Git Mailing List Archive mirror
 help / color / mirror / Atom feed
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 2/7] update-ref: add support for symref-verify
Date: Fri, 19 Apr 2024 14:53:01 -0700	[thread overview]
Message-ID: <CAOLa=ZQJmxrQ+n060P0X8BW4ay2XMvOHHyJ3vxrW7C+j+5kWSA@mail.gmail.com> (raw)
In-Reply-To: <ZiI8DmqrbvdCDWt0@tanuki>

[-- Attachment #1: Type: text/plain, Size: 9081 bytes --]

Patrick Steinhardt <ps@pks.im> writes:
>> +symref-verify::
>> +	Verify symbolic <ref> against <old-ref> but do not change it.
>> +	If <old-ref> is missing, the ref must not exist.  Can only be
>> +	used in `no-deref` mode.
>
> Should this say "is zero or missing", like the comment for "verify"
> does?
>

We don't allow users to enter OID here, we do convert it to zero OID
internally. But the user input is expected to be old_ref or nothing.

> [snip]
>> @@ -297,11 +321,48 @@ static void parse_cmd_verify(struct ref_transaction *transaction,
>>  		die("verify %s: extra input: %s", refname, next);
>>
>>  	if (ref_transaction_verify(transaction, refname, &old_oid,
>> -				   update_flags, &err))
>> +				   NULL, update_flags, &err))
>> +		die("%s", err.buf);
>> +
>> +	update_flags = default_flags;
>> +	free(refname);
>> +	strbuf_release(&err);
>> +}
>> +
>> +static void parse_cmd_symref_verify(struct ref_transaction *transaction,
>> +                                    const char *next, const char *end)
>> +{
>> +	struct strbuf err = STRBUF_INIT;
>> +	struct object_id old_oid;
>> +	char *refname, *old_ref;
>> +
>> +	if (!(update_flags & REF_NO_DEREF))
>> +		die("symref-verify: cannot operate with deref mode");
>
> This feels quite restrictive to me. Wouldn't it be preferable to simply
> ignore `REF_NO_DEREF` here? It basically means that this command can't
> ever be used in a normal `git update-ref --stdin` session.
>

We do support 'option' with the '--stdin' flag. So technically a user
should be able to do.

   $ git update-ref --stdin
   no-deref
   symref-verify refs/heads/symref refs/heads/master
   update-ref refs/heads/branch 0b3b55ad0e593ead604f80fe3f621239b34cce7e

I guess we could make it implicit, but I thought it's better to keep it
explicit so the user knows that there is no dereferencing taking place
here, eventhough the default option is to dereference.

[snip]
>>
>>  	update->flags = flags;
>>
>> -	if (flags & REF_HAVE_NEW)
>> -		oidcpy(&update->new_oid, new_oid);
>> -	if (flags & REF_HAVE_OLD)
>> -		oidcpy(&update->old_oid, old_oid);
>> +	/*
>> +	 * The ref values are to be considered over the oid values when we're
>> +	 * doing symref operations.
>> +	 */
>
> I feel like this is a statement that should be backed up by a deeper
> explanation of why that is. I'm still wondering here why we cannot
> assert that the old value is an object ID when I want to update it to a
> symref, or alternatively why it would even be possible to have both
> `REF_SYMREF_UPDATE` and a set of other, incompatible fields set. It
> feels like this should be a `BUG()` instead if this is supposedly an
> unsupported configuration rather than silently ignoring it.
>
> In any case, I feel like it would be easier to reason about if this was
> introduced together with the actual user. As far as I can see this code
> shouldn't ever be hit for "verify-symref", right? Currently, the reader
> is forced to figure out what is and isn't related to the new command.
>

I've changed this now to no longer have this condition and also added
'BUG' for cases where both old_{ref,target} and new_{ref,target} exist.

[snip]
>> @@ -2464,8 +2495,7 @@ static int lock_ref_for_update(struct files_ref_store *refs,
>>  			       struct strbuf *err)
>>  {
>>  	struct strbuf referent = STRBUF_INIT;
>> -	int mustexist = (update->flags & REF_HAVE_OLD) &&
>> -		!is_null_oid(&update->old_oid);
>> +	int mustexist = (update->flags & REF_HAVE_OLD) && !is_null_oid(&update->old_oid);
>
> This change is a no-op, right? If so, let's rather drop it.
>

Yeah, will do.

>>  	int ret = 0;
>>  	struct ref_lock *lock;
>>
>> @@ -2514,6 +2544,18 @@ static int lock_ref_for_update(struct files_ref_store *refs,
>>  					ret = TRANSACTION_GENERIC_ERROR;
>>  					goto out;
>>  				}
>> +			}
>> +
>> +			/*
>> +			 * For symref verification, we need to check the referent value
>> +			 * rather than the oid. If we're dealing with regular refs or we're
>> +			 * verifying a dereferenced symref, we then check the oid.
>> +			 */
>> +			if (update->flags & REF_SYMREF_UPDATE && update->old_ref) {
>> +				if (check_old_ref(update, referent.buf, err)) {
>> +					ret = TRANSACTION_GENERIC_ERROR;
>> +					goto out;
>> +				}
>>  			} else if (check_old_oid(update, &lock->old_oid, err)) {
>>  				ret = TRANSACTION_GENERIC_ERROR;
>>  				goto out;
>> diff --git a/refs/refs-internal.h b/refs/refs-internal.h
>> index 4c5fe02687..21c6b940d8 100644
>> --- a/refs/refs-internal.h
>> +++ b/refs/refs-internal.h
>> @@ -749,4 +749,11 @@ void base_ref_store_init(struct ref_store *refs, struct repository *repo,
>>   */
>>  struct ref_store *maybe_debug_wrap_ref_store(const char *gitdir, struct ref_store *store);
>>
>> +/*
>> + * Helper function to check if the new value is null, this
>> + * takes into consideration that the update could be a regular
>> + * ref or a symbolic ref.
>> + */
>> +int null_new_value(struct ref_update *update);
>
> When adding it to the header we should probably prefix this to avoid
> name collisions. `ref_update_is_null_new_value()` might be a mouth full,
> but feels preferable to me.
>

Makes sense.

