From: Jeff King <peff@peff.net>
To: "brian m. carlson" <sandals@crustytoothpaste.net>,
"Martin Ågren" <martin.agren@gmail.com>,
git@vger.kernel.org
Subject: Re: [PATCH 1/3] setup: drop return value from `read_repository_format()`
Date: Thu, 20 Dec 2018 09:53:22 -0500 [thread overview]
Message-ID: <20181220145322.GA27361@sigill.intra.peff.net> (raw)
In-Reply-To: <20181220034555.GC35965@genre.crustytoothpaste.net>
On Thu, Dec 20, 2018 at 03:45:55AM +0000, brian m. carlson wrote:
> > > I will point out that with the SHA-256 work, reading the config file
> > > becomes essential for SHA-256 repositories, because we need to know the
> > > object format. Removing the config file leads to things blowing up in a
> > > bad way (what specific bad way I don't remember).
> > >
> > > That may influence the direction we want to take in this work, or not.
> >
> > Wouldn't we just treat that the same way we do now? I.e., assume the
> > default of sha1, just like we assume repositoryformatversion==0?
>
> Yeah, we'll default to SHA-1, but the repository will be broken. HEAD
> can't be read. Trying to run git status dies with "fatal: Unknown index
> entry format". And so on. We've written data with 64-character object
> IDs, which can't be read by Git in SHA-1 mode.
Oh, I see. Yes, if you have a SHA-256 repository and you don't tell
anybody (via a config entry), then everything will fail to work. That
seems like a perfectly reasonable outcome to me.
> My point is essentially that in an SHA-256 repository, the config file
> isn't optional anymore. We probably need to consider that and error out
> in more situations (e.g. unreadable file or I/O error) instead of
> silently falling back to the defaults, since failing loudly in a visible
> way is better than having the user try to figure out why the index is
> suddenly "corrupt".
Yes, I agree that ideally we'd produce a better error message. I'd just
be wary of breaking compatibility for the existing cases by making new
requirements when we don't yet suspect the repo is SHA-256.
When we see such a corruption, would it be possible to poke at the data
as if it were the old SHA-1 format, and if _that_ looks sane, suggest to
the user what the problem might be? That would help a number of cases
beyond this one (i.e., you're missing config, you have config but it has
the wrong repo format, you're missing the correct extensions field,
etc).
-Peff
next prev parent reply other threads:[~2018-12-20 14:53 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-18 7:25 [PATCH 0/3] setup: add `clear_repository_format()` Martin Ågren
2018-12-18 7:25 ` [PATCH 1/3] setup: drop return value from `read_repository_format()` Martin Ågren
2018-12-19 15:27 ` Jeff King
2018-12-19 21:42 ` Martin Ågren
2018-12-20 0:17 ` brian m. carlson
2018-12-20 2:52 ` Jeff King
2018-12-20 3:45 ` brian m. carlson
2018-12-20 14:53 ` Jeff King [this message]
2018-12-18 7:25 ` [PATCH 2/3] setup: do not use invalid `repository_format` Martin Ågren
2018-12-19 0:18 ` brian m. carlson
2018-12-19 21:43 ` Martin Ågren
2018-12-19 15:38 ` Jeff King
2018-12-19 21:46 ` Martin Ågren
2018-12-19 23:17 ` Jeff King
2018-12-20 0:21 ` brian m. carlson
2018-12-18 7:25 ` [PATCH 3/3] setup: add `clear_repository_format()` Martin Ågren
2018-12-19 15:48 ` Jeff King
2018-12-19 21:49 ` Martin Ågren
2019-01-14 18:34 ` [PATCH v2 0/3] " Martin Ågren
2019-01-14 18:34 ` [PATCH v2 1/3] setup: free old value before setting `work_tree` Martin Ågren
2019-01-14 18:34 ` [PATCH v2 2/3] setup: do not use invalid `repository_format` Martin Ågren
2019-01-15 19:31 ` Jeff King
2019-01-17 6:31 ` Martin Ågren
2019-01-22 7:07 ` Jeff King
2019-01-22 13:34 ` Martin Ågren
2019-01-22 21:45 ` [PATCH v3 0/2] setup: fix memory leaks with `struct repository_format` Martin Ågren
2019-01-22 21:45 ` [PATCH v3 1/2] setup: free old value before setting `work_tree` Martin Ågren
2019-01-22 21:45 ` [PATCH v3 2/2] setup: fix memory leaks with `struct repository_format` Martin Ågren
2019-01-23 5:57 ` Jeff King
2019-01-24 0:14 ` brian m. carlson
2019-01-25 19:25 ` Martin Ågren
2019-01-25 19:24 ` Martin Ågren
2019-01-25 19:51 ` Jeff King
2019-02-25 19:21 ` Martin Ågren
2019-02-26 17:46 ` Jeff King
2019-02-28 20:36 ` [PATCH v4 0/2] " Martin Ågren
2019-02-28 20:36 ` [PATCH v4 1/2] setup: free old value before setting `work_tree` Martin Ågren
2019-02-28 20:36 ` [PATCH v4 2/2] setup: fix memory leaks with `struct repository_format` Martin Ågren
2019-03-06 4:56 ` [PATCH v4 0/2] " Jeff King
2019-01-14 18:34 ` [PATCH v2 3/3] setup: add `clear_repository_format()` Martin Ågren
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=20181220145322.GA27361@sigill.intra.peff.net \
--to=peff@peff.net \
--cc=git@vger.kernel.org \
--cc=martin.agren@gmail.com \
--cc=sandals@crustytoothpaste.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).