From: Karthik Nayak <karthik.188@gmail.com>
To: Patrick Steinhardt <ps@pks.im>
Cc: chris.torek@gmail.com, git@vger.kernel.org, gitster@pobox.com
Subject: Re: [PATCH v2 6/7] update-ref: add support for symref-update
Date: Tue, 23 Apr 2024 07:30:36 -0400 [thread overview]
Message-ID: <CAOLa=ZSMjhEzSMhb3BnRdOmd_NV9ZaBy6aOE4Sm9_1Y8OCBT2w@mail.gmail.com> (raw)
In-Reply-To: <ZidZ8N6WsvgxMcrv@tanuki>
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Patrick Steinhardt <ps@pks.im> writes:
> On Sun, Apr 21, 2024 at 03:00:11PM -0400, Karthik Nayak wrote:
>> Patrick Steinhardt <ps@pks.im> writes:
>> [snip]
>> >> + /*
>> >> + * Since the user can also send in an old-oid, we try to parse
>> >> + * it as such too.
>> >> + */
>> >> + if (old_ref && read_ref(old_ref, NULL)) {
>> >> + if (!repo_get_oid(the_repository, old_ref, &old_oid)) {
>> >> + old_ref = NULL;
>> >> + have_old = 1;
>> >> + } else
>> >> + die("symref-update %s: invalid <old-ref> or <old-oid>", refname);
>> >> + }
>> >
>> > So we first try to parse it as a ref, and then as an object ID? Wouldn't
>> > it preferable to try it the other way round and first check whether it
>> > is a valid object ID? That would likely be cheaper, even though it may
>> > be premature optimization.
>> >
>> > Patrick
>>
>> I think the issue is `repo_get_oid` would also parse a refname to an
>> OID. Whereas we want to first check and keep refnames and only if it
>> isn't a refname, we'd want to parse it as an OID.
>
> Okay. The question is whether this matches precedence rules that we have
> in other places. Namely, whether a reference name that looks like an
> object ID overrides an object with the same name. Testing it:
>
> ```
> $ rm -rf repo/
> $ git init --ref-format=files repo
> Initialized empty Git repository in /tmp/repo/.git/
> $ cd repo/
> $ git commit --allow-empty --message first
> [main (root-commit) 09293d8] first
> $ git commit --allow-empty --message second
> [main 1588e76] second
>
> $ git update-ref $(git rev-parse HEAD~) HEAD
> $ cat .git/09293d82c434cdc1f7f286cf7b90cf35a6e57c43
> 1588e76ce7ef1ab25ee6f846a7b5d7032f83a69e
>
> $ git rev-parse 09293d82c434cdc1f7f286cf7b90cf35a6e57c43
> warning: refname '09293d82c434cdc1f7f286cf7b90cf35a6e57c43' is ambiguous.
> Git normally never creates a ref that ends with 40 hex characters
> because it will be ignored when you just specify 40-hex. These refs
> may be created by mistake. For example,
>
> git switch -c $br $(git rev-parse ...)
>
> where "$br" is somehow empty and a 40-hex ref is created. Please
> examine these refs and maybe delete them. Turn this message off by
> running "git config advice.objectNameWarning false"
> 09293d82c434cdc1f7f286cf7b90cf35a6e57c43
> ```
>
> So the object ID has precedence over the reference with the same name.
> Unless I'm mistaken, your proposed order would reverse that, wouldn't
> it?
>
I wasn't talking about a reference being mistaken for a object ID,
rather I was talking about how a reference will be `rev-parse`'d into an
object ID.
So instead if we did something like:
```
if (old_target) {
if (!repo_get_oid(the_repository, old_target, &old_oid)) {
old_target = NULL;
have_old = 1;
} else if (read_ref(old_target, NULL)) {
} else {
die("symref-update %s: invalid <old-target> or <old-oid>", refname);
}
}
```
The problem is that now:
$ git init repo && cd repo
$ git commit --allow-empty -m"c1"
[master (root-commit) af416de] c1
$ git commit --allow-empty -m"c2"
[master 52e95b2] c2
$ git symbolic-ref refs/heads/symref refs/heads/master
$ git branch b1 master~1
$ git branch b2 master
$ cat .git/refs/heads/symref
ref: refs/heads/master
$ git update-ref --no-deref --stdin
symref-update refs/heads/symref refs/heads/b1 refs/heads/b2
$ cat .git/refs/heads/symref
ref: refs/heads/b1
This shouldn't have worked because symref was pointing to master, but
this did work, because `refs/heads/b2` was rev-parse'd to '52e95b2'
which is also what master is at.
