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From: Junio C Hamano <gitster@pobox.com>
To: "Han-Wen Nienhuys via GitGitGadget" <gitgitgadget@gmail.com>
Cc: git@vger.kernel.org, Han-Wen Nienhuys <hanwenn@gmail.com>,
	Han-Wen Nienhuys <hanwen@google.com>
Subject: Re: [PATCH 3/8] refs: make errno output explicit for read_raw_ref_fn
Date: Fri, 30 Apr 2021 15:02:24 +0900	[thread overview]
Message-ID: <xmqqeeescntb.fsf@gitster.g> (raw)
In-Reply-To: <xmqq35v8e982.fsf@gitster.g> (Junio C. Hamano's message of "Fri, 30 Apr 2021 12:34:37 +0900")

Junio C Hamano <gitster@pobox.com> writes:

> I like the general direction to move away from errno, which may make
> sense only in the context of files backend (e.g. ENOENT would be
> left in errno, only because the original "loose ref" implementation
> used one file per ref, when a ref we wanted to see did not exist)
> and having other backends use the same errno would not make much
> sense, as it is not the goal to make other backends like reftable
> emulate files backend.
>
> I wonder if in the ideal world, we'd rather want to define our own
> enum, not <errno.h>, that is specific to failure modes of ref API
> functions and signal failures by returning these values (and the
> enum includes 0 as a value to signal success, all other errors are
> negative values).
>
> What I am really getting at is if we need an extra "failure"
> out-parameter-pointer in the internal API.  I do not mind if it
> helps the transition to the ideal world, but I offhand do not see if
> we need result and failure as separate variables.

In any case, the change in the function signature helped me catch
that this series invalidates what has been queued on hn/reftable
without updating that topic to align with the new way to handle the
errno (it would have become a silent semantic failure if we instead
encoded the "failure" in the return value).

The following is what I am tentatively using for tonight's
integration when merging this and hn/reftable together to the 'seen'
branch.

Thanks.


 refs/reftable-backend.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git c/refs/reftable-backend.c w/refs/reftable-backend.c
index 1aff21adb4..4385d2d6f5 100644
--- c/refs/reftable-backend.c
+++ w/refs/reftable-backend.c
@@ -52,7 +52,8 @@ static struct reftable_stack *stack_for(struct git_reftable_ref_store *store,
 static int git_reftable_read_raw_ref(struct ref_store *ref_store,
 				     const char *refname, struct object_id *oid,
 				     struct strbuf *referent,
-				     unsigned int *type);
+				     unsigned int *type,
+				     int *failure_errno);
 
 static void clear_reftable_log_record(struct reftable_log_record *log)
 {
@@ -376,7 +377,8 @@ static int fixup_symrefs(struct ref_store *ref_store,
 						&old_oid, &referent,
 						/* mutate input, like
 						   files-backend.c */
-						&update->type);
+						&update->type,
+						&errno);
 		if (err < 0 && errno == ENOENT &&
 		    is_null_oid(&update->old_oid)) {
 			err = 0;
@@ -1538,7 +1540,7 @@ static int reftable_error_to_errno(int err)
 static int git_reftable_read_raw_ref(struct ref_store *ref_store,
 				     const char *refname, struct object_id *oid,
 				     struct strbuf *referent,
-				     unsigned int *type)
+				     unsigned int *type, int *failure_errno)
 {
 	struct git_reftable_ref_store *refs =
 		(struct git_reftable_ref_store *)ref_store;
@@ -1560,12 +1562,12 @@ static int git_reftable_read_raw_ref(struct ref_store *ref_store,
 
 	err = reftable_stack_read_ref(stack, refname, &ref);
 	if (err > 0) {
-		errno = ENOENT;
+		*failure_errno = ENOENT;
 		err = -1;
 		goto done;
 	}
 	if (err < 0) {
-		errno = reftable_error_to_errno(err);
+		*failure_errno = reftable_error_to_errno(err);
 		err = -1;
 		goto done;
 	}
@@ -1578,7 +1580,7 @@ static int git_reftable_read_raw_ref(struct ref_store *ref_store,
 		oidread(oid, reftable_ref_record_val1(&ref));
 	} else {
 		*type |= REF_ISBROKEN;
-		errno = EINVAL;
+		*failure_errno = EINVAL;
 		err = -1;
 	}
 done:

  reply	other threads:[~2021-04-30  6:02 UTC|newest]

