1 files changed, 1 insertions, 1 deletions

diff --git a/tree.h b/tree.h
index 056bd86fa9..74fe09d763 100644
--- a/tree.h
+++ b/tree.h
@@ -24,7 +24,7 @@ struct tree {
 	struct tree_entry_list *entries;
 };
 
-struct tree *lookup_tree(unsigned char *sha1);
+struct tree *lookup_tree(const unsigned char *sha1);
 
 int parse_tree_buffer(struct tree *item, void *buffer, unsigned long size);