--- a/util/datamanager.lua	Fri Dec 20 22:38:45 2019 +0100
+++ b/util/datamanager.lua	Mon Dec 23 21:01:55 2019 +0100
@@ -157,7 +157,8 @@
 
 local function atomic_store(filename, data)
 	local scratch = filename.."~";
-	local f, ok, msg, errno;
+	local f, ok, msg, errno; -- luacheck: ignore errno
+	-- TODO return util.error with code=errno?
 
 	f, msg, errno = io_open(scratch, "w");
 	if not f then