Thread overview: 137+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-29 15:32 [PATCH 0/8] refs: cleanup errno sideband ref related functions Han-Wen Nienhuys via GitGitGadget
2021-04-29 15:32 ` [PATCH 1/8] refs: remove EINVAL specification from the errno sideband in read_raw_ref_fn Han-Wen Nienhuys via GitGitGadget
2021-04-30  2:38   ` Junio C Hamano
2021-05-19 12:25     ` Han-Wen Nienhuys
2021-06-03  2:19   ` Jonathan Tan
2021-06-09 11:28     ` Han-Wen Nienhuys
2021-04-29 15:32 ` [PATCH 2/8] refs/files-backend: stop setting errno from lock_ref_oid_basic Han-Wen Nienhuys via GitGitGadget
2021-04-30  3:10   ` Junio C Hamano
2021-05-19 12:29     ` Han-Wen Nienhuys
2021-06-03  2:33   ` Jonathan Tan
2021-06-10 10:02     ` Han-Wen Nienhuys
2021-04-29 15:32 ` [PATCH 3/8] refs: make errno output explicit for read_raw_ref_fn Han-Wen Nienhuys via GitGitGadget
2021-04-30  3:34   ` Junio C Hamano
2021-04-30  6:02     ` Junio C Hamano [this message]
2021-05-19 12:33       ` Han-Wen Nienhuys
2021-06-03  2:37   ` Jonathan Tan
2021-06-10 10:05     ` Han-Wen Nienhuys
2021-04-29 15:32 ` [PATCH 4/8] refs: make errno output explicit for refs_resolve_ref_unsafe Han-Wen Nienhuys via GitGitGadget
2021-06-03  2:51   ` Jonathan Tan
2021-06-10 11:27     ` Han-Wen Nienhuys
2021-04-29 15:32 ` [PATCH 5/8] refs: add failure_errno to refs_read_raw_ref() signature Han-Wen Nienhuys via GitGitGadget
2021-04-29 15:32 ` [PATCH 6/8] refs: clear errno return in refs_resolve_ref_unsafe() Han-Wen Nienhuys via GitGitGadget
2021-06-03  2:53   ` Jonathan Tan
2021-06-10 11:45     ` Han-Wen Nienhuys
2021-04-29 15:32 ` [PATCH 7/8] refs: stop setting EINVAL and ELOOP in symref resolution Han-Wen Nienhuys via GitGitGadget
2021-06-03  2:55   ` Jonathan Tan
2021-06-10 11:58     ` Han-Wen Nienhuys
2021-04-29 15:32 ` [PATCH 8/8] refs: explicitly propagate errno from refs_read_raw_ref Han-Wen Nienhuys via GitGitGadget
2021-06-03  2:13 ` [PATCH 0/8] refs: cleanup errno sideband ref related functions Jonathan Tan
2021-06-09 11:29   ` Han-Wen Nienhuys
2021-06-10 12:57 ` [PATCH v2 " Han-Wen Nienhuys via GitGitGadget
2021-06-10 12:57   ` [PATCH v2 1/8] refs: remove EINVAL errno output from specification of read_raw_ref_fn Han-Wen Nienhuys via GitGitGadget
2021-06-10 12:57   ` [PATCH v2 2/8] refs/files-backend: stop setting errno from lock_ref_oid_basic Han-Wen Nienhuys via GitGitGadget
2021-07-01 11:13     ` Ævar Arnfjörð Bjarmason
2021-07-05 14:16       ` Han-Wen Nienhuys
2021-06-10 12:57   ` [PATCH v2 3/8] refs: make errno output explicit for read_raw_ref_fn Han-Wen Nienhuys via GitGitGadget
2021-07-01 11:34     ` Ævar Arnfjörð Bjarmason
2021-07-05 14:34       ` Han-Wen Nienhuys
2021-06-10 12:57   ` [PATCH v2 4/8] refs: make errno output explicit for refs_resolve_ref_unsafe Han-Wen Nienhuys via GitGitGadget
2021-07-01 11:56     ` Ævar Arnfjörð Bjarmason
2021-06-10 12:57   ` [PATCH v2 5/8] refs: use refs_resolve_ref_unsafe_with_errno() where needed Han-Wen Nienhuys via GitGitGadget
2021-07-01 11:58     ` Ævar Arnfjörð Bjarmason
2021-06-10 12:57   ` [PATCH v2 6/8] refs: add failure_errno to refs_read_raw_ref() signature Han-Wen Nienhuys via GitGitGadget
2021-07-01 12:06     ` Ævar Arnfjörð Bjarmason
2021-06-10 12:57   ` [PATCH v2 7/8] refs: clear errno return in refs_resolve_ref_unsafe() Han-Wen Nienhuys via GitGitGadget
