{fetch,receive}-pack: skip sha-1 integrity test on objects from new packnd/optim-connected

When we fetch or push, usually "git rev-list --verify-objects --not
--all --stdin" is used to make sure that all objects between existing
refs and new refs are good. This means no gaps in between, all objects
are well-formed, object content agrees with its sha-1 signature.

For the last one, --verify-objects calls check_sha1_signature() via
parse_object(). check_sha1_signature() is an expensive operation,
especially when new refs are far away from existing ones because all
objects in between are re-hashed. Because objects coming from the new
pack are already hashed by index-pack, we can trust their
integrity. The only objects left to check are existing ones in repo
but has no connection to any current refs.

Pass the new pack id down to--verify-objects and skip
check_sha1_signature() on objects from that pack.

As an (extreme) example, a repository is created with only one commit:
e83c516 (Initial revision of "git", the information manager from hell
- 2005-04-07). The rest of git.git is fetched on top. Without the
patch:

$ time git fetch file:///home/pclouds/w/git/.git
remote: Counting objects: 125656, done.
remote: Compressing objects: 100% (33280/33280), done.
remote: Total 125656 (delta 92585), reused 123464 (delta 90682)
Receiving objects: 100% (125656/125656), 34.60 MiB | 8.47 MiB/s, done.
Resolving deltas: 100% (92585/92585), done.
>From file:///home/pclouds/t/test/
 * branch            HEAD       -> FETCH_HEAD

real    1m30.437s
user    1m31.338s
sys     0m1.687s

With the patch:

$ time git fetch file:///home/pclouds/w/git/.git
remote: Counting objects: 125656, done.
remote: Compressing objects: 100% (33280/33280), done.
remote: Total 125656 (delta 92585), reused 123464 (delta 90682)
Receiving objects: 100% (125656/125656), 34.60 MiB | 7.86 MiB/s, done.
Resolving deltas: 100% (92585/92585), done.
>From file:///home/pclouds/t/test/
 * branch            HEAD       -> FETCH_HEAD

real    0m52.182s
user    0m53.151s
sys     0m1.465s

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 7 insertions, 5 deletions

diff --git a/builtin/fetch.c b/builtin/fetch.c
index 8ec4eae3eb..77c26caae2 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -368,7 +368,7 @@ static int iterate_ref_map(void *cb_data, unsigned char sha1[20])
 }
 
 static int store_updated_refs(const char *raw_url, const char *remote_name,
-		struct ref *ref_map)
+			      struct ref *ref_map, const char *pack_lockfile)
 {
 	FILE *fp;
 	struct commit *commit;
@@ -389,7 +389,7 @@ static int store_updated_refs(const char *raw_url, const char *remote_name,
 		url = xstrdup("foreign");
 
 	rm = ref_map;
-	if (check_everything_connected(iterate_ref_map, 0, &rm)) {
+	if (check_everything_connected(iterate_ref_map, 0, pack_lockfile, &rm)) {
 		rc = error(_("%s did not send all necessary objects\n"), url);
 		goto abort;
 	}
@@ -516,7 +516,8 @@ static int quickfetch(struct ref *ref_map)
 	 */
 	if (depth)
 		return -1;
-	return check_everything_connected(iterate_ref_map, 1, &rm);
+	return check_everything_connected(iterate_ref_map,
+					  CHECK_CONNECT_QUIET, NULL, &rm);
 }
 
 static int fetch_refs(struct transport *transport, struct ref *ref_map)
@@ -526,8 +527,9 @@ static int fetch_refs(struct transport *transport, struct ref *ref_map)
 		ret = transport_fetch_refs(transport, ref_map);
 	if (!ret)
 		ret |= store_updated_refs(transport->url,
-				transport->remote->name,
-				ref_map);
+					  transport->remote->name,
+					  ref_map,
+					  transport->pack_lockfile);
 	transport_unlock_pack(transport);
 	return ret;
 }