5 files changed, 36 insertions, 6 deletions
diff --git a/builtin/fsck.c b/builtin/fsck.c
index 2ab78129bd..2414190c04 100644
--- a/builtin/fsck.c
+++ b/builtin/fsck.c
@@ -872,8 +872,14 @@ static int check_pack_rev_indexes(struct repository *r, int show_progress)
 	}
 
 	for (struct packed_git *p = get_all_packs(the_repository); p; p = p->next) {
-		if (!load_pack_revindex(the_repository, p) &&
-		    verify_pack_revindex(p)) {
+		int load_error = load_pack_revindex_from_disk(p);
+
+		if (load_error < 0) {
+			error(_("unable to load rev-index for pack '%s'"), p->pack_name);
+			res = ERROR_PACK_REV_INDEX;
+		} else if (!load_error &&
+			   !load_pack_revindex(the_repository, p) &&
+			   verify_pack_revindex(p)) {
 			error(_("invalid rev-index for pack '%s'"), p->pack_name);
 			res = ERROR_PACK_REV_INDEX;
 		}
diff --git a/pack-bitmap.c b/pack-bitmap.c
index 38b35c4823..3828aab612 100644
--- a/pack-bitmap.c
+++ b/pack-bitmap.c
@@ -379,7 +379,7 @@ static int open_midx_bitmap_1(struct bitmap_index *bitmap_git,
 		goto cleanup;
 	}
 
-	if (load_midx_revindex(bitmap_git->midx) < 0) {
+	if (load_midx_revindex(bitmap_git->midx)) {
 		warning(_("multi-pack bitmap is missing required reverse index"));
 		goto cleanup;
 	}
@@ -2140,7 +2140,7 @@ uint32_t *create_bitmap_mapping(struct bitmap_index *bitmap_git,
 
 	if (!bitmap_is_midx(bitmap_git))
 		load_reverse_index(r, bitmap_git);
-	else if (load_midx_revindex(bitmap_git->midx) < 0)
+	else if (load_midx_revindex(bitmap_git->midx))
 		BUG("rebuild_existing_bitmaps: missing required rev-cache "
 		    "extension");
 
diff --git a/pack-revindex.c b/pack-revindex.c
index 62a9846470..146334e2c9 100644
--- a/pack-revindex.c
+++ b/pack-revindex.c
@@ -212,7 +212,8 @@ static int load_revindex_from_disk(char *revindex_name,
 	fd = git_open(revindex_name);
 
 	if (fd < 0) {
-		ret = -1;
+		/* "No file" means return 1. */
+		ret = 1;
 		goto cleanup;
 	}
 	if (fstat(fd, &st)) {
@@ -264,7 +265,7 @@ cleanup:
 	return ret;
 }
 
-static int load_pack_revindex_from_disk(struct packed_git *p)
+int load_pack_revindex_from_disk(struct packed_git *p)
 {
 	char *revindex_name;
 	int ret;
diff --git a/pack-revindex.h b/pack-revindex.h
index c8861873b0..6dd47efea1 100644
--- a/pack-revindex.h
+++ b/pack-revindex.h
@@ -52,6 +52,14 @@ struct repository;
 int load_pack_revindex(struct repository *r, struct packed_git *p);
 
 /*
+ * Specifically load a pack revindex from disk.
+ *
+ * Returns 0 on success, 1 on "no .rev file", and -1 when there is an
+ * error parsing the .rev file.
+ */
+int load_pack_revindex_from_disk(struct packed_git *p);
+
+/*
  * verify_pack_revindex verifies that the on-disk rev-index for the given
  * pack-file is the same that would be created if written from scratch.
  *
diff --git a/t/t5325-reverse-index.sh b/t/t5325-reverse-index.sh
index 5c3c80f88f..431a603ca0 100755
--- a/t/t5325-reverse-index.sh
+++ b/t/t5325-reverse-index.sh
@@ -190,4 +190,19 @@ test_expect_success 'fsck catches invalid row position' '
 		"invalid rev-index position"
 '
 
+test_expect_success 'fsck catches invalid header: magic number' '
+	corrupt_rev_and_verify 1 "\07" \
+		"reverse-index file .* has unknown signature"
+'
+
+test_expect_success 'fsck catches invalid header: version' '
+	corrupt_rev_and_verify 7 "\02" \
+		"reverse-index file .* has unsupported version"
+'
+
+test_expect_success 'fsck catches invalid header: hash function' '
+	corrupt_rev_and_verify 11 "\03" \
+		"reverse-index file .* has unsupported hash id"
+'
+
 test_done