2021-07-01 12:19     ` Ævar Arnfjörð Bjarmason
2021-06-10 12:57   ` [PATCH v2 8/8] refs: explicitly propagate errno from refs_read_raw_ref Han-Wen Nienhuys via GitGitGadget
2021-07-01 12:26     ` Ævar Arnfjörð Bjarmason
2021-07-05 16:09       ` Han-Wen Nienhuys
2021-07-05 19:08         ` Ævar Arnfjörð Bjarmason
2021-07-05 19:39           ` Han-Wen Nienhuys
2021-06-14 10:10   ` [PATCH v2 0/8] refs: cleanup errno sideband ref related functions Han-Wen Nienhuys
2021-07-05 20:56   ` [PATCH v3 0/5] " Han-Wen Nienhuys via GitGitGadget
2021-07-05 20:56     ` [PATCH v3 1/5] refs: remove EINVAL errno output from specification of read_raw_ref_fn Han-Wen Nienhuys via GitGitGadget
2021-07-05 20:56     ` [PATCH v3 2/5] refs/files-backend: stop setting errno from lock_ref_oid_basic Han-Wen Nienhuys via GitGitGadget
2021-07-05 20:56     ` [PATCH v3 3/5] refs: make errno output explicit for read_raw_ref_fn Han-Wen Nienhuys via GitGitGadget
2021-07-05 20:56     ` [PATCH v3 4/5] refs: add failure_errno to refs_read_raw_ref() signature Han-Wen Nienhuys via GitGitGadget
2021-07-06 19:28       ` Junio C Hamano
2021-07-05 20:56     ` [PATCH v3 5/5] refs: make errno output explicit for refs_resolve_ref_unsafe Han-Wen Nienhuys via GitGitGadget
2021-07-06  0:38     ` [PATCH v3 0/5] refs: cleanup errno sideband ref related functions Ævar Arnfjörð Bjarmason
2021-07-06  9:53       ` Han-Wen Nienhuys
2021-07-06 14:27         ` Ævar Arnfjörð Bjarmason
2021-07-06 18:36           ` Han-Wen Nienhuys
2021-07-06 18:55     ` [PATCH v4 0/6] " Han-Wen Nienhuys via GitGitGadget
2021-07-06 18:55       ` [PATCH v4 1/6] refs: remove EINVAL errno output from specification of read_raw_ref_fn Han-Wen Nienhuys via GitGitGadget
2021-07-06 18:55       ` [PATCH v4 2/6] refs/files-backend: stop setting errno from lock_ref_oid_basic Han-Wen Nienhuys via GitGitGadget
2021-07-06 18:55       ` [PATCH v4 3/6] refs: make errno output explicit for read_raw_ref_fn Han-Wen Nienhuys via GitGitGadget
2021-07-06 18:55       ` [PATCH v4 4/6] refs: add failure_errno to refs_read_raw_ref() signature Han-Wen Nienhuys via GitGitGadget
2021-07-06 19:39         ` Junio C Hamano
2021-07-06 18:55       ` [PATCH v4 5/6] refs: explicitly return failure_errno from parse_loose_ref_contents Han-Wen Nienhuys via GitGitGadget
2021-07-06 19:37         ` Junio C Hamano
2021-07-07  8:20           ` Han-Wen Nienhuys
2021-07-06 18:55       ` [PATCH v4 6/6] refs: make errno output explicit for refs_resolve_ref_unsafe Han-Wen Nienhuys via GitGitGadget
2021-07-07 19:07       ` [PATCH v5 0/6] refs: cleanup errno sideband ref related functions Han-Wen Nienhuys via GitGitGadget
2021-07-07 19:07         ` [PATCH v5 1/6] refs: remove EINVAL errno output from specification of read_raw_ref_fn Han-Wen Nienhuys via GitGitGadget
2021-07-07 19:07         ` [PATCH v5 2/6] refs/files-backend: stop setting errno from lock_ref_oid_basic Han-Wen Nienhuys via GitGitGadget
2021-07-11 11:38           ` Ævar Arnfjörð Bjarmason
2021-07-13  8:00             ` Han-Wen Nienhuys
2021-07-07 19:07         ` [PATCH v5 3/6] refs: make errno output explicit for read_raw_ref_fn Han-Wen Nienhuys via GitGitGadget
2021-07-11 11:52           ` Ævar Arnfjörð Bjarmason