The issue is that we call 'repo_get_oid', which takes in a commitish and
this could even be a reference. But ideally in 'symref' commands we want
to first treat refnames as refnames and not have them parsed as an OID.
Since, I'm not moving to 'refs:<target>' with the existing commands.
This is no longer an issue.
>> Also, why do you say it is cheaper?
>
> Checking whether a string can be parsed as an object ID should be faster
> than having to ask the ref backend whether it knows any reference with
> that name. So it should be fast for `repo_get_oid()` to bail out in case
> the provided string doesn't look like an object ID.
>
> Patrick
Yes. But for a valid refname, the `repo_get_oid()` is querying the
reference backend similar to `read_ref()`. Also `read_ref` also does
initial checks with `check_refname_format` which I think doesn't check
the ref backend.
Thanks
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next prev parent reply other threads:[~2024-04-23 11:30 UTC|newest]
Thread overview: 194+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-30 22:46 [PATCH 0/8] update-ref: add support for update-symref option Karthik Nayak
2024-03-30 22:46 ` [PATCH 1/8] files-backend: extract out `create_symref_lock` Karthik Nayak
2024-04-02 12:20 ` Patrick Steinhardt
2024-04-03 14:52 ` Karthik Nayak
2024-03-30 22:46 ` [PATCH 2/8] reftable-backend: extract out `write_symref_with_log` Karthik Nayak
2024-04-02 12:20 ` Patrick Steinhardt
2024-03-30 22:46 ` [PATCH 3/8] reftable-backend: move `write_symref_with_log` up Karthik Nayak
2024-03-30 22:46 ` [PATCH 4/8] refs: accept symref in `ref_transaction_add_update` Karthik Nayak
2024-03-30 22:46 ` [PATCH 5/8] refs/files-backend: add support for symref updates Karthik Nayak
2024-04-02 12:20 ` Patrick Steinhardt
2024-03-30 22:46 ` [PATCH 6/8] refs/reftable-backend: " Karthik Nayak
2024-04-02 12:20 ` Patrick Steinhardt
2024-03-30 22:46 ` [PATCH 7/8] refs: add 'update-symref' command to 'update-ref' Karthik Nayak
2024-03-31 22:08 ` Junio C Hamano
2024-03-31 22:27 ` Chris Torek
2024-03-31 23:14 ` Junio C Hamano
2024-04-01 1:31 ` Junio C Hamano
2024-04-02 12:20 ` Patrick Steinhardt
2024-04-02 16:40 ` Junio C Hamano
2024-04-09 11:55 ` Patrick Steinhardt
2024-04-09 16:15 ` Karthik Nayak
2024-04-10 4:20 ` Patrick Steinhardt
2024-04-10 16:06 ` Junio C Hamano
2024-04-10 17:31 ` Patrick Steinhardt
2024-04-01 10:38 ` Karthik Nayak
2024-04-01 11:48 ` Karthik Nayak
2024-04-01 16:17 ` Junio C Hamano
2024-04-01 20:40 ` Junio C Hamano
2024-04-01 22:37 ` Karthik Nayak
2024-03-30 22:46 ` [PATCH 8/8] refs: support symrefs in 'reference-transaction' hook Karthik Nayak
2024-04-02 12:20 ` Patrick Steinhardt
2024-04-12 9:59 ` [PATCH v2 0/7] update-ref: add symref oriented commands Karthik Nayak
2024-04-12 9:59 ` [PATCH v2 1/7] refs: accept symref values in `ref_transaction[_add]_update` Karthik Nayak
2024-04-18 14:25 ` Christian Couder
2024-04-19 10:28 ` Karthik Nayak
2024-04-18 15:08 ` Phillip Wood
2024-04-19 9:40 ` Patrick Steinhardt
2024-04-19 15:47 ` Karthik Nayak
2024-05-04 15:15 ` phillip.wood123
2024-04-19 9:40 ` Patrick Steinhardt
