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From: Junio C Hamano <gitster@pobox•com>
To: Johannes Sixt <j6t@kdbg•org>
Cc: Augie Fackler <augie@google•com>,
	git@vger•kernel.org, Stefan Beller <sbeller@google•com>
Subject: Re: [PATCH v2] fetch-pack: optionally save packs to disk
Date: Fri, 12 Jun 2015 08:07:36 -0700	[thread overview]
Message-ID: <xmqqmw05dkxz.fsf@gitster.dls.corp.google.com> (raw)
In-Reply-To: <557A7ABA.2000404@kdbg.org> (Johannes Sixt's message of "Fri, 12 Jun 2015 08:22:50 +0200")

Johannes Sixt <j6t@kdbg•org> writes:

> What is the problem with the current fetch-pack implementation? Does
> it remove a bogus packfile after download? Does it abort during
> download when it detects a broken packfile? Does --keep not do what
> you need?

Doesn't the incoming data still go through the fattening process,
though?  You will not be able to inspect the byte-for-byte identical
stream that came out of the server end whose packfile generation
logic is suspect.

For the purpose of debugging your own new server implementation, it
might be a better approach to capture the pack as it comes out at
the server end, instead of doing it at the fetch-pack end as it
comes in. But the approach to add this "dump" at the fetch-pack side
is that it gives us a tool to diagnose problems that come from
broken server (re)implementations by other people we cannot debug,
i.e. "you are spewing this corrupt pack against this request; here
is a dump we took to help you go fix your server".

> Instead of your approach (which forks off tee to dump a copy of the
> packfile), would it not be simpler to add an option --debug-pack
> (probably not the best name) that skips the cleanup step when a broken
> packfile is detected and prints the name of the downloaded packfile?

As long as we need to debug a thin pack that comes from the other
end, that approach is not sufficient, I am afraid.

I anticipated that you'd have problem with its use of "tee".  It
probably can do this internally with async interface, perhaps,
instead?

  reply	other threads:[~2015-06-12 15:07 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CAGZ79kaS4utvDbXOo7emmSUH6M-8LY-oA65Ss3PLDkFModkbSg@mail.gmail.com>
2015-06-11 18:59 ` [PATCH v2] fetch-pack: optionally save packs to disk Augie Fackler
2015-06-12  6:22   ` Johannes Sixt
2015-06-12 15:07     ` Junio C Hamano [this message]
2015-06-12 17:02       ` Augie Fackler
2015-06-12 18:00       ` Jeff King
2015-06-12 21:25         ` Jeff King
2015-06-12 21:28           ` [PATCH 1/3] pkt-line: simplify starts_with checks in packet tracing Jeff King
2015-06-12 21:35             ` Stefan Beller
2015-06-12 21:28           ` [PATCH 2/3] pkt-line: tighten sideband PACK check when tracing Jeff King
2015-06-12 21:39             ` Stefan Beller
2015-06-12 21:41               ` Jeff King
2015-06-12 21:43                 ` Stefan Beller
2015-06-12 21:28           ` [PATCH 3/3] pkt-line: support tracing verbatim pack contents Jeff King
2015-06-16 15:38             ` Augie Fackler
2015-06-16 16:39               ` Junio C Hamano
2015-06-16 16:43                 ` Jeff King
2015-06-16 16:52                   ` Augie Fackler
2015-06-16 17:23                     ` Jeff King
2015-06-16 17:10               ` Jeff King
2015-06-16 17:14                 ` Augie Fackler
2015-06-16 17:18                   ` Jeff King
2015-06-16 17:23                     ` Augie Fackler
2015-06-16 19:31                       ` [PATCH/RFC 0/3] add GIT_TRACE_STDIN Jeff King
2015-06-16 19:35                         ` [PATCH 1/3] trace: implement %p placeholder for filenames Jeff King
2015-06-16 19:36                         ` [PATCH 2/3] trace: add pid to each output line Jeff King
2015-06-16 19:37                         ` [PATCH 3/3] trace: add GIT_TRACE_STDIN Jeff King
2015-06-16 19:49                           ` Jeff King
2015-06-16 21:20                             ` Jeff King
2015-06-17 10:04                               ` Duy Nguyen
2015-06-17 19:10                                 ` Jeff King
2015-06-18 10:20                                   ` Duy Nguyen
2015-06-26 18:47                                   ` Junio C Hamano
2015-06-12 16:54     ` [PATCH v2] fetch-pack: optionally save packs to disk Augie Fackler

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