[PATCH v3 4/5] refs: add failure_errno to refs_read_raw_ref() signature

["Han-Wen Nienhuys via GitGitGadget" <gitgitgadget@gmail.com>]

From: Han-Wen Nienhuys <hanwen@google.com>

This lets us use the explicit errno output parameter in refs_resolve_ref_unsafe.

Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
Reviewed-by: Jonathan Tan <jonathantanmy@google.com>
Reviewed-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
 refs.c                | 60 +++++++++++++++++++++++++++----------------
 refs/files-backend.c  |  8 +++---
 refs/packed-backend.c |  7 ++---
 refs/refs-internal.h  |  6 ++---
 4 files changed, 49 insertions(+), 32 deletions(-)

diff --git a/refs.c b/refs.c
index 5e5e3af8da0..25d80e544d0 100644
--- a/refs.c
+++ b/refs.c
@@ -1671,34 +1671,35 @@ done:
 	return result;
 }
 
-int refs_read_raw_ref(struct ref_store *ref_store,
-		      const char *refname, struct object_id *oid,
-		      struct strbuf *referent, unsigned int *type)
+int refs_read_raw_ref(struct ref_store *ref_store, const char *refname,
+		      struct object_id *oid, struct strbuf *referent,
+		      unsigned int *type, int *failure_errno)
 {
-	int result;
-	int failure_errno;
+	int ignore;
+	if (failure_errno)
+		*failure_errno = 0;
+	else
+		failure_errno = &ignore;
+
 	if (!strcmp(refname, "FETCH_HEAD") || !strcmp(refname, "MERGE_HEAD")) {
 		return refs_read_special_head(ref_store, refname, oid, referent,
 					      type);
 	}
 
-	failure_errno = 0;
-	result = ref_store->be->read_raw_ref(ref_store, refname, oid, referent,
-					     type, &failure_errno);
-	if (failure_errno)
-		errno = failure_errno;
-	return result;
+	return ref_store->be->read_raw_ref(ref_store, refname, oid, referent,
+					   type, failure_errno);
 }
 
-/* This function needs to return a meaningful errno on failure */
-const char *refs_resolve_ref_unsafe(struct ref_store *refs,
-				    const char *refname,
-				    int resolve_flags,
-				    struct object_id *oid, int *flags)
+const char *refs_resolve_ref_unsafe_with_errno(struct ref_store *refs,
+					       const char *refname,
+					       int resolve_flags,
+					       struct object_id *oid,
+					       int *flags, int *failure_errno)
 {
 	static struct strbuf sb_refname = STRBUF_INIT;
 	struct object_id unused_oid;
 	int unused_flags;
+	int unused_errno;
 	int symref_count;
 
 	if (!oid)
@@ -1707,6 +1708,9 @@ const char *refs_resolve_ref_unsafe(struct ref_store *refs,
 		flags = &unused_flags;
 
 	*flags = 0;
+	if (!failure_errno)
+		failure_errno = &unused_errno;
+	*failure_errno = 0;
 
 	if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
 		if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
@@ -1728,11 +1732,14 @@ const char *refs_resolve_ref_unsafe(struct ref_store *refs,
 
 	for (symref_count = 0; symref_count < SYMREF_MAXDEPTH; symref_count++) {
 		unsigned int read_flags = 0;
+		int read_failure = 0;
 
-		if (refs_read_raw_ref(refs, refname,
-				      oid, &sb_refname, &read_flags)) {
+		if (refs_read_raw_ref(refs, refname, oid, &sb_refname,
+				      &read_flags, &read_failure)) {
 			*flags |= read_flags;
 