2024-04-19 18:09 ` Karthik Nayak
2024-04-23 6:31 ` Patrick Steinhardt
2024-04-23 10:48 ` Karthik Nayak
2024-04-12 9:59 ` [PATCH v2 2/7] update-ref: add support for symref-verify Karthik Nayak
2024-04-18 14:26 ` Christian Couder
2024-04-19 21:21 ` Karthik Nayak
2024-04-19 9:40 ` Patrick Steinhardt
2024-04-19 21:53 ` Karthik Nayak
2024-04-12 9:59 ` [PATCH v2 3/7] update-ref: add support for symref-delete Karthik Nayak
2024-04-18 14:52 ` Christian Couder
2024-04-21 10:43 ` Karthik Nayak
2024-04-19 9:40 ` Patrick Steinhardt
2024-04-21 10:45 ` Karthik Nayak
2024-04-12 9:59 ` [PATCH v2 4/7] files-backend: extract out `create_symref_lock` Karthik Nayak
2024-04-12 9:59 ` [PATCH v2 5/7] update-ref: add support for symref-create Karthik Nayak
2024-04-19 9:40 ` Patrick Steinhardt
2024-04-19 15:48 ` Junio C Hamano
2024-04-21 12:50 ` Karthik Nayak
2024-04-21 15:57 ` Karthik Nayak
2024-04-23 6:39 ` Patrick Steinhardt
2024-04-23 10:52 ` Karthik Nayak
2024-04-12 9:59 ` [PATCH v2 6/7] update-ref: add support for symref-update Karthik Nayak
2024-04-19 9:40 ` Patrick Steinhardt
2024-04-21 19:00 ` Karthik Nayak
2024-04-23 6:49 ` Patrick Steinhardt
2024-04-23 11:30 ` Karthik Nayak [this message]
2024-04-12 9:59 ` [PATCH v2 7/7] refs: support symrefs in 'reference-transaction' hook Karthik Nayak
2024-04-12 18:01 ` [PATCH v2 0/7] update-ref: add symref oriented commands Junio C Hamano
2024-04-12 18:49 ` Karthik Nayak
2024-04-18 15:05 ` Christian Couder
2024-04-21 19:06 ` Karthik Nayak
2024-04-20 6:16 ` Patrick Steinhardt
2024-04-21 19:11 ` Karthik Nayak
2024-04-23 21:28 ` [PATCH v3 0/8] refs: add symref support to 'git-update-ref' Karthik Nayak
2024-04-23 21:28 ` [PATCH v3 1/8] refs: accept symref values in `ref_transaction[_add]_update` Karthik Nayak
2024-04-23 21:28 ` [PATCH v3 2/8] update-ref: support parsing ref targets in `parse_next_oid` Karthik Nayak
2024-04-23 21:28 ` [PATCH v3 3/8] files-backend: extract out `create_symref_lock` Karthik Nayak
2024-04-23 21:28 ` [PATCH v3 4/8] update-ref: support symrefs in the verify command Karthik Nayak
2024-04-23 21:28 ` [PATCH v3 5/8] update-ref: support symrefs in the delete command Karthik Nayak
2024-04-23 21:28 ` [PATCH v3 6/8] update-ref: support symrefs in the create command Karthik Nayak
2024-04-23 21:28 ` [PATCH v3 7/8] update-ref: support symrefs in the update command Karthik Nayak
2024-04-23 21:28 ` [PATCH v3 8/8] ref: support symrefs in 'reference-transaction' hook Karthik Nayak
2024-04-23 22:03 ` [PATCH v3 0/8] refs: add symref support to 'git-update-ref' Jeff King
2024-04-24 1:17 ` Junio C Hamano
2024-04-24 16:25 ` Karthik Nayak
2024-04-25 6:40 ` Patrick Steinhardt
2024-04-25 21:12 ` Karthik Nayak
2024-04-25 18:01 ` Junio C Hamano
2024-04-25 21:14 ` Karthik Nayak
2024-04-25 21:55 ` Junio C Hamano
2024-04-26 12:48 ` Karthik Nayak
2024-04-26 20:41 ` Jeff King
2024-04-25 17:09 ` Junio C Hamano
2024-04-25 21:07 ` Karthik Nayak
2024-04-26 15:24 ` [PATCH v4 0/7] add symref-* commands to 'git-update-ref --stdin' Karthik Nayak
2024-04-26 15:24 ` [PATCH v4 1/7] refs: accept symref values in `ref_transaction[_add]_update` Karthik Nayak
