Convert lookup_tree to struct object_id

Convert the lookup_tree function to take a pointer to struct object_id.

The commit was created with manual changes to tree.c, tree.h, and
object.c, plus the following semantic patch:

@@
@@
- lookup_tree(EMPTY_TREE_SHA1_BIN)
+ lookup_tree(&empty_tree_oid)

@@
expression E1;
@@
- lookup_tree(E1.hash)
+ lookup_tree(&E1)

@@
expression E1;
@@
- lookup_tree(E1->hash)
+ lookup_tree(E1)

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/builtin/diff.c b/builtin/diff.c
index a25b4e4ae6..895f928978 100644
--- a/builtin/diff.c
+++ b/builtin/diff.c
@@ -381,7 +381,7 @@ int cmd_diff(int argc, const char **argv, const char *prefix)
 				add_head_to_pending(&rev);
 				if (!rev.pending.nr) {
 					struct tree *tree;
-					tree = lookup_tree(EMPTY_TREE_SHA1_BIN);
+					tree = lookup_tree(&empty_tree_oid);
 					add_pending_object(&rev, &tree->object, "HEAD");
 				}
 				break;