various fixes

data.lua

@@ -8,9 +8,12 @@ function mapsync.save_data(key, value)
         return
     end
 
-    local f = assert(global_env.io.open(data_backend_def.path .. "/" .. key .. ".lua", "w"))
-    f:write(minetest.serialize(value))
+    local filename = data_backend_def.path .. "/" .. key .. ".lua"
+    local f = assert(global_env.io.open(filename, "w"))
+    local data = minetest.serialize(value)
+    f:write(data)
     f:close()
+    minetest.log("action", "[mapsync] wrote " .. #data .. " bytes of data to '" .. filename .. "'")
 end
 
 -- load simple key-value data

integrations/elevator.lua

@@ -8,8 +8,12 @@ function elevator.save_elevator()
     old_elevator_save_elevator()
 end
 
--- load from backend if available
-local data = mapsync.load_data("elevator")
-if data and data.motors then
-    elevator.motors = data.motors
-end
+local function load()
+    -- load from backend if available
+    local data = mapsync.load_data("elevator")
+    if data and data.motors then
+        elevator.motors = data.motors
+    end
+end
+
+minetest.register_on_mods_loaded(load)

integrations/hyperloop.lua

@@ -21,4 +21,4 @@ local function load()
 end
 
 -- load on startup
-load()
+minetest.register_on_mods_loaded(load)