diff --git a/builtin/merge.c b/builtin/merge.c
index b3f75f5..da11dfa 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -1375,7 +1375,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 		goto done;
 	}
 
-	if (read_cache_unmerged())
+	if (repo_read_index_unmerged(the_repository))
 		die_resolve_conflict("merge");
 
 	if (file_exists(git_path_merge_head(the_repository))) {