[PATCH v4 5/6] refs: explicitly return failure_errno from parse_loose_ref_contents - Han-Wen Nienhuys via GitGitGadget

From: "Han-Wen Nienhuys via GitGitGadget" <gitgitgadget@gmail.com>
To: git@vger.kernel.org
Cc: "Han-Wen Nienhuys" <hanwen@google.com>,
	"Jonathan Tan" <jonathantanmy@google.com>,
	"Ævar Arnfjörð Bjarmason" <avarab@gmail.com>,
	"Han-Wen Nienhuys" <hanwenn@gmail.com>,
	"Han-Wen Nienhuys" <hanwen@google.com>
Subject: [PATCH v4 5/6] refs: explicitly return failure_errno from parse_loose_ref_contents
Date: Tue, 06 Jul 2021 18:55:56 +0000	[thread overview]
Message-ID: <ab147afb38d6e74e0e2fc1fbb83346e6ee32cdd5.1625597757.git.gitgitgadget@gmail.com> (raw)
In-Reply-To: <pull.1012.v4.git.git.1625597757.gitgitgadget@gmail.com>

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

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@google.com>
Reviewed-By: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
 refs.c               |  8 +++++---
 refs/files-backend.c | 13 +++++++++----
 refs/refs-internal.h |  6 ++++--
 3 files changed, 18 insertions(+), 9 deletions(-)

diff --git a/refs.c b/refs.c
index 25d80e544d0..eca7310e7a4 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);
@@ -1683,7 +1685,7 @@ int refs_read_raw_ref(struct ref_store *ref_store, const char *refname,
 
 	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..b43ec4c66cb 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -455,9 +455,13 @@ 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:
+	/* Collect all types of failures from errno. Many system calls in this
+	 * function can fail with ENOTDIR/EISDIR, and we want to collect all of
+	 * them.
+	 */
 	*failure_errno = errno;
 	strbuf_release(&sb_path);
 	strbuf_release(&sb_contents);
@@ -465,7 +469,8 @@ 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 +489,7 @@ 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
-- 
gitgitgadget