2021-07-07 19:07         ` [PATCH v5 4/6] refs: add failure_errno to refs_read_raw_ref() signature Han-Wen Nienhuys via GitGitGadget
2021-07-11 11:59           ` Ævar Arnfjörð Bjarmason
2021-07-13  8:02             ` Han-Wen Nienhuys
2021-07-07 19:07         ` [PATCH v5 5/6] refs: explicitly return failure_errno from parse_loose_ref_contents Han-Wen Nienhuys via GitGitGadget
2021-07-11 12:41           ` Ævar Arnfjörð Bjarmason
2021-07-07 19:07         ` [PATCH v5 6/6] refs: make errno output explicit for refs_resolve_ref_unsafe Han-Wen Nienhuys via GitGitGadget
2021-07-07 20:44         ` [PATCH v5 0/6] refs: cleanup errno sideband ref related functions Junio C Hamano
2021-07-11 16:30         ` [PATCH v6? 00/17] refs API: get rid of errno setting entirely Ævar Arnfjörð Bjarmason
2021-07-11 16:30           ` [PATCH v6? 01/17] refs: remove EINVAL errno output from specification of read_raw_ref_fn Ævar Arnfjörð Bjarmason
2021-07-11 16:30           ` [PATCH v6? 02/17] refs/files-backend: stop setting errno from lock_ref_oid_basic Ævar Arnfjörð Bjarmason
2021-07-11 16:30           ` [PATCH v6? 03/17] refs: make errno output explicit for read_raw_ref_fn Ævar Arnfjörð Bjarmason
2021-07-11 16:30           ` [PATCH v6? 04/17] refs: add failure_errno to refs_read_raw_ref() signature Ævar Arnfjörð Bjarmason
2021-07-11 16:30           ` [PATCH v6? 05/17] refs: explicitly return failure_errno from parse_loose_ref_contents Ævar Arnfjörð Bjarmason
2021-07-11 16:30           ` [PATCH v6? 06/17] refs: make errno output explicit for refs_resolve_ref_unsafe Ævar Arnfjörð Bjarmason
2021-07-11 16:30           ` [PATCH v6? 07/17] refs: make errno ignoring explicit in lock_ref_oid_basic() Ævar Arnfjörð Bjarmason
2021-07-11 16:30           ` [PATCH v6? 08/17] refs file-backend.c: stop setting "EBUSY" in verify_lock() Ævar Arnfjörð Bjarmason
2021-07-13  8:08             ` Han-Wen Nienhuys
2021-07-11 16:30           ` [PATCH v6? 09/17] refs file-backend.c: deal with errno directly " Ævar Arnfjörð Bjarmason
2021-07-11 16:30           ` [PATCH v6? 10/17] refs API: remove refs_read_ref_full() wrapper Ævar Arnfjörð Bjarmason
2021-07-11 16:30           ` [PATCH v6? 11/17] refs API: make resolve_gitlink_ref() not set errno Ævar Arnfjörð Bjarmason
2021-07-11 16:30           ` [PATCH v6? 12/17] refs API: make refs_resolve_ref_unsafe() static Ævar Arnfjörð Bjarmason
2021-07-11 16:30           ` [PATCH v6? 13/17] refs API: make refs_resolve_refdup() not set errno Ævar Arnfjörð Bjarmason
2021-07-11 16:30           ` [PATCH v6? 14/17] refs API: make refs_ref_exists() " Ævar Arnfjörð Bjarmason
2021-07-11 16:30           ` [PATCH v6? 15/17] refs API: make resolve_ref_unsafe() " Ævar Arnfjörð Bjarmason
2021-07-13  8:13             ` Han-Wen Nienhuys
2021-07-14  8:32               ` Ævar Arnfjörð Bjarmason
2021-07-11 16:30           ` [PATCH v6? 16/17] refs API: make expand_ref() and repo_dwim_log() " Ævar Arnfjörð Bjarmason
2021-07-11 16:30           ` [PATCH v6? 17/17] refs API: don't leak "errno" in run_transaction_hook() Ævar Arnfjörð Bjarmason
2021-07-13  8:28           ` [PATCH v6? 00/17] refs API: get rid of errno setting entirely Han-Wen Nienhuys
2021-07-13 18:26             ` Ævar Arnfjörð Bjarmason
2021-07-14  8:38               ` Ævar Arnfjörð Bjarmason
2021-07-14  8:43                 ` Han-Wen Nienhuys
