From: Junio C Hamano <gitster@pobox.com>
To: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Cc: Jeff King <peff@peff.net>,
Johannes Schindelin via GitGitGadget <gitgitgadget@gmail.com>,
git@vger.kernel.org
Subject: Re: [PATCH 2/2] repack -ad: prune the list of shallow commits
Date: Fri, 20 Jul 2018 02:30:23 -0700 [thread overview]
Message-ID: <xmqqeffycl00.fsf@gitster-ct.c.googlers.com> (raw)
In-Reply-To: <xmqq7elrdk8x.fsf@gitster-ct.c.googlers.com> (Junio C. Hamano's message of "Thu, 19 Jul 2018 13:49:02 -0700")
Junio C Hamano <gitster@pobox.com> writes:
> Sorry, but I do not think I can relay that as an explanation why it
> won't cause problems to a third person.
OK, ignore this. I was being stupid.
> The entries in shallow file says that history behind them may not
> exist in the repository due to its shallowness but history after
> them are supposed to be traversable (otherwise we have a repository
> corruption). It is true that an entry that itself no longer exists
> in this repository should not be in shallow file, as the presence of
> that entry breaks that promise the file is making---that commit
> ought to exist and it is safe to traverse down to it, so keeping the
> entry in the file is absolutely a wrong thing to do.
>
> But that does not automatically mean that just simply removing it
> makes the resulting repository good, does it? Wouldn't the solution
> for that corruption be to set a new entry to stop history traversal
> before reaching that (now-missing) commit?
The above is overly pessimistic and worried about an impossible
situation, I would think. The reason why a commit that used to be
in the shallow file is being pruned during a "repack" is because it
has become unreachable. By definition, no future history traversal
that wants to enumerate reachable commits needs to be stopped from
finding that commits that are older than this commit being pruned
are missing by having this in the shallow list. If there is a ref
or a reflog entry from which such a problematic traversal starts at,
we wouldn't be pruing this commit in the first place, because the
commit has not become unreachable yet.
So a repository does not become corrupt by pruning the commit *and*
removing it from the shallow file at the same time.
next prev parent reply other threads:[~2018-07-20 9:30 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-13 20:18 [PATCH 0/2] repack -ad: fix after `fetch --prune` in a shallow repository Johannes Schindelin via GitGitGadget
2018-07-11 22:17 ` [PATCH 1/2] repack: point out a bug handling stale shallow info Johannes Schindelin via GitGitGadget
2018-07-11 22:23 ` [PATCH 2/2] repack -ad: prune the list of shallow commits Johannes Schindelin via GitGitGadget
2018-07-13 20:31 ` Jeff King
2018-07-14 21:56 ` Johannes Schindelin
2018-07-16 17:36 ` Jeff King
2018-07-17 16:25 ` Junio C Hamano
2018-07-19 16:42 ` Johannes Schindelin
2018-07-19 20:49 ` Junio C Hamano
2018-07-20 9:30 ` Junio C Hamano [this message]
2018-07-20 19:31 ` Jeff King
2018-07-17 17:28 ` Duy Nguyen
2018-07-17 19:41 ` Jeff King
2018-07-18 17:31 ` Duy Nguyen
2018-07-18 17:45 ` Jeff King
2018-07-18 17:48 ` Duy Nguyen
2018-07-17 16:39 ` Duy Nguyen
2018-07-17 16:48 ` Duy Nguyen
2018-07-19 17:50 ` Johannes Schindelin
2018-07-17 13:51 ` [PATCH v2 0/2] repack -ad: fix after `fetch --prune` in a shallow repository Johannes Schindelin via GitGitGadget
2018-07-17 13:51 ` [PATCH v2 1/2] repack: point out a bug handling stale shallow info Johannes Schindelin via GitGitGadget
2018-07-17 13:51 ` [PATCH v2 2/2] repack -ad: prune the list of shallow commits Johannes Schindelin via GitGitGadget
2018-07-17 17:45 ` Eric Sunshine
2018-07-17 19:15 ` [PATCH v2 0/2] repack -ad: fix after `fetch --prune` in a shallow repository Jeff King
2018-07-17 19:20 ` Jeff King
2018-07-19 17:48 ` Johannes Schindelin
2018-10-22 22:05 ` [PATCH v3 0/3] repack -ad: fix after fetch --prune " Johannes Schindelin via GitGitGadget
2018-10-22 22:05 ` [PATCH v3 1/3] repack: point out a bug handling stale shallow info Johannes Schindelin via GitGitGadget
2018-10-24 3:39 ` Junio C Hamano
2018-10-24 8:12 ` Johannes Schindelin
2018-10-24 8:38 ` Johannes Schindelin
2018-10-22 22:05 ` [PATCH v3 2/3] shallow: offer to prune only non-existing entries Johannes Schindelin via GitGitGadget
2018-10-24 3:47 ` Junio C Hamano
2018-10-24 8:01 ` Johannes Schindelin
2018-10-24 15:56 ` Johannes Schindelin
2018-10-25 18:54 ` Jonathan Tan
2018-10-26 7:59 ` Johannes Schindelin
2018-10-26 20:49 ` Jonathan Tan
2018-10-29 20:45 ` Johannes Schindelin
2018-10-22 22:05 ` [PATCH v3 3/3] repack -ad: prune the list of shallow commits Johannes Schindelin via GitGitGadget
2018-10-24 3:56 ` Junio C Hamano
2018-10-24 8:02 ` Johannes Schindelin
2018-10-23 10:15 ` [PATCH v3 0/3] repack -ad: fix after fetch --prune in a shallow repository Johannes Schindelin
2018-10-24 15:56 ` [PATCH v4 " Johannes Schindelin via GitGitGadget
2018-10-24 15:56 ` [PATCH v4 1/3] repack: point out a bug handling stale shallow info Johannes Schindelin via GitGitGadget
2018-10-24 15:56 ` [PATCH v4 2/3] shallow: offer to prune only non-existing entries Johannes Schindelin via GitGitGadget
2018-10-24 15:56 ` [PATCH v4 3/3] repack -ad: prune the list of shallow commits Johannes Schindelin via GitGitGadget
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=xmqqeffycl00.fsf@gitster-ct.c.googlers.com \
--to=gitster@pobox.com \
--cc=Johannes.Schindelin@gmx.de \
--cc=git@vger.kernel.org \
--cc=gitgitgadget@gmail.com \
--cc=peff@peff.net \
/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).