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From: Jeff King <peff@peff.net>
To: Derrick Stolee <stolee@gmail.com>
Cc: Junio C Hamano <gitster@pobox.com>, Taylor Blau <me@ttaylorr.com>,
	git@vger.kernel.org, dstolee@microsoft.com
Subject: Re: [PATCH] builtin/repack.c: invalidate MIDX only when necessary
Date: Tue, 25 Aug 2020 13:34:46 -0400	[thread overview]
Message-ID: <20200825173446.GE1414394@coredump.intra.peff.net> (raw)
In-Reply-To: <c78b3108-b760-d252-9428-6f03549fea11@gmail.com>

On Tue, Aug 25, 2020 at 12:18:42PM -0400, Derrick Stolee wrote:

> The best I can see is that prepare_midx_pack() will return 1 if the
> pack no longer exists, and this would cause a die("error preparing
> packfile from multi-pack-index") in nth_midxed_pack_entry(), killing
> the following stack trace:
> 
> + find_pack_entry():packfile.c
>  + fill_midx_entry():midx.c
>   + nth_midxed_pack_entry():midx.c
> 
> Perhaps that die() is a bit over-zealous since we could return 1
> through this stack and find_pack_entry() could continue searching
> for the object in the packed_git list. However, it could start
> returning false _negatives_ if there were duplicates of the object
> in the multi-pack-index but only the latest copy was deleted (and
> the object does not appear in a pack-file outside of the multi-
> pack-index).

Hmm, yeah.

I thought this code is already doing the right thing, because I'd expect
the is_pack_valid() call later in nth_midxed_pack_entry() to be where we
notice the problem. But add_packed_git() does stat the packfile and
return an error.

So that die() really ought to be just "return 0". The caller already has
to (and does) handle similar errors (including that the pack went away
after we added it to the packed_git list, or that it exists but has
bogus data, etc).

-Peff

  reply	other threads:[~2020-08-25 17:34 UTC|newest]

Thread overview: 78+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-25  2:01 [PATCH] builtin/repack.c: invalidate MIDX only when necessary Taylor Blau
2020-08-25  2:26 ` Jeff King
2020-08-25  2:37   ` Taylor Blau
2020-08-25 13:14     ` Derrick Stolee
2020-08-25 14:41       ` Taylor Blau
2020-08-25 15:14         ` Derrick Stolee
2020-08-25 15:42           ` Taylor Blau
2020-08-25 16:56             ` Jeff King
2020-08-25 15:58   ` Junio C Hamano
2020-08-25 16:08     ` Taylor Blau
2020-08-25 16:18     ` Derrick Stolee
2020-08-25 17:34       ` Jeff King [this message]
2020-08-25 17:22     ` Jeff King
2020-08-25 18:05       ` Junio C Hamano
2020-08-25 18:27         ` Jeff King
2020-08-25 22:45           ` [PATCH] pack-redundant: gauge the usage before proposing its removal Junio C Hamano
2020-08-25 23:09             ` Taylor Blau
2020-08-25 23:22               ` Junio C Hamano
2020-08-26  1:17             ` [PATCH v1 0/3] War on dashed-git Junio C Hamano
2020-08-26  1:17               ` [PATCH v1 1/3] transport-helper: do not run git-remote-ext etc. in dashed form Junio C Hamano
2020-08-26  1:24                 ` Eric Sunshine
2020-08-26  7:55                   ` Johannes Schindelin
2020-08-26 16:27                   ` Junio C Hamano
2020-08-26  1:17               ` [PATCH v1 2/3] cvsexportcommit: do not run git programs " Junio C Hamano
2020-08-26  1:28                 ` Eric Sunshine
2020-08-26  1:42                   ` Junio C Hamano
2020-08-26 16:08                   ` Junio C Hamano
2020-08-26 16:28                     ` Junio C Hamano
2020-08-26  8:02                 ` Johannes Schindelin
2020-08-26  1:17               ` [PATCH v1 3/3] git: catch an attempt to run "git-foo" Junio C Hamano
2020-08-26  1:19                 ` Junio C Hamano
2020-08-26  8:06                 ` Johannes Schindelin
2020-08-26 16:30                   ` Junio C Hamano
2020-08-28  2:13                 ` Johannes Schindelin
2020-08-28 22:03                   ` Junio C Hamano
2020-08-31  9:59                     ` Johannes Schindelin
2020-08-31 17:45                       ` Junio C Hamano
2020-12-20 15:25                   ` Johannes Schindelin
2020-12-21 22:24                     ` Junio C Hamano
2020-12-30  5:30                       ` Johannes Schindelin
2020-08-26  8:09               ` [PATCH v1 0/3] War on dashed-git Johannes Schindelin
2020-08-26 16:45                 ` Junio C Hamano
2020-08-26 19:46                   ` [PATCH v2 0/2] avoid running "git-subcmd" in the dashed form Junio C Hamano
2020-08-26 19:46                     ` [PATCH v2 1/2] transport-helper: do not run git-remote-ext etc. in " Junio C Hamano
2020-08-26 19:46                     ` [PATCH v2 2/2] cvsexportcommit: do not run git programs " Junio C Hamano
2020-08-26 21:37                       ` [PATCH v2 3/2] credential-cache: use child_process.args Junio C Hamano
2020-08-26 22:25                         ` [PATCH] run_command: teach API users to use embedded 'args' more Junio C Hamano
2020-08-27  4:21                           ` Jeff King
2020-08-27  4:30                             ` Junio C Hamano
2020-08-27  4:31                             ` Eric Sunshine
2020-08-27  4:44                               ` Jeff King
2020-08-27  5:03                                 ` Eric Sunshine
2020-08-27  5:25                                   ` [PATCH] worktree: fix leak in check_clean_worktree() Jeff King
2020-08-27  5:56                                     ` Eric Sunshine
2020-08-27 15:31                                       ` Junio C Hamano
2020-08-27  4:13                         ` [PATCH v2 3/2] credential-cache: use child_process.args Jeff King
2020-08-27  4:22                           ` Jeff King
2020-08-27  4:31                           ` Junio C Hamano
2020-08-27  4:14                         ` Jeff King
2020-08-27 15:34                           ` Junio C Hamano
2020-08-31 22:56                         ` Junio C Hamano
2020-09-01  4:49                           ` Jeff King
2020-09-01 16:11                             ` Junio C Hamano
2020-08-27  0:57                     ` [PATCH v2 0/2] avoid running "git-subcmd" in the dashed form Derrick Stolee
2020-08-27  1:22                       ` Junio C Hamano
2020-08-28  9:14             ` [PATCH] pack-redundant: gauge the usage before proposing its removal Jeff King
2020-08-28 22:45               ` Junio C Hamano
2020-08-25  7:55 ` [PATCH] builtin/repack.c: invalidate MIDX only when necessary Son Luong Ngoc
2020-08-25 12:45   ` Derrick Stolee
2020-08-25 14:45   ` Taylor Blau
2020-08-25 16:04     ` [PATCH v2] " Taylor Blau
2020-08-26 20:51       ` Derrick Stolee
2020-08-26 20:54         ` Junio C Hamano
2020-08-25 16:47     ` [PATCH] " Jeff King
2020-08-25 17:10       ` Derrick Stolee
2020-08-25 17:29         ` Jeff King
2020-08-25 17:34           ` Taylor Blau
2020-08-25 17:42             ` Jeff King

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