From: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
To: Johannes Schindelin via GitGitGadget <gitgitgadget@gmail.com>
Cc: git@vger.kernel.org, Jeff King <peff@peff.net>,
Junio C Hamano <gitster@pobox.com>,
Johannes Schindelin <johannes.schindelin@gmx.de>
Subject: Re: [PATCH 1/4] rebase -i: demonstrate obscure loose object cache bug
Date: Wed, 13 Mar 2019 17:11:44 +0100 [thread overview]
Message-ID: <87k1h2bvpb.fsf@evledraar.gmail.com> (raw)
In-Reply-To: <b3fcd377652103584b6f307c6ee209980b44529f.1552472189.git.gitgitgadget@gmail.com>
On Wed, Mar 13 2019, Johannes Schindelin via GitGitGadget wrote:
> From: Johannes Schindelin <johannes.schindelin@gmx.de>
>
> We specifically support `exec` commands in `git rebase -i`'s todo lists
> to rewrite the very same todo list. Of course, we need to validate that
> todo list when re-reading it.
>
> It is also totally legitimate to extend the todo list by `pick` lines
> using short names of commits that were created only after the rebase
> started.
>
> And this is where the loose object cache interferes with this feature:
> if *some* loose object was read whose hash shares the same first two
> digits with a commit that was not yet created when that loose object was
> created, then we fail to find that new commit by its short name in
> `get_oid()`, and the interactive rebase fails with an obscure error
> message like:
>
> error: invalid line 1: pick 6568fef
> error: please fix this using 'git rebase --edit-todo'.
As a further improvement, is there a good reason for why we wouldn't
pass something down to the oid machinery to say "we're only interested
in commits". I have a WIP series somewhere to generalize that more, but
e.g. here locally:
$ git rev-parse 80b06
error: short SHA1 80b06 is ambiguous
hint: The candidates are:
hint: 80b06b942e commit 2019-03-13 - Revert "this patch fail whales"
hint: 80b063bb9b blob
hint: 80b06f0714 blob
80b06
$ git rev-parse 80b06^{commit}
80b06b942ed33e597a0152b3e6ba45b7d8ead94b
I can't remember if there's some caveat with that particular peel syntax
I meant to fix, but I mean if we could pass something down to say "no
blobs or trees" shouldn't we?
Then stuff like this wouldn't die:
$ git rebase -i
hint: Waiting for your editor to close the file... Waiting for Emacs...
error: short SHA1 80b06 is ambiguous
hint: The candidates are:
hint: 80b06b942e commit 2019-03-13 - Revert "this patch fail whales"
hint: 80b063bb9b blob
hint: 80b06f0714 blob
error: invalid line 2: p 80b06 Revert "this patch fail whales"
You can fix this with 'git rebase --edit-todo' and then run 'git rebase --continue'.
> [...]
> +test_expect_failure SHA1 'loose object cache vs re-reading todo list' '
> + GIT_REBASE_TODO=.git/rebase-merge/git-rebase-todo &&
> + export GIT_REBASE_TODO &&
> + write_script append-todo.sh <<-\EOS &&
> + # For values 5 and 6, this yields SHA-1s with the same first two digits
> + echo "pick $(git rev-parse --short \
> + $(printf "%s\\n" \
> + "tree $EMPTY_TREE" \
> + "author A U Thor <author@example.org> $1 +0000" \
> + "committer A U Thor <author@example.org> $1 +0000" \
> + "" \
> + "$1" |
> + git hash-object -t commit -w --stdin))" >>$GIT_REBASE_TODO
> +
> + shift
> + test -z "$*" ||
> + echo "exec $0 $*" >>$GIT_REBASE_TODO
> + EOS
> +
> + git rebase HEAD -x "./append-todo.sh 5 6"
> +'
> +
> test_done
This is a test for rebase, but perhaps it would be best put in
t1512-rev-parse-disambiguation.sh. Then when we finally port that
somehow to SHA256 we'll have all this SHA-1 golfing in the same file &
can fix it at once. Just a thought...
next prev parent reply other threads:[~2019-03-13 16:11 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-13 10:16 [PATCH 0/4] get_oid: cope with a possibly stale loose object cache Johannes Schindelin via GitGitGadget
2019-03-13 10:16 ` [PATCH 1/4] rebase -i: demonstrate obscure loose object cache bug Johannes Schindelin via GitGitGadget
2019-03-13 16:11 ` Ævar Arnfjörð Bjarmason [this message]
2019-03-13 16:35 ` Jeff King
2019-03-13 16:53 ` Jeff King
2019-03-13 22:40 ` Johannes Schindelin
2019-03-14 0:07 ` Jeff King
2019-03-13 22:27 ` Johannes Schindelin
2019-03-14 0:05 ` Jeff King
2019-03-14 6:40 ` Johannes Sixt
2019-03-14 13:06 ` Johannes Schindelin
2019-03-14 1:12 ` Junio C Hamano
2019-03-14 12:44 ` Johannes Schindelin
2019-03-13 10:16 ` [PATCH 2/4] sequencer: improve error message when an OID could not be parsed Johannes Schindelin via GitGitGadget
2019-03-14 1:14 ` Junio C Hamano
2019-03-13 10:16 ` [PATCH 3/4] sequencer: move stale comment into correct location Johannes Schindelin via GitGitGadget
2019-03-13 10:16 ` [PATCH 4/4] get_oid(): when an object was not found, try harder Johannes Schindelin via GitGitGadget
2019-03-14 1:29 ` Junio C Hamano
2019-03-14 2:22 ` Jeff King
2019-03-14 2:40 ` Jeff King
2019-03-14 4:05 ` Junio C Hamano
2019-03-14 18:55 ` Jeff King
2019-03-14 3:49 ` Junio C Hamano
2019-03-14 13:17 ` Johannes Schindelin
2019-03-14 18:57 ` Jeff King
2019-03-14 19:55 ` Johannes Schindelin
2019-03-13 15:33 ` [PATCH 0/4] get_oid: cope with a possibly stale loose object cache Jeff King
2019-03-14 15:33 ` [PATCH v2 0/4] get_short_oid: " Johannes Schindelin via GitGitGadget
2019-03-14 15:33 ` [PATCH v2 1/4] rebase -i: demonstrate obscure loose object cache bug Johannes Schindelin via GitGitGadget
2019-03-14 15:33 ` [PATCH v2 2/4] sequencer: improve error message when an OID could not be parsed Johannes Schindelin via GitGitGadget
2019-03-14 15:33 ` [PATCH v2 3/4] sequencer: move stale comment into correct location Johannes Schindelin via GitGitGadget
2019-03-14 15:33 ` [PATCH v2 4/4] get_oid(): when an object was not found, try harder 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=87k1h2bvpb.fsf@evledraar.gmail.com \
--to=avarab@gmail.com \
--cc=git@vger.kernel.org \
--cc=gitgitgadget@gmail.com \
--cc=gitster@pobox.com \
--cc=johannes.schindelin@gmx.de \
--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).