>>  #endif /* REFS_REFS_INTERNAL_H */
>> diff --git a/refs/reftable-backend.c b/refs/reftable-backend.c
>> index 6104471199..7a03922c7b 100644
>> --- a/refs/reftable-backend.c
>> +++ b/refs/reftable-backend.c
>> @@ -938,7 +938,28 @@ static int reftable_be_transaction_prepare(struct ref_store *ref_store,
>>  		 * individual refs. But the error messages match what the files
>>  		 * backend returns, which keeps our tests happy.
>>  		 */
>> -		if (u->flags & REF_HAVE_OLD && !oideq(&current_oid, &u->old_oid)) {
>> +		if ((u->flags & REF_HAVE_OLD) &&
>> +		    (u->flags & REF_SYMREF_UPDATE) &&
>> +		    u->old_ref) {
>> +			if   (strcmp(referent.buf, u->old_ref)) {
>
> s/   / /
>
>> +				if (!strcmp(u->old_ref, ""))
>> +					strbuf_addf(err, "cannot lock ref '%s': "
>> +						    "reference already exists",
>> +						    original_update_refname(u));
>> +				else if (!strcmp(referent.buf, ""))
>> +					strbuf_addf(err, "cannot lock ref '%s': "
>> +						    "reference is missing but expected %s",
>> +						    original_update_refname(u),
>> +						    u->old_ref);
>> +				else
>> +					strbuf_addf(err, "cannot lock ref '%s': "
>> +						    "is at %s but expected %s",
>> +						    original_update_refname(u),
>> +						    referent.buf, u->old_ref);
>
> I'd use better-matching error messages here. I know that we talk about
> "cannot lock ref" in the next branch, as well. But the only reason we
> did this is to have the same error messages as the "files" backend.
> Semantically, those errors don't make much sense as the "reftable"
> backend never locks specific refs, but only the complete stack.
>

Fair enough, will change.

>> +				ret = -1;
>> +				goto done;
>> +			}
>> +		} else if (u->flags & REF_HAVE_OLD && !oideq(&current_oid, &u->old_oid)) {
>>  			if (is_null_oid(&u->old_oid))
>>  				strbuf_addf(err, _("cannot lock ref '%s': "
>>  					    "reference already exists"),
>> diff --git a/t/t1400-update-ref.sh b/t/t1400-update-ref.sh
>> index ec3443cc87..d8ffda4096 100755
>> --- a/t/t1400-update-ref.sh
>> +++ b/t/t1400-update-ref.sh
>> @@ -890,17 +890,23 @@ test_expect_success 'stdin update/create/verify combination works' '
>>  '
>>
>>  test_expect_success 'stdin verify succeeds for correct value' '
>> +	test-tool ref-store main for-each-reflog-ent $m >before &&
>>  	git rev-parse $m >expect &&
>>  	echo "verify $m $m" >stdin &&
>>  	git update-ref --stdin <stdin &&
>>  	git rev-parse $m >actual &&
>> -	test_cmp expect actual
>> +	test_cmp expect actual &&
>> +	test-tool ref-store main for-each-reflog-ent $m >after &&
>> +	test_cmp before after
>>  '
>>
>>  test_expect_success 'stdin verify succeeds for missing reference' '
>> +	test-tool ref-store main for-each-reflog-ent $m >before &&
>>  	echo "verify refs/heads/missing $Z" >stdin &&
>>  	git update-ref --stdin <stdin &&
>> -	test_must_fail git rev-parse --verify -q refs/heads/missing
>> +	test_must_fail git rev-parse --verify -q refs/heads/missing &&
>> +	test-tool ref-store main for-each-reflog-ent $m >after &&
>> +	test_cmp before after
>>  '
>
> The updated tests merely assert that the refs didn't change, right?
>

Yes, also that we didn't add anything unexpected to the reflog.


>>  test_expect_success 'stdin verify treats no value as missing' '
>> @@ -1641,4 +1647,74 @@ test_expect_success PIPE 'transaction flushes status updates' '
>>  	test_cmp expected actual
>>  '
>>
>> +create_stdin_buf ()
>> +{
>
> The curly brace should go on the same line as the function name.
>

Right, will change.

>> +	if test "$1" = "-z"
>> +	then
>> +		shift
>> +		printf "$F" "$@" >stdin
>> +	else
>> +		echo "$@" >stdin
>> +	fi
>> +}
>> +
>> +for type in "" "-z"
>> +do
>
> We should probably indent all of the tests to make it easier to see that
> they run in a loop.
>
> Patrick
>

I was a bit confused about this, I saw smaller tests with loops
indented, while some larger ones not indented. I think its better to do
so too, let me do that.

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 690 bytes --]

  reply	other threads:[~2024-04-19 21:53 UTC|newest]

Thread overview: 146+ 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
2024-04-19  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 [this message]
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

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

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to='CAOLa=ZQJmxrQ+n060P0X8BW4ay2XMvOHHyJ3vxrW7C+j+5kWSA@mail.gmail.com' \
    --to=karthik.188@gmail.com \
    --cc=chris.torek@gmail.com \
    --cc=git@vger.kernel.org \
    --cc=gitster@pobox.com \
    --cc=ps@pks.im \
    /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.
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).