[PATCH] list-objects: mark fewer commits as edges for non-shallow clones

["brian m. carlson" <sandals@crustytoothpaste.net>]

In commit fbd4a70 (list-objects: mark more commits as edges in
mark_edges_uninteresting - 2013-08-16), we made --thin much more
aggressive by reading lots more trees.  This produces much smaller packs
for shallow clones; however, it causes a significant performance
regression for non-shallow clones with lots of refs (23.322 seconds vs.
4.785 seconds with 22400 refs).  Limit this extra edge-marking to
shallow clones to avoid poor performance.

Suggested-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 list-objects.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/list-objects.c b/list-objects.c
index 2910bec..274ebb4 100644
--- a/list-objects.c
+++ b/list-objects.c
@@ -151,13 +151,14 @@ void mark_edges_uninteresting(struct rev_info *revs, show_edge_fn show_edge)
 {
 	struct commit_list *list;
 	int i;
+	int shallow = is_repository_shallow();
 
 	for (list = revs->commits; list; list = list->next) {
 		struct commit *commit = list->item;
 
 		if (commit->object.flags & UNINTERESTING) {
 			mark_tree_uninteresting(commit->tree);
-			if (revs->edge_hint && !(commit->object.flags & SHOWN)) {
+			if (shallow && revs->edge_hint && !(commit->object.flags & SHOWN)) {
 				commit->object.flags |= SHOWN;
 				show_edge(commit);
 			}
@@ -165,6 +166,8 @@ void mark_edges_uninteresting(struct rev_info *revs, show_edge_fn show_edge)
 		}
 		mark_edge_parents_uninteresting(commit, revs, show_edge);
 	}
+	if (!shallow)
+		return;
 	if (revs->edge_hint) {
 		for (i = 0; i < revs->cmdline.nr; i++) {
 			struct object *obj = revs->cmdline.rev[i].item;
-- 
2.2.0.rc0.207.ga3a616c