git@vger.kernel.org list mirror (unofficial, one of many)
 help / color / mirror / code / Atom feed
From: "SZEDER Gábor" <szeder.dev@gmail.com>
To: Jeff King <peff@peff.net>
Cc: Derrick Stolee <stolee@gmail.com>,
	Derrick Stolee via GitGitGadget <gitgitgadget@gmail.com>,
	git@vger.kernel.org, Junio C Hamano <gitster@pobox.com>,
	Derrick Stolee <dstolee@microsoft.com>
Subject: Re: [PATCH 1/1] upload-pack: fix race condition in error messages
Date: Fri, 30 Aug 2019 00:06:30 +0200	[thread overview]
Message-ID: <20190829220630.GH8571@szeder.dev> (raw)
In-Reply-To: <20190829215818.GG8571@szeder.dev>

On Thu, Aug 29, 2019 at 11:58:18PM +0200, SZEDER Gábor wrote:
> On Thu, Aug 29, 2019 at 10:38:05AM -0400, Jeff King wrote:
> > So any fixes there have to happen on the client side. I am still
> > confused about why the client is writing in this case, per the argument
> > in 014ade7484 (upload-pack: send ERR packet for non-tip objects,
> > 2019-04-13). It would be nice to use GIT_TRACE_PACKET to see what it's
> > trying to write, but I still haven't been able to reproduce the issue.
> 
> It's the "done" line:
> 
>   + cat trace-packet
>   packet:  upload-pack> 5e26403b4485d7a44fd8b65dc3f71e21c0dd6fad HEAD\0multi_ack thin-pack side-band side-band-64k ofs-delta shallow deepen-since deepen-not deepen-relative no-progress include-tag multi_ack_detailed allow-tip-sha1-in-want allow-reachable-sha1-in-want symref=HEAD:refs/heads/master agent=git/2.23.0.40.g4d780d4382.dirty
>   packet:  upload-pack> 5e26403b4485d7a44fd8b65dc3f71e21c0dd6fad refs/heads/master
>   packet:  upload-pack> 0000
>   packet:        fetch< 5e26403b4485d7a44fd8b65dc3f71e21c0dd6fad HEAD\0multi_ack thin-pack side-band side-band-64k ofs-delta shallow deepen-since deepen-not deepen-relative no-progress include-tag multi_ack_detailed allow-tip-sha1-in-want allow-reachable-sha1-in-want symref=HEAD:refs/heads/master agent=git/2.23.0.40.g4d780d4382.dirty
>   packet:        fetch< 5e26403b4485d7a44fd8b65dc3f71e21c0dd6fad refs/heads/master
>   packet:        fetch< 0000
>   packet:        fetch> want 64ea4c133d59fa98e86a771eda009872d6ab2886 multi_ack_detailed side-band-64k thin-pack no-progress ofs-delta deepen-since deepen-not agent=git/2.23.0.40.g4d780d4382.dirty
>   packet:        fetch> 0000
>   packet:  upload-pack< want 64ea4c133d59fa98e86a771eda009872d6ab2886 multi_ack_detailed side-band-64k thin-pack no-progress ofs-delta deepen-since deepen-not agent=git/2.23.0.40.g4d780d4382.dirty
>   packet:  upload-pack< 0000
>   packet:  upload-pack> ERR upload-pack: not our ref 64ea4c133d59fa98e86a771eda009872d6ab2886
>   packet:  upload-pack> 0000
>   packet:        fetch> done
> 
> In the avarage successful run that "fetch> done" pkt-line is
> immediately after the "fetch> 0000".
> 
> The above is on my Linux box; here is a failure on macOS, essentially
> the same:
> 
>   https://travis-ci.org/szeder/git/jobs/578555606#L3453
> 

Try this patch to reliably reproduce this failure:

diff --git a/fetch-pack.c b/fetch-pack.c
index 65be043f2a..e18864458b 100644
--- a/fetch-pack.c
+++ b/fetch-pack.c
@@ -471,6 +471,7 @@ static int find_common(struct fetch_negotiator *negotiator,
 	}
 done:
 	if (!got_ready || !no_done) {
+		sleep(1);
 		packet_buf_write(&req_buf, "done\n");
 		send_request(args, fd[1], &req_buf);
 	}
diff --git a/t/t5516-fetch-push.sh b/t/t5516-fetch-push.sh
index c81ca360ac..ebecc81c89 100755
--- a/t/t5516-fetch-push.sh
+++ b/t/t5516-fetch-push.sh
@@ -1252,7 +1252,9 @@ do
 			git fetch ../testrepo/.git $SHA1_2 &&
 			git cat-file commit $SHA1_2 &&
 			test_must_fail env GIT_TEST_PROTOCOL_VERSION= \
+				GIT_TRACE_PACKET="$(pwd)/trace-packet" \
 				git fetch ../testrepo/.git $SHA1_3 2>err &&
+			cat trace-packet &&
 			test_i18ngrep "remote error:.*not our ref.*$SHA1_3\$" err
 		)
 	'


  reply	other threads:[~2019-08-29 22:06 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-28  1:43 [PATCH 0/1] upload-pack: fix race condition in t5516 Derrick Stolee via GitGitGadget
2019-08-28  1:43 ` [PATCH 1/1] upload-pack: fix race condition in error messages Derrick Stolee via GitGitGadget
2019-08-28  9:34   ` SZEDER Gábor
2019-08-28 14:54     ` Jeff King
2019-08-28 15:39       ` Jeff King
2019-08-28 16:15         ` SZEDER Gábor
2019-08-29 12:58           ` Derrick Stolee
2019-08-29 14:13             ` Jeff King
2019-08-29 14:27               ` Derrick Stolee
2019-08-29 14:38                 ` Jeff King
2019-08-29 21:58                   ` SZEDER Gábor
2019-08-29 22:06                     ` SZEDER Gábor [this message]
2019-08-30 12:10                       ` SZEDER Gábor
2019-09-04  5:04                         ` Jeff King
2019-09-10 12:08                           ` SZEDER Gábor

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

  List information: http://vger.kernel.org/majordomo-info.html

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20190829220630.GH8571@szeder.dev \
    --to=szeder.dev@gmail.com \
    --cc=dstolee@microsoft.com \
    --cc=git@vger.kernel.org \
    --cc=gitgitgadget@gmail.com \
    --cc=gitster@pobox.com \
    --cc=peff@peff.net \
    --cc=stolee@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
Code repositories for project(s) associated with this public inbox

	https://80x24.org/mirrors/git.git

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).