From: Junio C Hamano <gitster@pobox.com>
To: Patrick Steinhardt <ps@pks.im>
Cc: Karthik Nayak <karthik.188@gmail.com>,
Chris Torek <chris.torek@gmail.com>,
git@vger.kernel.org
Subject: Re: [PATCH 7/8] refs: add 'update-symref' command to 'update-ref'
Date: Wed, 10 Apr 2024 09:06:45 -0700 [thread overview]
Message-ID: <xmqqzfu1w6ay.fsf@gitster.g> (raw)
In-Reply-To: <ZhYTe2zpJyHJ8iIT@tanuki> (Patrick Steinhardt's message of "Wed, 10 Apr 2024 06:20:11 +0200")
Patrick Steinhardt <ps@pks.im> writes:
>> > I might have missed it while scanning through this thread, but why
>> > exactly is the zero OID not a good enough placeholder here to say that
>> > the ref must not exist? A symref cannot point to a ref named after the
>> > zero OID anyway.
>
>> > In my opinion, "update-symref" with an old-value must be able to accept
>> > both object IDs and symrefs as old value. Like this it would be possible
>> > to update a proper ref to a symref in a race-free way. So you can say:
>> >
>> > git update-ref SYMREF refs/heads/main 19981daefd7c147444462739375462b49412ce33
>
>> > To update "SYRMEF" to "refs/heads/main", but only in case it currently
>> > is a proper ref that points to 19981daefd7c147444462739375462b49412ce33.
>> > Similarly...
>> >
>> > git update-ref SYMREF refs/heads/main refs/heads/master
>
>> > would update "SYMREF" to "refs/heads/main", but only if it currently
>> > points to the symref "refs/heads/master".
I think that would work well. We need to explicitly forbid a file
$GIT_DIR/[0-9a-f]{40} to be used as a pseudoref, which I think that
is an improvement. I do not know how the transition to move to a
world with a stricter rule would look like, though.
>> > And by extension I think that
>> > the zero OID should retain its established meaning of "This ref must not
>> > exist":
>> >
>> > git update-ref SYMREF refs/heads/main 0000000000000000000000000000000000000000
>> >
>> > This would only update "SYMREF" to "refs/heads/main" if it does not yet
>> > exist.
We express "SYMREF must currently be a symref" by naming an old-ref,
and we say "SYMREF can currently be either a ref or symref, but it
must point at this object" by naming an old-oid. The looseness of
the latter (i.e. we cannot express "Before making HEAD point at ref
X, ensure that it is detached at OID") looks a bit disturbing, but
otherwise looks good. I offhand do not know how expressive we would
want the "old" requirement to be.
>> On a side-note: This would also mean that we should somehow support
>> moving from symrefs to a regular ref via a transaction, so that means we
>> should allow
>>
>> update SP <ref> SP <new-oid> [SP (<old-oid> | <old-rev>)] LF
>>
>> too, but I'm not going to tackle that in my patches.
>
> Yes, I think that would be a sensible idea, even though we have to be
> careful with backwards compatibility here. In any case, I think it makes
> sense to not extend the scope of your patch series and leave this for
> the future.
Likewise, we may want to be able to express "Before making HEAD
detached at commit X, ensure that HEAD points at ref Y that points
at commit Z". IOW, the "old" part might have to be not
[SP (<old-oid> | <old-ref>)]
but
[SP <old-oid> SP <old-ref>]
to specify both, perhaps?
next prev parent reply other threads:[~2024-04-10 16:06 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 [this message]
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
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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