From d96075428a9a1de720f6019242dadb5dbaa0ac16 Mon Sep 17 00:00:00 2001 From: Derrick Stolee Date: Mon, 17 Aug 2020 14:04:48 +0000 Subject: multi-pack-index: use hash version byte Similar to the commit-graph format, the multi-pack-index format has a byte in the header intended to track the hash version used to write the file. This allows one to interpret the hash length without having the context of the repository config specifying the hash length. This was not modified as part of the SHA-256 work because the hash length was automatically up-shifted due to that config. Since we have this byte available, we can make the file formats more obviously incompatible instead of relying on other context from the repository. Add a new oid_version() method in midx.c similar to the one in commit-graph.c. This is specifically made separate from that implementation to avoid artificially linking the formats. The test impact requires a few more things than the corresponding change in the commit-graph format. Specifically, 'test-tool read-midx' was not writing anything about this header value to output. Since the value available in 'struct multi_pack_index' is hash_len instead of a version value, we output "20" or "32" instead of "1" or "2". Since we want a user to not have their Git commands fail if their multi-pack-index has the incorrect hash version compared to the repository's hash version, we relax the die() to an error() in load_multi_pack_index(). This has some effect on 'git multi-pack-index verify' as we need to check that a failed parse of a file that exists is actually a verify error. For that test that checks the hash version matches, we change the corrupted byte from "2" to "3" to ensure the test fails for both hash algorithms. Helped-by: brian m. carlson Signed-off-by: Derrick Stolee Reviewed-by: brian m. carlson Signed-off-by: Junio C Hamano --- t/helper/test-read-midx.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 't/helper') diff --git a/t/helper/test-read-midx.c b/t/helper/test-read-midx.c index 831b586d02..2430880f78 100644 --- a/t/helper/test-read-midx.c +++ b/t/helper/test-read-midx.c @@ -7,14 +7,18 @@ static int read_midx_file(const char *object_dir) { uint32_t i; - struct multi_pack_index *m = load_multi_pack_index(object_dir, 1); + struct multi_pack_index *m; + + setup_git_directory(); + m = load_multi_pack_index(object_dir, 1); if (!m) return 1; - printf("header: %08x %d %d %d\n", + printf("header: %08x %d %d %d %d\n", m->signature, m->version, + m->hash_len, m->num_chunks, m->num_packs); -- cgit v1.2.3