1 files changed, 2 insertions, 2 deletions
diff --git a/commit.h b/commit.h
index 51d9576..57c1b62 100644
--- a/commit.h
+++ b/commit.h
@@ -19,8 +19,8 @@ struct commit {
 
 extern const char *commit_type;
 
-struct commit *lookup_commit(unsigned char *sha1);
-struct commit *lookup_commit_reference(unsigned char *sha1);
+struct commit *lookup_commit(const unsigned char *sha1);
+struct commit *lookup_commit_reference(const unsigned char *sha1);
 
 int parse_commit_buffer(struct commit *item, void *buffer, unsigned long size);