2021-07-14 11:43           ` [PATCH v7 0/6] refs: cleanup errno sideband ref related functions Ævar Arnfjörð Bjarmason
2021-07-14 11:43             ` [PATCH v7 1/6] refs: remove EINVAL errno output from specification of read_raw_ref_fn Ævar Arnfjörð Bjarmason
2021-07-14 11:43             ` [PATCH v7 2/6] refs/files-backend: stop setting errno from lock_ref_oid_basic Ævar Arnfjörð Bjarmason
2021-07-14 11:43             ` [PATCH v7 3/6] refs: make errno output explicit for read_raw_ref_fn Ævar Arnfjörð Bjarmason
2021-07-14 11:43             ` [PATCH v7 4/6] refs: add failure_errno to refs_read_raw_ref() signature Ævar Arnfjörð Bjarmason
2021-07-14 11:43             ` [PATCH v7 5/6] refs: explicitly return failure_errno from parse_loose_ref_contents Ævar Arnfjörð Bjarmason
2021-07-14 11:43             ` [PATCH v7 6/6] refs: make errno output explicit for refs_resolve_ref_unsafe Ævar Arnfjörð Bjarmason
2021-07-16 14:22             ` [PATCH v8 0/7] refs: cleanup errno sideband ref related functions Ævar Arnfjörð Bjarmason
2021-07-16 14:22               ` [PATCH v8 1/7] refs file backend: move raceproof_create_file() here Ævar Arnfjörð Bjarmason
2021-07-16 14:22               ` [PATCH v8 2/7] refs: remove EINVAL errno output from specification of read_raw_ref_fn Ævar Arnfjörð Bjarmason
2021-07-16 14:22               ` [PATCH v8 3/7] refs/files-backend: stop setting errno from lock_ref_oid_basic Ævar Arnfjörð Bjarmason
2021-07-16 14:22               ` [PATCH v8 4/7] refs: make errno output explicit for read_raw_ref_fn Ævar Arnfjörð Bjarmason
2021-07-16 14:22               ` [PATCH v8 5/7] refs: add failure_errno to refs_read_raw_ref() signature Ævar Arnfjörð Bjarmason
2021-07-16 14:22               ` [PATCH v8 6/7] refs: explicitly return failure_errno from parse_loose_ref_contents Ævar Arnfjörð Bjarmason
2021-07-16 14:22               ` [PATCH v8 7/7] refs: make errno output explicit for refs_resolve_ref_unsafe Ævar Arnfjörð Bjarmason
2021-07-20 10:33               ` [PATCH v9 0/7] refs: cleanup errno sideband ref related functions Ævar Arnfjörð Bjarmason
2021-07-20 10:33                 ` [PATCH v9 1/7] refs file backend: move raceproof_create_file() here Ævar Arnfjörð Bjarmason
2021-07-20 10:33                 ` [PATCH v9 2/7] refs: remove EINVAL errno output from specification of read_raw_ref_fn Ævar Arnfjörð Bjarmason
2021-07-20 10:33                 ` [PATCH v9 3/7] refs/files-backend: stop setting errno from lock_ref_oid_basic Ævar Arnfjörð Bjarmason
2021-07-20 10:33                 ` [PATCH v9 4/7] refs: make errno output explicit for read_raw_ref_fn Ævar Arnfjörð Bjarmason
2021-07-20 10:33                 ` [PATCH v9 5/7] refs: add failure_errno to refs_read_raw_ref() signature Ævar Arnfjörð Bjarmason
2021-07-20 10:33                 ` [PATCH v9 6/7] refs: explicitly return failure_errno from parse_loose_ref_contents Ævar Arnfjörð Bjarmason
2021-07-20 10:33                 ` [PATCH v9 7/7] refs: make errno output explicit for refs_resolve_ref_unsafe Ævar Arnfjörð Bjarmason
2021-07-26 23:49                 ` [PATCH v9 0/7] refs: cleanup errno sideband ref related functions Ævar Arnfjörð Bjarmason
2021-07-27  0:18                   ` Junio C Hamano

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