King
2020-05-18  9:08     ` Denton Liu
2020-05-18 15:49       ` Jeff King
2020-05-13 18:04 ` [PATCH 6/6] remote-curl: ensure last packet is a flush Denton Liu
2020-05-15 21:02   ` Denton Liu
2020-05-15 21:41     ` Jeff King
2020-05-18 16:34       ` Junio C Hamano
2020-05-18 16:52         ` Jeff King
2020-05-18 21:00           ` Jeff King
2020-05-18 15:47 ` [PATCH v2 0/7] remote-curl: fix deadlocks when remote server disconnects Denton Liu
2020-05-18 15:47   ` [PATCH v2 1/7] remote-curl: fix typo Denton Liu
2020-05-18 15:47   ` [PATCH v2 2/7] remote-curl: remove label indentation Denton Liu
2020-05-18 18:37     ` Junio C Hamano
2020-05-18 15:47   ` [PATCH v2 3/7] transport: extract common fetch_pack() call Denton Liu
2020-05-18 18:40     ` Junio C Hamano
2020-05-18 15:47   ` [PATCH v2 4/7] pkt-line: extern packet_length() Denton Liu
2020-05-18 16:04     ` Jeff King
2020-05-18 17:50       ` Eric Sunshine
2020-05-18 20:08         ` Jeff King
2020-05-18 18:44       ` Junio C Hamano
2020-05-18 15:47   ` [PATCH v2 5/7] remote-curl: error on incomplete packet Denton Liu
2020-05-18 16:22     ` Jeff King
2020-05-18 16:51       ` Denton Liu
2020-05-18 15:47   ` [PATCH v2 6/7] pkt-line: PACKET_READ_RESPONSE_END Denton Liu
2020-05-18 15:47   ` [PATCH v2 7/7] stateless-connect: send response end packet Denton Liu
2020-05-18 16:43     ` Jeff King
2020-05-18 17:12       ` Denton Liu
2020-05-18 17:26         ` Jeff King
2020-05-18 16:50   ` [PATCH v2 0/7] remote-curl: fix deadlocks when remote server disconnects Jeff King
2020-05-18 17:36     ` Denton Liu
2020-05-18 20:58       ` Jeff King
2020-05-18 22:52         ` Junio C Hamano
2020-05-19  2:38           ` Jeff King [this message]
2020-05-18 19:36     ` Junio C Hamano
2020-05-19 10:53   ` [PATCH v3 " Denton Liu
2020-05-19 10:53     ` [PATCH v3 1/7] remote-curl: fix typo Denton Liu
2020-05-19 10:53     ` [PATCH v3 2/7] remote-curl: remove label indentation Denton Liu
2020-05-19 10:53     ` [PATCH v3 3/7] transport: extract common fetch_pack() call Denton Liu
2020-05-19 10:53     ` [PATCH v3 4/7] pkt-line: extern packet_length() Denton Liu
2020-05-19 16:23       ` Eric Sunshine
2020-05-19 10:53     ` [PATCH v3 5/7] remote-curl: error on incomplete packet Denton Liu
2020-05-19 10:53     ` [PATCH v3 6/7] pkt-line: define PACKET_READ_RESPONSE_END Denton Liu
2020-05-19 10:54     ` [PATCH v3 7/7] stateless-connect: send response end packet Denton Liu
2020-05-19 18:40     ` [PATCH v3 0/7] remote-curl: fix deadlocks when remote server disconnects Jeff King
2020-05-19 21:14       ` Denton Liu
2020-05-19 20:51     ` [PATCH v3 8/7] fixup! pkt-line: extern packet_length() Denton Liu
2020-05-22 13:33     ` [PATCH v3 9/9] fixup! remote-curl: error on incomplete packet Denton Liu
2020-05-22 15:54       ` Jeff King
2020-05-22 16:05         ` Denton Liu
2020-05-22 16:31           ` Jeff King

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