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From: Jonathan Nieder <jrnieder@gmail.com>
To: Taylor Blau <me@ttaylorr.com>
Cc: git@vger.kernel.org, jonathantanmy@google.com, gitster@pobox.com,
	newren@gmail.com, Jay Conrod <jayconrod@google.com>,
	Derrick Stolee <stolee@gmail.com>
Subject: Re: [PATCH v2 2/2] shallow.c: use '{commit,rollback}_shallow_file'
Date: Tue, 2 Jun 2020 20:42:13 -0700	[thread overview]
Message-ID: <20200603034213.GB253041@google.com> (raw)
In-Reply-To: <296e70790d7a391d471554b0bc5a58e2a091ce88.1587601501.git.me@ttaylorr.com>

Hi,

Taylor Blau wrote:

> Signed-off-by: Taylor Blau <me@ttaylorr.com>
> ---
>  builtin/receive-pack.c   |  4 ++--
>  commit.h                 |  2 ++
>  fetch-pack.c             | 10 +++++-----
>  shallow.c                | 30 +++++++++++++++++++++---------
>  t/t5537-fetch-shallow.sh | 29 +++++++++++++++++++++++++++++
>  5 files changed, 59 insertions(+), 16 deletions(-)

I haven't investigated the cause yet, but I've run into an interesting
bug that bisects to this commit.  Jay Conrod (cc-ed) reports:

| I believe this is also the cause of Go toolchain test failures we've
| been seeing. Go uses git to fetch dependencies.
|
| The problem we're seeing can be reproduced with the script below. It
| should print "success". Instead, the git merge-base command fails
| because the commit 7303f77963648d5f1ec5e55eccfad8e14035866c
| (origin/master) has no history.

-- 8< --
#!/bin/bash

set -euxo pipefail
if [ -d legacytest ]; then
  echo "legacytest directory already exists" >&2
  exit 1
fi
mkdir legacytest
cd legacytest
git init --bare
git config protocol.version 2
git config fetch.writeCommitGraph true
git remote add origin -- https://github.com/rsc/legacytest
git fetch -f --depth=1 origin refs/heads/master:refs/heads/master
git fetch -f origin 'refs/heads/*:refs/heads/*' 'refs/tags/*:refs/tags/*'
git fetch --unshallow -f origin
git merge-base --is-ancestor -- v2.0.0 7303f77963648d5f1ec5e55eccfad8e14035866c
echo success
-- >8 --

The fetch.writeCommitGraph part is interesting.  When does a commit
graph file get written in this sequence of operations?  In an
unshallow operation, does the usual guard against writing a commit
graph in a shallow repo get missed?

"rm -fr objects/info/commit-graphs" recovers the full history in the
repo, so this is not a case of writing the wrong shallows --- it's
only a commit graph issue.

I'll take a closer look, but thought I'd give others a chance to look
to in case there's something obvious. :)

Thanks,
Jonathan

  parent reply	other threads:[~2020-06-03  3:42 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-21 18:09 [PATCH] shallow.c: use 'reset_repository_shallow' when appropriate Taylor Blau
2020-04-21 20:41 ` Junio C Hamano
2020-04-21 20:45   ` Taylor Blau
2020-04-21 20:52     ` Junio C Hamano
2020-04-21 22:21       ` Taylor Blau
2020-04-21 23:06         ` Junio C Hamano
2020-04-22 18:05       ` Jonathan Tan
2020-04-22 18:02 ` Jonathan Tan
2020-04-22 18:15   ` Junio C Hamano
2020-04-23  0:14     ` Taylor Blau
2020-04-23  0:25       ` [PATCH v2 0/2] shallow.c: reset shallow-ness after updating Taylor Blau
2020-04-23  0:25         ` [PATCH v2 1/2] t5537: use test_write_lines, indented heredocs for readability Taylor Blau
2020-04-23  1:14           ` Jonathan Nieder
2020-04-24 17:11             ` Taylor Blau
2020-04-24 17:17               ` Jonathan Nieder
2020-04-24 20:45               ` Junio C Hamano
2020-04-23  0:25         ` [PATCH v2 2/2] shallow.c: use '{commit,rollback}_shallow_file' Taylor Blau
2020-04-23  1:23           ` Jonathan Nieder
2020-04-23 18:09           ` Jonathan Tan
2020-04-23 20:40             ` Junio C Hamano
2020-04-24 17:13               ` Taylor Blau
2020-06-03  3:42           ` Jonathan Nieder [this message]
2020-06-03  4:52             ` Taylor Blau
2020-06-03  5:16               ` Taylor Blau
2020-06-03 13:08                 ` Derrick Stolee
2020-06-03 19:26                   ` Taylor Blau
2020-06-03 21:23                   ` Jonathan Nieder
2020-06-03 20:51                 ` Jonathan Nieder
2020-06-03 22:14                   ` Taylor Blau
2020-06-03 23:06                     ` Jonathan Nieder
2020-06-04 17:45                       ` Taylor Blau
2020-04-23 19:05       ` [PATCH] shallow.c: use 'reset_repository_shallow' when appropriate Junio C Hamano

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