Subject: [PATCH] refs: remove EINVAL specification from the errno sideband in read_raw_ref_fn

From: "Han-Wen Nienhuys via GitGitGadget" <[email-masked]>
Date: Fri, 23 Apr 2021 10:24:06 +0000

From: Han-Wen Nienhuys <[email-masked]>

A grep for EINVAL */*c reveals that no code inspects EINVAL after reading
references.

The files ref backend does use EINVAL so parse_loose_ref_contents() can
communicate to lock_raw_ref() about garbage following the hex SHA1, or a short
read in files_read_raw_ref(), but the files backend does not call into
refs_read_raw_ref(), so its EINVAL sideband error is unused.

As the errno sideband is unintuitive and error-prone, remove EINVAL
value, as a step towards getting rid of the errno sideband altogether.

Spotted by Ævar Arnfjörð Bjarmason <[email-masked]>.

Signed-off-by: Han-Wen Nienhuys <[email-masked]>
---
    refs: remove EINVAL specification from the errno sideband in read_raw…
    
    …_ref_fn
    
    A grep for EINVAL */*c reveals that no code inspects EINVAL after
    reading references.
    
    The files ref backend does use EINVAL so parse_loose_ref_contents() can
    communicate to lock_raw_ref() about garbage following the hex SHA1, or a
    short read in files_read_raw_ref(), but the files backend does not call
    into refs_read_raw_ref(), so its EINVAL sideband error is unused.
    
    As the errno sideband is unintuitive and error-prone, remove EINVAL
    value, as a step towards getting rid of the errno sideband altogether.
    
    Spotted by Ævar Arnfjörð Bjarmason [email-masked].
    
    Signed-off-by: Han-Wen Nienhuys [email-masked]

Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-1011%2Fhanwen%2Feinval-sideband-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-1011/hanwen/einval-sideband-v1
Pull-Request: https://github.com/git/git/pull/1011

 refs.c               | 2 --
 refs/refs-internal.h | 9 ++++-----
 2 files changed, 4 insertions(+), 7 deletions(-)

diff --git a/refs.c b/refs.c
index 261fd82beb98..3179ebd71b2f 100644
--- a/refs.c
+++ b/refs.c
@@ -1705,7 +1705,6 @@ const char *refs_resolve_ref_unsafe(struct ref_store *refs,
 	if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
 		if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
 		    !refname_is_safe(refname)) {
-			errno = EINVAL;
 			return NULL;
 		}
 
@@ -1765,7 +1764,6 @@ const char *refs_resolve_ref_unsafe(struct ref_store *refs,
 		if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
 			if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
 			    !refname_is_safe(refname)) {
-				errno = EINVAL;
 				return NULL;
 			}
 
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index 467f4b3c936d..29728a339fed 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -617,11 +617,10 @@ typedef int reflog_expire_fn(struct ref_store *ref_store,
  * properly-formatted or even safe reference name. NEITHER INPUT NOR
  * OUTPUT REFERENCE NAMES ARE VALIDATED WITHIN THIS FUNCTION.
  *
- * Return 0 on success. If the ref doesn't exist, set errno to ENOENT
- * and return -1. If the ref exists but is neither a symbolic ref nor
- * an object ID, it is broken; set REF_ISBROKEN in type, set errno to
- * EINVAL, and return -1. If there is another error reading the ref,
- * set errno appropriately and return -1.
+ * Return 0 on success. If the ref doesn't exist, set errno to ENOENT and return
+ * -1. If the ref exists but is neither a symbolic ref nor an object ID, it is
+ * broken; set REF_ISBROKEN in type, and return -1. If there is another error
+ * reading the ref, set errno appropriately and return -1.
  *
  * Backend-specific flags might be set in type as well, regardless of
  * outcome.

base-commit: 311531c9de557d25ac087c1637818bd2aad6eb3a
-- 
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