2024-04-26 19:31 ` Junio C Hamano
2024-04-26 21:15 ` Jeff King
2024-04-29 7:02 ` Patrick Steinhardt
2024-04-29 7:55 ` Jeff King
2024-04-29 9:29 ` phillip.wood123
2024-04-29 9:32 ` phillip.wood123
2024-04-29 16:18 ` Junio C Hamano
2024-04-30 10:33 ` Jeff King
2024-04-30 10:30 ` Jeff King
2024-04-28 19:36 ` Karthik Nayak
2024-04-29 13:38 ` Phillip Wood
2024-04-29 14:01 ` Karthik Nayak
2024-04-26 15:24 ` [PATCH v4 2/7] files-backend: extract out `create_symref_lock` Karthik Nayak
2024-04-26 21:39 ` Junio C Hamano
2024-04-28 19:57 ` Karthik Nayak
2024-04-26 15:24 ` [PATCH v4 3/7] update-ref: add support for 'symref-verify' command Karthik Nayak
2024-04-26 22:51 ` Junio C Hamano
2024-04-28 22:28 ` Karthik Nayak
2024-04-26 15:24 ` [PATCH v4 4/7] update-ref: add support for 'symref-delete' command Karthik Nayak
2024-04-26 15:24 ` [PATCH v4 5/7] update-ref: add support for 'symref-create' command Karthik Nayak
2024-04-26 15:24 ` [PATCH v4 6/7] update-ref: add support for 'symref-update' command Karthik Nayak
2024-04-26 15:24 ` [PATCH v4 7/7] ref: support symrefs in 'reference-transaction' hook Karthik Nayak
2024-04-30 10:14 ` [PATCH v4 0/7] add symref-* commands to 'git-update-ref --stdin' Karthik Nayak
2024-05-01 20:22 ` [PATCH v5 0/7] refs: add support for transactional symref updates Karthik Nayak
2024-05-01 20:22 ` [PATCH v5 1/7] refs: accept symref values in `ref_transaction_update()` Karthik Nayak
2024-05-01 20:22 ` [PATCH v5 2/7] files-backend: extract out `create_symref_lock()` Karthik Nayak
2024-05-01 22:06 ` Junio C Hamano
2024-05-02 7:47 ` Patrick Steinhardt
2024-05-02 11:05 ` Karthik Nayak
2024-05-02 16:49 ` Junio C Hamano
2024-05-01 20:22 ` [PATCH v5 3/7] refs: support symrefs in 'reference-transaction' hook Karthik Nayak
2024-05-01 23:05 ` Junio C Hamano
2024-05-02 5:32 ` Karthik Nayak
2024-05-01 20:22 ` [PATCH v5 4/7] refs: add support for transactional symref updates Karthik Nayak
2024-05-01 23:52 ` Junio C Hamano
2024-05-02 5:50 ` Karthik Nayak
2024-05-02 7:47 ` Patrick Steinhardt
2024-05-02 11:10 ` Karthik Nayak
2024-05-02 16:51 ` Junio C Hamano
2024-05-02 16:00 ` Junio C Hamano
2024-05-02 17:53 ` Junio C Hamano
2024-05-01 20:22 ` [PATCH v5 5/7] refs: use transaction in `refs_create_symref()` Karthik Nayak
2024-05-02 7:47 ` Patrick Steinhardt
2024-05-01 20:22 ` [PATCH v5 6/7] refs: rename `refs_create_symref()` to `refs_update_symref()` Karthik Nayak
2024-05-02 7:47 ` Patrick Steinhardt
2024-05-02 11:34 ` Karthik Nayak
2024-05-01 20:22 ` [PATCH v5 7/7] refs: remove `create_symref` and associated dead code Karthik Nayak
2024-05-02 7:47 ` Patrick Steinhardt
2024-05-02 16:53 ` Junio C Hamano
2024-05-02 0:20 ` [PATCH v5 0/7] refs: add support for transactional symref updates Junio C Hamano
2024-05-02 5:53 ` Karthik Nayak
2024-05-03 12:41 ` [PATCH v6 " Karthik Nayak
2024-05-03 12:41 ` [PATCH v6 1/7] refs: accept symref values in `ref_transaction_update()` Karthik Nayak
2024-05-04 15:18 ` Phillip Wood
2024-05-05 15:10 ` Karthik Nayak
2024-05-05 15:19 ` phillip.wood123
2024-05-03 12:41 ` [PATCH v6 2/7] files-backend: extract out `create_symref_lock()` Karthik Nayak
