[PATCH v5 5/6] refs: explicitly return failure_errno from parse_loose_ref_contents

["Han-Wen Nienhuys via GitGitGadget" <gitgitgadget@xxxxxxxxx>]

From: Han-Wen Nienhuys <hanwen@xxxxxxxxxx>

The EINVAL error from parse_loose_ref_contents is used in files-backend
to create a custom error message.

Signed-off-by: Han-Wen Nienhuys <hanwen@xxxxxxxxxx>
Reviewed-by: Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx>
---
 refs.c               |  8 +++++---
 refs/files-backend.c | 14 ++++++++++----
 refs/refs-internal.h |  6 ++++--
 3 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/refs.c b/refs.c
index de3826f60c9..96df78a9509 100644
--- a/refs.c
+++ b/refs.c
@@ -1653,7 +1653,8 @@ int for_each_fullref_in_prefixes(const char *namespace,
 
 static int refs_read_special_head(struct ref_store *ref_store,
 				  const char *refname, struct object_id *oid,
-				  struct strbuf *referent, unsigned int *type)
+				  struct strbuf *referent, unsigned int *type,
+				  int *failure_errno)
 {
 	struct strbuf full_path = STRBUF_INIT;
 	struct strbuf content = STRBUF_INIT;
@@ -1663,7 +1664,8 @@ static int refs_read_special_head(struct ref_store *ref_store,
 	if (strbuf_read_file(&content, full_path.buf, 0) < 0)
 		goto done;
 
-	result = parse_loose_ref_contents(content.buf, oid, referent, type);
+	result = parse_loose_ref_contents(content.buf, oid, referent, type,
+					  failure_errno);
 
 done:
 	strbuf_release(&full_path);
@@ -1681,7 +1683,7 @@ int refs_read_raw_ref(struct ref_store *ref_store, const char *refname,
 	*failure_errno = 0;
 	if (!strcmp(refname, "FETCH_HEAD") || !strcmp(refname, "MERGE_HEAD")) {
 		return refs_read_special_head(ref_store, refname, oid, referent,
-					      type);
+					      type, failure_errno);
 	}
 
 	return ref_store->be->read_raw_ref(ref_store, refname, oid, referent,
diff --git a/refs/files-backend.c b/refs/files-backend.c
index f38c9703504..7aafdf2ce3d 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -455,9 +455,14 @@ stat_ref:
 	strbuf_rtrim(&sb_contents);
 	buf = sb_contents.buf;
 
-	ret = parse_loose_ref_contents(buf, oid, referent, type);
-
+	ret = parse_loose_ref_contents(buf, oid, referent, type, failure_errno);
+	errno = *failure_errno;
 out:
+	/*
+	 * Many system calls in this function can fail with ENOTDIR/EISDIR, and
+	 * we want to collect all of them, so simply copy the error out from
+	 * errno.
+	 */
 	*failure_errno = errno;
 	strbuf_release(&sb_path);
 	strbuf_release(&sb_contents);
@@ -465,7 +470,8 @@ out:
 }
 
 int parse_loose_ref_contents(const char *buf, struct object_id *oid,
-			     struct strbuf *referent, unsigned int *type)
+			     struct strbuf *referent, unsigned int *type,
+			     int *failure_errno)
 {
 	const char *p;
 	if (skip_prefix(buf, "ref:", &buf)) {
@@ -484,7 +490,7 @@ int parse_loose_ref_contents(const char *buf, struct object_id *oid,
 	if (parse_oid_hex(buf, oid, &p) ||
 	    (*p != '\0' && !isspace(*p))) {
 		*type |= REF_ISBROKEN;
-		errno = EINVAL;
+		*failure_errno = EINVAL;
 		return -1;
 	}
 	return 0;
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index 54f57c6a2df..bf581e70cf6 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -689,10 +689,12 @@ struct ref_store {
 };
 
 /*
- * Parse contents of a loose ref file.
+ * Parse contents of a loose ref file. *failure_errno maybe be set to EINVAL for
+ * invalid contents.
  */
 int parse_loose_ref_contents(const char *buf, struct object_id *oid,
-			     struct strbuf *referent, unsigned int *type);
+			     struct strbuf *referent, unsigned int *type,
+			     int *failure_errno);
 
 /*
  * Fill in the generic part of refs and add it to our collection of
-- 
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