diff --git a/source/dub/package_.d b/source/dub/package_.d
index 963b0d7..8ecba78 100644
--- a/source/dub/package_.d
+++ b/source/dub/package_.d
@@ -261,6 +261,7 @@
 			if (!is_main_package && conf.buildSettings.targetType == TargetType.executable) continue;
 			ret ~= conf.name;
 		}
+		if (ret.data.length == 0) ret.put(null);
 		return ret.data;
 	}