multi-pack-index: verify bad header

When verifying if a multi-pack-index file is valid, we want the
command to fail to signal an invalid file. Previously, we wrote
an error to stderr and continued as if we had no multi-pack-index.
Now, die() instead of error().

Add tests that check corrupted headers in a few ways:

* Bad signature
* Bad file version
* Bad hash version
* Truncated hash count
* Extended hash count

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 6 insertions, 12 deletions

diff --git a/midx.c b/midx.c
index 8b6c855d48..7199b8392b 100644
--- a/midx.c
+++ b/midx.c
@@ -76,24 +76,18 @@ struct multi_pack_index *load_multi_pack_index(const char *object_dir, int local
 	m->local = local;
 
 	m->signature = get_be32(m->data);
-	if (m->signature != MIDX_SIGNATURE) {
-		error(_("multi-pack-index signature 0x%08x does not match signature 0x%08x"),
+	if (m->signature != MIDX_SIGNATURE)
+		die(_("multi-pack-index signature 0x%08x does not match signature 0x%08x"),
 		      m->signature, MIDX_SIGNATURE);
-		goto cleanup_fail;
-	}
 
 	m->version = m->data[MIDX_BYTE_FILE_VERSION];
-	if (m->version != MIDX_VERSION) {
-		error(_("multi-pack-index version %d not recognized"),
+	if (m->version != MIDX_VERSION)
+		die(_("multi-pack-index version %d not recognized"),
 		      m->version);
-		goto cleanup_fail;
-	}
 
 	hash_version = m->data[MIDX_BYTE_HASH_VERSION];
-	if (hash_version != MIDX_HASH_VERSION) {
-		error(_("hash version %u does not match"), hash_version);
-		goto cleanup_fail;
-	}
+	if (hash_version != MIDX_HASH_VERSION)
+		die(_("hash version %u does not match"), hash_version);
 	m->hash_len = MIDX_HASH_LEN;
 
 	m->num_chunks = m->data[MIDX_BYTE_NUM_CHUNKS];