1 files changed, 1 insertions, 1 deletions
diff --git a/delta.h b/delta.h
index 8e4efdf4ac..df97ff84f7 100644
--- a/delta.h
+++ b/delta.h
@@ -12,7 +12,7 @@ extern void *patch_delta(void *src_buf, unsigned long src_size,
 /* handling of delta objects */
 struct delta;
 struct object_list;
-extern struct delta *lookup_delta(unsigned char *sha1);
+extern struct delta *lookup_delta(const unsigned char *sha1);
 extern int parse_delta_buffer(struct delta *item, void *buffer, unsigned long size);
 extern int parse_delta(struct delta *item, unsigned char sha1);
 extern int process_deltas(void *src, unsigned long src_size,