+			*failure_errno = read_failure;
+
 			/* In reading mode, refs must eventually resolve */
 			if (resolve_flags & RESOLVE_REF_READING)
 				return NULL;
@@ -1742,9 +1749,8 @@ const char *refs_resolve_ref_unsafe(struct ref_store *refs,
 			 * may show errors besides ENOENT if there are
 			 * similarly-named refs.
 			 */
-			if (errno != ENOENT &&
-			    errno != EISDIR &&
-			    errno != ENOTDIR)
+			if (read_failure != ENOENT && read_failure != EISDIR &&
+			    read_failure != ENOTDIR)
 				return NULL;
 
 			oidclr(oid);
@@ -1783,6 +1789,15 @@ const char *refs_resolve_ref_unsafe(struct ref_store *refs,
 	return NULL;
 }
 
+const char *refs_resolve_ref_unsafe(struct ref_store *refs, const char *refname,
+				    int resolve_flags, struct object_id *oid,
+				    int *flags)
+{
+	int ignore = 0;
+	return refs_resolve_ref_unsafe_with_errno(refs, refname, resolve_flags,
+						  oid, flags, &ignore);
+}
+
 /* backend functions */
 int refs_init_db(struct strbuf *err)
 {
@@ -2244,7 +2259,8 @@ int refs_verify_refname_available(struct ref_store *refs,
 		if (skip && string_list_has_string(skip, dirname.buf))
 			continue;
 
-		if (!refs_read_raw_ref(refs, dirname.buf, &oid, &referent, &type)) {
+		if (!refs_read_raw_ref(refs, dirname.buf, &oid, &referent,
+				       &type, NULL)) {
 			strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
 				    dirname.buf, refname);
 			goto cleanup;
diff --git a/refs/files-backend.c b/refs/files-backend.c
index f98b1be9386..f38c9703504 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -383,8 +383,8 @@ stat_ref:
 	if (lstat(path, &st) < 0) {
 		if (errno != ENOENT)
 			goto out;
-		if (refs_read_raw_ref(refs->packed_ref_store, refname,
-				      oid, referent, type)) {
+		if (refs_read_raw_ref(refs->packed_ref_store, refname, oid,
+				      referent, type, NULL)) {
 			errno = ENOENT;
 			goto out;
 		}
@@ -423,8 +423,8 @@ stat_ref:
 		 * ref is supposed to be, there could still be a
 		 * packed ref:
 		 */
-		if (refs_read_raw_ref(refs->packed_ref_store, refname,
-				      oid, referent, type)) {
+		if (refs_read_raw_ref(refs->packed_ref_store, refname, oid,
+				      referent, type, NULL)) {
 			errno = EISDIR;
 			goto out;
 		}
diff --git a/refs/packed-backend.c b/refs/packed-backend.c
index a457f18e93c..530dba29788 100644
--- a/refs/packed-backend.c
+++ b/refs/packed-backend.c
@@ -1347,6 +1347,7 @@ int is_packed_transaction_needed(struct ref_store *ref_store,
 	ret = 0;
 	for (i = 0; i < transaction->nr; i++) {
 		struct ref_update *update = transaction->updates[i];
+		int failure_errno = 0;
 		unsigned int type;
 		struct object_id oid;
 
@@ -1357,9 +1358,9 @@ int is_packed_transaction_needed(struct ref_store *ref_store,
 			 */
 			continue;
 
-		if (!refs_read_raw_ref(ref_store, update->refname,
-				       &oid, &referent, &type) ||
-		    errno != ENOENT) {
+		if (!refs_read_raw_ref(ref_store, update->refname, &oid,
+				       &referent, &type, &failure_errno) ||
+		    failure_errno != ENOENT) {
 			/*
 			 * We have to actually delete that reference
 			 * -> this transaction is needed.
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index 79dfb3af484..54f57c6a2df 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -149,9 +149,9 @@ struct ref_update {
 	const char refname[FLEX_ARRAY];
 };
 
-int refs_read_raw_ref(struct ref_store *ref_store,
-		      const char *refname, struct object_id *oid,
-		      struct strbuf *referent, unsigned int *type);
+int refs_read_raw_ref(struct ref_store *ref_store, const char *refname,
+		      struct object_id *oid, struct strbuf *referent,
+		      unsigned int *type, int *failure_errno);
 
 /*
  * Write an error to `err` and return a nonzero value iff the same
-- 
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