2024-05-03 12:41 ` [PATCH v6 3/7] refs: support symrefs in 'reference-transaction' hook Karthik Nayak
2024-05-03 12:41 ` [PATCH v6 4/7] refs: add support for transactional symref updates Karthik Nayak
2024-05-05 14:09 ` Phillip Wood
2024-05-05 16:09 ` Karthik Nayak
2024-05-06 9:35 ` Phillip Wood
2024-05-06 11:19 ` Karthik Nayak
2024-05-06 13:19 ` Phillip Wood
2024-05-06 9:54 ` Phillip Wood
2024-05-06 11:22 ` Karthik Nayak
2024-05-06 13:17 ` Phillip Wood
2024-05-03 12:41 ` [PATCH v6 5/7] refs: use transaction in `refs_create_symref()` Karthik Nayak
2024-05-03 12:41 ` [PATCH v6 6/7] refs: rename `refs_create_symref()` to `refs_update_symref()` Karthik Nayak
2024-05-03 12:41 ` [PATCH v6 7/7] refs: remove `create_symref` and associated dead code Karthik Nayak
2024-05-03 23:09 ` Junio C Hamano
2024-05-04 9:30 ` Karthik Nayak
2024-05-03 16:45 ` [PATCH v6 0/7] refs: add support for transactional symref updates Junio C Hamano
2024-05-06 7:36 ` Patrick Steinhardt
2024-05-07 6:00 ` [PATCH v7 0/8] " Karthik Nayak
2024-05-07 6:00 ` [PATCH v7 1/8] refs: accept symref values in `ref_transaction_update()` Karthik Nayak
2024-05-07 6:00 ` [PATCH v7 2/8] files-backend: extract out `create_symref_lock()` Karthik Nayak
2024-05-07 6:00 ` [PATCH v7 3/8] refs: support symrefs in 'reference-transaction' hook Karthik Nayak
2024-05-07 6:00 ` [PATCH v7 4/8] refs: move `original_update_refname` to 'refs.c' Karthik Nayak
2024-05-07 6:00 ` [PATCH v7 5/8] refs: add support for transactional symref updates Karthik Nayak
2024-05-07 6:00 ` [PATCH v7 6/8] refs: use transaction in `refs_create_symref()` Karthik Nayak
2024-05-07 6:00 ` [PATCH v7 7/8] refs: rename `refs_create_symref()` to `refs_update_symref()` Karthik Nayak
2024-05-07 6:00 ` [PATCH v7 8/8] refs: remove `create_symref` and associated dead code Karthik Nayak
2024-05-07 6:25 ` [PATCH v7 0/8] refs: add support for transactional symref updates Junio C Hamano
2024-05-07 6:31 ` Junio C Hamano
2024-05-07 12:58 ` [PATCH v8 " Karthik Nayak
2024-05-07 12:58 ` [PATCH v8 1/8] refs: accept symref values in `ref_transaction_update()` Karthik Nayak
2024-05-07 12:58 ` [PATCH v8 2/8] files-backend: extract out `create_symref_lock()` Karthik Nayak
2024-05-07 12:58 ` [PATCH v8 3/8] refs: support symrefs in 'reference-transaction' hook Karthik Nayak
2024-05-07 12:58 ` [PATCH v8 4/8] refs: move `original_update_refname` to 'refs.c' Karthik Nayak
2024-05-07 12:58 ` [PATCH v8 5/8] refs: add support for transactional symref updates Karthik Nayak
2024-05-07 12:58 ` [PATCH v8 6/8] refs: use transaction in `refs_create_symref()` Karthik Nayak
2024-05-07 12:58 ` [PATCH v8 7/8] refs: rename `refs_create_symref()` to `refs_update_symref()` Karthik Nayak
2024-05-07 12:58 ` [PATCH v8 8/8] refs: remove `create_symref` and associated dead code Karthik Nayak
2024-05-07 15:50 ` [PATCH v8 0/8] refs: add support for transactional symref updates phillip.wood123
2024-05-07 16:32 ` Junio C Hamano
2024-05-12 17:17 ` Karthik Nayak
2024-05-13 17:15 ` Junio C Hamano
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