Default: Prevent possible nil-crash on invalid book metadata

diff --git a/mods/default/craftitems.lua b/mods/default/craftitems.lua
index d821af06e536a374e1e41afc7149c29bdaaf3c1a..59539f37afe54d6b5d5bfde99e2b822840dab315 100644 (file)
--- a/mods/default/craftitems.lua
+++ b/mods/default/craftitems.lua
@@ -105,7 +105,9 @@ minetest.register_on_player_receive_fields(function(player, formname, fields)
 
        elseif fields.book_next or fields.book_prev then
                local data = minetest.deserialize(stack:get_metadata())
-               if not data.page then return end
+               if not data or not data.page then
+                       return
+               end
 
                if fields.book_next then
                        data.page = data.page + 1