[PATCH 4/5] fetch-pack: sort the list of incoming refs

[Jeff King <peff@peff.net>]

Having the list sorted means we can avoid some quadratic
algorithms when comparing lists.

These should typically be sorted already, but they do come
from the remote, so let's be extra careful. Our ref-sorting
implementation does a mergesort, so we do not have to care
about performance degrading in the common case that the list
is already sorted.

Signed-off-by: Jeff King <peff@peff.net>
---
 builtin/fetch-pack.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/builtin/fetch-pack.c b/builtin/fetch-pack.c
index 3522d8e..bee329f 100644
--- a/builtin/fetch-pack.c
+++ b/builtin/fetch-pack.c
@@ -777,6 +777,8 @@ static struct ref *do_fetch_pack(int fd[2],
 	struct ref *ref = copy_ref_list(orig_ref);
 	unsigned char sha1[20];
 
+	sort_ref_list(&ref, ref_compare_name);
+
 	if (is_repository_shallow() && !server_supports("shallow"))
 		die("Server does not support shallow clients");
 	if (server_supports("multi_ack_detailed")) {
-- 
1.7.10.1.19.g711d603