Teach git-fetch to exploit server side automatic tag following

If the remote peer upload-pack process supports the include-tag
protocol extension then we can avoid running a second fetch cycle
on the client side by letting the server send us the annotated tags
along with the objects it is packing for us.  In the following graph
we can now fetch both "tag1" and "tag2" on the same connection that
we fetched "master" from the remote when we only have L available
on the local side:

         T - tag1          S - tag2
        /                 /
   L - o ------ o ------ B
    \                     \
     \                     \
      origin/master         master

The objects for "tag1" are implicitly downloaded without our direct
knowledge.  The existing "quickfetch" optimization within git-fetch
discovers that tag1 is complete after the first connection and does
not open a second connection.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Shawn O. Pearce
2008-03-03 22:27:40 -05:00
committed by Junio C Hamano
parent 348e390b17
commit 41fa7d2eae
4 changed files with 37 additions and 0 deletions

View File

@ -555,6 +555,8 @@ static int do_fetch(struct transport *transport,
read_ref(rm->peer_ref->name, rm->peer_ref->old_sha1);
}
if (tags == TAGS_DEFAULT && autotags)
transport_set_option(transport, TRANS_OPT_FOLLOWTAGS, "1");
if (fetch_refs(transport, ref_map)) {
free_refs(ref_map);
return 1;
@ -568,6 +570,7 @@ static int do_fetch(struct transport *transport,
ref_map = NULL;
find_non_local_tags(transport, &ref_map, &tail);
if (ref_map) {
transport_set_option(transport, TRANS_OPT_FOLLOWTAGS, NULL);
transport_set_option(transport, TRANS_OPT_DEPTH, "0");
fetch_refs(transport, ref_map);
}